Patch Manufacturing

Abstract

1. A method for manufacturing a patch for application to a biological subject, the method comprising: molding a moldable material to form a plurality of microstructures on a substrate, the microstructures being shaped to breach a functional barrier of the subject.

Description

[Technical Field]

[0001] The present invention relates to a method for manufacturing a patch for application to a living subject, and in one particular example, to a method for manufacturing a microstructured patch for use in taking measurements or delivering therapy or stimuli to a living subject. [Background technology]

[0002] Reference herein to any prior publication (or information derived therefrom) or known matter is not, and should not be taken as, an acknowledgment or admission, or any form of suggestion, that the prior publication (or information derived therefrom) or known matter forms part of the common general knowledge in the field of endeavor to which this specification pertains.

[0003] Biological markers, such as proteins, antibodies, cells, small chemicals, hormones, and nucleic acids, the presence of which can indicate a disease state in excess or insufficiency, are found in serum, and their levels are routinely measured for research and clinical diagnostics. Standard tests include antibody assays to detect infections, allergic reactions, and blood-borne cancer markers (e.g., prostate-specific antigen assays to detect prostate cancer). Biological markers can originate from many organ systems in the body, but are extracted from one compartment: venous blood.

[0004] However, this is not suitable for all conditions as blood often does not contain important biological markers of diseases that occur in solid tissues, and although this problem has been partially overcome by performing tissue biopsies, these can be time-consuming, painful, risky, expensive and require highly skilled personnel such as surgeons.

[0005] Another serum-rich fluid is interstitial fluid (ISF), which fills the intercellular spaces of solid tissues and facilitates the passage of nutrients, biomarkers, and waste products through the bloodstream.

[0006] Patent Document 1 describes a device for delivering bioactive materials and other stimuli to living cells, a method for manufacturing the device, and various uses of the device, including several medical applications. The device includes multiple structures that can penetrate the body surface to deliver the bioactive material or stimuli to the required site. The structures are typically solid, and the delivery end section of the structure is sized so that it can be inserted into the target cell to deliver the bioactive material or stimuli without causing significant damage to the target cell or a specific site therein.

[0007] Patent document 2 describes a system for performing measurements on a biological subject, the system including at least one substrate including a plurality of plate microstructures configured to break through the subject's stratum corneum, at least one sensor operably connected to the at least one microstructure, the at least one sensor configured to measure a response signal from the at least one microstructure, and one or more electronic processing devices configured to determine the measured response signal and to perform at least one of the following: provide an output based on the measured response signal, perform an analysis at least in part using the measured response signal, and store data at least in part indicative of the measured response signal.

[0008] Attempts have been made to fabricate microstructures using injection molding and other similar techniques. While injection molding can result in low-cost, high-volume structures, and micro-injection molding has made significant advances, the technique cannot produce micron or submicron features and is not suitable for downstream continuous processing such as metallization or dielectric coating. Semiconductor processing can be performed on wafer-scale or large-area substrates, which offers cost efficiencies and allows for precise downstream processing, either batch or, in some cases, in-line, but this process is usually prohibitively expensive. [Prior art documents] [Patent documents]

[0009] [Patent Document 1] International Publication No. 2005 / 072630 [Patent Document 2] International Publication No. 2020 / 069565 Summary of the Invention [Means for solving the problem]

[0010] In one broad form, the present invention seeks to provide a method for manufacturing a patch for application to a biological subject, the method comprising molding a moldable material to form a plurality of microstructures on a substrate, the microstructures being molded to breach a functional barrier of the subject.

[0011] In one embodiment, the method includes providing a substrate, depositing a formable material layer on the substrate, forming a plurality of microstructures in the formable material layer, the microstructures being shaped to breach a functional barrier of interest, and solidifying the formable material.

[0012] In one embodiment, the method includes forming a plurality of microstructures by one of hot embossing and imprinting.

[0013] In one embodiment, the formable material layer is imprinted using at least one of nanoimprint lithography, roll-to-plate lithography, roll-to-roll lithography, plate-to-plate lithography, and plate-to-roll lithography.

[0014] In one embodiment, the method includes micro-injection molding a plurality of microstructures shaped to breach a functional barrier of interest.

[0015] In one embodiment, the formable material is a monomer, oligomer, photoinitiator, crosslinking acrylate groups, curable sol gel, epoxy, resin, polymer, curable formable material, UV curable formable material, sealant, UV adhesive UV nanoimprint lithography polymer, Helioseal, urethane dimethacrylate, bisphenol A-glycidyl methacrylate, triethylene glycol dimethacrylate, NOA61, mercaptoester * , triallyl isocyanurate, Inoflex RP+, PAK01, NIF2 (Asahi Glass Co., Ltd.), NIF1 (Asahi Glass Co., Ltd.), and Z Resist (t-butyl acrylate (96.5%), photoinitiator Irgacure 369 (3.5%)).

[0016] In one embodiment, the method includes solidifying the moldable material using at least one of heat, electromagnetic radiation, visible electromagnetic radiation, ultraviolet electromagnetic radiation, and curing the material.

[0017] In one embodiment, the moldable material is a low viscosity, 10 -3 It has at least one of a viscosity between Pa·s and 1 Pa·s and a viscosity between 0.4 and 0.05 Pa·s.

[0018] In one embodiment, the hardened moldable material has at least one of high mechanical strength, high resistivity, and high conductivity.

[0019] In one embodiment, the substrate is substantially rigid and flexible and is at least one of polycarbonate, polymethacrylimide (PMI), polyethylene terephthalate (PET), polycarbonate (PC), poly(methyl methacrylate) (PMMA), stainless steel, metal, polymer, and silicon.

[0020] In one embodiment, the method includes at least one of applying at least one coating to at least a portion of at least some of the microstructures, applying a primer before applying the at least one coating, and applying a coating to the formable material between at least some of the microstructures.

[0021] In one embodiment, the coating comprises at least one of a conductive coating, a dielectric coating, a mechanical coating, gold, titanium nitride, a metal, a ceramic, parylene, poly(3,4-ethylenedioxythiophene), and iridium oxide (IrO2).

[0022] In one embodiment, the coating has a thickness of at least one of at least 10 nm, at least 100 nm, at least 200 nm, at least 300 nm, at least 400 nm, at least 500 nm, about 3 μm, less than 4 μm, and less than 5 μm.

[0023] In one embodiment, the method includes applying the coating using at least one of sputtering, electroplating, electroless plating, spin coating, thermal evaporation, vapor deposition, chemical vapor deposition, plasma enhanced chemical vapor deposition, and inkjet printing.

[0024] In one embodiment, at least some of the microstructures are conductive microstructures, and the method includes fabricating the conductive microstructures by at least one of applying a conductive coating to at least some of the microstructures and using a conductive formable material.

[0025] In one embodiment, the method includes applying a dielectric coating to at least a portion of the conductive microstructure.

[0026] In one embodiment, the method includes applying a dielectric coating over the conductive microstructure and removing at least a portion of the dielectric coating to expose a surface of the conductive microstructure.

[0027] In one embodiment, the microstructure includes a dielectric coating extending over at least one of a portion of the surface of the microstructure, the proximal end of the microstructure, at least half of the length of the microstructure, approximately 90 μm of the proximal end of the microstructure, and at least a portion of the tip portion of the microstructure.

[0028] In one embodiment, at least some of the microstructures include at least one electrode that is at least one of: extending the length of a distal portion of the microstructure; extending the length of a portion of the microstructure spaced from the tip; positioned proximate the distal end of the microstructure; positioned proximate the tip of the microstructure; extending over at least 25% of the length of the microstructure; extending over less than 50% of the length of the microstructure; extending over approximately 60 μm of the microstructure; and configured to be placed within the living epidermis of a subject in use.

[0029] In one embodiment, the method includes one of the steps of electrically isolating at least some of the microstructures by at least one of removing material between the microstructures, selectively coating at least some of the microstructures, and removing electrically conductive material between the conductive microstructures to electrically isolate at least some of the microstructures.

[0030] In one embodiment, the method includes removing material using at least one of etching, laser ablation, plasma etching, chemical plasma etching, inductively coupled plasma etching, deep reactive ion etching, physical etching, oxygen plasma etching, reactive ion etching, and imprinting.

[0031] In one embodiment, the moldable material includes a lower layer adjacent to the substrate and an upper layer incorporating microstructures.

[0032] In one embodiment, the method includes removing material by imprinting an upper layer.

[0033] In one embodiment, the method includes providing electrical connections in electrical contact with at least some of the conductive microstructures.

[0034] In one embodiment, the electrical connections are at least one of extending through vias in the substrate, provided on a surface of the substrate, and provided on a surface of the moldable material.

[0035] In one embodiment, the moldable material includes mesas with microstructures extending therefrom and electrical connections provided between the mesas.

[0036] In one embodiment, the method includes creating a microfluidic channel in a surface of at least one of the substrate and the moldable material.

[0037] In one embodiment, the method includes creating pores in at least some of the microstructures.

[0038] In one embodiment, at least some of the microstructures are at least one of blades, ridges, needles, and plates.

[0039] In one embodiment, at least some of the microstructures have a cross-sectional shape that is at least one of at least partially tapered, circular, rectangular, cross-shaped, square, rounded square, rounded rectangular, oval, and at least partially hollow; have a surface that is at least one of at least partially smooth, serrated, containing one or more pores, containing one or more ridges, and rough; are at least partially hollow; are porous; and contain an internal structure.

[0040] In one embodiment, the microstructures include at least one of plate microstructures, at least partially tapered plate microstructures, plate microstructures having a substantially rounded rectangular cross-sectional shape, spaced apart substantially parallel plate microstructures, rows of spaced apart microstructures, pairs of spaced apart microstructures, and groups of microstructures.

[0041] In one embodiment, at least some of the microstructures are angularly offset, at least some of the microstructures are arranged orthogonally, pairs of adjacent microstructures are arranged orthogonally, pairs of adjacent microstructures are angularly offset, pairs of microstructures are arranged in rows, pairs of microstructures in one row are arranged orthogonally relative to pairs of microstructures in another row, and pairs of microstructures are arranged in rows, pairs of microstructures in one row are angularly offset relative to pairs of microstructures in another row.

[0042] In one embodiment, the microstructures have a spacing that is at least one of less than 1 mm, about 0.5 mm, about 0.2 mm, about 0.1 mm, and greater than 10 μm.

[0043] In one embodiment, at least some of the microstructures have at least one of a length that is less than 300 μm, about 150 μm, more than 100 μm, and more than 50 μm, a maximum width that is greater than the length, about the same as the length, less than 300 μm, about 150 μm, and more than 50 μm, and a thickness that is at least one of less than 50 μm, about 25 μm, and more than 10 μm.

[0044] In one embodiment, at least some of the microstructures have a tip with a length that is at least one of less than 50% of the length of the microstructure, at least 10% of the length of the microstructure, and about 30% of the length of the microstructure, and a sharpness that is at least one of at least 0.01 μm, at least 0.05 μm, at least 0.1 μm, less than 5 μm, and about 1 μm.

[0045] In one embodiment, the microstructure has a density of 5000 / cm 2 Less than 10 / cm 2 Super, 100 / cm 2 Super, about 25~50 / cm 2 , and approximately 600 / cm 2 The density is at least one of:

[0046] In one embodiment, at least some of the microstructures are 0.2 mm 2 Less than 0.13 mm 2 , 0.07mm 2 and 0.02 mm 2 and at least 0.01 mm 2 The electrode has a surface area of ​​at least one of

[0047] In one embodiment, the microstructures include anchor microstructures used to secure the substrate to a subject, the anchor microstructures including anchoring structures, having a length greater than other microstructures, and penetrating the dermis.

[0048] In one embodiment, the microstructure comprises materials including at least one of a bioactive material, a reagent for reacting with an analyte in a subject, a binder for binding to the analyte of interest, a probe for selectively targeting the analyte of interest, a material that reduces biofouling, a material that attracts at least one substance to the microstructure, a material that repels at least one substance from the microstructure, a material that attracts at least some of the analytes to the protrusions, and a material that repels at least some of the analytes from the protrusions.

[0049] In one embodiment, at least some of the microstructures are coated with a coating that modifies surface properties to at least one of increase hydrophilicity, increase hydrophobicity, and minimize biofouling; attracts at least one substance to the microstructure; repels at least one substance from the microstructure; acts as a barrier to exclude at least one substance from the microstructure; and comprises at least one of polyethylene, polyethylene glycol, polyethylene oxide, zwitterions, peptides, hydrogels, and SAMs.

[0050] It will be understood that the broad aspects of the invention and their respective features can be used together and / or independently, and reference to separate broad aspects is not intended to be limiting. Furthermore, it will be understood that method features can be performed using a system or an apparatus, and system or apparatus features can be implemented using a method.

[0051] Various examples and embodiments of the present invention will now be described with reference to the accompanying drawings. [Brief explanation of the drawings]

[0052] [Figure 1A] 1 is a schematic diagram of an example system for performing measurements on a living subject; [Figure 1B] FIG. 1B is a schematic bottom view of an example patch for the system of FIG. 1A. [Figure 2] 1 is a flowchart of an example method for manufacturing a patch. [Figure 3A] 1 is a schematic side view of an example substrate for use in manufacturing a patch. FIG. [Figure 3B] 3B is a schematic side view of an example of a formable material layer applied to the substrate of FIG. 3A. [Figure 3C] 3C is a schematic side view of an example of a mold applied to the moldable material of FIG. 3B. [Figure 3D]3B is a schematic side view of an example patch formed using a moldable material layer applied to the substrate of FIG. 3A. [Figure 3E] 1 is an image of an example of a first microstructure formed using hot embossing. [Figure 3F] 1 is an image of an example of a first microstructure formed using hot embossing. [Figure 3G] 1 is an image of an example of a first microstructure formed using hot embossing. [Figure 3H] 10 is an image of a second example microstructure formed using hot embossing. [Figure 3I] 10 is an image of a second example microstructure formed using hot embossing. [Figure 3J] 10 is an image of a second example microstructure formed using hot embossing. [Figure 4A] FIG. 1 is a schematic side view of an example of a roll-to-plate nanoimprint lithography apparatus. [Figure 4B] 1 is an image of an example of a microstructure formed using nanoimprint lithography. [Figure 4C] 1 is an image of an example of a microstructure formed using nanoimprint lithography. [Figure 4D] 1 is an image of an example of a microstructure formed using nanoimprint lithography. [Figure 4E] 1 is an image of an example of a microstructure formed using nanoimprint lithography. [Figure 4F] 1 is a schematic diagram of a microstructure including regions with modified properties; [Figure 4G] FIG. 1 is a schematic diagram of a microstructure containing pores formed by dissolving nanospheres. [Figure 4H] FIG. 1 is a schematic illustration of a microstructure containing surface porosity formed by surface treatment of the hardened microstructure. [Figure 5] 10 is a flow chart of an example method for coating a patch to form a microstructure electrode. [Figure 6A]FIG. 3E is a schematic side view of the example patch of FIG. 3D coated with a primer. [Figure 6B] FIG. 6B is a schematic side view of the patch of FIG. 6A coated with a conductive coating. [Figure 6C] FIG. 6C is a schematic side view of the patch of FIG. 6B in which the conductive coating has been selectively ablated to electrically isolate the microstructures. [Figure 6D] FIG. 6D is a schematic side view of the patch of FIG. 6C coated with a dielectric coating. [Figure 6E] FIG. 6E is a schematic side view of the patch of FIG. 6D in which the dielectric coating has been selectively ablated to expose the conductive coating. [Figure 7A] 1 is a schematic side view of an example of a conductive microstructure coated with a dielectric coating. [Figure 7B] 7B is a schematic side view of a first example of selective ablation of the dielectric coating of FIG. 7A. FIG. [Figure 7C] 7B is a schematic side view of a second example of selective ablation of the dielectric coating of FIG. 7A. FIG. [Figure 7D] 7B is a schematic side view of a third example of selective ablation of the dielectric coating of FIG. 7A. FIG. [Figure 7E] 1 is an image of an example of a microstructure coated with a dielectric coating. [Figure 7F] 7D is an image of the microstructure of FIG. 7E with the dielectric coating removed from the face of the tip. [Figure 7G] 7F is a colorized image of the microstructure of FIG. 7F showing exposed conductive material. [Figure 8A] 1 is a schematic side view of an apparatus for selectively masking patches. [Figure 8B] 1 is an image of a selectively etched microstructure. [Figure 8C] 1 is an image of a plate-to-plate apparatus for selectively masking patches. [Figure 8D] FIG. 8D is a side view of the plate-to-plate apparatus of FIG. 8C in use. [Figure 8E] FIG. 8D is a side view of the plate-to-plate apparatus of FIG. 8C in use. [Figure 8F]1 is an image of an example of a microstructure that has been etched to remove parylene. [Figure 8G] 1 is an image of an example of a microstructure that has been etched to remove parylene. [Figure 8H] 1 is an image of an example of a microstructure that has been etched to remove parylene. [Figure 8I] 1 is an image of an example of a microstructure that has been etched to remove parylene. [Figure 8J] 1 is an image of an example of a microstructure that has been etched to remove parylene. [Figure 8K] 1 is an image of an example of a microstructure that has been etched to remove parylene. [Figure 8L] 1 is an image of an example of a microstructure that has been etched to remove parylene. [Figure 9A] 1 is a schematic side view of a first example of a patch including electrical connection vias in a substrate. FIG. [Figure 9B] FIG. 10 is a schematic side view of a second example of a patch including electrical connection vias in a substrate. [Figure 9C] FIG. 10 is a schematic side view of an example patch including microstructures resting on mesas with corresponding surface-based electrical connections. [Figure 9D] FIG. 1 is a schematic side view of an example patch including surface-based electrical connections on a flexible substrate. [Figure 10A] 1 is a schematic side view of an example plate microstructure. FIG. [Figure 10B] FIG. 10B is a schematic front view of the microstructure of FIG. 10A. [Figure 10C] FIG. 10B is a schematic bottom view of an example patch including the microstructure of FIG. 10A. [Figure 10D] 10C is a schematic perspective top view of an example substrate including the pair of blade microstructures of FIGS. 10A and 10B. FIG. [Figure 10E] FIG. 1 is a schematic plan view of a grid of microstructure pairs including electrical connections. [Figure 10F] 10 is an image of an example patch containing an array of angularly offset plate microstructure pairs. [Figure 10G] 1 is a schematic side view of an embodiment of a plate microstructure. [Figure 10H] FIG. 5H is a schematic perspective view of the plate microstructure of FIG. 5G. [Figure 10I] 1 is a schematic side view of an example pair of microstructures inserted into a subject for epidermal measurements. FIG. [Figure 10J] 1 is a schematic side view of an example pair of microstructures inserted into a subject for dermal measurements. FIG. [Figure 10K] 10 is an image of a further example of an array of microstructures. [Figure 10L] 10 is an image of a further example of an array of microstructure pairs resting on a mesa. [Figure 11A] 9D is a schematic side view of an example of steps in micromachining a master to create a mold for manufacturing the microstructure of FIG. 9C. [Figure 11B] 9D is a schematic side view of an example of steps in micromachining a master to create a mold for manufacturing the microstructure of FIG. 9C. [Figure 11C] 9D is a schematic side view of an example of steps in micromachining a master to create a mold for manufacturing the microstructure of FIG. 9C. [Figure 11D] 9D is a schematic side view of an example of steps in micromachining a master to create a mold for manufacturing the microstructure of FIG. 9C. [Figure 12A] 1A-1C are schematic side views of a first example of steps in forming microstructures on a pre-patterned substrate. [Figure 12B] 1A-1C are schematic side views of a first example of steps in forming microstructures on a pre-patterned substrate. [Figure 12C] 1A-1C are schematic side views of a second example of steps in forming microstructures on a pre-patterned substrate. [Figure 12D] 1A-1C are schematic side views of a second example of steps in forming microstructures on a pre-patterned substrate. [Figure 12E]1A-1C are schematic side views of example steps in selective resin curing using a shadow mask applied to the backside of a mold. [Figure 12F] 1A-1C are schematic side views of example steps in selective resin curing using a shadow mask applied to the backside of a mold. [Figure 13A] 1 is an example of a complex microstructure master geometry fabricated using wafer dicing. [Figure 13B] 1 is an example of a complex microstructure master geometry fabricated using wafer dicing. [Figure 13C] 1 is an example of a complex microstructure master geometry fabricated using wafer dicing. [Figure 13D] 13B is an image of an example of a microstructure formed using the master geometry of FIG. 13A. [Figure 13E] 13C is an image of an example of a microstructure formed using the master geometry of FIG. 13B. [Figure 13F] 13D is an image of an example of a microstructure formed using the master geometry of FIG. 13C. [Figure 14A] 1 is an image of a first example of a master mold fabricated on a silicon wafer. [Figure 14B] 1 is an image of a first example of a master mold fabricated on a silicon wafer. [Figure 14C] FIG. 14C is a schematic diagram of example dimensions of the microstructures in the master mold of FIGS. 14A and 14B. [Figure 14D] 10 is an image of a second example of a master mold fabricated on a silicon wafer. [Figure 14E] 10 is an image of a second example of a master mold fabricated on a silicon wafer. [Figure 14F] 10 is an image of a second example of a master mold fabricated on a silicon wafer. [Figure 14G] 10 is an image of a second example of a master mold fabricated on a silicon wafer. [Figure 14H]10 is an image of a second example of a master mold fabricated on a silicon wafer. [Figure 14I] 10 is an image of a second example of a master mold fabricated on a silicon wafer. [Figure 14J] 14D-14I are images of example microstructures fabricated using the molds of FIGS. 14D-14I. [Figure 14K] 14D-14I are additional images of example microstructures fabricated using the molds of FIGS. 14D-14I. [Figure 14L] 14D-14I are additional images of example microstructures fabricated using the molds of FIGS. 14D-14I. [Figure 14M] 14D-14I are additional images of example microstructures fabricated using the molds of FIGS. 14D-14I. [Figure 14N] 14D-14I are additional images of example microstructures fabricated using the molds of FIGS. 14D-14I. DETAILED DESCRIPTION OF THE INVENTION

[0053] definition Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Although any methods and materials similar or equivalent to those described herein can be used in the practice or testing of the present invention, preferred methods and materials are described. For purposes of the present invention, the following terms are defined below.

[0054] The articles "a" and "an" are used herein to refer to one or to more than one (i.e., to at least one) of the grammatical object of the article. By way of example, "an element" means one element or more than one element.

[0055] The terms "about" and "approximately" are used herein to refer to a condition (e.g., amount, level, concentration, time, etc.) that varies by up to 20% (i.e., ±20%) from a specified condition, particularly by 10%, 9%, 8%, 7%, 6%, 5%, 4%, 3%, 2%, or 1%.

[0056] As used herein, the term "analyte" refers to a naturally occurring and / or synthetic compound that is a marker of a condition (e.g., substance abuse), a disease state (e.g., infectious disease), a disorder (e.g., neurological disorder), or a normal or pathological process (e.g., drug metabolism) occurring in a subject, or a compound that can be used to monitor the level of an administered or ingested substance in a subject, such as a drug (a substance that treats, prevents, and / or alleviates the symptoms of a disease, disorder, or condition, e.g., a medication, vaccine, etc.), an illicit substance (e.g., illegal drug), a non-illicit abused substance (e.g., alcohol or prescription drugs taken for non-medical reasons), a poison or toxin (including environmental pollutants), a chemical weapon (e.g., nerve agent, etc.) or their metabolites. The term "analyte" can refer to any substance, including chemical and / or biological agents, that can be measured in an analytical procedure, including nucleic acids, peptides, enzymes, antibodies, proteins, illicit drugs, explosives, toxins, pharmaceuticals, carcinogens, poisons, allergens, and infectious agents that can be measured in an analytical procedure. The analyte can be a compound found directly in a sample, such as biological tissue, including bodily fluids (e.g., interstitial fluid) from a subject, particularly in the dermis and / or epidermis. In certain embodiments, the analyte is a compound found in interstitial fluid. In some embodiments, the analyte is a compound with a molecular weight ranging from about 30 Da to about 100 kDa, particularly from about 50 Da to about 40 kDa. Other suitable analytes are as described herein.

[0057] As used herein, the term "and / or" refers to and includes any and all possible combinations of one or more of the associated listed items, as well as the lack of combinations when interpreted as alternatives (or).

[0058] As used herein, the term "aptamer" refers to a single-stranded oligonucleotide (e.g., DNA or RNA) that binds to a specific target molecule, such as an analyte. Aptamers can be of any size suitable for binding such a target molecule, such as a length of about 10 to about 200 nucleotides, particularly a length of about 30 to about 100 nucleotides.

[0059] The term "bind" and variations such as "binding" are used herein to refer to an interaction between two entities, such as an analyte and an aptamer, or an analyte and a molecularly imprinted polymer. The interaction can be a covalent or non-covalent interaction, particularly a non-covalent interaction.

[0060] Throughout this specification and the claims that follow, unless the context dictates otherwise, the word "comprise" and variations such as "comprise" and "comprising" are understood to mean the inclusion of a stated integer or step or group of integers or steps, but not the exclusion of other integers or steps or group of integers or steps. Thus, the use of terms such as "comprising" indicates that the recited integer is required or mandatory, but that other integers are optional and may or may not be present. "Consisting of" means including and limited to what precedes the phrase "consisting of." Thus, the phrase "consisting of" indicates that the recited elements are required or mandatory, and that no other elements may be present. "Consisting essentially of" means including any elements listed before the phrase, and is limited to other elements that do not interfere with or contribute to the activity or function specified in this disclosure for the recited elements. Thus, the phrase "consisting essentially of" indicates that the recited elements are required or mandatory, but that other elements are optional and may or may not be present depending on whether they affect the activity or function of the recited elements.

[0061] The term "plurality" as used herein refers to 2, 10, 100, 1000, 10000, 1 x 10 6 , 1×107 , 1×10 8 , 1×10 9 , 1×10 10 , 1×10 11 , 1×10 12 , 1×10 13 , 1×10 14 , 1×10 15 2 to 1×10, etc. (and all integers in between) 15 (or any integer in between) and more, is used to refer to more than one.

[0062] As used herein, the term "predetermined threshold" refers to a value above or below which indicates the presence, absence, or progression of a disease, disorder, or condition, the presence or absence of an illicit or non-illicit substance of abuse, or the presence or absence of a chemical weapon, poison, and / or toxin. For example, for purposes of the present invention, a predetermined threshold can represent the level or concentration of a particular analyte in a corresponding sample from an appropriate control subject, such as a healthy subject, or in a pooled sample from multiple control subjects, or the average or median value of multiple control subjects. Thus, a level or concentration above or below the threshold indicates the presence, absence, or progression of a disease, disorder, or condition, the presence or absence of an illicit or non-illicit substance of abuse, or the presence or absence of a chemical weapon, poison, and / or toxin, as taught herein. In other examples, the predetermined threshold may represent a value greater than or less than the level or ratio determined for a control subject, to incorporate an additional degree of confidence that a level or ratio above or below the predetermined threshold indicates the presence, absence, or progression of a disease, disorder, or condition, the presence or absence of an illicit or non-illicit substance of abuse, or the presence or absence of a chemical weapon, poison, and / or toxin. One of skill in the art can readily determine an appropriate predetermined threshold based on analysis of samples from appropriate control subjects.

[0063] As used herein, the terms "selective" and "selectivity" refer to a molecularly imprinted polymer or aptamer that binds an analyte of interest without exhibiting substantial binding of one or more other analytes. Thus, a molecularly imprinted polymer or aptamer that is selective for an analyte, such as troponin or a subunit thereof, exhibits greater than about 2-fold, 5-fold, 10-fold, 20-fold, 50-fold, 100-fold, or greater than about 500-fold selectivity relative to binding of one or more other analytes.

[0064] As used herein, the term "subject" refers to a vertebrate subject, particularly a mammalian subject, for which monitoring and / or diagnosis of a disease, disorder, or condition is desired. Suitable subjects include, but are not limited to, primates, avians (birds), livestock animals such as sheep, cows, horses, deer, donkeys, and pigs, laboratory animals such as rabbits, mice, rats, guinea pigs, and hamsters, pets such as cats and dogs, bats, and captive wild animals such as foxes, deer, and dingoes. In particular, the subject is a human.

[0065] A system for interacting with objects An example of a system for performing measurements on a living subject will now be described with reference to Figures 1A and 1B.

[0066] In this example, system 120 includes at least one substrate 111 having one or more microstructures 113. In use, the microstructures are configured to breach a functional barrier associated with a subject. In the current example, the functional barrier is the stratum corneum SC, and the microstructures are configured to breach the stratum corneum SC by penetrating the stratum corneum SC and entering at least the viable epidermis VE. In one particular example, the microstructures are configured not to penetrate the boundary between the viable epidermis VE and the dermis D, although this is not required and structures that penetrate into the dermis can also be used, as described in more detail below.

[0067] While this example is described with respect to breaking through the stratum corneum (SC), it will be understood that this is not required and that the technique can be applied to other functional barriers as well. In this regard, a functional barrier is understood to include any structure, boundary, or feature, physical or otherwise, that prevents the passage of an analyte, such as a signal and / or a biomarker. For example, a functional barrier can include one or more layers, a mechanical discontinuity, such as a discrete change in the mechanical properties of a tissue, a tissue discontinuity, a cellular discontinuity, a nerve barrier, a sensor barrier, a cellular layer, a skin layer, a mucosal layer, an internal or external barrier, an inner barrier within an organ, an outer barrier of an organ other than the skin, an epithelial or endothelial layer, etc. Functional barriers can also include light barriers, such as a melanin layer, an electrical barrier, a molecular weight barrier that prevents the passage of biomarkers of certain molecular weights, and other internal layers or boundaries, including the basal layer boundary between the viable epidermis and dermis.

[0068] The nature of the microstructures will vary depending on the preferred embodiment, in one example the microstructures may comprise needles, although this is not required and plates, blades and like structures are more commonly used, as described in more detail below.

[0069] The substrate and microstructures can be made from any suitable material, and the material used can depend on the intended use, for example, whether the structures need to be optically and / or electrically conductive, etc. The substrate can form part of a patch 110 that can be applied to a subject, although other arrangements can be used, for example, the substrate forming part of a housing that contains other components.

[0070] In one example, at least one sensor 121 is provided that is operatively connected to at least one microstructure 113, whereby a response signal can be measured from each microstructure 113. In this regard, the term response signal will be understood to encompass signals that are intrinsic in the subject, such as ECG (electrocardiograph) signals, or signals that are induced as a result of application of a stimulus, such as bioimpedance signals.

[0071] The nature of the sensor will vary depending on the preferred embodiment and the nature of the sensing being performed. For example, sensing may involve sensing of an electrical signal, in which case the sensor may be a voltage or current sensor, etc. Alternatively, an optical signal may be sensed, in which case the sensor may be an optical sensor such as a photodiode, CCD (Charge Coupled Device) array, etc., while a temperature signal may be sensed using a thermistor, etc.

[0072] The manner in which the sensor 121 is connected to the microstructure(s) 113 also varies depending on the preferred embodiment. In one example, this is achieved using a connection between the microstructure(s) 113 and the sensor; the nature of the connection varies depending on the signal to be sensed; the connection may include an electrically conductive element to conduct an electrical signal, a waveguide to conduct an electromagnetic signal, an optical fiber or other conductor, or a thermal conductor to conduct a thermal signal. The connection may also include a wireless connection, allowing the sensor to be located remotely. Ionic connections may also be used. Furthermore, the connection may be provided as a separate element, although in other examples, the substrate provides the connection, for example, if the substrate is made from a conductive plate that is further electrically connected to all of the microstructures. As a further alternative, the sensor may be embedded in or formed from part of the microstructure, eliminating the need for a connection.

[0073] The sensors 121 may be operatively connected to all of the microstructures 113 by joint and / or independent connections. For example, one or more sensors may be connected to different microstructures to allow different measurement response signals to be measured from different groups of microstructures 113. However, this is not required and any suitable arrangement may be used.

[0074] In addition to providing sensing, in some examples, the microstructure 113 may additionally and / or alternatively be configured to provide a stimulus. For example, the microstructure may be coupled to a signal generator that generates a stimulus signal, as described in more detail below. Such stimuli may also include electrical stimuli using a voltage or current source, optical stimuli using a visible or non-visible radiation source such as an LED or laser, thermal stimuli, etc., and may be delivered through the same or a different microstructure used to measure the response signal, depending on the preferred embodiment. Additionally and / or alternatively, stimuli may be achieved using other techniques, such as through exposure of the subject to the microstructure and materials thereon or therein. For example, a coating may be applied to the microstructure to allow a material to be delivered across a barrier to the subject, thereby stimulating a response within the subject.

[0075] These options allow for various types of sensing to be performed, including detection of electrical signals within the body such as ECG signals, plethysmographic signals, electromagnetic signals or electrical potentials generated by muscle, nerve tissue, blood etc; detection of photoplethysmographic effects such as fluorescence; detection of electromagnetic effects; detection of mechanical properties such as stress or strain; etc. Sensing may include detection of the body's response to an applied electrical signal to measure, for example, bioimpedance, bioconductance or biocapacitance; detection of the presence, absence, level or concentration of an analyte by detecting, for example, an electrical or optical property, etc.

[0076] The system may further include one or more electronic processing devices 122 which may form part of a measurement device as described in more detail below, and / or may include an electronic processing device which forms part of one or more processing systems, such as a computer system, a server, a client device, etc. In use, the processing device 122 is adapted to receive signals from the sensors 121 and store or process the signals. For ease of explanation, the remainder of the description will refer generally to the processing device, however it will be understood that multiple processing devices may be used, with processing distributed between devices if desired, and that references to the singular encompass plural equipment and vice versa.

[0077] An example of how this can be done is now described.

[0078] In particular, in one example, a substrate is applied to a subject such that one or more microstructures breach, and in one example, penetrate, a functional barrier. For example, when applied to the skin, the microstructures can penetrate the stratum corneum and enter the viable epidermis, as shown in FIG. 1A. This can be accomplished manually and / or through the use of an actuator to help ensure successful penetration.

[0079] A response signal in the subject is measured and a signal indicative of the measured response signal is provided to electronic processing device 121. This may occur after application of the stimulus, but this is not required and will vary depending on the nature of the sensing being performed.

[0080] The one or more processing devices may then analyze the resulting measurement data and / or store data based on the measurement data for later analysis or provide an output based on the measured response signals. For example, the processing device may display an indicator indicative of the measured response signals and / or values ​​derived therefrom. Alternatively, the processing device may generate intervention recommendations, trigger actions such as alerting a clinician, trainer, or parent, etc.

[0081] The analysis can be performed in any suitable manner, which will vary depending on the nature of the measurements being made. For example, this may involve examining the values ​​of the measured response signals and using them to calculate an index that indicates a health status, including the presence, absence, degree, or prognosis of one or more medical conditions, a prognosis associated with a medical condition, the presence, absence, level, or concentration of a biomarker, the presence, absence, level, or concentration of an analyte, the presence, absence, or grade of cancer, fluid levels in the subject, blood oxygenation, tissue inflammatory state, bioelectrical activity such as nerve, brain, muscle, or heart activity, or various other health conditions. This may be achieved by monitoring changes in values ​​over time and may involve comparison with values ​​measured for reference subjects with known medical conditions. Additionally and / or alternatively, the index may indicate a measured parameter associated with the subject, such as the measured level or concentration of an analyte or other biomarker.

[0082] For example, when measuring fluid levels, this may involve examining the values ​​of the applied stimulation signal and the measured response signal and using these to calculate bioimpedance within the epidermis, which may further derive an index indicative of fluid levels. In this regard, fluids within the body, such as interstitial fluid, contain sodium (Na+), potassium (K+), calcium (Ca+), and argon (Ar+). 2 +), chloride (Cl-), bicarbonate (HCO3-) and phosphate (HPO4 2It will be appreciated that an increase or decrease in fluid level, for example as a subject's hydration level increases or decreases, will result in a corresponding decrease or increase in ion concentration, resulting in a change in the conductivity of the fluid. Accordingly, measurements of the impedance of the fluid can be used to further derive information about the fluid's conductivity, which in turn indicates ion concentration and therefore fluid level. It will be appreciated that this allows changes in impedance to be used to track changes in fluid level and therefore the hydration status of a subject. Such fluid levels may include any one or more of interstitial fluid level, changes in interstitial fluid level, ion concentration in interstitial fluid, changes in ion concentration in interstitial fluid, ion concentration, changes in ion concentration, total body water, intracellular fluid level, extracellular fluid level, plasma water level, fluid volume, or hydration level.

[0083] Fluid level indicators may further be used in monitoring hydration levels and / or health status, such as the presence, absence, degree or prognosis of one or more medical conditions, prognosis related to a medical condition, etc. This may include monitoring changes in values ​​over time, for example to provide a longitudinal hydration measurement, and may include comparison with values ​​measured for a reference subject of known hydration levels, thereby allowing an assessment of whether the subject is under- or overhydrated.

[0084] In any event, it will be appreciated that the above-described systems operate by providing microstructures configured to penetrate a barrier, such as the stratum corneum, and using these to enable measurement of response signals within a subject, such as within the epidermis and / or dermis. These response signals can be further processed and then analyzed to derive specific measurements or various values ​​that may be indicative of one or more aspects of the subject's health.

[0085] For example, the system may be configured to measure the level or concentration of an analyte, such as the level or concentration of a particular biomarker. The response signal may also be used to generate visualization, one-, two-, or three-dimensional spatial mapping, mechanical properties, force, pressure, muscle movement, blood pulse wave details, analyte concentrations, such as the presence, absence, level, or concentration of a particular biomarker, blood oxygen saturation, bioimpedance, biocapacitance, bioconductance, or electrical signals within the body, such as ECG (electrocardiogram) signals.

[0086] In one example, a system can be configured to perform measurements at specific locations within a subject, such as only within the epidermis, only within the dermis, etc. This allows for high accuracy in detecting target analytes and provides higher quality data for more precise measurement of the analyte. Furthermore, limiting the locations at which measurements are performed ensures that measurements are reproducible, allowing for more accurate long-term monitoring.

[0087] In contrast to conventional approaches, breaking through and / or at least partially penetrating a functional barrier such as the stratum corneum allows measurements to be taken from within or below the barrier, particularly within the epidermis and / or dermis, resulting in significantly improved quality and magnitude of the detected response signal. In particular, this ensures that the response signal accurately reflects conditions within the human body, particularly within the epidermis and / or dermis, such as the presence, absence, level or concentration of biomarkers, interstitial fluid impedance, etc., in contrast to conventional external measurements that are overly affected by the environment outside the barrier, such as the material properties of the skin, the presence or absence of hair, sweat, and physical properties of the skin surface, such as the mechanical behavior of an applied sensor. Additionally, penetrating the stratum corneum but not the dermis limits measurements to the epidermis alone, thereby avoiding interference from changes in dermal fluid levels.

[0088] For example, this allows for accurate measurement of high molecular weight biomarkers that would otherwise barely penetrate the skin. A good example is glucose, which, when present externally, such as in sweat, is typically present at low concentrations and often time-delayed, meaning that the concentration in sweat does not necessarily reflect the current glucose level in the body. In contrast, breaking through a barrier, in this case the stratum corneum, allows for much more accurate measurements. It will be appreciated that similar considerations apply to a wide range of different biomarkers or signals and associated barriers that would otherwise prevent accurate measurement of the biomarker or signal.

[0089] For example, in the case of impedance measurements, microstructured electrodes tend to measure a different impedance compared to standard surface electrodes, indicating that microstructured electrodes do not measure the impedance of the surface skin, i.e., the measured impedance is more indicative of conditions within the body and its fluid compartments, such as the intracellular and extracellular fluid compartments. Because the impedance contribution of the skin surface is significant, this can cause changes in impedance within the covered body, making skin-based measurements less likely to detect meaningful changes.

[0090] Additionally, in some instances, the microstructures penetrate the barrier far enough to allow measurements to be taken. For example, in the case of skin, the microstructures are typically configured to enter the viable epidermis but not the dermal layer. This results in several improvements over other invasive techniques, including avoiding problems associated with penetrating the dermis, such as pain, erythema, and petechia caused by nerve exposure. Avoiding penetration of the dermal boundary also significantly reduces the risk of infection and allows the microstructures to remain implanted for extended periods, such as several days, which can further be used for long-term longitudinal monitoring. However, penetration of the dermal barrier may be necessary in some cases, such as when detecting troponin or its subunits.

[0091] It will be appreciated that being able to keep the microstructures in situ is particularly beneficial as it ensures that measurements are taken at the same location within the subject, reducing the inherent variability that arises from inaccuracies in repositioning the measurement device that can occur with conventional techniques. Nevertheless, it will be appreciated that the system may be used in other ways, such as to provide single point in time monitoring.

[0092] In one example, this allows the equipment to be provided as part of a wearable device, providing significantly better measurements than existing surface-based measurement technologies, for example, by providing access to signals or biomarkers that would otherwise be unable to penetrate barriers, while still allowing measurements to be taken while the subject is engaged in normal activities and / or over extended periods of time. This further allows measurements to be obtained that more accurately reflect the subject's health or other status. For example, this allows fluctuations in a subject's condition over the course of a day to be measured, avoiding measurements being taken in artificial settings, such as in a clinic, that may not be representative of the subject's actual situation. This also allows monitoring to be performed substantially continuously, thereby allowing conditions, such as myocardial infarction, cardiovascular disease, vomiting, diarrhea, etc., to be detected as they arise, allowing for more rapid intervention.

[0093] The above-described system can be applied to any part of the body and thus can be used with a wide range of different functional barriers. For example, the functional barrier can be an internal or external barrier, a skin layer, a mucous layer, an inner barrier within an organ, an outer barrier of an organ, an epithelial layer, an endothelial layer, a melanin layer, a light barrier, an electrical barrier, a molecular barrier, a basal layer, or a stratum corneum. Thus, the microstructures can be applied to the buccal mucosa, the eye, or another epithelial layer, an endothelial layer, etc. Although the following examples focus specifically on application to the skin and the functional barrier includes some or all of the stratum corneum, it will be understood that this is intended to be illustrative and not limiting.

[0094] Patch Manufacturing Typically, the patch, and any associated electronics, are disposable. From this, it can be understood that it is desirable for the patch to be manufactured in an inexpensive and sustainable manner. Nevertheless, it is important that the patch, and in particular the microstructure, be manufactured in a manner that not only ensures consistency of construction, but also has desirable functional parameters such as conductivity, durability or strength, sharpness, etc., since the breach of the functional barrier may affect the measurement being performed.

[0095] While silicon etching is conventionally used to fabricate microstructure patches, this approach is very expensive and impractical for mass production. Thus, in a preferred example, a method for fabricating a patch is provided that includes forming a plurality of microstructures on a substrate using a moldable material, where the microstructures are molded to breach a functional barrier of interest, and then solidifying the moldable material.

[0096] Such an approach has several advantages. For example, by forming the microstructures from a moldable material, they can be fabricated using a variety of techniques, including not only molding but also imprinting (UV and / or thermal) and hot embossing. In either case, these allow the patches to be manufactured inexpensively and in large quantities, making the resulting devices readily available.

[0097] Additionally, the moldable material can be configured to be strong enough to allow the microstructures to breach and optionally penetrate functional barriers, and bio-inert to ensure they do not interfere with or irritate the subject.

[0098] Moldable materials can be impregnated with materials to modify the properties of the microstructures, for example, to ensure that the microstructures are conductive and / or to be used to deliver materials to a subject. Other examples include modifying surface properties such as mechanical properties, porosity, hydrophobicity, surface charge, and zeta potential. Additionally, they can be used to functionalize the microstructures, enabling them to detect specific analytes and allowing them to be used in a wide range of different applications.

[0099] Next, a specific example of an approach for forming a microstructure will be described with reference to FIGS. 2 and 3A to 3D.

[0100] In this example, a substrate 311 is provided in step 200. The substrate may be of any suitable shape and may be a rigid, semi-rigid or flexible material, examples of which are described in more detail below.

[0101] Then, in step 210, formable material layer 312 is deposited on substrate 311 using, for example, spraying, inkjet printing, drop casting, spin coating, doctor blading, etc. As part of this process, surface treatments may be applied to substrate 311 to prepare the surface and aid in bonding of formable material layer 312 to the substrate. Various surface pretreatments may be used, including, for example, coating the substrate with a primer by spraying a primer solution onto the patch, and / or using a plasma pretreatment such as oxygen plasma, argon plasma, etc. for surface cleaning and / or activation. Other treatments may also be applied, such as treating the surface with ozone.

[0102] In step 220, a plurality of microstructures 313 are formed in the moldable material layer 312. In one example, this is achieved using a mold 314 having cavities 314.1 in the shape of the microstructures used in an imprinting and / or hot embossing approach. The imprinting approach may use UV imprinting, thermal imprinting, or a combination of both UV and thermal imprinting, depending on the preferred embodiment. Thus, the moldable material is typically a low-viscosity moldable material so that it can fill the mold, while the solidified moldable material typically has relatively high mechanical strength, and optionally high resistivity and / or high conductivity, depending on the application. Examples of moldable materials are described in more detail below. The cavities 314.1 are typically smooth-sided to facilitate mold removal, although this is not required; surface features may be provided, for example, to create porous or undulating microstructures, thereby increasing the surface area of ​​the microstructures.

[0103] Following the embossing / imprinting step, the moldable material is solidified in step 230, for example, by curing the moldable material using visible or non-visible electromagnetic radiation, heat, etc., depending on the particular moldable material used.

[0104] In the case of hot embossing, this is typically achieved by stamping a pattern into a polymer that has been softened by raising the polymer's temperature above its glass transition temperature. Micron-scale (and smaller) features have been successfully hot embossed into a variety of polymers, including polycarbonate and PMMA. Examples of microstructures formed using hot embossing are shown in Figures 3E-3J.

[0105] When imprinting is used, the formable material layer may be imprinted using nanoimprint lithography, roll-to-plate lithography, roll-to-roll lithography, plate-to-plate lithography, and / or plate-to-roll lithography. In one preferred example, roll-to-plate lithography is used, which will now be described with reference to Figure 4A.

[0106] In this example, imprinting is performed using an apparatus including a movable support 431, such as a conveyor belt, that receives a substrate 411. The substrate is transported past a formable material applicator 432, which deposits a formable material onto the substrate 411, typically in one or more layers 412. The apparatus further includes an endless belt 433 entrained around roller 434 such that the belt is engaged with the formable material layer 412 as the substrate moves in the direction of arrow 441. The belt surface incorporates the mold, so that the formable material layer is formed during engagement. A curing device, such as a heat or radiation source 435, is provided so that the microstructures are cured before being removed from the mold as the substrate exits from under the belt. Examples of systems for imprinting in this manner include the Morphotronics Portis imprint machine. However, it will be appreciated that other approaches, such as microinjection molding, can also be used to fabricate the microstructures.

[0107] Examples of microstructures formed using this approach are shown in Figures 4B-4E.

[0108] The mold 314 can incorporate one or more materials, coatings, or other additives, either within the body of the microstructure or through the addition of a coating containing the additive. The nature of the material or additive varies depending on the preferred embodiment and can also include an anti-stiction coating, such as a low-surface-energy material, to enable easy release or peeling of the mold 314 from the moldable material 312 bonded to the substrate. The coating or additive can also be a material or self-assembled monolayer coating to repel the moldable material or any residue left behind after curing. Example materials include 1H,1H,2H,2H-perfluorodecyltrichlorosilane, diamond-like carbon (DLC), fluorine-doped diamond-like carbon (F-DLC) films, perfluorooctyltrichlorosilane (PFOTCS), chlorosilanes, fluorosilanes, mold materials containing fluorinated additives, Daikin Industries' OPTOOL, and the like. The coating can be deposited on the mold from the vapor or liquid phase. It will also be appreciated that other coatings may be applied to the mold so that materials are incorporated into or applied to the surfaces of the resulting microstructures.

[0109] The anti-stiction coating may be applied to the mold 314 by one and / or more methods, such as spin coating, vapor coating, liquid coating, and the like.

[0110] In spin coating, the anti-stiction material is applied to the mold 314 at a given speed and dwell time until the entire surface area of ​​the mold is covered with the anti-stiction material. This method allows for uniform and homogeneous coverage. The resulting film does not necessarily form a monolayer, but it does provide the mold surface with low surface energy for easy release after imprinting.

[0111] In vapor-phase coating, an anti-stiction material is applied to create a monolayer on the mold surface. Prior to vapor-phase coating, the mold surface needs to be activated by a suitable surface treatment procedure. Coating is performed by placing the mold and anti-stiction material in a desiccator under low pressure or vacuum. Under these conditions, the resulting vapor of the anti-stiction material adheres to the activated surface of the mold and forms a monolayer. The same can be done in dedicated SAM coating equipment.

[0112] In liquid-phase coating of anti-stiction material, the mold is immersed in a container containing the anti-stiction material. After leaving the mold for a few minutes to a few hours, a thin coating forms on the mold surface. Depending on the material properties of the mold and the anti-stiction material, the coating can result in the formation of a monolayer or a thin polymer film, imparting a low surface energy to the surface.

[0113] In another example, a mold material can be used that has inherently low surface energy properties, or an additive (that provides low surface energy) can be added to the mold material when the mold is made.

[0114] Without a suitable anti-stiction material (coating) or a mold material with suitable low surface energy properties, any imprint on the moldable material can damage the mold and / or contaminate the imprinted substrate, thereby potentially rendering it unsuitable for further use.

[0115] To facilitate filling of the mold cavity and thereby ensure that the resulting microstructure has the desired shape, the moldable material is preferably 10 -3 Pa·s~10 -1The imprinting agent may have a low viscosity, such as between 0.40 and 0.05 Pa·s. Filling of the mold cavity may also be assisted in other ways, such as by conducting the molding process in a low pressure environment and / or vacuum, thereby removing air from the mold cavity. Similarly, ports may be provided in the mold cavity to allow air to be evacuated or sucked out of the mold cavity as the imprinting process occurs.

[0116] In one example, the formable material used may be a monomer, oligomer, photoinitiator, crosslinking acrylate groups, curable sol-gel, epoxy, resin, polymer, curable formable material such as UV curable formable material, thermoset formable material, sealant, UV adhesive, UV nanoimprint lithography polymer, conductive polymer, Helioseal, urethane dimethacrylate, bisphenol A-glycidyl methacrylate, triethylene glycol dimethacrylate, NOA61, mercaptoester. *Examples of suitable moldable materials include one or more of: 1, triallyl isocyanurate, Inoflex RP+, PAK01, NIF2 (Asahi Glass Co., Ltd.), NIF1 (Asahi Glass Co., Ltd.), Z Resist (t-butyl acrylate (96.5%), or photoinitiator Irgacure 369 (3.5%)), although it will be understood that other suitable moldable materials can also be used. When resins are used, they can be either solvent-based or solventless formulations. In one example described below, solventless resins are tried, specifically using the MM series resins from Morphotonics™, which contain acrylic backbones, such as MM1043C, MM2138B2, MM2017A, MM2394G, MM1158, or MM1158A. However, solvent-based and solventless formulations also exist from other resin manufacturers, such as microresist technology GmbH, DELO adhesives, and Daikin Industries, Ltd. The mr‐NIL210SF series, OrmoClearFX, and OrmoClear30 from microresist technology GmbH are other potential options. Depending on the solvent-based or solvent-free resin formulation, a complementary porous or non-porous intermediate polymer stamp (IPS) needs to be used.

[0117] Moldable materials can have a variety of properties, such as being hydrophobic or hydrophilic, depending on whether it is desired to attract or repel fluids. For example, a base moldable material layer on a patch can be hydrophobic to repel sweat from the surface of the patch, while the microstructures can be hydrophilic to aid in coverage. It will be appreciated, therefore, that different moldable materials can be applied to different regions of a substrate, e.g., a hydrophilic moldable material can be used to construct rows of microstructures, with a hydrophobic moldable material provided between the rows. Alternatively, moldable materials can be provided in layers, e.g., forming microstructures in an upper moldable material layer while a lower moldable material layer is provided on the substrate. An example of this is shown in FIG. 4F, which shows areas of increased hydrophilicity or hydrophobicity on microstructure tips 413.1 and on portions 411.1 of the substrate.

[0118] Moldable materials may include additives to modify the physical properties of the moldable material, including additives to, for example, increase mechanical strength, introduce porosity, etc. Additionally and / or alternatively, moldable materials may be manipulated after curing to introduce surface features or structures, such as pores or relief, thereby altering the structural strength or surface area of ​​the moldable material or microstructure. This may also be done to introduce fluid channels, for example, to facilitate sweat removal or fluid sampling, as described in more detail below.

[0119] In the example shown in Figure 4G, a moldable material is used that incorporates polystyrene nanospheres 411.2, which are then dissolved in a solvent to yield a microstructure 411 containing nanopores 411.3. Conversely, in the example of Figure 4H, the microstructure 411 is treated after curing to introduce surface porosity 411.4.

[0120] As mentioned above, a primer can be used to help the moldable material adhere to the substrate; for example, for NIL, example primers include Prim1-ARK, Prim2-ARK, Prim3-ARK, and Prim4-ARK (ARKEMA Development, doi:10.1117 / 12.2515607). Another popular option is (hexamethyldisilazane) HMDS, which can be used as a wet coating or applied from the gas phase. One example of a commercially available primer formulation based on HMDS is mr-Primer 80 / 20 from microresist (https: / / www.microresist.de / en / produkt / mr-primer-80-20 / ).

[0121] In one example, the method includes solidifying the formable material by curing, for example, with heat, electromagnetic radiation, visible electromagnetic radiation, or ultraviolet electromagnetic radiation, although again, other suitable curing approaches can be used depending on the preferred embodiment and the nature of the formable material. Additionally, curing parameters can be controlled to optimize the properties of the resulting microstructure, for example, to ensure sufficient mechanical strength without making the microstructure too brittle. Examples of parameters that can be controlled include pressure, air pressure, temperature, duration or radiation exposure, roller speed, roller temperature, plate speed, plate temperature, exposure time, exposure intensity, etc.

[0122] The nature of the substrate varies depending on the preferred embodiment. For example, the substrate can be made of or contain fabric, woven fabric, electronic fabric, natural fiber, silk, organic material, natural composite material, artificial composite material, ceramic, stainless steel, ceramic, stainless steel, metal such as titanium or platinum, polymer such as rigid or semi-rigid plastic including doped polymer, silicon or other semiconductor including doped semiconductor, organosilicate, gold, silver, carbon, carbon nanomaterial, etc. Specific examples of materials include polycarbonate, polymethacrylimide (PMI), polyethylene terephthalate (PET), polycarbonate (PC), poly(methyl methacrylate) (PMMA). In another example, nanoimprint lithography can be used to define microstructures directly on printed circuit boards (PCBs), such as thin flexible PCBs, which typically contain a metal layer of traces, usually copper, bonded to a dielectric layer such as polyimide.

[0123] In one example, the method includes applying at least one coating to at least a portion of at least some of the microstructures. The coating can be applied using a variety of techniques, including sputtering, electroplating, electroless plating, spin coating, or inkjet printing, although other approaches such as dip coating, spray coating, deposition coating, electropolymerization, drop casting, etc. can also be used.

[0124] The coatings typically include conductive, dielectric, and / or mechanical coatings. Specific examples of coatings include gold, silver, titanium, titanium nitride, metals, ceramics, parylene, poly(3,4-ethylenedioxythiophene), or iridium oxide (IrO2), although it will be understood that other suitable coatings may also be used.

[0125] The coating can have a thickness of at least 100 nm, at least 200 nm, at least 300 nm, at least 400 nm, about 500 nm, less than 3 μm, less than 4 μm, or less than 5 μm, although other thicknesses can be used depending on the function and intended use of the coating.

[0126] The coating can be applied to the entire microstructure and optionally to the formable material layer and / or substrate, and / or to a portion of the microstructure, such as the tip or base, or can be applied and removed so that the microstructure is only partially coated. As described in more detail below, various approaches can be used to remove material, such as ablation, selective plasma or chemical etching, oxygen plasma etching, etc., and the technique used will depend on the nature of the material being removed and the preferred embodiment. For example, laser ablation may be preferred in some situations, as etching is easier for bulk processing but has limitations in removing some materials, such as parylene.

[0127] The coating may also be applied in multiple layers, for example to provide a functional coating and an overlying protective coating configured to dissolve upon contact with fluid within the object, thereby exposing the functional coating.

[0128] In one example, at least some of the microstructures are conductive microstructures, and the method includes fabricating the conductive microstructures by applying a conductive coating to at least some of the microstructures and / or using a conductive moldable material. The conductive microstructures can act as electrodes, which can be used to apply an electrical signal to a subject and measure an endogenous or exogenous response electrical signal, such as measuring an ECG or impedance. In another example, the microstructures interact with one or more analytes of interest, and the electrodes are used to detect a response signal that depends on the presence, absence, level, or concentration of the one or more analytes of interest, thereby allowing the level or concentration of the one or more analytes to be quantified.

[0129] Additionally and / or alternatively, a dielectric coating can be applied to selectively insulate at least some of the microstructures, e.g., a dielectric coating can be applied to at least a portion of a conductive microstructure such that only selected portions of the conductive microstructure are exposed. Thus, the microstructure can also include an electrically conductive material covered by a non-conductive (insulating) layer, with openings providing access to the conductive material to allow conduction of electrical signals therethrough, thereby defining electrodes.

[0130] In one example, when an insulating layer is used, it extends over a portion of the surface of the microstructure, including the proximal end of the microstructure adjacent to the substrate. The insulating layer may extend over at least half of the length of the microstructure and / or approximately 60 μm, 90 μm, or 150 μm of the proximal end of the microstructure, and optionally over at least a portion of the distal portion of the microstructure. In one specific example, this is done so that the uninsulated portions defining the electrodes are provided within the epidermis and / or dermis to apply stimulation signals to and / or receive response signals from the epidermis and / or dermis. In this case, the electrodes may extend over the length of a distal portion of the microstructure or a portion of the microstructure spaced from the distal tip. The electrodes may be positioned near the distal end of the microstructure or near the distal tip of the microstructure, depending on the intended application. The electrodes may extend over at least 25% of the length of the microstructure, less than 50% of the length of the microstructure, or over approximately 60 μm of the microstructure.

[0131] In one example, such a device is made by applying a dielectric coating over a conductive microstructure and then removing at least a portion of the dielectric coating to expose the conductive surface. This approach has the advantage that the entire microstructure can be conductive, making it easier to provide electrical connection to the microstructure, but only a portion of the microstructure is exposed, thereby controlling the extent of the resulting electrode, further enabling measurements / stimulation to occur at defined locations within the body. However, it will be appreciated that other approaches can be used to define the electrodes, such as coating only a portion of the microstructure with conductive material, removing conductive material applied to a portion of the microstructure, or using a conductive molding material that is optionally partially covered with a dielectric coating.

[0132] The insulating layer can also extend over part or all of the surface of the substrate. In this regard, in some cases, connections are formed on the surface of the substrate, in which case a coating can be used to insulate them from the subject. For example, electrical connections to the electrodes can be provided using electrical tracks on the surface of the substrate, with an insulating layer provided over the connections to ensure that the connections do not make electrical contact with the subject's skin or any sweat present, which could further adversely affect the measured response signal. As described in more detail below, electrically conductive via holes can also be provided in the substrate to be used to transfer the electrical tracks to the underside of the substrate.

[0133] In addition to providing electrodes over only a portion of the microstructures, it may also be necessary to electrically isolate at least some of the microstructures, for example so that different signals can be applied to or measured from different rows of microstructures. In one example, this can be achieved by removing material between the microstructures, selectively coating at least some of the microstructures, or removing electrically conductive material between conductive microstructures to electrically isolate at least some of the microstructures.

[0134] In one example, a method of removing material, for example to remove either a dielectric coating or a conductive coating, may include removing material using etching, ablation, plasma etching, chemical plasma etching, inductively coupled plasma etching, deep reactive ion etching, physical etching, oxygen plasma etching, reactive ion etching, imprinting, etc. For example, portions of the material may be masked using a chemical mask such as a photoresist, a shadow mask, or a physical mask such as a foil material to allow selective etching.

[0135] In another example, the formable material layer includes a lower layer adjacent to the substrate and an upper layer incorporating microstructures, where imprinting the upper layer removes material between the electrodes. In this example, if only the upper layer is conductive, it can be used to electrically isolate adjacent microstructures.

[0136] Coatings can also be used to provide additional functionality, for example, the coating can incorporate materials such as therapeutic materials that can be used to release material from, disrupt, dissolve, or otherwise strip the coating on the microstructures upon stimulation, such as chemical, biochemical, electrical, optical, or mechanical stimulation.

[0137] In another example, the microstructure can be coated with a selectively dissolvable coating. The coating can be adapted to dissolve after a defined period of time, such as after the microstructure has been present in a subject for a set length of time, in response to the presence, absence, level, or concentration of one or more analytes in the subject, upon breaching or penetration of a functional barrier, or in response to application of a stimulus signal, such as an electrical signal, an optical signal, etc. Dissolution of the coating can be used to trigger the measurement process, for example, by exposing a binding agent or other functional feature, such that the analyte is detected only after the coating has dissolved.

[0138] In a further example, dissolution of the coating can be detected, for example, through a change in an optical or electrical property, and measurements can be taken after the coating has dissolved, and thus dissolution of the coating can be detected based on a change in the response signal.

[0139] In one example, the coating can be used to provide mechanical properties. For example, the coating can provide a physical structure that can be used to facilitate barrier penetration, such as by providing the microstructure with a smoothly tapered outer profile. The coating can reinforce the microstructure to prevent it from breaking, crushing, buckling, or otherwise being damaged during insertion, or can be used to help anchor the microstructure within a subject. For example, the coating can include a hydrogel, which expands when exposed to moisture, causing the microstructure and coating to increase in size upon insertion into a subject, thereby making the microstructure more difficult to remove. Additionally, in addition to aiding in skin engagement, the gel can be used to seal the penetration hole, preventing fluids from leaking out or sweat from entering the hole.

[0140] Coatings can also be used to modify the surface properties of the microstructure, for example, to increase or decrease hydrophilicity, increase or decrease hydrophobicity, and / or minimize biofouling. Coatings can also be used to attract, repel, or repel at least one substance, such as an analyte, cell, or fluid. Coatings can also dissolve to expose the microstructure, additional coatings, or materials, which can be used to control the detection process. For example, a sustained-release coating can be used to allow measurements to be taken a set time after application of the patch. This can also be used to provide a stimulus to a subject, for example, by releasing a treatment or therapeutic material.

[0141] The microstructures can also be differentially coated such that different microstructures respond differentially to the analytes, for example, different microstructures can respond to different analytes, different combinations of analytes, different levels or concentrations of analytes, etc.

[0142] In one example, at least some of the microstructures attract at least one substance to the microstructure and / or repel or repel at least one substance from the microstructure. The nature of the substance varies depending on the preferred embodiment and may include one or more analytes or may include other substances that contain analytes, such as ISF, blood, etc. This can be used to attract, repel, or repel analytes, for example, to attract analytes of interest so that they can be concentrated and / or detected, or to repel or repel analytes other than those of interest.

[0143] The ability to repel or exclude substances can also help prevent biofouling. For example, microstructures can contain or include a coating of a material such as polyethylene glycol (PEG), which generally repels substances from the surface of the microstructure. Biofouling reduction can also be achieved based on the selection of microstructure materials or the structure of the microstructure, for example, a binder coating within the pores of a porous microstructure, a surface coating that peels off to expose the sensing surface when sensing is to occur, a permeable coating such as a porous polymer, for example, a nylon membrane, a polyvinylidene fluoride coating, a polyphenylenediamine coating, a polyethersulfone coating, or a hydrogel coating such as poly(hydroxyethyl methacrylate) or PEG coating, an isoporous silica micelle membrane, a protein membrane such as a fibroin membrane, a polysaccharide membrane such as a cellulose membrane or a chitosan membrane, or a diol or silane membrane, a strippable coating that interferes with biofouling substances, and / or a porous coating. In certain embodiments, the microstructure is porous and a binder is coated within the pores of the microstructure.

[0144] The coating can also be used to enable detection of an analyte, for example, the coating may include an aptamer or molecularly imprinted polymer that responds to the analyte, allowing the analyte concentration to be detected using a change in electrical signal.

[0145] To optimize the coating process, the properties of the coating can be controlled by the addition of one or more other agents, such as thickeners, detergents or other surfactants, and adjuvants. These components can be provided in various concentrations. For example, the thickener or surfactant can form between 0% and 90% of the coating solution.

[0146] A variety of viscosity-increasing agents can be used, examples include methylcellulose, carboxymethylcellulose (CMC), gelatin, agar, and agarose, as well as any other viscosity-adjusting agent. The viscosity of the solution is typically 10 -3 Pa·s~10 -1 In one example, a coating solution containing 1-2% methylcellulose provides a suitable uniform coating, resulting in a viscosity in the range of 0.011 (1%) to 0.055 (2%) Pa·s.

[0147] Similarly, the surface tension of the coating solution can be adjusted using various surfactants, such as any detergent or any suitable agent that reduces surface tension and is biocompatible at low concentrations. The solution properties are typically similarly controlled by the addition of one or more other agents, such as thickeners, detergents, other surfactants, or any other suitable materials. These components can be provided in various concentrations. For example, the thickener or surfactant can form between 0% and 90% of the coating solution.

[0148] In some embodiments, it may be desirable to increase the bonding (adhesion) of the coating to the microstructure. Thus, in such embodiments, a primer agent can be applied to the formable material layer and the microstructure before applying the coating, thereby increasing the bonding of the coating to the microstructure. Suitable agents include, but are not limited to, organosilanes, silicones, siloxanes, amide- and amine-containing compounds, organophosphorus compounds, self-assembled monolayers, or other coupling agents such as titanium, chromium, metal, and semi-metal wetting layers.

[0149] Next, a specific example of manufacturing a microstructure with electrodes using multiple coatings will be described with reference to FIG. 5 and FIGS. 6A to 6E.

[0150] In this example, a patch is provided that includes a substrate 611 and a moldable material layer 612 having microstructures 613 imprinted thereon. It will be understood that this is similar to the patch of FIG. 3D and may be fabricated using steps 200-230 described above, plus optional steps such as priming and / or mold coating with an anti-stiction material. The patch including the microstructures 613 is optionally first pretreated by optionally coating with a primer 614, e.g., in step 500, for example, by spraying the patch with a primer solution, and / or by using a plasma pretreatment for surface cleaning and activation. Other treatments, such as treating the surface with ozone, may also be performed.

[0151] In step 510, a conductive coating 615 is applied to the microstructures 613 and moldable material layer 612, for example using a sputter coating of gold or other similar conductive material. At this stage, the entire top surface of the patch, including all of the microstructures, is conductive. However, it is usually necessary to isolate some of the microstructures, for example to isolate rows of microstructures or to isolate individual microstructures so that they can be used independently. Thus, in this example, laser ablation is used in step 520 to create openings 616 in the conductive coating, thereby electrically isolating adjacent microstructures and / or rows of microstructures.

[0152] Following this, in step 530, a dielectric coating 617 is applied to insulate the surface of the conductive coating 615. In step 540, the dielectric coating 617 is optionally selectively removed, for example using ablation or etching, in which case material in the tip region is removed to expose the conductive coating in the tip region of the microstructure, which can function as an electrode. However, it will be appreciated that this may not be required and the dielectric coating could be kept in place, for example if the microstructure is to be used for capacitive sensing.

[0153] In step 550, a functionalization coating, such as an aptamer or molecularly imprinted polymer coating, can optionally be applied using inkjet printing, dip coating, spray coating, etc. depending on the intended use of the device. Portions of the functionalization coating can also optionally be removed in step 560, e.g., by removing the functionalization coating from the substrate or from portions of the microstructure, e.g., so that only the tip or other portions of the microstructure are functionalized.

[0154] An example of this will now be described with reference to Figures 7A-7D, although it will be appreciated that dielectric material may be removed at other locations.

[0155] In this example, the substrate 711 and conductive microstructure 713 are coated with a dielectric material 717. In the example of Figure 7B, the dielectric material 717, such as parylene, is removed from the top half of the microstructure, leaving approximately 100 μm on the microstructure base insulated. In the example of Figure 7C, a small section of the dielectric material 717 on the microstructure tip is removed to create an open window 717.1 on the sloped top surface of the microstructure, while in Figure 7D, the dielectric material is removed over the entire extent of the microstructure, leaving the substrate coating intact.

[0156] An example of a microstructure before and after etching of the dielectric coating is shown in Figures 7E-7G. In this example, the coated microstructure is shown in Figure 7E, and the etched microstructure, with the dielectric coating removed from the tip face, is shown in Figure 7F. In this case, a false color image highlighting the exposed conductive material on the tip face is shown in Figure 7G.

[0157] An alternative technique for removing material will now be described with reference to Figures 8A and 8B.

[0158] In this example, a patch including a substrate 811 having conductive microstructures 813, a moldable material layer 812, and an overlying dielectric layer (not shown) has a mask layer 851, such as a foil, plastic, polymer, or other similar material, applied using a roller 852. In one example, the roller 852 is deformable so that the microstructures deform the roller and penetrate the mask layer, or the roller has holes that align with the microstructures. In either case, the mask layer covers only the upper surface of the substrate, and optionally the underside of the microstructures, so that etching can be used to remove the dielectric layer near the tips of the microstructures, thereby exposing the conductive surface in the tip regions, as shown in FIG. 8B.

[0159] While the example shown in Figure 8A is an example of a roll-to-plate process, roll-to-roll or plate-to-plate are also possible, and Figure 8C shows an example of a plate-to-plate foil applicator aligned using a microscope with a substrate masked with a piece of foil (described in more detail below). As shown in Figures 8D and 8E, the microstructures on the substrate are aligned with a matching array of grooves in a piece of silicon, and then a piece of aluminum foil is lowered into the grooves to mask the base of the substrate, leaving only the blade tip exposed to subsequent plasma treatment.

[0160] 8A-8E may not be necessary if material can be selectively removed using laser ablation or other similar approaches. In particular, a mask may only be needed to protect the base of the microstructure and substrate if material cannot otherwise be selectively removed, for example, if laser ablation is too slow or does not have sufficient resolution.

[0161] It will be appreciated that different etches can be used to remove different materials. For example, parylene is known to be a difficult material to remove. Oxygen plasma is the only dry etching method for removing parylene, and in this case, the lateral and vertical etch rates can be controlled by varying various process parameters, such as pressure, flow rate, and DC bias, as described, for example, in the article by Ellis Meng, Po-Ying Li, and Yu-Chong Tai, "Plasma removal of Parylene C," Journal of Micromechanics and Microengineering, 18 (2008), 045004 (13 pp.). This allows for anisotropic etching, thereby providing a higher degree of material removal.

[0162] Other methods exist, such as mechanical removal through micro-ablation and chemical softening of the coating using the organic solvent tetrahydrofuran, which allows the layer to be subsequently peeled off. Alternatively, laser ablation can be used to selectively remove parylene on a microscale.

[0163] 8F-8L are images of example microstructures that have been etched to remove parylene.

[0164] The examples in Figures 8F, 8G, and 8J show complete parylene removal from only the beveled tip. Figures 8H, 8I, 8K, and 8L show microstructures where the sidewalls have also been etched / cleared. In the case of image 8I, the aluminum masking foil was further up the needle, resulting in less of the needle tip being etched.

[0165] Conversely, gold can be dry etched using different gases, such as Cl2 or a mixture of CF4 and CCl4. Ion milling is another good dry etching option.

[0166] As mentioned above, in one example, the method can include providing electrical connections in electrical contact with at least some of the conductive microstructures. This can be used to apply signals to or measure signals from the microstructures. The electrical connections can be provided in a variety of ways depending on the preferred embodiment, and can include vias extending through the substrate and / or surface contacts on a surface of the substrate and / or on a surface of the moldable material layer.

[0167] Next, this example will be described with reference to FIGS. 9A to 9D.

[0168] In the example of FIG. 9A , a patch is provided that includes a substrate 911, a moldable material layer 912, and an imprinted microstructure 913. While openings 916 are provided to isolate the microstructures as described above, vias 918 extend through the substrate 911 in alignment with the openings 916, allowing electrical connections to be made to the microstructures 913 using a conductive layer applied to the microstructures and extending to the vias 918. This provision allows electrical connections to be provided on the backside of the substrate, so they are easy to make and do not interfere with insertion of the microstructures into the target. Furthermore, by using a conductive coating to form the electrical connections to the vias, the vias can be offset from the microstructures, thus eliminating the need for precise alignment of the microstructures and vias. Depending on the preferred embodiment, the microstructures can be formed on a substrate with pre-formed vias, or alternatively, the vias can be formed after the microstructures.

[0169] In the example of Figure 9B, a patch is provided that includes a substrate 911, a moldable material layer 912, and an imprinted microstructure 913. An opening 916 is provided to isolate the microstructure as described above, while a via 918 extends through the substrate 911 in registration with the underside of the microstructure 913. In this case, assuming the moldable material layer and the microstructure are conductive, this allows an electrical connection to be made to the underside of the moldable material layer. Again, this allows an electrical connection to be provided on the backside of the substrate. Additionally, if the moldable material is conductive, this avoids the need to use an additional conductive coating to form the electrical connection between the via and the microstructure.

[0170] 9C, a patch is provided that includes a substrate 911, a moldable material layer 912, and an imprinted microstructure 913 provided on a mesa 913.1. Electrical connections 919 are made on the moldable material layer 912, and the mesa 913.1 supports the microstructure 913 such that the base of the microstructure is elevated above the height of the electrical connections, thereby preventing the electrical connections from interfering with penetration of the microstructure into the target. The mesa also spaces the microstructure from the substrate, which may further help ensure penetration of the microstructure into the target.

[0171] In the example of Figure 9D, a patch is provided that includes a flexible and / or curved substrate 911, a formable material layer 912, and imprinted microstructures 913. Electrical connections 919 are made on the formable material layer 912, and bending or curving of the substrate ensures that the base of the microstructures is raised above the height of the electrical connections, thereby preventing the electrical connections from interfering with the penetration of the microstructures into the object.

[0172] In one example, the method can further include creating microfluidic channels in the substrate and / or the moldable material layer. The microfluidic channels can be used to aid in the removal of surface moisture, such as sweat, that may accumulate between the upper surface of the patch and the subject's skin. In this case, the channels can be provided on the upper surface of the substrate, for example, before applying the moldable material layer, with the moldable material layer near the channels subsequently removed by ablation, etching, or the like. Alternatively, the channels can be created directly in the moldable material layer using ablation or etching, or by creating the channels in the same imprinting step used to create the microstructures. In one example, the channels are formed by cutouts in the conductive coating and are used to electrically isolate various microstructures, allowing the cutouts to serve a dual purpose.

[0173] Similarly, openings can be provided in the substrate to allow fluid to flow to the backside of the substrate. In one example, the openings are offset from the microstructures to allow surface moisture, such as sweat, to be removed to the backside of the patch. Alternatively, the openings can be aligned with channeled microstructures to allow sampling of fluids, for example, from within a subject. In this latter example, the openings in the substrate can be pre-formed, and a suitable imprint mold is used to create hollow microneedles. Alternatively, this can be achieved by ablation of the microstructures and substrate after imprinting.

[0174] The hollow microstructures can also be used, optionally in conjunction with appropriate microfluidic technology, to allow fluid extraction from the subject, allowing the use of external detection mechanisms. For example, ISF can be extracted via hollow microneedles and subjected to testing and / or detection behind the patch and / or external to the patch. This can have certain advantages, such as allowing the ISF to be exposed to substances that would be dangerous or harmful within the subject. Creation of such hollow openings can be achieved in a variety of ways, including using an appropriate imprinting process, or during post-processing using, for example, laser ablation, microdrilling, appropriate etching techniques, etc.

[0175] In one example, the method includes creating pores in at least some of the microstructures. Creating porous microstructures can increase the effective surface area of ​​the microstructures, which can be used to help capture analytes and / or increase the effective surface area of ​​electrodes formed on the microstructures. The pores can be of any suitable size that allows the analyte of interest to enter the pores while excluding one or more other analytes or substances, and thus depends on the size of the analytes of interest. In some embodiments, the pores can be less than about 10 μm in diameter, preferably less than about 1 μm in diameter. Pores are typically created by providing additives in the moldable material that dissolve or are released after the microstructures are formed, although it will be appreciated that other techniques can be used, such as exposing the moldable material to heat or radiation to induce bubble formation and further cause porosity when the moldable material hardens.

[0176] The microstructures may have a variety of shapes, including ridges, needles, plates, blades, etc. In this regard, the terms plate and blade are used interchangeably to refer to microstructures whose width is on the same order of magnitude as their length but are significantly thinner. The microstructures may be tapered to facilitate insertion into a subject and may have different cross-sectional shapes, for example, depending on the intended use. The microstructures typically have a rounded rectangular shape and may include shape variations along the length of the microstructure. For example, the microstructures may include a shoulder configured to abut the stratum corneum to control the depth of penetration, and / or a shaft extending to a tip configured to control the position of the tip within the subject and / or provide a surface for an electrode.

[0177] Examples of other shapes include circles, rectangles, cross shapes, squares, rounded squares, rounded rectangles, ovals, etc., which can allow for increased surface area, which is useful in coating microstructures to maximize the coating volume and therefore the amount of payload delivered per microstructure, although it will be understood that various other shapes can also be used. The microstructures can have rough or smooth surfaces or can include surface features such as pores, ridges, or serrations that can increase the surface area and / or help penetrate or engage tissue, thereby anchoring the microstructure within a subject. This can also help reduce biofouling, for example, by preventing biofilm adhesion and therefore accumulation. The microstructures can also be hollow or porous and can include internal structures such as holes, in which case the cross-sectional shape can also be at least partially hollow. In certain embodiments, the microstructures are porous, which can increase the effective surface area of ​​the microstructure. The pores may be of any suitable size that allows the analyte of interest to enter the pore while excluding one or more other analytes or substances, and thus depends on the size of the analyte of interest, hi some embodiments, the pores may be less than about 10 μm in diameter, and preferably less than about 1 μm in diameter.

[0178] In one example, the microstructure has a rounded rectangular shape when viewed in cross section through a plane extending laterally through the microstructure and parallel to but offset from the substrate. The microstructure may include a shape variation along the length of the microstructure. For example, the microstructure may include a shoulder configured to abut the stratum corneum to control the depth of penetration, and / or a shaft extending to a tip configured to control the position of the tip within the subject and / or provide a surface for an electrode.

[0179] Different microstructures can also be provided on a common substrate, e.g., differently shaped microstructures can be provided to achieve different functions. In one example, this can include performing different types of measurements. In another example, microstructures can be provided on different substrates, e.g., sensing can be performed via microstructures on one patch and therapy delivery via microstructures on a different patch. In this example, this allows therapy patches to be replaced when depleted, while the sensing patch can remain in situ. Additionally, measurements can be made between patches, e.g., impedance measurements of the whole body or a body segment, such as a limb or body part, can be performed between patches provided at different locations on a subject.

[0180] Additionally and / or alternatively, anchor microstructures may be provided that can be used to anchor the substrate to a subject. In this regard, the anchor microstructures will typically be longer in length than the microstructures, which may help hold the substrate in place on the subject and ensure that the substrate does not move or is inadvertently removed during measurement. The anchor microstructures may include anchoring structures, such as raised portions, that can aid in tissue engagement, which may be formed by the shape of the microstructure and / or the shape of the coating. Additionally, the coating may include a hydrogel or other similar material that expands upon exposure to moisture within the subject, thereby further facilitating engagement with the subject. Similarly, the microstructures may undergo a shape change, such as swelling, in response to exposure to substances such as water or moisture within the subject or in response to an applied stimulus. The anchor microstructures may penetrate the dermis when applied to the skin and thus be longer than the other microstructures, helping to hold the substrate in place, although it will be understood that this is not required and depends on the preferred embodiment. In other examples, the anchor microstructures may be rougher than the other microstructures, have more surface friction than the other microstructures, be duller than the other microstructures, or be thicker than the other microstructures.

[0181] In a further example, at least a portion of the substrate can be coated with an adhesive coating to allow the substrate, and therefore the patch, to adhere to a subject.

[0182] As mentioned above, when applied to skin, the microstructures typically penetrate the viable epidermis, and in one example, they do not penetrate the dermis, but in other examples, they may penetrate the dermis. However, this is not required, and in some applications, it may be necessary for the microstructures to penetrate the dermis, for example, to protrude briefly through the viable epidermis / dermis boundary, or to penetrate a significant distance into the dermis, depending primarily on the nature of the sensing being performed. In one example, for skin, the microstructures have a length that is at least one of less than 2500 μm, less than 1000 μm, less than 750 μm, less than 600 μm, less than 500 μm, less than 400 μm, less than 300 μm, less than 250 μm, more than 100 μm, more than 50 μm, and more than 10 μm, although it will be understood that other lengths may also be used. More generally, when applied to a functional barrier, the microstructure typically has a length greater than the thickness of the functional barrier, at least 10% greater than the thickness of the functional barrier, at least 20% greater than the thickness of the functional barrier, at least 50% greater than the thickness of the functional barrier, at least 75% greater than the thickness of the functional barrier, and at least 100% greater than the thickness of the functional barrier.

[0183] In another example, the microstructure has a length that is 2000% greater than the thickness of the functional barrier, 1000% greater than the thickness of the functional barrier, 500% greater than the thickness of the functional barrier, 100% greater than the thickness of the functional barrier, 75% greater than the thickness of the functional barrier, or 50% greater than the thickness of the functional barrier. This avoids deep penetration of potentially undesirable underlying layers within the body, and it will be understood that the length of the microstructure used will vary depending on the intended use and, in particular, the nature of the barrier to be breached and / or the signal to be applied or measured. The length of the microstructure may also be non-uniform, for example, a blade may be taller at one end than the other, thereby facilitating penetration of the target or functional barrier.

[0184] Similarly, the microstructures can have different widths depending on the preferred embodiment. Typically, the width is at least one of less than 25% of the length, less than 20% of the length, less than 15% of the length, less than 10% of the length, or less than 5% of the length. Thus, for example, the microstructures can have a width of less than 50 μm, less than 40 μm, less than 30 μm, less than 20 μm, or less than 10 μm when applied to the skin. However, the microstructures can alternatively comprise blades and be wider than their length. In some examples, the microstructures can have widths of less than 50,000 μm, less than 40,000 μm, less than 30,000 μm, less than 20,000 μm, less than 10,000 μm, less than 5,000 μm, less than 2,500 μm, less than 1,000 μm, less than 500 μm, or less than 100 μm. In the example of a blade, it is also possible to use microstructures with widths substantially up to the width of the substrate.

[0185] Generally, the thickness of the microstructure is fairly small to facilitate penetration, typically less than 1000 μm, less than 500 μm, less than 200 μm, less than 100 μm, less than 50 μm, less than 20 μm, less than 10 μm, at least 1 μm, at least 0.5 μm, or at least 0.1 μm. Generally, the thickness of the microstructure is dictated by mechanical requirements, particularly the need to ensure that the microstructure does not break, fracture, or deform upon penetration. However, this problem can be mitigated by the use of coatings that add additional mechanical strength to the microstructure.

[0186] In one specific example, for epidermal detection, the microstructures have lengths of less than 300 μm, more than 50 μm, more than 100 μm, and about 150 μm, and widths greater than or equal to the length of the microstructures, typically less than 300 μm, more than 50 μm, and about 150 μm. In another example, for dermal detection, the microstructures have lengths of less than 450 μm, more than 100 μm, and about 250 μm, and widths greater than or equal to the length of the microstructures, typically less than 450 μm, more than 100 μm, and about 250 μm, and widths greater than or equal to the length of the microstructures, and at least similar in magnitude to the length. In other examples, longer microstructures can be used, so that, for example, for hyperdermal detection, the length of the microstructures will be longer. The microstructures typically have thicknesses that are less than, significantly less than, or on the order of magnitude smaller than the width. In one example, the thickness is less than 50 μm, more than 10 μm, and about 25 μm, although the microstructures typically include an extended base for additional strength, thus comprising a base thickness proximate to the substrate that is about three times the thickness, typically less than 150 μm, more than 30 μm, and about 75 μm. The microstructures typically have a tip that is less than 50% of the length of the microstructure, at least 10% of the length of the microstructure, and more typically about 30% of the length of the microstructure. The tip further has a sharpness of at least 0.01 μm, at least 0.05 μm, at least 0.1 μm, less than 5 μm, and typically about 1 μm.

[0187] In one example, the microstructure is 1000 / cm 2 Less than 500 / cm 2 Less than 100 / cm 2 Less than 10 / cm 2 Less than or even 5 / cm 2 Less than 10000 / cm 2 The density is relatively low, such as less than 50,000 / cm. The use of a relatively low density facilitates penetration of the microstructures through the stratum corneum, particularly avoiding problems associated with skin penetration with high density arrays, which may require higher power actuators to properly apply the array. However, this is not required, and the density may be less than 50,000 / cm. 2 Fine structures less than 30,000 / cm 2Higher density microstructure arrangements can also be used, including microstructures of less than 100 μm. As a result, the microstructures typically have spacings of less than 20 mm, less than 10 mm, less than 1 mm, less than 0.1 mm, or less than 10 μm. It should be noted that in some circumstances, the microstructures are provided in pairs, with the microstructures in each pair having small spacings, such as less than 10 μm, while the pairs have larger spacings, such as greater than 1 mm, to ensure that a low overall density is maintained. However, it will be understood that this is not required, and higher densities may be used in some circumstances.

[0188] In one embodiment, the microstructures may have a density of 5000 / cm depending on the intended application. 2 Less than 100 / cm 2 Over 25-50 / cm 2 or approximately 600 / cm 2 This results in spacings of less than 1 mm, greater than 10 μm, and about 0.5 mm, 0.2 mm, or 0.1 mm.

[0189] In one example, the microstructure comprises a plate having a substantially planar surface with an electrode thereon. The use of a plate shape maximizes the surface area of ​​the electrode while minimizing the cross-sectional area of ​​the microstructure, thereby aiding in the penetration of the microstructure into a target. This also allows the electrode to act as a capacitive plate, enabling capacitive sensing. In one example, the electrode is at least 10 mm 2 , at least 1 mm 2 , at least 100,000 μm 2 , 10,000 μm 2 , at least 7,500 μm 2 , at least 5,000 μm 2 , at least 2,000 μm 2 , at least 1,000 μm 2 , at least 500 μm 2 , at least 100 μm 2 , or at least 10 μm 2In one example, the electrode has a width or height of at most 2500 μm, at least 500 μm, at least 200 μm, at least 100 μm, at least 75 μm, at least 50 μm, at least 20 μm, at least 10 μm, or at least 1 μm. In the case of electrodes provided on a blade, the width of the electrode can be less than 50,000 μm, less than 40,000 μm, less than 30,000 μm, less than 20,000 μm, less than 10,000 μm, or less than 1,000 μm, including the widths outlined above. In this regard, it should be noted that these dimensions apply to individual electrodes, and that in some instances each microstructure may include multiple electrodes.

[0190] In one embodiment, the surface area of ​​the electrodes is less than 0.2 mm, depending on the configuration. 2 Less than 0.01mm 2 , and approximately 0.13 mm 2 , 0.07mm 2 , and 0.02 mm 2 The electrode extends the length of the distal portion of the microstructure, optionally spaced from the tip, and optionally positioned proximate the distal end of the microstructure, as well as proximate the tip of the microstructure. The electrode may extend over at least 25% and less than 50% of the length of the microstructure, so that the electrode typically extends over about 60 μm, 90 μm, or 150 μm of the microstructure and is therefore positioned within the living epidermis and / or dermis of a subject during use.

[0191] In one example, at least some of the microstructures are arranged in groups, such as pairs, and a response signal or stimulus is measured from or applied to the microstructures within the group. The microstructures within a group can have a specific configuration that enables a particular measurement to be made. For example, when arranged in pairs, the separation distance can be used to affect the nature of the measurement made. For example, when making bioimpedance measurements, if the separation between the microstructures is greater than a few millimeters, this tends to measure the properties of the interstitial fluid located between the electrodes, while decreasing the distance between the microstructures makes the measurement more influenced by surface properties, such as the presence of material bound to the surface of the microstructures. The measurement is also affected by the nature of the applied stimulus; for example, low-frequency currents tend to flow through extracellular fluid, while higher-frequency currents are more influenced by intracellular fluid.

[0192] In one particular example, plate microstructures are provided in pairs, each pair including spaced apart plate microstructures that define opposing, substantially planar electrodes. This can be used to generate a highly uniform field in a subject in the region between the electrodes and / or for capacitive or conductive sensing of materials between the electrodes. This effect can be further enhanced by providing an array of microstructures, with the microstructures in the array electrically connected so that measurements can be made between the array of microstructures, thereby increasing the effective electrode surface area. However, this is not required, and other configurations, such as circumferentially spaced electrodes around a central electrode, can be used. Typically, the spacing between electrodes within each group is less than 50 mm, less than 20 mm, less than 10 mm, less than 1 mm, less than 0.1 mm, or less than 10 μm, although it will be appreciated that larger spacings, including spacings up to and / or greater than the dimensions of the substrates, can also be used when the microstructures are distributed across multiple substrates.

[0193] Thus, in one embodiment, at least some of the microstructures are arranged in pairs or arrays, and response signals are measured between the microstructures in the pairs or arrays, and / or stimuli are applied between the microstructures in the pairs or arrays. Each microstructure pair typically includes spaced apart plate microstructures having opposing substantially planar electrodes and / or spaced apart substantially parallel plate microstructures.

[0194] In one example, at least some pairs of microstructures are angularly offset, and in one particular example, orthogonal. Thus, in the case of plate microstructures, at least some pairs of microstructures extend in different, optionally orthogonal, directions. This also serves to reduce lateral slippage of the patch by distributing stresses associated with patch insertion in different directions and ensuring that the plates at least partially face the direction of any lateral force. Reducing slippage during or after insertion can help reduce discomfort, erythema, etc., and can help make the patch more comfortable to wear over long periods of time. Additionally, this can help account for any electrical anisotropy in the tissue, for example, as a result of fibrin structure in the skin, cellular anisotropy, etc.

[0195] In one embodiment, pairs of adjacent microstructures are angularly offset and / or orthogonally arranged, and additionally and / or alternatively, pairs of microstructures can be arranged in rows, with pairs of microstructures in one row being orthogonal or angularly offset relative to pairs of microstructures in another row.

[0196] In one specific example, when pairs of microstructures are used, the spacing between the microstructures within each pair is typically less than 0.25 mm, greater than 10 μm, and about 0.1 mm, while the spacing between groups of microstructures is typically less than 1 mm, greater than 0.2 mm, and about 0.5 mm. Such arrangements help ensure that electrical signals are applied and measured primarily within pairs, reducing crosstalk between pairs and allowing independent measurements to be recorded for each microstructure / electrode pair.

[0197] To create an array of electrode pairs, this can be done by fabricating a first substrate having first microstructures and corresponding first apertures. Next, an insulating layer is provided on the side of the first substrate opposite the first microstructures, after which a second substrate is provided on the insulating layer. In this example, the second substrate has second microstructures that extend through the insulating layer and the first apertures to form pairs of first and second microstructures, an example of which is described in more detail below. In one example, the first and second apertures are offset to reduce capacitive coupling between the first and second substrates. Alternatively, other mechanisms for capacitive coupling between the substrates can be used.

[0198] The microstructures can be configured to interact with, and in particular bind to, one or more analytes of interest, allowing them to be detected. In particular, in one example, binding of one or more analytes to the microstructure can alter the charge transport capability, resulting in a change in the capacitance of the electrode pair, which can then be monitored to derive the level or concentration of the analyte. Binding of the analyte can be achieved using a variety of techniques, including mechanical properties of the microstructure, such as the presence of pores or other physical structures, the selection of materials from which the microstructure is fabricated, the use of coatings, or otherwise affecting the properties of the microstructure, such as the use of magnetic microstructures.

[0199] Additionally, the microstructures and / or substrates can incorporate one or more materials or other additives, either within the body of the microstructure or through the addition of a coating containing the additive. The nature of the material or additive varies depending on the preferred embodiment and may include bioactive materials, reagents for reacting with analytes in a subject, binders for binding to analytes of interest, materials for binding one or more analytes of interest, probes for selectively targeting analytes of interest, materials for reducing biofouling, materials for attracting at least one substance to the microstructure, materials for repelling or excluding at least one substance from the microstructure, materials for attracting at least some analytes to the microstructure, or materials for repelling or excluding analytes. In this regard, materials may include any one or more of cells, fluids, analytes, etc. Examples of materials include polyethylene, polyethylene glycol, polyethylene oxide, zwitterions, peptides, hydrogels, and self-assembled monolayers.

[0200] The material may be contained within the microstructure itself, for example, by impregnating the microstructure during fabrication, for example, by introducing the material into an imprint mold so that the material is applied to the microstructure surface during the molding process. Additionally and / or alternatively, the material may be incorporated into the moldable material prior to molding or may be provided in a coating.

[0201] It will therefore be appreciated that at least some of the microstructures may include materials for binding one or more analytes of interest, which may be used to target particular analytes of interest, allowing these analytes to bind or otherwise attach to the microstructures, so that these analytes can then be detected in situ using an appropriate detection mechanism, such as by detecting a change in optical or electrical properties.

[0202] The analyte can be any compound that can be detected in the epidermis and / or dermis. In certain embodiments, the analyte is a marker of a condition, disease, disorder, or normal or pathological process occurring in a subject, or a compound that can be used to monitor the level of an administered substance in a subject, such as a drug (e.g., a medication, a vaccine), an illicit substance (e.g., an illegal drug), a non-illicit substance of abuse (e.g., alcohol or a prescription drug taken for non-medical reasons), a poison or toxin, a chemical weapon (e.g., a nerve agent, etc.) or a metabolite thereof. Suitable analytes include: Nucleic acids, including DNA and RNA, including short RNA species, including microRNA, siRNA, snRNA, shRNA, etc. antibodies, or antigen-binding fragments thereof, allergens, antigens or adjuvants, chemokines or cytokines, ·hormone, Parasites, bacteria, viruses, or virus-like particles, or compounds therefrom, such as surface proteins, endotoxins, etc. epigenetic markers such as DNA methylation status or chromatin modifications of specific genes / regions, ·peptide, Polysaccharides (glycans), Polypeptides, Protein, and ·Small molecules These include, but are not limited to:

[0203] In certain embodiments, the analyte of interest is selected from the group consisting of nucleic acids, antibodies, peptides, polypeptides, proteins and small molecules, particularly polypeptides and proteins, especially proteins.

[0204] In a further example, one or more of the microstructures contain a treatment material and at least one treatment delivery mechanism is provided that controls the release of the treatment material, hi one preferred example, the release of the treatment material is controlled by applying a stimulus to the microstructure(s), for example, by applying light, heat, or an electrical stimulus to release the treatment material.

[0205] In one preferred example, the treatment material is contained in a coating on at least one microstructure, and a stimulus is used to dissolve the coating on the microstructure, thereby delivering the treatment material. It will be appreciated that this technique is applicable to any treatment material that can be incorporated into a coating and selectively released using a stimulus, such as a mechanical, magnetic, thermal, electrical, electromagnetic, or optical stimulus.

[0206] The nature of the treatment material will vary depending on the preferred embodiment and / or the nature of the treatment being performed, including whether the treatment is cosmetic or therapeutic. Examples of treatment materials include, but are not limited to, nanoparticles, nucleic acids, antigens or allergens, parasites, bacteria, viruses, or virus-like particles, metals or metal compounds, molecules, elements or compounds, DNA, proteins, RNA, siRNA, sfRNA, iRNA, synthetic biomaterials, polymers, drugs, etc.

[0207] However, it will be appreciated that the use of a coating is not required, and that the treatment material may additionally and / or alternatively be incorporated into the microstructure itself.

[0208] Regardless of how the treatment material is provided, the substrate can include multiple microstructures, with different microstructures having different treatment materials and / or different treatment dosages. In this case, a processing device can control the therapy delivery mechanism to release the treatment material from selected microstructures, thereby enabling different treatments and / or differential dosing depending on the results of measurements made on the subject. In particular, as described in more detail below, the processing device typically performs an analysis using, at least in part, the measured response signal and controls at least one therapy delivery mechanism using the results of the analysis, thereby enabling personalized treatments to be performed substantially in real time.

[0209] Specific examples of plate microstructures are shown in Figures 10A-10D.

[0210] In this example, the microstructures are plates having a body 1013.1 extending from a substrate 1011 and a tip 1013.2 that is tapered to facilitate penetration of the microstructures 1013 into the stratum corneum. As shown in Figures 10C and 10D, although different setups can be used, typically pairs of microstructures are formed such that the microstructures face each other to apply or measure signals between the microstructures. Different separations between the electrodes within an electrode pair can be used to make different measurements and / or change the profile of stimulation of the tissue between the electrodes.

[0211] 10C, pairs of microstructures are provided in rows, with electrical connections 1014 extending to each microstructure in the row. It will be appreciated that in practice this may be achieved by ensuring that the microstructures in each row are electrically connected, with openings being provided between the rows to electrically isolate the rows.

[0212] A further example of an implementation is shown in FIG. 10E, where the microstructures 1013 are arranged in pairs 1013.3, and the pairs are arranged in offset rows 1013.4, 1013.5. In this example, the pairs in different rows are arranged orthogonally, so that the microstructures extend in different directions. This aligns all of the microstructures, further avoiding potential vulnerability of the patch to lateral slippage in the direction aligned with the microstructures. Additionally, orthogonal pairing reduces interference, such as crosstalk, between different electrode pairs, improving measurement accuracy and accounting for tissue anisotropy, especially when performing simultaneous measurements via multiple microstructure pairs.

[0213] In one example, each row of microstructure pairs can be provided with respective connections 1014.41, 1014.42; 1014.51, 1014.52 to allow an entire row of microstructure pairs to be interrogated and / or stimulated simultaneously while allowing different rows to be interrogated and / or stimulated independently.

[0214] A scanning electron microscopy (SEM) image showing an array of offset plate microstructure pairs is shown in Figure 10F.

[0215] Examples of microstructures for making measurements in the epidermis are shown in Figures 10G and 10H.

[0216] In this example, the microstructure is a plate or blade having a body 1013.1 with an flared base 1013.11 where the body joins with the substrate to enhance the strength of the microstructure. The body narrows at a waist 1013.12 to define a shoulder 1013.13, which in this example extends via a non-tapered shaft 1013.14 to a tapered tip 1013.2. Typical dimensions are shown in Table 2 below.

[0217] [Table 1]

[0218] An example of a pair of microstructures upon insertion into a subject is shown in Figure 10I.

[0219] In this example, the microstructure is configured so that the tip 1013.2 penetrates the stratum corneum SC and enters the viable epidermis VE. The waist 1013.12, and particularly the shoulder 1013.13, abuts the stratum corneum SC, preventing the microstructure from penetrating further into the subject and preventing the tip from entering the dermis. This helps to avoid contact with nerves that could lead to pain.

[0220] In this configuration, the body 1013.1 of the microstructure can be covered with a layer of insulating material (not shown) with only the tip exposed. As a result, a current signal applied across the microstructure generates an electric field E within the subject, particularly within the living epidermis VE, and the resulting measurements reflect the fluid level within the living epidermis VE.

[0221] However, it will be appreciated that other configurations can be used, for example, in the setup of Figure 10J, the shaft 1013.14 is extended so that the tip 1013.2 enters the dermis, allowing measurements to be taken of the dermis (and optionally the epidermis).

[0222] In this example, typical dimensions are shown in Table 3 below.

[0223] [Table 2]

[0224] Examples of inter-pair and intra-pair spacing for these configurations are shown in Table 4 below.

[0225] [Table 3]

[0226] As mentioned above, the molding process uses a mold with a cavity in the shape of the microstructure. To form the mold, a highly accurate and durable master is created, typically using silicon etching or a similar process, to create the master patch.

[0227] Images of further example microstructures fabricated using the techniques described above are shown in Figures 10K and 10L.

[0228] An example sequence of steps for etching a master microstructure for mesa implementation of FIG. 9C will now be described with reference to FIGS. 11A-11D.

[0229] First, the silicon is etched to create the mesa slope 1113.1 as shown in Figure 11A, and the needle tip profile 1113.2 is etched as shown in Figure 11B. Next, the mesa is cleared as shown in Figure 11C, and then the top of the mesa is removed to create the microstructure body 1113.1 as shown in Figure 11D.

[0230] While the above examples focus on the use of a substantially planar substrate, this is not required; pre-patterned substrates with surface reliefs or features can be used. An example of this is shown in FIGS. 12A and 12B, as well as FIGS. 12C and 12D, where substrate 1211 is pre-patterned with mesas 1211.1. In this example, moldable material 1212 is applied to the top of the mesas, and mold 1214 is used to create microstructures 1213. This example therefore provides an alternative method for fabricating microstructures that combines the fabrication of a support substrate with a mesa platform and the imprinting of moldable material selectively deposited on the mesa blocks. This approach allows for inexpensive, mass-produced production of patches, making the resulting devices readily available. This further enables patches to be produced in low-volume or high-volume production runs, since imprinting occurs only in areas where moldable material is present.

[0231] In one example, injection molding of mesa blocks requires micro-inserts with the opposite polarity of the mesa to be manufactured. Typically, the micro-inserts are made of stainless steel, nickel, or metal alloys. This manufacturing method allows thousands of mesa block shots to be produced in a short period of time, such as within a few hours.

[0232] Selective placement of moldable material 1212 can be done using an automated dispenser, inkjet coating, guided by preset geometric values ​​to precisely coat selective areas as needed. A suitable coating material or primer can be applied onto the mesa block to ensure good adhesion of the moldable material after imprinting.

[0233] Examples of injection molded polymers include cycloolefin polymers, polyvinyl chloride, polypropylene, polyethylene terephthalate, polymethylmethacrylate, high density polyethylene, low density polyethylene, acrylonitrile butadiene styrene, styrene, styrene acrylonitrile, polyamide, polyoxymethylene, and the like.

[0234] The imprint mold has features (vias) with opposite polarity that, when used to imprint a moldable material, result in microstructures such as blades. The advantage is that the mold can have features over its entire surface, but only produce microstructure imprints in areas where moldable material is selectively deposited onto the injection molded substrate with the mesa blocks. The mold design and imprint process can be tailored so that each mesa block has one microblade (one-to-one) or multiple blades (one-to-many).

[0235] It will be appreciated that a wide variety of different surface features may be incorporated into the substrate, including, but not limited to, vias, mesas, channels, and the like.

[0236] In another example, curing can be facilitated through the use of a shadow mask incorporated into the mold, an example of which is shown in Figures 12E and 12F.

[0237] In this example, a moldable material 1212 is applied to the pre-patterned substrate 1211 of Figure 12A to cover the mesa and surrounding substrate surface. The applied mold 1214 includes a mask 1214.1 aligned with the area around the mesa so that the moldable material in the mesa region can be exposed and cured, and the remaining moldable material can be removed as shown in Figure 12D. While this example is described using a pre-patterned substrate, it will be understood that this is not required and this approach can also be used with unpatterned substrates.

[0238] It should be noted that while the description and figures focus on fabricating plate or blade style microstructures, this is not required and a wide range of different shapes of microstructures can be fabricated using these techniques, including microneedles and other shapes, and further including microstructures containing channels to allow sampling of fluids from within a subject.

[0239] Additionally, complex microstructure geometries can be easily fabricated using these techniques. Examples of complex master projections fabricated using wafer slicing are shown in Figures 13A-13C, and corresponding microstructures fabricated using these approaches are shown in Figures 13D-13F.

[0240] Thus, throughout the above, it will be understood that the use of blade or plate type microstructures is for illustrative purposes only and is not intended to be limiting.

[0241] Using the above approach, further examples of polymer microstructures fabricated using, in particular, nanoimprint lithography are described.

[0242] In this example, a silicon master mold with predefined micro-projections was used to create an intermediate polymer stamp (IPS) that mirrored the surface topology of the master mold, which was then used to imprint into a resin to create micro-projections of similar geometry to the master mold.

[0243] A 1300 μm thick 6-inch Si mold (M1) was used to fabricate the master mold shown in Figures 14A and 14B. Together with the 450 μm mesas and 350 μm protrusions, the features reached a total height of approximately 800 μm. After dicing, 500 μm of undiced silicon remained. While thicker silicon was used, significant residual Si was left behind after the fine features were carved out of the dicing process. This ensured the sturdy bottom support required during the fabrication of the IPS, which was later used for imprinting. The top view of the substrate, shown in Figure 14A, shows that the mesas were approximately 550 μm x 550 μm in size, and the microneedles were approximately 80 μm x 80 μm, spaced 1 mm apart. The wafer was patterned with a 5 x 5 array of 5.5 mm x 5.5 mm microprotrusions.

[0244] During development of the imprinting process, it was found that the aspect ratio used in M1 was too high to produce any proper IPS. Therefore, the feature height was modified while maintaining the same feature morphology, as shown in Figure 14C. The overall height was reduced to approximately 320 μm (microneedles approximately 260 μm, mesas approximately 60 μm). Cubic mesas were fabricated instead of pyramidal ones, and due to the reduced feature height, thinner wafers (1 mm) were found to be sufficient for both masters. A new master mold (M2) with the same morphology was fabricated on a 10.6 cm × 10.6 cm square wafer with a 3 cm bleed area around the active area. The distance between microprojections and the chip size remained consistent with the first wafer. SEM images of the second master mold are shown in Figures 14D–14I.

[0245] M2 was then used to prepare an intermediate polymer stamp (IPS), typically made from a low-surface-energy polymer, typically including fluoropolymers. In one example, the IPS uses the FlexStamp from Morphotonics™. Other examples of IPS include polydimethylsiloxane (PDMS) from Dow Corning and the OrmoStamp from microresist technology. The IPS was then used to test imprints of various resins believed to enable the closest possible replication of Si features. Although the IPS was fabricated, the quality of the replication could only be confirmed by making an imprint. Resin MM1158 was used to make the imprints. This resin also exhibited good wetting behavior. The imprint conditions used were a speed of 50 mm / min and a pressure of 10 N / cm.

[0246] An optical microscope image of the resulting structure is shown in Figure 14J. The imprint showed several broken needles 1403 resulting from hardened resin that had become stuck in the IPS vias during demolding, and several broken needles 1402 resulting from trapped air bubbles resulting from capillary action. Several fully formed needles 1401 were also observed.

[0247] During process development, it was observed that changing the aspect ratio could enhance the filling of the resin into the IPS features. Using this as a basis, further optimization was performed, with better results obtained under the following conditions: a speed of 50 mm / min, 10 N / cm pressure during the first two laminations (no curing), and 7 N / cm pressure during the third lamination (curing step). This resulted in slightly taller polymer needles with fewer air bubbles / trapping. However, the needles still had broken features and incomplete filling, but the results were better than the first trial.

[0248] A thorough examination of the imprints was performed using SEM, and the resulting images are shown in Figures 14K–14N. As can be seen, the optimization process resulted in several good microfeatures over the correct area. The tips of the microstructures were slightly rounded, which could be due to improper filling caused by capillary action or air entrapment in the vias of the IPS features. The mesas were replicated almost perfectly. The microprojection shafts also showed good replication. Due to demolding, the sides of the imprinted features were rough, likely due to some amount of resin delaminating along with the IPS. The cause of some missing features could be either air filling the vias, preventing resin from filling, or contamination with resin (possibly broken needles) when the IPS was used several times. A slight variation of MM1158, which has an even lower surface free energy (SFE), appears favorable, but this needs further testing.

[0249] Several resins were tested during this investigation and are summarized in the table below.

[0250] [Table 4]

[0251] These results demonstrate the ability of imprinting techniques to produce usable microstructures.

[0252] Those skilled in the art will appreciate that numerous variations and modifications will become apparent, and all such variations and modifications that become apparent to those skilled in the art are to be considered within the spirit and scope as described by the invention as broadly outlined above.

Claims

1. 1. A method for manufacturing a patch for application to a biological subject, the method comprising: molding a moldable material to form a plurality of microstructures on a substrate, the microstructures being shaped to breach a functional barrier of the subject.

2. The method comprises: a) providing a substrate; b) depositing a layer of formable material onto the substrate; c) forming a plurality of microstructures in the moldable material layer, the microstructures being shaped to breach a functional barrier of the object; d) allowing the moldable material to solidify; The method of claim 1 , comprising:

3. The method comprises: a) hot embossing, and b) Imprint The method of claim 2 , further comprising forming the plurality of microstructures by one of:

4. The moldable material layer comprises: a) nanoimprint lithography; b) roll-to-plate lithography; c) roll-to-roll lithography; d) plate-to-plate lithography, and e) Plate-to-roll lithography The method according to claim 2 or 3, wherein the imprinting is performed using at least one of the following:

5. The method of claim 1 , wherein the method comprises micro-injection molding a plurality of microstructures shaped to breach a functional barrier of the object.

6. The moldable material comprises: a) a monomer, b) oligomers, c) a photoinitiator; d) crosslinking acrylate groups; e) curable sol-gels; f) epoxy; g) resin; h) polymers, i) a curable moldable material; j) UV curable moldable material; k) sealants; l) UV adhesive m) UV nanoimprint lithography polymers; n) Helioseal; o) urethane dimethacrylate, p) bisphenol A-glycidyl methacrylate, q) triethylene glycol dimethacrylate, r) NOA61, s) mercaptoester ＊ , t) triallyl isocyanurate, u) Inoflex RP+, v) PAK01, w) NIF2 (Asahi Glass Co., Ltd.), x) NIF1 (Asahi Glass Co., Ltd.), and y) Z Resist (t-butyl acrylate (96.5%), photoinitiator Irgacure 369 (3.5%)) The method according to any one of claims 1 to 5, comprising at least one of:

7. The method comprises: a) heat; b) electromagnetic radiation; c) visible electromagnetic radiation; d) ultraviolet electromagnetic radiation, and e) hardening of said material The method of claim 6, comprising solidifying the moldable material using at least one of:

8. The moldable material comprises: a) low viscosity; b) c) 10 －３ Between Pa·s and 1 Pa·s and d) Between 0.4 and 0.05 Pa·s At least one viscosity of 8. The method according to claim 6 or claim 7, comprising at least one of:

9. The hardened moldable material comprises: a) high mechanical strength, b) high resistivity, and c) High conductivity The method according to any one of claims 6 to 8, comprising at least one of:

10. The substrate is a) i) substantially rigid and ii) Flexibility One of them, b) polycarbonate; c) polymethacrylimide (PMI); d) polyethylene terephthalate (PET); e) polycarbonate (PC); f) poly(methyl methacrylate) (PMMA); g) stainless steel; h) metal; i) a polymer, and j) Silicon The method according to any one of claims 1 to 9, wherein the method is at least one of the following:

11. The method comprises: a) applying at least one coating to at least a portion of at least some of said microstructures; b) applying a primer before applying at least one coating; and c) applying a coating to the moldable material between at least some of said microstructures. The method according to any one of claims 1 to 10, comprising at least one of:

12. The coating is a) a conductive coating; b) a dielectric coating; c) mechanical coating; d) gold; e) Titanium f) titanium nitride; g) metal; h) ceramic, i) Parylene, j) poly(3,4-ethylenedioxythiophene), and k) Iridium oxide (IrO ２ ) The method of claim 11 , comprising at least one of:

13. The coating is a) at least 10 nm; b) at least 100 nm; c) at least 200 nm; d) at least 300 nm; e) at least 400 nm; f) at least 500 nm; g) Approximately 3 μm, h) less than 4 μm, and i) Less than 5 μm 13. The method according to claim 11 or claim 12, wherein the thickness is at least one of:

14. The method comprises: a) sputtering, b) electroplating; c) electroless plating; d) spin coating; e) thermal evaporation; f) vapor deposition; g) chemical vapor deposition; h) plasma-enhanced chemical vapor deposition, and i) Inkjet printing 14. The method of any one of claims 11 to 13, comprising applying a coating with at least one of:

15. At least some of the microstructures are conductive microstructures, and the method comprises: a) applying a conductive coating to at least some of the microstructures; and b) Using a conductive moldable material The method of any one of claims 1 to 14, comprising fabricating the conductive microstructure by at least one of:

16. The method of any one of claims 1 to 15, wherein the method comprises applying a dielectric coating to at least a portion of the conductive microstructure.

17. The method comprises: a) applying a dielectric coating over the conductive microstructure; b) removing at least a portion of the dielectric coating to expose a surface of the conductive microstructure; 17. The method of claim 16, comprising:

18. The microstructure comprises: a) a portion of the surface of the microstructure; b) the proximal end of the microstructure; c) at least half the length of the microstructure; d) approximately 90 μm of the proximal end of the microstructure; and e) at least a part of the tip portion of the microstructure 18. The method of claim 16 or claim 17, including a dielectric coating extending over at least one of:

19. At least some of the microstructures are a) extending the length of the distal portion of the microstructure; b) extending the length of a portion of the microstructure spaced from the tip; c) positioned proximate the distal end of the microstructure; d) positioned adjacent to the tip of the microstructure; e) extending over at least 25% of the length of the microstructure; f) extending over less than 50% of the length of the microstructure; g) extending across about 60 μm of said microstructure; and h) configured to be placed within the living epidermis of said subject in use.

19. The method of any one of claims 1 to 18, comprising at least one electrode that is at least one of:

20. The method comprises: a) removing material between said microstructures; b) selectively coating at least some of said microstructures; and c) removing electrically conductive material between the conductive microstructures to electrically isolate at least some of said microstructures; 20. The method of claim 1, further comprising one of the steps of: electrically isolating at least some of the microstructures by at least one of:

21. The method comprises: a) etching, b) laser ablation; c) plasma etching; d) chemical plasma etching; e) inductively coupled plasma etching; f) deep reactive ion etching; g) physical etching; h) oxygen plasma etching; i) reactive ion etching, and j) Imprint 21. The method of claim 20, comprising removing material using at least one of:

22. The method of any one of claims 1 to 21, wherein the moldable material comprises a lower layer adjacent to the substrate and an upper layer incorporating the microstructures.

23. The method of claim 22 , wherein the method includes removing material by imprinting the upper layer.

24. The method of any one of claims 1 to 23, wherein the method comprises providing electrical connections in electrical contact with at least some of the conductive microstructures.

25. The electrical connection portion is a) extending through a via in the substrate; b) provided on a surface of said substrate; and c) provided on the surface of said moldable material.

25. The method of claim 24, wherein the at least one of

26. 26. The method of claim 24 or claim 25, wherein the moldable material includes mesas from which the microstructures extend and electrical connections are provided between the mesas.

27. The method comprises: a) the substrate, and b) said moldable material 27. The method of any one of claims 1 to 26, comprising creating a microfluidic channel in the surface of at least one of:

28. The method of any one of claims 1 to 27, wherein the method comprises creating pores in at least some of the microstructures.

29. At least some of the microstructures are a) a blade; b) ridges; c) needles, and d) Plate The method according to any one of claims 1 to 28, wherein the method is at least one of

30. At least some of the microstructures are a) at least partially tapered; b) i) circular; ii) rectangular; iii) a cross; iv) square; v) rounded square; vi) rounded rectangle; vii) oval and viii) at least partially hollow and having a cross-sectional shape that is at least one of: c) i) at least partially smooth; ii) serrated; iii) comprises one or more pores; iv) comprises one or more raised portions; and v) rough having a surface that is at least one of d) at least partially hollow; e) is porous; and f) Includes internal structure The method according to any one of claims 1 to 29, wherein the method is at least one of

31. The microstructure comprises: a) plate microstructures; b) an at least partially tapered plate microstructure; c) a plate microstructure having a substantially rounded rectangular cross-sectional shape; d) spaced apart substantially parallel plate microstructures; e) an array of spaced apart microstructures; f) a pair of spaced apart microstructures; and g) Group of microstructures The method according to any one of claims 1 to 28, comprising at least one of:

32. a) at least some of the microstructures are angularly offset; b) at least some of the microstructures are orthogonally disposed; c) adjacent pairs of microstructures are disposed orthogonally; d) adjacent pairs of microstructures are angularly offset; e) the pairs of microstructures are arranged in rows, the pairs of microstructures in one row being arranged orthogonal to the pairs of microstructures in another row; and f) the pairs of microstructures are arranged in rows, the pairs of microstructures in one row being angularly offset relative to the pairs of microstructures in another row; 32. The method of claim 31 , wherein the at least one of

33. The microstructure comprises: a) less than 1 mm; b) Approximately 0.5mm, c) Approximately 0.2mm, d) about 0.1 mm, and e) More than 10 μm The method according to any one of claims 1 to 32, wherein the interval is at least one of:

34. At least some of the microstructures are a) i) less than 300 μm; ii) approximately 150 μm, iii) greater than 100 μm, and iv) More than 50μm a length that is at least one of b) i) greater than said length; ii) about the same length; iii) less than 300 μm; iv) about 150 μm, and v) More than 50 μm a maximum width that is at least one of c) i) less than 50 μm; ii) about 25 μm, and iii) More than 10 μm thickness that is at least one of The method according to any one of claims 1 to 33, comprising at least one of:

35. At least some of the microstructures are a) i) less than 50% of the length of the microstructure; ii) at least 10% of the length of the microstructure; and iii) about 30% of the length of the microstructure and a length that is at least one of b) i) at least 0.01 μm; ii) at least 0.05 μm; iii) at least 0.1 μm; iv) less than 5 μm, and v) Approximately 1 μm Sharpness that is at least one of The method according to any one of claims 1 to 34, wherein the tip is at least one of:

36. The microstructure comprises: a) 5000 / cm ２ less than, b) 10 / cm ２ overtake, c) 100 / cm ２ overtake, d) About 25-50 / cm ２ , and e) Approximately 600 / cm ２ The method of any one of claims 1 to 35, wherein the density is at least one of:

37. At least some of the microstructures are a) 0.2 mm ２ less than, b) Approximately 0.13mm ２ , 0.07 mm ２ and 0.02 mm ２ One of the c) at least 0.01 mm ２ 37. The method of any one of claims 1 to 36, comprising an electrode having a surface area of ​​at least one of:

38. The microstructures include anchor microstructures used to anchor the substrate to the object, the anchor microstructures comprising: a) comprising an anchoring structure; b) have a length greater than the other microstructures; and c) Enter the dermis The method according to any one of claims 1 to 37, wherein the method is at least one of

39. The microstructure comprises: a) bioactive materials; b) a reagent for reacting with an analyte in said subject; c) a binding agent for binding to the analyte of interest; d) a probe for selectively targeting the analyte of interest; e) materials that reduce biofouling; f) a material that attracts at least one substance to said microstructure; g) a material that repels at least one substance from said microstructure; h) a material that attracts at least some of the analytes to said projections; and i) a material that repels at least some of the analytes from the projections; 39. The method of any one of claims 1 to 38, comprising a material comprising at least one of:

40. At least some of the microstructures are a) i) To increase hydrophilicity, ii) to increase hydrophobicity, and iii) To minimize biofouling modifying the surface properties due to at least one of b) attracting at least one substance to said microstructure; c) repelling at least one substance from said microstructure; d) acting as a barrier to exclude at least one substance from said microstructure; and e) i) polyethylene, ii) polyethylene glycol, iii) polyethylene oxide; iv) zwitterions, v) peptides, vi) a hydrogel, and vii) SAM Contains at least one of The method according to any one of claims 1 to 39, wherein the surface is coated with a coating that is at least one of the following:

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