Flexible phase-transitioning needles for shear stress reduction

Abstract

Articles for conveying a fluid, such as needles, and related methods are generally provided. In some embodiments, the articles are configured to reversibly change stiffness in response to a temperature change, such as exposure to physiological temperature. In some embodiments, the article is configured to substantially conform to an external shape of an object present within the needle.

Description

[0001] FLEXIBLE PHASE-TRANSITIONING NEEDLES FOR SHEAR STRESS REDUCTION

[0002] RELATED APPLICATIONS

[0003] This application claims priority under 35 U.S.C. § 119(e) to U.S. Provisional Patent Application Serial No. 63 / 733,933, filed December 13, 2024, and entitled “FLEXIBLE PHASETRANSITIONING NEEDLES FOR SHEAR STRESS REDUCTION,” which is incorporated herein by reference in its entirety for all purposes.

[0004] TECHNICAL FIELD

[0005] Articles for conveying a fluid, such as needles configured to reversibly change stiffness in response to a temperature change, and related methods are generally described.

[0006] BACKGROUND

[0007] Objects, such as cells, flowing through a needle may experience various mechanical forces, including shear forces from linear shear flow, a pressure drop, and an extensional force. The mechanical forces exerted during needle-based cell transport may compromise cell viability and functionality. Accordingly, improvements are needed.

[0008] SUMMARY

[0009] The subject matter of the present disclosure involves, in some cases, interrelated products, alternative solutions to a particular problem, and / or a plurality of different uses of one or more systems and / or articles.

[0010] In one aspect, articles for conveying a fluid are provided. In some embodiments, the article comprises a lumen, a phase-changing layer comprising a low-melting-point metal, and an elastomeric fiber layer adjacent a phase-changing layer, wherein the article has a first stiffness above physiological temperature and a second stiffness, different than the first stiffness, below physiological temperature.

[0011] In some embodiments, the article comprises a lumen and a phase-changing layer comprising a low-melting-point metal impregnated within a porous elastomeric fiber layer.

[0012] In another aspect, a needle with the capacity for phase transition in a biological tissue in vivo is provided. In some embodiments, the needle, under physiological conditions, is configured to substantially conform to an external shape of an object present within the needle.

[0013] #14660029vl In yet another aspect, methods for conveying fluid are provided. In some embodiments, the method comprises providing a needle configured to change stiffness in response to a temperature change, heating the needle, and flowing an object through the needle such that the needle conforms to a shape of the object.

[0014] In some embodiments, the method comprises providing a needle configured to change stiffness in response to a temperature change, exposing the needle to physiological conditions, such that at least a portion of the needle changes phase, and flowing an object through the needle such that at least a portion of the needle conforms to an external shape of the object.

[0015] Other advantages and novel features of the present disclosure will become apparent from the following detailed description of various non-limiting embodiments of the disclosure when considered in conjunction with the accompanying figures. In cases where the present specification and a document incorporated by reference include conflicting and / or inconsistent disclosure, the present specification shall control.

[0016] BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Non-limiting embodiments of the present disclosure will be described by way of example with reference to the accompanying figures, which are schematic and are not intended to be drawn to scale unless otherwise indicated. In the figures, each identical or nearly identical component illustrated is typically represented by a single numeral. For purposes of clarity, not every component is labeled in every figure, nor is every component of each embodiment of the disclosure shown where illustration is not necessary to allow those of ordinary skill in the art to understand the disclosure. In the figures:

[0018] FIG. 1A shows a schematic illustration of an article for conveying a fluid, according to one set of embodiments.

[0019] FIG. IB shows a schematic illustration of an article having a multilayered arrangement, according to one set of embodiments.

[0020] FIG. 2A-FIG. 2K shows design and characteristics of a DOLCE needle, according to one set of embodiments. FIG. 2A shows schematic illustrations describing a DOLCE needle before and after skin penetration. FIG. 2B shows a photograph of a 27 -gauge stainless steel needle (left) and a 27-gauge DOLCE needle (right). Scale bar, 5 mm. FIG. 2C shows photographs of the DOLCE needle at room temperature (top) and after dipping in 37 °C water (bottom). Scale bars, 1 cm. FIG. 2D shows a plot of tensile stress versus strain for the DOLCE needle before (rigid) and after phase transition (soft). FIG. 2E shows a von Mises plot of FEA simulation of the soft

[0021] #14660029vl DOLCE needle with the cluster-like soft sphere. FIG. 2F shows a von Mises plot of FEA simulation of stainless steel needle. FIG. 2G shows a schematic illustration (top) and SEM (bottom) of multi-layered gallium and polyurethane fiber network structures. Scale bar, 20 pm. FIG. 2H shows a comparison of bending strengths of rigid-state DOLCE needles with different wall structures. FIG. 21 shows a comparison of bending stiffnesses between stainless steel needle and DOLCE needles. FIG. 2J shows a scanning electron micrograph of the tip of a DOLCE needle. Scale bar, 500 pm. FIG. 2K shows a plot of insertion load versus penetration depth for a stainless steel needle and a DOLCE needle.

[0022] FIG. 3A-FIG. 31 shows mechanical characterization of needles with cluster-like matters, according to one set of embodiments. FIG. 3A shows a schematic illustration of the experimental procedure of mechanical force measurement during cluster-like bead extrusion through the needle. FIG. 3B shows a comparison of maximum loads during extrusion of pure PBS and bead- dispersed PBS using different diameters of needles. FIG. 3C-FIG. 3F show plots of load versus compressive strain during extrusion of bead dispersion using (FIG. 3C) 18-gauge stainless steel needle, (FIG. 3D) 23-gauge stainless steel needle, (FIG. 3E) 27-gauge stainless steel needle, and (FIG. 3F) 27-gauge soft-state DOLCE needle. FIG. 3G shows a von Mises plot of FEA simulation of the cluster-like soft sphere in a soft DOLCE needle. FIG. 3H shows a von Mises plot of FEA simulation of the cluster-like soft sphere in stainless steel needle. FIG. 31 shows a von Mises plot of FEA simulation of the needle while flowing the dispersion media.

[0023] FIG 4A-FIG. 4E shows characterization of cellular cluster after delivery, according to one set of embodiments. FIG 4A shows optical micrographs of cardiac muscle cell (HL-1) clusters extruded through commercially-available stainless steel needles and a DOLCE needle. Scale bars, 200 pm. FIG 4B shows optical micrographs of Insulinoma cell (INS-1) clusters extruded through commercially-available stainless steel needles and a DOLCE needle. Scale bars, 200 pm. FIG 4C shows immunofluorescent images of Calcein-AM (LIVE) and ethidium homodimer- 1 (DEAD) in INS-1 clusters extruded through commercially available stainless steel needles and a DOLCE needle. Scale bars, 200 pm. FIG 4D shows a plot of relative fluorescence intensity after Celltox green cytotoxicity assay. ****p<0.0001. FIG. 4E shows a plot of glucose-stimulated insulin secretion of the INS-1 clusters extruded through commercially available stainless steel needles and a soft DOLCE needle. ***p<0.001.

[0024] FIG. 5A-FIG. 5B shows characterization of cell-cell interaction after delivery, according to one set of embodiments. FIG. 5A shows representative immunofluorescent images of E- cadherin (ECAD) in INS-1 clusters extruded through stainless steel needles and a DOLCE

[0025] #14660029vl needle. Scale bars, 50 pm. FIG. 5B shows plots of fluorescent intensity across each fluorescent image in (a).

[0026] FIG. 6A-FIG. 6J shows tissue identification function of a DOLCE needle, according to one set of embodiments. FIG. 6A shows schematic illustrations of a tissue identification sensor integrated into a DOLCE needle. Inset: photograph of a blood vessel sensor. Scale bar, 1 mm. FIG. 6B shows impedances of tissues and blood measured by a DOLCE needle. FIG. 6C shows phase angles of tissues and blood measured by a DOLCE needle. FIG. 6D shows a plot of impedance and phase angle versus depth of muscle tissue at 1 kHz measurement frequency. FIG. 6E shows a plot of impedance and phase angle versus depth of fat tissue at 1 kHz measurement frequency. FIG. 6F shows a photograph of the cross-section of tissue. Scale bar, 2 mm. FIG. 6G shows real-time impedance change during needle insertion to the skin tissue. FIG. 6H shows realtime measurement of impedance and phase angle at 1 kHz during tissue penetration with a DOLCE needle. FIG. 61 shows impedance change at the point of the jugular vein during tissue penetration. **p=0.0348. FIG. 6J shows real-time impedance change during needle insertion to the jugular vein. ****p<0.0001

[0027] FIG. 7 shows schematic illustration describing types of mechanical stresses and resulting cellular damage, according to one set of embodiments.

[0028] FIG. 8 shows SEM of electrospun polyurethane fiber (left) and the polyurethane fiber layer on the gallium layer of the needle (right), according to one set of embodiments.

[0029] FIG. 9A-FIG. 9B shows needle penetration tests, according to one set of embodiments. FIG. 9A shows photographs of tissue phantom fabricated with silicone elastomers (1 mm of Sylgard 184 on 8 mm of Ecoflex 00-10). FIG. 9B shows tissue penetration setup and peak force measurements during penetration testing on swine skin tissue. SS: stainless steel.

[0030] FIG. 10 shows infrared images of skin tissue of a swine after euthanization, according to one set of embodiments. The temperature of the skin tissue was maintained throughout the penetration force measurement.

[0031] FIG. 11 shows fabrication process of a DOLCE needle, according to one set of embodiments. First, stainless steel wire with a diameter of 210 pm was prepared as a temporary support, and a biocompatible release agent was deposited on the support’s surface. A silicone elastomer was spray-coated on the support to a thickness of 20 pm. Next, pure gallium (99.99%) was melted at 40 °C and dip-coated on the elastomer layer to a thickness of 40 pm. For the porous elastomeric interlayer, a polyurethane (PU) fiber network was coated on the gallium layer through electrospinning. Gallium coating and PU fiber network deposition were alternately

[0032] #14660029vl repeated 4 times to form a multi-layered structure with a thickness of -140 pm. The coated support was cast into a mold with a lancet-point tip structure at an elevated temperature of 40 °C. After quenching the coated support in liquid nitrogen, the support and needle were released from the mold. The support was then removed, leaving the needle with a lancet-point tip. A silicone elastomer was then spray-coated (-10 pm) to encapsulate the needle. The tissue identification sensor was integrated onto the surface of the needle using silicone adhesive. After that, the needle was assembled with a drilled Luer-lock syringe cap.

[0033] FIG. 12 shows blood loss during the penetration of different gauges of needles into the ear vein of swine, according to one set of embodiments.

[0034] FIG. 13 shows schematic illustrations comparing conventional needles and a DOLCE needle, according to one set of embodiments. The cell-needle interaction during extrusion damages cellular clusters delivered by the conventional (stainless steel) narrow needle. The larger needles can extrude the cellular clusters without damage, but their large diameters increase the risk of procedure -related complications. A DOLCE needle with a narrow diameter can deliver cellular clusters with high viability and functionality by mitigating mechanical stresses, while its narrow diameter minimizes the invasiveness during the procedure.

[0035] FIG. 14 shows immunofluorescent images of E-cadherin (ECAD) and DAPI in INS-1 clusters extruded through stainless steel needles (23G, 27G, 30G) and a DOLCE needle (27G), according to one set of embodiments.

[0036] FIG. 15A-FIG. 15C shows depth independence test of the tissue identification sensor, according to one set of embodiments. FIG. 15A shows photographs of cross-sections of separated fat and muscle tissues. Dots indicate each measurement point. FIG. 15B shows an impedance plot according to the depth of each tissue type. FIG. 15C shows a phase angle plot according to the depth of each tissue type. The impedance and phase angle indicate significant differences between fat and muscle tissues, but there is no significant difference according to the depth of the needle in each tissue.

[0037] FIG. 16A-FIG. 16B shows tissue type profiling test with constant velocity, according to one set of embodiments. FIG. 16A shows photographs of tissue sample preparation. A porcine skin tissue was constrained in a tissue chamber, and the top of the tissue was also constrained using polyimide film. A 3 mm-diameter hole at the center of the polyimide film enabled the direct contact of the needle with the tissue surface. FIG. 16B shows photographs of the experimental setup. The syringe with the needle was mounted to the holder and maintained a

[0038] #14660029vl static position. The tissue sample in the tissue chamber was attached to the z-axis stage and the tissue chamber was moved upward at a constant velocity.

[0039] FIG. 17 shows a photograph of tissue around the portal vein (left) and the photographs describing the regions of the jugular vein for blood injection and sealing (right), according to one set of embodiments.

[0040] FIG. 18 shows a schematic cartoon describing an article that can conform to an external shape of an object, according to one set of embodiments.

[0041] FIG. 19 shows an example of a snake body that can conform to an external shape of an object flowing through the body, according to one set of embodiments.

[0042] FIG. 20 shows a phase transitioning material, according to one set of embodiments.

[0043] FIG. 21 shows a multilayered structure of gallium and polyurethane, according to one set of embodiments.

[0044] FIG. 22 shows a finite element analysis of force between needle wall and larger cluster, according to one set of embodiments.

[0045] FIG. 23 shows a finite element analysis of flow of cluster suspension, according to one set of embodiments.

[0046] FIG. 24 shows assays of morphology and functionality proteins (E-cadherin, Laminin, Connexin 36), according to one set of embodiments.

[0047] FIG. 25 shows impedance measurements of skin, fat, muscles, and blood, according to one set of embodiments

[0048] FIG. 26 shows blood vessel detection based on impedance measurement, according to one set of embodiments.

[0049] FIG. 27A-FIG. 27F show a DOLCE needle as a tissue intervention, according to one set of embodiments.

[0050] FIG. 27A shows a schematic illustration of intravitreal injection of solid suspension or high-viscosity formulations, according to one set of embodiments. The schematic illustration was created with BioRender.com.

[0051] FIG. 27B shows schematic illustrations of an intravitreal injection of therapeutics using conventional large- diameter needle and DOLCE needle, according to one set of embodiments. The schematic illustrations were created with BioRender.com.

[0052] FIG. 27C shows a schematic illustration of intravitreal injection of radiopaque microspheres into a swine eye, according to one set of embodiments. The schematic illustration was created with BioRender.com.

[0053] #14660029vl FIG. 27D shows X-ray images of radiopaque microbeads delivered to the vitreous chamber of a post-mortem swine, according to one set of embodiments. Dashed circle: region of eye. Square: radiopaque microspheres. Scale bars, 3 cm.

[0054] FIG. 27E shows a plot of maximum injection force for high- viscosity formulations (300 cP and 600 cP) delivered through a conventional 27-gauge SS needle and the 27-gauge DOLCE needle, according to one set of embodiments. ***p=0.0003, ****p<0.0001.

[0055] FIG. 27F shows H&E- stained histological sections of scleral tissue following intravitreal injection using 18-gauge SS, 23-gauge SS, and 27-gauge DOLCE needles, according to one set of embodiments. Scale bars, 500 pm.

[0056] DETAILED DESCRIPTION

[0057] Articles for conveying a fluid, such as needles, configured to reversibly change stiffness in response to a temperature change and related methods are generally described. In some embodiments, articles for conveying a fluid (e.g., comprising a plurality of cells, comprising a plurality of particles such as nanoparticles and / or microparticles, comprising an aggregate of particles, comprising one or more therapeutic agents) are provided. In some embodiments, at least a portion of the article exhibits a phase change under physiological conditions (e.g., physiological temperature) as compared to a temperature less than physiological temperature (e.g., less than or equal to 20 °C). In some embodiments, the article and / or methods disclosed herein may advantageously reduce and / or mitigate any shear forces on a plurality of particles (e.g., a plurality of cells) flowed along a fluidic channel of the article in contrast to conventional techniques (e.g., rigid fluidic conduits such as polymeric catheters, steel needles, etc.). Conventional techniques generally create mechanical stress that affects particles such as cells, according to some embodiments. In some embodiments, it has been appreciated that the articles and methods disclosed herein may have reduced mechanical forces exerted on cells, which may increase cell viability and / or functionality of cells (e.g., for administration to a subject, for subsequent diagnostics and / or analysis, etc.).

[0058] As shown illustratively in FIG. 1A, exemplary article 100 comprises lumen 102 and phase -changing layer 104 adjacent to elastomeric fiber layer 106. In some embodiments, the phasechanging layer is adjacent the lumen and the positioned closer to the lumen relative to the elastomeric fiber layer. However, in some other embodiments, the elastomeric fiber layer 106 is positioned closer to the lumen 102 relative to the phase-changing layer 104. While FIG. 1A

[0059] #14660029vl depicts a single phase-changing layer and a single elastomeric fiber layer, two or more phasechanging layers and / or two or more elastomeric fiber layers are also possible. For example, in some embodiments, the article comprises two phase-changing layers and a single elastomeric fiber layer. In some embodiments, the article comprises a single phase-changing layer and two elastomeric fiber layers. In some embodiments, the article comprises two or more, three or more, four or more, five or more, six or more, or seven or more phase-changing layers. In some embodiments, the article comprises two or more, three or more, four or more, five or more, six or more, or seven or more elastomeric fiber layers. The phase-changing layers and elastomeric fiber layers may be arranged in any suitable configuration. In some embodiments, at room temperature, the article is rigid and capable of penetrating human tissue (e.g., skin, ocular). When the article reaches a target region within biological tissue, the tissue’s temperature may cause the phase-changing layer(s) of the article to transition into a liquid state. This phase transition makes the article soft and deformable, which may minimize damage to cellular clusters during insertion, e.g., despite the article’s narrow diameter.

[0060] As used herein, when a portion is referred to as being “adjacent” another portion, it can be directly adjacent to (e.g., in contact with) the portion, or one or more intervening components (e.g., a liquid, a hollow portion) also may be present. A portion that is “directly adjacent” another portion means that no intervening component(s) is present.

[0061] In some embodiments, the article may be administered to a subject (e.g., the article may pierce a tissue of the subject such that a fluid may be conveyed into the subject via a fluidic channel (e.g., a lumen) of the article). In some embodiments, the article (e.g., and / or the particles and / or therapeutic agent contained therein) is administered by contacting the skin of a subject with the article (e.g., such that the article punctures at least a portion of the skin). The article may be administered such that an outlet of the article is present within a blood vessel of the subject (e.g., an artery, a vein, a capillary). In some embodiments, the fluid may be injected into the blood vessel of the subject.

[0062] In some embodiments, upon contacting the tissue of the subject, at least a portion of the article may increase in temperature (e.g., to a physiological temperature) such that at least the phase-changing layer undergoes a phase change. In some embodiments, the article softens (e.g., the Young’s elastic modulus decreases) under physiological conditions. Advantageously, the phase change of the article upon administration to the subject may provide desirable conditions for administration of a plurality of particles to the subject (e.g., cells) without damaging the particles.

[0063] #14660029vl A “subject” refers to any animal such as a mammal (e.g., a human). Non-limiting examples of subjects include a human, a non-human primate, a cow, a horse, a pig, a sheep, a goat, a dog, a cat or a rodent such as a mouse, a rat, a hamster, a bird, a fish, or a guinea pig. Generally, the invention is directed toward use with humans. In some embodiments, a subject may demonstrate health benefits, e.g., upon administration of a fluid via the articles described herein. In some embodiments, the articles described herein may be useful for the administration of a plurality of particles to a subject (e.g., a plurality of cells). In some embodiments, the plurality of cells are derived from a different subject (e.g., a different human, a different species) than the subject to which the cells are administered.

[0064] As used herein, a “fluid” is given its ordinary meaning, i.e., a liquid or a gas. A fluid cannot maintain a defined shape and will flow during an observable time frame to fill the container in which it is put. Thus, the fluid may have any suitable viscosity that permits flow. The fluid may be a pure substance, mixture, dispersion, or solution. The fluid may be Newtonian (viscosity not dependent on shear rate) or non-Newtonian (e.g., shear thinning, shear thickening). If two or more fluids are present, each fluid may be independently selected among essentially any fluids (liquids, gases, and the like) by those of ordinary skill in the art.

[0065] In certain embodiments, articles and methods described herein may facilitate the delivery of high-viscosity formulations to physiological tissue, even at a smaller article lumen diameter (e.g., 27G to 30G). For example, in some embodiments, articles and methods described herein may facilitate the delivery of formulations having a viscosity of greater than or equal to 100 cP, greater than or equal to 150 cP, greater than or equal to 200 cP, greater than or equal to 300 cP, greater than or equal to 400 cP, or greater than or equal to 500 cP (1 cP = 10“3Pa-s = 1 mPa-s). In some embodiments, articles and methods described herein may facilitate the delivery of formulations having a viscosity of less than or equal to 700 cP, less than or equal to 600 cP, less than or equal to 500 cP, or less than or equal to 400 cP. Combinations of the above-referenced ranges are also possible (e.g., greater than or equal to 100 cP and less than or equal to 700 cP, greater than or equal to 300 cP and less than or equal to 600 cP). Other ranges are also possible.

[0066] In some embodiments, the article is a multilayered article comprising two or more phasechanging layers alternating with two or more elastomeric fibers layers. For example, as shown illustratively in FIG. IB, exemplary article 120 comprises lumen 124 and multilayer 126 (e.g., comprising a plurality of phase-changing layers and elastomeric fiber layers). In some embodiments, multilayer 126 comprises a plurality of alternating phase-changing layers and elastomeric fiber layers. In some embodiments, as shown in FIG. IB, article 120 is encapsulated

[0067] #14660029vl with silicone elastomer 122. In some embodiments, silicone elastomer 122 is deposited on an outer surface of the article. In some embodiments, silicone elastomer 122 is deposited on an inner surface of the article (e.g., a surface of the lumen). In some embodiments, the article is encapsulated with the silicone elastomer such that the silicone elastomer is adjacent the inner and outer surfaces of the article (e.g., as shown illustratively in FIG. IB).

[0068] In some embodiments, the article comprises a phase-changing layer. In some embodiments, the phase-changing layer comprises a low-melting-point metal. Non-limiting examples of suitable low-melting-point metals include gallium, bismuth, tin, and combinations thereof. In some embodiments, the low-melting-point metal comprises an alloy (e.g., gallium and indium). In some embodiments, the low-melting-point metal is configured to undergo a phase transition that impacts the properties of the article, as described in more detail below.

[0069] In some embodiments, the article comprises an elastomeric fiber layer adjacent to the phase-changing layer. In some embodiments, the phase-changing layer (e.g., low -melting-point metal) is impregnated within an elastomeric fiber layer (e.g., porous elastomeric fiber layer). For example, in some embodiments, the elastomeric fiber layer comprises a plurality of pores such that at least a portion of the pores is filled with the phase-changing material of the phasechanging layer.

[0070] In some embodiments, the elastomeric fiber layer comprises a silicone elastomer and / or a copolymer.

[0071] In some embodiments, the elastomeric fiber layer comprises a plurality of polymeric fibers. Non-limiting examples of suitable polymers include poly-dimethylsiloxane, polyurethane, polybutadiene, polystyrene, polyethylene, polybutylene, co-polymers thereof, and derivatives thereof. Other polymers are possible. Combinations of polymers (e.g., polystyrene and polybutadiene) are also possible.

[0072] In some embodiments, at least one of the phase-changing layer and the elastomeric fiber layer is encapsulated within a silicone elastomer. In some embodiments, the silicone elastomer forms a layer on an outer portion and / or an inner portion of the article. For example, the silicone elastomer layer can be on an outer portion of a needle, but, in some embodiments, the silicone elastomer layer can be on an inner portion of the needle (instead of or in addition to on the outer portion of the needle). Without wishing to be bound by theory, the silicone elastomer may prevent leakage or contamination of any of the components of the article (e.g., phase-changing layer). Non-limiting examples of a silicone elastomer that can encapsulate the phase-changing layer and / or the elastomeric fiber layer are siloxanes and silicones. In some embodiments,

[0073] #14660029vl the article comprises a lumen. In some embodiments, the lumen is capable of conveying a fluid (e.g., comprising a plurality of particles such as cells, comprising a therapeutic agent).

[0074] The lumen may have any suitable inner diameter. In some embodiments, the lumen has an inner diameter that is greater than or equal to 10 microns, greater than or equal to 20 microns, greater than or equal to 50 microns, greater than or equal to 100 microns, greater than or equal to 150 microns, greater than or equal to 200 microns, greater than or equal to 250 microns, greater than or equal to 300 microns, greater than or equal to 350 microns, greater than or equal to 400 microns, greater than or equal to 450 microns, greater than or equal to 500 microns, greater than or equal to 750 microns, greater than or equal to 1 mm, or greater than or equal to 2 mm. In some embodiments, the lumen has an inner diameter that is less than or equal to 2 mm, less than or equal to 1 mm, less than or equal to 750 microns, less than or equal to 500 microns, less than or equal to 450 microns, less than or equal to 400 microns, less than or equal to 350 microns, less than or equal to 300 microns, less than or equal to 250 microns, less than or equal to 200 microns, less than or equal to 150 microns, less than or equal to 100 microns, less than or equal to 50 microns, less than or equal to 20 microns, or less than or equal to 10 microns. Combinations of the above referenced ranges are also possible (e.g., greater than or equal to 10 microns and less than or equal to 2 mm). Other ranges are also possible. In an exemplary embodiment, the lumen (e.g., lumen of a needle) has an inner diameter that is greater than or equal to 50 microns and / or less than or equal to 500 microns.

[0075] In some embodiments, the inner diameter is relatively small such as less than or equal to 10 microns, less than or equal to 5 microns, less than or equal to 1 micron, less than or equal to 500 nm, less than or equal to 250 nm, less than or equal to 100 nm, or less than or equal to 50 nm. In some embodiments, the inner diameter is greater than or equal to 10 nm, greater than or equal to 50 nm, greater than or equal to 100 nm, greater than or equal to 250 nm, greater than or equal to 500 nm, greater than or equal to 1 micron, greater than or equal to 5 microns, or greater than or equal to 10 microns. Combinations of the above-referenced ranges are also possible (e.g., less than or equal to 10 microns and greater than or equal to 10 nm).

[0076] The lumen of the needle may be any dimension known to those of skill in the art. Without wishing to be bound to any particular theory, those of skill in the art will know that needles are commonly sized by gauge (e.g., 14G, 15G, 16G, 18G, 20G, 21G, 22G, 23G, 25G, 27G, 28G, 29G, 30G, 31G, 32G, 33G, 34G, etc.) with each gauge having a standardized external diameter and length. For example, a standard 14G needle typically has an external diameter of 1.83 mm whereas an 18G needle has a 1.27 mm external diameter.

[0077] #14660029vl The elastomeric fiber layer of the article may have any suitable thickness. For example, in some embodiments, the elastomeric fiber layer of the article has a thickness in accordance with one or more of the gauge sizes listed above. In some embodiments, the elastomeric fiber layer has a thickness of greater than or equal to 1 micron, greater than or equal to 5 microns, greater than or equal to 10 microns, greater than or equal to 20 microns, greater than or equal to 30 microns, greater than or equal to 40 microns, greater than or equal to 50 microns, greater than or equal to 75 microns, greater than or equal to 100 microns, greater than or equal to 200 microns, greater than or equal to 300 microns, or greater than or equal to 400 microns. In some embodiments, the thickness of the elastomeric fiber layer has a thickness of less than or equal to 500 microns, less than or equal to 400 microns, less than or equal to 300 microns, less than or equal to 200 microns, less than or equal to 100 microns, less than or equal to 75 microns, less than or equal to 50 microns, less than or equal to 40 microns, less than or equal to 30 microns, less than or equal to 20 microns, less than or equal to 10 microns, or less than or equal to 5 microns. Combinations of the above -referenced ranges are also possible (e.g., greater than or equal to 1 micron and less than or equal to 500 microns).

[0078] In some embodiments, for example, as described above in the context of FIG. IB, the elastomeric fiber layer and the phase-changing layer form a multilayered arrangement. In some embodiments, the multilayered arrangement is formed from one or more layers of phasechanging layer and elastomeric fiber layer. One skilled in the art may appreciate that having one or more layers may be useful for a variety of reasons. For example, in some embodiments, having a multilayered arrangement may facilitate a needle to conform to an external shape of an object present within the needle. With the present disclosure, one skilled in the art may determine the number of layers within the multilayered arrangement needed to achieve desired results. Referring again to FIG. IB, article 120 comprises lumen 124 and multilayered arrangement (e.g., phase-changing layer(s) and elastomeric fiber layer(s)) 126.

[0079] In some embodiments, the article may have a suitable stiffness under different conditions. In some embodiments, the article has a first stiffness at or above physiological temperature (37 °C). In some embodiments, the article has a second stiffness that is different from the first stiffness at a temperature less than physiological temperature. For example, a needle exposed to a temperature at or above physiological temperature may have a first stiffness, whereas the same needle may have a second stiffness that is different from the first stiffness below physiological temperature. For example, exposed to a temperature at or above physiological temperature, a

[0080] #14660029vl needle may have a first, lower stiffness, whereas below physiological temperature, the same needle may have a second, higher stiffness than the first stiffness.

[0081] In some embodiments, the article and / or the phase-changing layer undergoes a phase change at a temperature greater than or equal to 20 °C, greater than or equal to 25 °C, greater than or equal to 30 °C, greater than or equal to 32 °C, greater than or equal to 35 °C, greater than or equal to 37 °C, or greater than or equal to 40 °C. In some embodiments, the article and / or the phase-changing layer undergoes a phase change at a temperature less than or equal to 40 °C, less than or equal to 37 °C, less than or equal to 35 °C, less than or equal to 32 °C, less than or equal to 30 °C, or less than or equal to 25 °C. Combinations of the above-referenced ranges are also possible (e.g., greater than or equal to 20 °C and less than or equal to 40 °C). Other ranges are also possible.

[0082] In some embodiments, the article is exposed to physiological conditions. In some embodiments, the article, under physiological conditions, has a Young’s modulus that is greater than or equal to 1 kPa, greater than or equal to 10 kPa, greater than or equal to 50 kPa, greater than or equal to 100 kPa, greater than or equal to 500 kPa, or greater than or equal to 1 MPa. In some embodiments, the needle, under physiological conditions, has a Young’s modulus that is less than or equal to 1 MPa, less than or equal to 500 kPa, less than or equal to 100 kPa, less than or equal to 50 kPa, or less than or equal to 1 kPa. Combinations of the above-recited ranges are possible. In some embodiments, physiological conditions refer to at least a physiological temperature. While the Young’s modulus ranges above are generally described in the context of physiological conditions, those of ordinary skill in the art would understand that such Young’s elastic moduli are also possible above the phase-change temperature of the article as described above.

[0083] In some embodiments, the article or needle, at a temperature less than or equal to 20 °C has a Young’s modulus of greater than or equal to 1 MPa, greater than or equal to 10 MPa, greater than or equal to 50 MPa, greater than or equal to 100 MPa, greater than or equal to 500 MPa, greater than or equal to 1 GPa, greater than or equal to 5 GPa, greater than or equal to 10 GPa, greater than or equal to 50 GPa or greater than or equal to 100 GPa. In some embodiments, the article or needle, at a temperature less than or equal to 20 °C has a Young’s modulus of less than or equal to 100 GPa, less than or equal to 50 GPa, less than or equal to 10 GPa, less than or equal to 5 GPa, less than or equal to 1 GPa, less than or equal to 500 MPa, less than or equal to 100 MPa, less than or equal to 50 MPa, less than or equal to 10 MPa, or less than or equal to 1 MPa. Combinations of the above-recited ranges are possible.

[0084] #14660029vl In some embodiments, the article exhibits conformational deformation in the phase- changed configuration (e.g., at a temperature greater than or equal to 20 °C such as physiological temperature). As used herein, conformational deformation generally refers to the ability of a material to conform to the shape and / or features of an object with which it is in contact. For illustrative purposes only and without wishing to be limited to such, a fabric draped over an object that follows the shape, features, and / or contours of the object (e.g., similar to a bedsheet covering a person) would be considered to exhibit conformational deformation with respect to the object. FIG. 18 shows an exemplary embodiment in which an arbitrary object is placed within a hollow portion of the body and the body changes shape to generally conform to the shape of the object within. FIG. 19 shows an example of a snake body that can conform to an external shape of an object flowing through the body, according to one set of embodiments. In FIG. 19, an adjustable lumen of a needle may result from a phase change at physiological temperature, such that, like a snake swallowing a mouse, individual cells may be delivered into physiological tissue undamaged as the lumen conforms to the cell shape.

[0085] For example, in some embodiments, the article may expand (e.g., radially, stretch) and / or contract to accommodate one or more objects (e.g., particles) within the lumen of the article. Advantageously, the flexible shape changing nature of the article may facilitate damage-free flow of sensitive materials and components (e.g., cells) along the fluidic channel of the article.

[0086] In some embodiments, the article, in the phase-changed configuration, may exhibit conformation deformation with respect to an object within the article such that an inner surface of the article substantially conforms to the shape, contours, and / or features of the object in contact with the inner surface (e.g., disposed within the fluidic channel of the article). In some embodiments, the inner surface of the article, in the phase-changed configuration, is able to conform substantially to the peaks and troughs of an object disposed within the article. Advantageously, such conformation deformation may permit the flow of particles (e.g., particles sensitive to deformation by shear flow) without damaging the particles by shear forces.

[0087] In some embodiments, as described above and herein, at least a portion of the article exhibits a phase change under physiological conditions. For example, when exposed to at or above physiological temperature, the article may exhibit a phase change. In some embodiments, the phase change is related to a change in stiffness (e.g., a first stiffness changing to a second stiffness) in the article. In some embodiments, the phase change may be reversible (e.g., upon change in temperature). Without wishing to be bound by theory, the phase change behavior of the

[0088] #14660029vl article may be related to a phase change of certain components within the article (e.g., low- melting-point metal).

[0089] In some embodiments, the article is configured to flow a fluid. In some embodiments, the fluid comprises a plurality of cells. In some embodiments, the plurality of cells being flowed within the article has a fluid flow that does not substantially shear the cells. Without wishing to be bound by theory, the phase-changing behavior of the article may prevent undesirable shear of the cells (e.g., upon administration of the cells to a subject and / or to a fluidic device). In some embodiments, the article is configured to increase cell viability and / or functionality of the plurality of cells, e.g., relative to cell viability and / or functionality of a plurality of cells through an article that does not undergo a phase change and has the same gauge as the article.

[0090] In some embodiments, the article comprises an electronic component such as a sensor. For example, the sensor may be disposed on a surface of the article. In an exemplary set of embodiments, the sensor is an impedance detector such that, upon administration of the article to a subject, the location of the article may be determined (e.g., the impedance may change indicating that the tip of the article is in a blood vessel of the subject). In some embodiments, the sensor is configured to determine cell viability and / or functionality.

[0091] Electronic components may be any suitable electronic component known to the skilled artisan. In some embodiments, the article may comprise an electrical system. In some embodiments, an electrical system may include two or more electronic components. For instance, in some embodiments, the electrical system comprises a power source (e.g., a battery as described above), an actuator such as an electrical actuation control system, a microcontroller, a PCB, a wireless component, a central processor, a power management system, a system wakeup controller, and / or one or more electronic sensors such as temperature sensors, a microphone, and / or humidity sensors. In some embodiments, the electronic component comprises a temperature sensor. In some embodiments, the electronic component comprises a microphone. In some embodiments, the electronic component comprises a pH sensor. In some embodiments, the electronic component comprises a carbon dioxide sensor. In some embodiments, the electronic component comprises an accelerometer. In some embodiments, the electronic component comprises an oxygen sensor. In some embodiments, the electronic component comprises a hydrogen sulfide sensor. In some embodiments, the electronic component comprises a pressure sensor. In some embodiments, where the electronic component comprises a sensor (e.g., a temperature sensor, a pressure sensor, an oxygen sensor, etc.), the sensor is configured to operate within a liquid, e.g., at physiological conditions.

[0092] #14660029vl In some embodiments, the article (e.g., the lumen of the article) is configured to substantially conform to a shape of an object present within the needle. The shape of an object may be an external shape or a particular morphology. In some embodiments, the object present within the needle is a cell of a plurality of cells. For example, under physiological conditions, the cell being flowed through the needle may have a shape, where the needle may conform to such shape, such that shear of the cell is reduced or mitigated.

[0093] In some embodiments, physiological conditions induce a phase transition of the article. Physiological conditions (e.g., physiological temperature) may be achieved through various ways. In some embodiments, physiological conditions comprise conditions generally encountered in a biological tissue in vivo. Nonetheless, in some embodiments, physiological conditions are achieved outside a biological tissue. For example, physiological conditions may be achieved outside a biological tissue such as a cell culture conditions.

[0094] In some embodiments, the article is configured to flow a fluid comprising a particle and / or a therapeutic agent. Non-limiting example of particles that can be flowed include metal particles, non-metal particles, colloidal particles, polymer particles, or the like.

[0095] According to some embodiments, the composition and methods described herein are compatible with one or more therapeutic, diagnostic, and / or enhancement agents, such as drugs, nutrients, microorganisms, in vivo sensors, and tracers. In some embodiments, the active substance, is a therapeutic, nutraceutical, prophylactic or diagnostic agent. While much of the specification describes the use of therapeutic agents, other agents listed herein are also possible. Agents can include, but are not limited to, any synthetic or naturally-occurring biologically active compound or composition of matter which, when administered to a subject (e.g., a human or nonhuman animal), induces a desired pharmacologic, immunogenic, and / or physiologic effect by local and / or systemic action. For example, useful or potentially useful within the context of certain embodiments are compounds or chemicals traditionally regarded as drugs, vaccines, and biopharmaceuticals, Certain such agents may include molecules such as proteins, peptides, hormones, nucleic acids, gene constructs, etc., for use in therapeutic, diagnostic, and / or enhancement areas, including, but not limited to medical or veterinary treatment, prevention, diagnosis, and / or mitigation of disease or illness (e.g., HMG co-A reductase inhibitors (statins) like rosuvastatin, nonsteroidal anti-inflammatory drugs like meloxicam, selective serotonin reuptake inhibitors like escitalopram, blood thinning agents like clopidogrel, steroids like prednisone, antipsychotics like aripiprazole and risperidone, analgesics like buprenorphine, antagonists like naloxone, montelukast, and memantine, cardiac glycosides like digoxin, alpha

[0096] #14660029vl blockers like tamsulosin, cholesterol absorption inhibitors like ezetimibe, metabolites like colchicine, antihistamines like loratadine and cetirizine, opioids like loperamide, proton-pump inhibitors like omeprazole, anti(retro)viral agents like entecavir, dolutegravir, rilpivirine, and cabotegravir, antibiotics like doxycycline, ciprofloxacin, and azithromycin, anti-malarial agents, and synthroid / levothyroxine); substance abuse treatment (e.g., methadone and varenicline); family planning (e.g., hormonal contraception); performance enhancement (e.g., stimulants like caffeine); and nutrition and supplements (e.g., protein, folic acid, calcium, iodine, iron, zinc, thiamine, niacin, vitamin C, vitamin D, and other vitamin or mineral supplements).

[0097] In some embodiments, the active substance is one or more specific therapeutic agents. As used herein, the term “therapeutic agent” or also referred to as a “drug” refers to an agent that is administered to a subject to treat a disease, disorder, or other clinically recognized condition, or for prophylactic purposes, and has a clinically significant effect on the body of the subject to treat and / or prevent the disease, disorder, or condition. Listings of examples of known therapeutic agents can be found, for example, in the United States Pharmacopeia (USP), Goodman and Gilman’s The Pharmacological Basis of Therapeutics, 10th Ed., McGraw Hill, 2001; Katzung, B. (ed.) Basic and Clinical Pharmacology, McGraw-Hill / Appleton & Lange; 8th edition (September 21, 2000); Physician’s Desk Reference (Thomson Publishing), and / or The Merck Manual of Diagnosis and Therapy, 17th ed. (1999), or the 18th ed (2006) following its publication, Mark H. Beers and Robert Berkow (eds.), Merck Publishing Group, or, in the case of animals, The Merck Veterinary Manual, 9th ed., Kahn, C.A. (ed.), Merck Publishing Group, 2005; and “Approved Drug Products with Therapeutic Equivalence and Evaluations," published by the United States Food and Drug Administration (F.D.A.) (the “Orange Book"). Examples of drugs approved for human use are listed by the FDA under 21 C.F.R. §§ 330.5, 331 through 361, and 440 through 460, incorporated herein by reference; drugs for veterinary use are listed by the FDA under 21 C.F.R. §§ 500 through 589, incorporated herein by reference. In certain embodiments, the therapeutic agent is a small molecule. Exemplary classes of therapeutic agents include, but are not limited to, analgesics, anti-analgesics, anti-inflammatory drugs, antipyretics, antidepressants, antiepileptics, antipsychotic agents, neuroprotective agents, anti-proliferatives, such as anticancer agents, antihistamines, antimigraine drugs, hormones, prostaglandins, antimicrobials (including antibiotics, antifungals, antivirals, antiparasitics), antimuscarinics, anxioltyics, bacteriostatics, immunosuppressant agents, sedatives, hypnotics, antipsychotics, bronchodilators, anti-asthma drugs, cardiovascular drugs, anesthetics, anti-coagulants, inhibitors of an enzyme, steroidal agents, steroidal or non-steroidal anti-inflammatory agents, corticosteroids,

[0098] #14660029vl dopaminergics, electrolytes, gastro-intestinal drugs, muscle relaxants, nutritional agents, vitamins, parasympathomimetics, stimulants, anorectics and anti-narcoleptics. Nutraceuticals can also be incorporated into the drug delivery device. These may be vitamins, supplements such as calcium or biotin, or natural ingredients such as plant extracts or phytohormones.

[0099] In some embodiments, the therapeutic agent is one or more antimalarial drugs. Exemplary antimalarial drugs include quinine, lumefantrine, chloroquine, amodiaquine, pyrimethamine, proguanil, chlorproguanil-dapsone, sulfonamides such as sulfadoxine and sulfamethoxypyridazine, mefloquine, atovaquone, primaquine, halofantrine, doxycycline, clindamycin, artemisinin and artemisinin derivatives. In some embodiments, the antimalarial drug is artemisinin or a derivative thereof. Exemplary artemisinin derivatives include artemether, dihydroartemisinin, arteether and artesunate. In certain embodiments, the artemisinin derivative is artesunate.

[0100] In some embodiments, the therapeutic agent is an immunosuppressive agent. Exemplary immunosuppressive agents include glucocorticoids, cytostatics (such as alkylating agents, antimetabolites, and cytotoxic antibodies), antibodies (such as those directed against T-cell recepotors or 11-2 receptors), drugs acting on immunophilins (such as cyclosporine, tacrolimus, and sirolimus) and other drugs (such as interferons, opioids, TNF binding proteins, mycophenolate, and other small molecules such as fingolimod).

[0101] In some embodiments, the therapeutic agent is a hormone or derivative thereof. Nonlimiting examples of hormones include insulin, growth hormone (e.g., human growth hormone), vasopressin, melatonin, thyroxine, thyrotropin-releasing hormone, glycoprotein hormones (e.g., luteinzing hormone, follicle-stimulating hormone, thyroid-stimulating hormone), eicosanoids, estrogen, progestin, testosterone, estradiol, cortisol, adrenaline, and other steroids.

[0102] In some embodiments, the therapeutic agent is a small molecule drug having molecular weight less than about 2500 Daltons, less than about 2000 Daltons, less than about 1500 Daltons, less than about 1000 Daltons, less than about 750 Daltons, less than about 500 Daltons, less or than about 400 Daltons. In some cases, the therapeutic agent is a small molecule drug having molecular weight between 200 Daltons and 400 Daltons, between 400 Daltons and 1000 Daltons, or between 500 Daltons and 2500 Daltons.

[0103] In some embodiments, the therapeutic agent is selected from the group consisting of active pharmaceutical agents such as insulin, nucleic acids, peptides, bacteriophage, DNA, mRNA, human growth hormone, monoclonal antibodies, adalimumab, epinephrine, GLP-1 Receptor agoinists, semaglutide, liraglutide, dulaglitide, exenatide, factor VIII, small molecule

[0104] #14660029vl drugs, progrstin, vaccines, subunit vaccines, recombinant vaccines, polysaccharide vaccines, and conjugate vaccines, toxoid vaccines, influenza vaccine, shingles vaccine, prevnar pneumonia vaccine, mmr vaccine, tetanus vaccine, hepatitis vaccine, HIV vaccine Ad4-env Clade C, HIV vaccine Ad4-mGag, dna vaccines, ma vaccines, etanercept, infliximab, filgastrim, glatiramer acetate, rituximab, bevacizumab, any molecule encapsulated in a nanoparticle, epinephrine, lysozyme, glucose-6-phosphate dehydrogenase, other enzymes, certolizumab pegol, ustekinumab, ixekizumab, golimumab, brodalumab, gusellu,ab, secikinumab, omalizumab, tnf- alpha inhibitors, interleukin inhibitors, vedolizumab, octreotide, teriperatide, crispr cas9, insulin glargine, insulin detemir, insulin lispro, insulin aspart, human insulin, antisense oligonucleotides, and ondansetron.

[0105] The methods disclosed herein may convey fluids. In some embodiments, a needle configured to change stiffness in response to a temperature change is provided. In some embodiments, the needle is exposed to heat. For example, the needle is exposed to physiological conditions after being exposed to room temperature. In some embodiments, a needle is exposed to physiological conditions, such that at least a portion of the needle changes phase. In some embodiments, an object is flowed through the needle such that the needle (e.g., at least a portion of the needle) conforms to the shape (e.g., external shape) of the object.

[0106] In an exemplary set of embodiments, the articles described herein may be prepared by providing a temporary support layer and coating the support layer with an elastomer coating (e.g., comprising a plurality of polymeric fibers). In some embodiments, a metal coating (e.g., solid, liquid, powder) such as gallium is deposited on the elastomer coating. In some embodiments, the article may be heated (e.g., to a melting temperature of the metal) thereby impregnating the elastomer coating with the metal. In some embodiments, a multilayer of alternating metal coating layer and elastomeric fiber layer (e.g., one of each layer alternating, two of each layer alternating, three of each layer alternating, four of each layer alternating, five of each layer alternating) is formed. In some embodiments, the support layer may be removed thereby forming the article. Optionally, in some embodiments, the article may be further encapsulated with an elastomer. Optionally, in some embodiments, a sensor may be integrated with the article (e.g., an impedance sensor). In some embodiments, a connector such as a luer connector (e.g., luer lock, luer slip, and combinations thereof) may be integrated with the article.

[0107] The following examples are intended to illustrate certain embodiments of the present invention, but do not exemplify the full scope of the invention.

[0108] #14660029vl EXAMPLES

[0109] This example generally describes an exemplary article (e.g., a needle) and related methods. Here, a needle with dynamic optimization of a lumen to cellular clusters (DOLCE) is introduced by its phase-transitioning ability for stress reduction in cellular cluster delivery while maintaining a narrow diameter. The needle's wall consists of a multi-layered stack of gallium (Ga) and a polyurethane (PU) fiber network, encapsulated by a thin layer (>40 pm) of silicone elastomer both inside and outside. At room temperature, the solid gallium provides enough stiffness to penetrate soft tissue, while the liquid transitioning of gallium inside the body gives the needle cellular-cluster-level softness, mitigating the stress on cellular clusters through needle deformation. A DOLCE needle, with dimensions corresponding to a conventional 27-gauge needle (inner diameter: 210 pm; outer diameter: 500 pm), preserves the morphology, viability, and functionality of the cellular clusters. To verify this, experimental force measurements and finite element analysis were conducted to identify the mechanical interaction between the soft needle wall and cells. A tissue identification sensor was integrated onto the tip of the DOLCE needle, demonstrating real-time recognition of tissues and blood vessels where the needle is placed. From this, it was determined that the DOLCE needle i) maximizes the viability and functionality of delivered cellular clusters, ii) reduces procedure-related complications due to its small diameter, and iii) enables quick and accurate identification of target regions for cell delivery. These features comprehensively suggest a high-efficacy solution for cell therapy.

[0110] Design and characterization of a DOLCE needle

[0111] FIG. 1A illustrates the concept of the DOLCE needle. At room temperature, the needle is rigid and capable of penetrating skin tissue. When the needle reaches the target region within the biological tissue, the tissue’s temperature causes the gallium layers inside the needle to transition into a liquid state. This phase transition makes the needle soft and deformable, allowing it to minimize damage to cellular clusters during insertion, despite its narrow diameter (FIG. 7). FIG. 2B shows a photograph comparing the DOLCE needle (left) with a conventional stainless steel needle (right). The inner and outer diameters of the DOLCE needle are 210 pm and 500 pm, respectively, matching the dimensions of a 27-gauge stainless steel needle. The temperature- assisted softening of the DOLCE needle is presented in the photograph in FIG. 2C. In its solid gallium state, the needle has a Young’s modulus of approximately 30 GPa. However, once the gallium transitions to a liquid state, the soft needle exhibits a significantly lower modulus of around 110 kPa with about 200% deformability. This cell-like softness of needle mitigates the stress to the clusters by its ability to conformable radial expansion during the cell delivery.

[0112] #14660029vl Despite this deformation, the cylindrical needle structure is maintained by the multi-layered structure of the PU fiber network (FIG. ID).

[0113] The adaptive deformation of DOLCE needles in response to soft cellular clusters was investigated using finite element analysis (FEA) simulation (FIG. 2E and FIG. 2F). Specifically, a section of a 27-gauge DOLCE needle was modelled and compared with a conventional stainless-steel needle. Both the DOLCE needle and the stainless-steel needle were modeled with an inner diameter of 210 pm. A soft spherical model with a diameter of 215 pm and a Young’s modulus of 10 kPa, representing the cellular clusters, was moved through the needles, considering both normal and tangential contact between the cell clusters and the needle wall. The results demonstrated that the wall of the soft DOLCE needle deformed when in contact with a cluster-like soft sphere (FIG. 2E). In contrast, the stainless steel needle maintained its structure during sphere contact, causing the sphere to compress (FIG. 3F). Details of the modeling parameters are described herein.

[0114] The wall of the DOLCE needle consists of a multi-layered structure of gallium and elastomer (FIG. 2G). The elastomeric layer is a PU fiber network fabricated by electrospinning (FIG. 8). The presence of the PU layer between the gallium layers ensures that the needle maintains its overall shape while in its soft phase (FIG. 2C). By alternately depositing gallium on the elastomeric layers multiple times, the preexisting elastomer layer serves as an wetting layer which promotes uniform coating of the gallium, ensuring a consistent radial thickness. The porous structure facilitates the vertical bonding of gallium layers covering the PU layer, thereby increasing the effective thickness of the gallium. This thicker gallium formation enhanced the mechanical strength and stiffness of the needle against bending stress during tissue penetration in its rigid state. Without the PU nanofiber networks, the needle's wall thickness was not uniform during the multiple gallium deposition processes, leading to reduced bending strength and stiffness. In contrast, the DOLCE needle wall incorporating PU layers demonstrated a 1.5-fold increase in bending strength compared to the Ga-only needle (FIG. 2H). Furthermore, it exhibited approximately 80% of the bending stiffness of the conventional stainless steel needle (FIG. 21), providing reliability against bending stress during the tissue penetration.

[0115] Part of the focus was the design of the needle tip because the sharpness of the needle is important for reducing pain and minimizing tissue trauma. The tip of the DOLCE needle was shaped into a sharp bevel through remolding after the deposition of the gallium and PU multilayers (FIG. 2J). The mold used was configured as a 3-plane lancet-point bevel, similar to the bevel structure of commercially available needles. The sharpness of the needle was characterized

[0116] #14660029vl by penetration force measurement. For the penetration test, a skin tissue phantom was created, and the force characteristics were measured according to depth (See Methods and FIG. 9A). The DOLCE needle exhibited a force profile and peak penetration force similar to that of a 27-gauge stainless steel needle (FIG. IK). In actual pig skin tests (FIG. 9B), the DOLCE needle demonstrated an average peak penetration force of 2.67 N, comparable to that of a stainless steel needle. This low penetration force elicits less trauma during tissue passage and provides dexterous positioning to the target tissue with minimal needle bending. The temperature of the skin surface before and after the measurement was monitored using infrared camera to ensure the preservation of the tissue’s mechanical properties (FIG. 10). The detailed fabrication process of the DOLCE needle is described in Methods and FIG. 11.

[0117] The needle commonly used for islet transplantation applications has an inner diameter of about 1.3 mm. In comparison, it was tested how the 27-gauge (210 pm inner diameter) DOLCE needle could reduce bleeding by penetrating the ear vein of a swine (FIG. 12). The total blood loss with the 18-gauge needle was 120 pl, whereas using the 27-gauge needle resulted in only 10 pl. The results indicate the narrower needle’s potential advantage for reducing bleeding-induced complications and possible backflow of delivered cellular clusters. The comprehensive comparison of a DOLCE needle with conventional needles is summarized in FIG. 13.

[0118] Analyses on cluster-needle interaction

[0119] To measure the mechanical stresses experienced by cellular clusters as they pass through the needle, an experiment was conducted using polyester beads with a diameter of 150 pm, comparable to the dimensions of cellular clusters. The beads were dispersed in PBS and passed through the needle at a constant flow rate while measuring the force exerted on the syringe (FIG. 3 A). Since polyester beads are incompressible, any agglomeration of beads or increased friction with the needle wall necessitated higher pressure to push the beads through the syringe.

[0120] To that end, the compressive force recorded on the syringe were compared while extruding bead dispersion and PBS through stainless steel needles of various diameters and the 27-gauge DOLCE needle (FIG. 3B). For the 18-gauge stainless steel needle (inner diameter: 840 pm), there was no difference in compressive force between extruding PBS and bead dispersion (FIG. 3C), suggesting that cellular clusters can pass through an 18-gauge needle without experiencing significant stress. As the needle diameter decreased to 23-gauge (inner diameter: 340 pm), the force used to extrude the bead dispersion was approximately double that needed for PBS (FIG. 3D), indicating increased mechanical resistance between the beads and the needle wall. When the needle diameter was further reduced to 27-gauge (inner diameter: 210 pm),

[0121] #14660029vl nearly matching the diameter of the cellular clusters, the force used to extrude the bead dispersion became significantly higher (60 N), compared to PBS (FIG. 3E). After the plunger of the syringe traveled more than 12 mm, the compressive force rapidly increased due to the clogging of beads inside the narrow needle. This increase in force and clogging indicates that the beads experienced severe mechanical forces from the needle wall, which could deform or rupture soft cellular clusters. In contrast, the soft DOLCE needle exhibited no significant difference in the force used to extrude PBS and bead dispersion, despite having the same 27-gauge diameter (FIG. 3F). This suggests that the soft needle wall absorbs the stress between the beads and the needle wall as strain, allowing the beads to pass through without significant resistance or clogging.

[0122] To better understand the capacity of the DOLCE needle to dissipate shear and compression stress on the needle wall, the interaction between the needle wall and cellular clusters was quantitatively analysed using finite element analysis (FEM). Simulation results revealed that the stress concentration of the cellular cluster’s movement in the DOLCE needle (FIG. 3G) was about 14 orders of magnitude smaller than that of the stainless steel needle (FIG. 3H). Further, the analysis determined that the DOLCE needle deformed its wall to accommodate the cellular clusters, as previously shown in FIG. 2E. Additionally, the scenario where the dispersion of cellular clusters flows through the DOLCE needle was modelled (FIG. 31). The results showed that while the DOLCE needle is soft and bendable under gravitational force, it maintained its cylindrical structures when the dispersion media flushes through it.

[0123] Post-extrusion analyses of cellular behaviors

[0124] To validate cell clusters’ non-destructive delivery, a detailed morphological analysis was conducted to compare the effects of the DOLCE needle with a commercially available stainless steel needle. The morphological assessment of cardiac muscle cell (HL-1) and insulinoma cell (INS-1) clusters post-extrusion showed significant differences between the needle types (FIG. 4A and FIG. 4B). Clusters extruded through a 30-gauge needle, which has a narrower inner diameter than the cluster diameter, exhibited destroyed morphologies, with the clusters ripped into single cells due to the mechanical stresses during extrusion. Optical micrographs of the clusters extruded through the 27-gauge DOLCE needle maintained their cluster form with clear, intact edges, similar to that of the positive control group (no extrusion through a needle), and preserved their compact and cohesive cluster integrity. In contrast, clusters extruded through the commercially available 27-gauge stainless steel needle exhibited severe morphological damage.

[0125] #14660029vl These clusters were largely destroyed, with numerous single cells dissociated from the main cluster body, indicating extensive mechanical stress and disruption.

[0126] Whether the rigidity of the needle could affect not only the morphological integrity but also cellular viability and functionality was investigated. A cell viability assay was performed using both chemical staining (Calcein-AM and Ethidium homodimer- 1) and the Celltox assay kit. The 27-gauge DOLCE soft needle group demonstrated high cluster viability, with a large proportion of live cells, similar to that of the positive control group. Conversely, the commercially available 27-gauge stainless steel needle group exhibited low viability with a significant number of dead cells (FIG. 4C). Furthermore, results from the Celltox assay demonstrated that clusters extruded through the commercially available 27-gauge stainless steel needle exhibited changes in membrane integrity, which is indicative of cell death (FIG. 4D). This decrease in viability is consistent with the observed morphological damage, suggesting that the mechanical stresses imposed by commercially available stainless steel needles not only disrupt cluster structures but also compromise cell survival.

[0127] It was evaluated whether the DOLCE needle could preserve the cellular functionality of the clusters post-extrusion. The insulin secretion of INS- 1 clusters in response to glucose levels, a test used for islet functionality analysis, was evaluated. To test the glucose-stimulated insulin secretion (GSIS), INS-1 clusters extruded through different needle types were exposed to varying glucose environments. Clusters extruded using the DOLCE needle secreted insulin at levels similar to the control group. On the other hand, clusters extruded through the commercially available stainless-steel needle showed decreased functionality in insulin secretion (FIG. 4E). These results demonstrate that the DOLCE needle provides a non-destructive platform for the delivery of cell clusters, preserving both their structural integrity and functional capacity.

[0128] Post-extrusion analyses of cell-cell interaction

[0129] Cell-cell interaction plays an important role in cell function, allowing cells to communicate and respond to changes in their microenvironment. To further validate the nondestructive delivery of cell clusters, the expression of cell-cell adhesion molecules on the surface of the clusters was investigated. The expression of E-cadherin, a transmembrane protein within adherent junctions, was evaluated. Clusters extruded through the 27-gauge DOLCE needle exhibited clear and intact E-cadherin expression (FIG. 5 A and FIG. 14). In contrast, clusters extruded through the commercially available 27-gauge stainless steel needle showed destroyed or damaged E-cadherin expression on the cluster surface. The results from fluorescence signal testing (FIG. 5B) demonstrate that the DOLCE soft needle can provide a non-destructive cluster

[0130] #14660029vl delivery platform through preserving cell-cell interactions, whereas the commercially available stainless steel needle can damage these interactions during extrusion.

[0131] Intravitreal delivery of complex therapeutics

[0132] Intravitreal injection is a clinical method for delivering therapeutic agents directly into the vitreous cavity of the eye, facilitating localized treatment of retinal diseases such as age-related macular degeneration, diabetic retinopathy, and retinal vein occlusion. While conventional smallgauge needles (e.g., 27 -gauge to 30-gauge) are sufficient for current low-viscosity drug delivery, the delivery of advanced high- viscosity or particulate formulations remains challenging due to the narrow inner diameter of standard needles, which leads to high injection resistance and increased risk of ocular tissue damage. Conversely, the use of larger-gauge needles to reduce injection resistance increases the likelihood of patient discomfort, scleral injury, and postinjection complications such as reflux or inflammation. These limitations are also pronounced in emerging cell therapy applications, where intravitreal cell delivery requires both structural preservation of the therapeutic payload and minimal invasiveness to protect the delicate ocular environment. Simultaneously, emerging injectable therapeutics — such as long-acting anti-VEGF formulations, high-concentration biologies, cell suspensions, and genes — are significantly more viscous than standard intravitreal drugs, often requiring higher injection forces and larger- diameter needles that increase patient discomfort and complication risk (FIG. 27 A). To address the limitations, the inventors demonstrated the performance of the DOLCE needle for intravitreal delivery of i) solid microspheres of a size similar to that of cellular clusters, and ii) a high- viscosity formulation. The unique combination of soft, adjustable lumen geometry and a small diameter facilitated the delivery of unconventional payloads to delicate ocular tissue (FIG. 27B). First, the intravitreal delivery of a microsphere suspension was tested. Radiopaque microspheres (diameter: 150 pm- 190 pm) were selected that had a size comparable to cellular clusters and could be imaged inside the eye (FIG. 27C). After penetration of the sclera, 100 pL suspension containing ~80 microspheres was delivered through a 27-gauge DOLCE needle with a 10 pL s1flow rate, a modest clinically-used volume and flow rate for intravitreal injection. The X-ray image in FIG. 27D shows the delivered microspheres inside the vitreous chamber of a swine. Despite the needle’s inner diameter being comparable to the microspheres' size (-200 pm), the DOLCE needle facilitated smooth manual extrusion of the microspheres without clogging or operational difficulties. Based on the microsphere extrusion experiment shown in FIG. 3F, the injection force required for this procedure was estimated to be below 10 N.

[0133] To further explore the applicability of the DOLCE needle in therapeutic delivery,

[0134] #14660029vl experiments were conducted using high- viscosity formulations, which are increasingly considered for sustained intravitreal therapy. Conventional 27-gauge stainless-steel needles often struggle to deliver formulations with viscosities above 100 cP-150 cP, with manual injectability limits typically around 20 N, and user-comfortable injection force considered below 10 N. To evaluate performance under more demanding conditions, the inventors compared the maximum injection force required to deliver 300 cP and 600 cP formulations using conventional 27-gauge needles and DOLCE needles, both with identical inner diameters (FIG. 27E). At a flow rate of 10 pL s’1, the 27-gauge stainless-steel needle required injection forces of approximately 12.7 N and 20.8 N for 300 cP and 600 cP formulations, respectively. In contrast, the DOLCE needle delivered the same formulations with significantly lower forces of 7.8 N and 11.4 N, respectively. According to Poiseuille’s law, hydraulic resistance in fluid flow is inversely proportional to the fourth power of the lumen diameter. The soft, expandable wall of the DOLCE needle likely reduced local hydraulic resistance by temporarily enlarging the lumen during injection, thereby lowering the required pressure.

[0135] The relationship between needle diameter and tissue invasiveness was also assessed via histological analysis of the sclera using H&E staining (FIG. 27F). Following intravitreal penetration, the tissue disruption width was measured at 402.4 pm for the 18-gauge needle and 165.1 pm for the 23-gauge needle. Both cases showed extensive physical tearing and splaying of scleral fibers, indicative of significant shear- induced trauma. In contrast, the 27-gauge DOLCE needle produced a narrow, linear damage tract approximately 46.7 pm wide, with adjacent tissues remaining largely intact and exhibiting minimal lateral displacement or tearing. These findings demonstrate that the DOLCE needle caused substantially less mechanical trauma, nearly an order of magnitude less than conventional 18-gauge needles, suggesting superior biocompatibility. The reduced invasiveness is expected to lower the risk of post-injection complications, such as inflammation, delayed wound healing, fibrosis, or infection, making the DOLCE needle an attractive option for pharmacological and cell-based therapeutic delivery.

[0136] DOLCE needle with tissue identification function

[0137] Each cell therapy generally requires the precise delivery of therapeutic cells to specific tissues or blood vessels to ensure the cells' effective engraftment and performance. Sophisticated yet bulky equipment such as real-time magnetic resonance imaging (MRI), augmented reality, and ultrasonography have been used to better identify the target site and guide needle placement. However, these additive devices also complicate the accessibility of needle insertion procedures.

[0138] #14660029vl To address this, a DOLCE needle integrated with a tissue identification sensor was developed. It allows for real-time tracking of the tissue types during insertion, ensuring accurate and prompt placement in the target region.

[0139] Biological tissues differ in their electrical properties based on their cellular structure, water content, and ion composition, and the principle of tissue identification through bioimpedance spectroscopy is well-established. Using the sensor, located at the tip of the needle and featuring two tissue-interface electrodes (FIG. 6A), the impedance and phase angle of skin tissue layers, including the skin, fat, muscle, and blood, were measured. For impedance, fat presented the highest values due to its lower water content and fewer conductive pathways. In contrast, muscle and blood, with their higher water content and ionic concentrations, exhibited lower impedance, with blood having the lowest impedance among the tissues measured (FIG. 6B). The phase angle, a parameter explaining the relationship between a tissue's resistance and reactance, is typically higher in tissues with higher ionic concentration due to the capacitive behavior of ions. As shown in FIG. 6C, blood showed the highest phase angle of 60° at 1 kHz, while muscles, containing a lower concentration of water and ions than blood, presented a phase angle of -40°.

[0140] Furthermore, it was important that the sensor could distinguish between tissue types independently of penetration depth. To verify this, fat and muscle tissues were separated and impedance measurements were conducted as the needle penetrated each tissue from the surface to a depth of 4 mm (FIG. 15). The impedance and phase angle remained consistent at all depths in both muscle (FIG. 6D) and fat tissue (FIG. 6E), demonstrating the sensor’s independence.

[0141] The real-time profiling of tissue type using the sensor was examined using porcine skin tissue. To accurately evaluate the relationship between tissue type and impedance with respect to insertion depth, the needle's penetration velocity was fixed at 1 mm s1using the z-axis translational stage (H-820, Physik Instrumente, Germany) and penetrated the tissue for 20 seconds. To prevent errors from compression affecting tissue thickness during needle insertion and measurement, the tissue sample was constrained in a chamber (FIG. 16A-FIG. 16B). The measured impedance and phase angle profiles at 1 kHz were compared with a cross-sectional photograph of the tissue along the needle's penetration path. The tissue used in the experiment consisted of fat and muscle (FIG. 6F). High impedance and low phase angle were measured in the subcutaneous region just below the skin, indicating the impedance characteristics of fat tissue (FIG. 6G). From 12 to 18 mm, the presence of muscle tissue was identified by a decrease in impedance and an increase in phase angle. Beyond 18 mm, the impedance and phase angle in the

[0142] #14660029vl fat region returned to levels similar to those in the subcutaneous region. The transition region between fat and muscle tissue displayed sensing results indicative of the coexistence of both tissue types.

[0143] Numerous trials of cell therapies involve cell delivery via intravenous injection. In accordance with this, the blood vessel detection capability of the DOLCE needle was demonstrated. The measurement was conducted on euthanized swine to maintain the tissue structure from the skin to the jugular vein. Blood was filled in the jugular vein, and both ends were sealed with clamps to ensure a consistent environment where the needle could contact the blood (FIG. 17). During the needle's penetration from the skin to the vein (approximately 4 cm from the surface of the skin), impedance and phase angle were measured in real-time at a frequency of 1 kHz. Blood has lowest impedance and highest phase angle (FIG. 6C), allowing us to identify the point of vein penetration in real-time measurements. As shown in FIG. 6H, the impedance and phase angle changed according to the tissue types during needle’s penetration, with a clearly distinctive phase angle indicating contact with blood. To ensure the reliability of vein region identification through sensor signals, five blinded penetration tests were conducted. It was consistently observed that, upon contacting blood, the impedance decreased to around 30 kQ (FIG. 61), and the phase angle increased to around 60° (FIG. 61), compared to the tissue impedance just before reaching the vein. The real-time change of sensor signals allows for more accurate real-time tracking of the needle’s position and verification of its arrival at the target location, thereby augmenting the needle insertion procedure.

[0144] Here, a phase-transitioning needle (DOLCE) capable of delivering 3D cellular clusters with high viability and functionality by reducing mechanical stress is disclosed, making it suitable for cell therapy applications. By combining rigidity for tissue penetration and softness to mitigate mechanical stress on cellular clusters, this needle design addresses the major challenges, including the viability and functionality of cellular clusters as well as procedure-related complications of patients, associated with traditional delivery methods. The multilayered structure of gallium layers and the PU fiber network with cluster-level softness, ensures the needle's effectiveness in maintaining the morphology, viability, and functionality of cellular clusters despite its smaller diameter. Experimental results and FEA have confirmed the needle's ability to reduce mechanical forces experienced by cellular clusters, thereby enhancing their posttransplantation outcomes.

[0145] #14660029vl It was determined that the integration of a tissue identification sensor at the needle tip allows precise and real-time recognition of tissues and blood vessels, ensuring accurate and safe cell delivery.

[0146] Overall, the DOLCE needle offers a promising advancement for improving the efficacy and safety of cell therapies. Its ability to preserve cell integrity and functionality while reducing procedural risks paves the way for the broader clinical adoption of cell therapies, potentially transforming the treatment landscape for a range of diseases and disorders.

[0147] Methods

[0148] Fabrication of a DOLCE needle

[0149] Stainless steel wire with a diameter of 210 pm was prepared as a temporary support, and a biocompatible release agent was deposited on the support’s surface. A silicone elastomer was spray-coated on the support to a thickness of 20 pm. Next, pure gallium (99.99%) was melted at 40 °C and dip-coated on the elastomer layer to a thickness of 40 pm. For the porous elastomeric interlayer, a PU fiber network was deposited on the gallium layer through electrospinning. Gallium coating and PU fiber network deposition was repeated 4 times to form a multi-layered structure. Following that, the coated support was cast into a mold with a lancet-point tip structure at an elevated temperature of 40 °C. After quenching the coated support in liquid nitrogen, the support and needle were released from the mold. The support was then removed, leaving the needle with a lancet-point tip. A silicone elastomer was then spray-coated to encapsulate the needle. The tissue identification sensor was integrated onto the surface of the needle using silicone adhesive. After that, the needle was assembled with a drilled Luer-lock syringe cap.

[0150] Electrospinning of porous elastomeric interlayer

[0151] A solution of thermoplastic polyurethane (solvent: dimethylformamide (DMF); concentration=20 wt%) was used as an ink. The inner diameter of the electrospinning nozzle was 413 pm, and the nozzle was maintained 15 cm distance from the ground substrate, and the needle was placed between the nozzle and the substrate with 10 cm distance from the nozzle. The applied voltage between the nozzle tip and the substrate was 15 kV. The temperature and relative humidity in the electrospinning chamber were 20 °C and 4%, respectively. The flow rate of the ink was controlled to 0.5 ml h1using the syringe pump. The conformal elastomeric interlayer was formed in 20 sec with the needle rotation with 30 rpm.

[0152] Fabrication of a tissue identification sensor

[0153] The tissue identification sensor consists of two platinum electrodes and encapsulation layers of parylene (500 nm each) on the top and bottom. First, Cu (200 nm) was deposited on the

[0154] #14660029vl Si wafer by e-beam evaporation for the sacrificial layer. Parylene-C (500 nm) was then deposited on the bottom encapsulation layers. After that, the electrode pattern was predefined by a photolithographic process using lift-off resist and positive photoresist. On the pre-patterned substrate, Ti (10 nm) / Pt (200 nm) was e-beam evaporated, and the electrode was patterned by a lift-off process with a photoresist stripper. On the patterned electrodes, the top encapsulation layer of parylene-C (500 nm) was deposited and photographically patterned using reactive ion etching (O240 s.c.c.m., 100 W / 120 s) to expose tissue interfaces and interconnection pads. On the tissue interfaces, platinum nanostructures were electrodeposited with a solution consisting of 50 ml deionized water, 10 mg of lead acetate trihydrate, and 0.5 g of platinum tetrachloride. The electrodeposition was performed using a cathodic current density of 0.03 A cm'2for 10 min. Finally, the sensor was released from the Si wafer by wet-etching of the Cu layer. The fabricated sensor was then rinsed by gently immersing it in 70% ethanol solution and deionized water, and was sterilized by ultraviolet exposure.

[0155] Mechanical characterization

[0156] The mechanical stress versus strain characteristics of the needle were measured using a universal testing machine.

[0157] Tensile test: Both ends of a needle were fixed and the needle was then stretched with a tensile strain rate of 0.5 mm s’1.

[0158] Bending test: Both ends of a needle were fixed, and one end was loaded with a compressive force. The stress versus strain was measured during the needle deflection with a compressive strain rate of 0.5 mm s’1. The bending strength and bending stiffness were measured as the maximum load and the slope from the stress-strain curve, respectively.

[0159] Penetration force test: For skin tissue phantom, Ecoflex 00-10 was used, topped with a 1 mm-thick layer of poly-dimethyl siloxane. The needle was attached to a force gauge on a universal testing machine, and the load was measured during the penetration of the skin tissue phantom. For the penetration test with the skin of the euthanized pig, a needle was attached to the handheld force gauge, and the peak force was measured during penetration. The temperature of the skin tissue was also monitored during the penetration test to ensure that mechanical properties, which can be changed by temperature, were maintained.

[0160] Finite element analysis

[0161] Finite element analysis was performed using commercial software Abaqus. A 27-gauge stainless steel needle was benchmarked to compare performance with that of the DOLCE needle. For the stainless steel needle, the density of stainless steel was defined as 7.5g cm’3. For the

[0162] #14660029vl DOLCE needle, the liquid gallium was defined as a fluid cavity inside the needle with a density of 5.9 g cm'3. The Young’s modulus of the elastomer surrounding the liquid metal was set as 97 kPa, with a density of 1.07 g cm'3and a Poisson ratio of 0.49. The Young’s modulus of the stem cell was set as 10 kPa, with a density of 1.09 g cm'3and a Poisson ratio of 0.38. Contact between the cellular cluster and the needle was modeled as both normal hard contact and tangential contact with a friction coefficient of 0.02. For simulating the flushing of phosphate-buffered saline (PBS) inside the phase-transition needle, coupled-Eulerian-Lagrangian (CEL) techniques were used to model the interactions between solids and fluids. The PBS was defined with a density of 1.072 g cm'3, dynamic viscosity of 1.01 cP, and flow rate of 0.4 pL min1.

[0163] Cellular cluster culture

[0164] INS-1 832 / 13 rat insulinoma cell line (Cat. SCC207) was used. Cells were grown and expanded in RPML1640 medium, supplemented with 2 mM L-Glutamine, 1 mM sodium pyruvate, 10 mM HEPES, 0.05 mM P-mercaptoethanol and 10% FBS. Additionally, 100 U ml1penicillin and 100 pg ml1streptomycin at 37 °C was used to prevent contamination. Cells were cultured in a humidified incubator containing 5% CO2.

[0165] For the cluster formation, INS-1 cells were seeded at a density of 50 x 106in 500 mL polycarbonate Erlenmeyer flask with a total medium volume of 75 ml. The flask was placed on the orbital shaker set to 70 rpm and cultured for 48 to 72 hours.

[0166] HL-1 Cardiac Muscle Cell Line (Cat. SCC065) was used. Cells were grown and expanded in Claycomb medium supplemented with 10% FBS, 100 U ml1penicillin, and 100 pg ml1streptomycin, 0.1 mM Norepinephrine, 2 mM L-Glutamine at 37 °C was used to prevent contamination. Cells were cultured in a humidified incubator containing 5% CO2.

[0167] For the cluster formation, HL-1 cells were seeded at a density of 100 x 106in 500 mL polycarbonate Erlenmeyer flask with total medium volume 75 ml. The flask was placed on the orbital shaker set to 70 rpm and cultured for 3 to 5 days.

[0168] Extrusion of cellular clusters through needles

[0169] Dispersion of cellular clusters was prepared with a density of 200 clusters ml1. 3 ml of the cellular cluster suspension was filled in the syringe barrel through the plunger side, and the plunger was assembled into the syringe. After that, the needle was assembled into the syringe. The dish was prepared with culture media to receive the extruded cellular clusters. The syringe with a needle was fit to the syringe pump, and the distance between the needle tip and the culture dish was maintained to 1 cm. The flow rate of the syringe pump was 5 ml min1.

[0170] E-cadherin immunocytochemistry

[0171] #14660029vl Cells were fixed using Neutralized formalin solution for 60 min, respectively. The fixed samples were then washed with PBS for 30 min, permeabilized by 0.1% Triton X-100 for 30 min. After washing with PBS for 30 min and blocking with 4% bovine serum albumin for 1 hour, the cells were incubated with primary antibodies at 4 °C overnight. The antibodies used in this study were mouse monoclonal anti-E-Cadherin (4A2). After thorough washing with PBS, secondary antibodies conjugated with Rabbit anti-Mouse IgG Recombinant Secondary Antibody, Alexa Fluor™ Plus 488 were used. Nuclei were visualized with 4',6-diamidino-2-phenylindole, dihydrochloride. Samples were imaged with confocal microscopy.

[0172] Viability assay

[0173] Cell viability was assessed using the Live / Dead viability / cytotoxicity kit according to the manufacturer's protocol. Stained cells were then observed using confocal microscopy.

[0174] The cell viability was additionally evaluated using the CellTox™ Green Cytotoxicity Assay, following the manufacturer’s protocol.

[0175] Glucose-stimulated insulin secretion (GSIS)

[0176] To assess the function of INS cells, static GSIS was performed with cells after extrusion. Approximately 1000 clusters were used for each group. All cells were first washed twice with KRB buffer (128 mM NaCl, 5 mM KC1, 2.7 mM CaCl2, 1.2 mM MgSO4, 1 mM Na2HPO4, 1.2 mM KH2PO4, 5 mM NaHCO?, 10 mM HEPES and 0.1% BSA). Cells were first incubated in KRB buffer containing 2 mM glucose at 37 °C for 1 hour, after which this solution was discarded and replaced with fresh 2 mM glucose KRB buffer. After an additional two hours, the supernatant was collected. Then, 16 mM glucose KRB buffer was added for the next two hours, after which the supernatant was again collected. Cells were washed with fresh KRB buffer during each solution change. Collected samples from the 2- and 16-mM glucose challenges were quantified with a human insulin ELISA kit (80-INSHU-E10.1, ALPCO).

[0177] Electrical impedance spectroscopy

[0178] The impedance spectroscopy was performed over a frequency range of 0.01 to 100 kHz using an impedance analyzer. For real-time measurements, the frequency was fixed to 1 kHz.

[0179] Statistical analysis

[0180] Statistical analysis was conducted using a two- sample t-test using OriginPro 2024 software. A probability value of *p < 0.05 was considered indicative of a significant difference.

[0181] #14660029vl

Claims

1. CLAIMSWhat is claimed is:

1. An article for conveying a fluid, comprising: a lumen; a phase-changing layer comprising a low-melting-point metal; and an elastomeric fiber layer adjacent a phase-changing layer, wherein the article has a first stiffness above physiological temperature and a second stiffness, different than the first stiffness, below physiological temperature.

2. An article for conveying a fluid, comprising: a lumen; and a phase-changing layer comprising a low-melting-point metal impregnated within a porous elastomeric fiber layer.

3. An article as in any preceding claim, wherein the article is a needle having needle gauge of less than or equal to 20G and greater than or equal to 34G.

4. An article as in any preceding claim, wherein a surface of the article, at a temperature greater than or equal to physiological temperature, exhibits conformational deformation.

5. An article as in any preceding claim, wherein at least a portion of the article exhibits a phase change under physiological conditions.

6. An article as in claim 5, wherein the phase change is reversible.

7. An article as in any preceding claim, wherein the article is configured to flow a fluid comprising a plurality of cells such that the fluid flow does not shear the cells.

8. An article as in claim 7, wherein the article is configured to increase cell viability and / or functionality of the plurality of cells.#14660029vl9. An article as in any preceding claim, wherein the lumen has an inner diameter of greater than or equal to 10 nanometers and less than or equal to 10 mm, or greater than or equal to 50 microns and less than or equal to 500 microns.

10. An article as in any preceding claim, wherein the article is a needle.

11. A needle as in claim 10, wherein the lumen of the needle has an inner diameter of greater than or equal to 50 microns.

12. An article as in any preceding claim, wherein the article is configured to flow a fluid comprising a particle and / or a therapeutic agent.

13. An article as in any preceding claim, wherein the article is a catheter.

14. An article as in any preceding claim, wherein at least one of the phase-changing layer and the elastomeric fiber layers is encapsulated within a silicone elastomer.

15. An article as in any preceding claim, wherein the elastomeric fiber layer comprises a silicone elastomer and / or a co-polymer.

16. An article as in any preceding claim, wherein the elastomeric fiber layer comprises polydimethylsiloxane, polyurethane, polybutadiene, polystyrene, polyethylene, and / or polybutylene.

17. An article as in any preceding claim, wherein the low-melting-point metal comprises gallium, bismuth, tin, or their alloys.

18. A needle with the capacity for phase transition in a biological tissue in vivo, wherein the needle, under physiological conditions, is configured to substantially conform to an external shape of an object present within the needle.

19. A needle as in claim 18, wherein the object present within the needle is a cell.#14660029vl20. An article or needle as in any preceding claim, wherein the article or needle, under physiological conditions, has a Young’s modulus of less than or equal to 1 MPa and greater than or equal to 1 kPa.

21. An article or needle in any preceding claim, wherein the article or needle, at a temperature less than or equal to 20 °C has a Young’s modulus of less than or equal to 100 GPa and greater than or equal to 1 MPa.

22. An article or needle in any preceding claim, wherein the phase-changing layer and the elastomeric fiber layer form a multilayered arrangement.

23. An article or needle in any preceding claim, further comprising a sensor wherein, upon administration of the article to a subject, the location of the article may be determined.

24. An article or needle as in claim 23, wherein the sensor comprises an impedance detector.

25. A method for conveying fluid, the method comprising: providing a needle configured to change stiffness in response to a temperature change; heating the needle; and flowing an object through the needle such that the needle conforms to a shape of the object.

26. A method for conveying fluid, the method comprising: providing a needle configured to change stiffness in response to a temperature change; exposing the needle to physiological conditions, such that at least a portion of the needle changes phase; and flowing an object through the needle such that at least a portion of the needle conforms to an external shape of the object.#14660029vl

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