Barrier for hindering microbial transfer and method of manufacturing
Disposable gloves with hydrophobic materials and non-wetting microtopographies effectively reduce microbial transfer by 1.5-2.5 logs, addressing the challenge of pathogen transmission in healthcare settings.
Patent Information
- Authority / Receiving Office
- US · United States
- Patent Type
- Applications(United States)
- Current Assignee / Owner
- THE GOVERNING COUNCIL OF THE UNIV OF TORONTO
- Filing Date
- 2026-01-23
- Publication Date
- 2026-07-30
AI Technical Summary
Existing disposable gloves fail to effectively hinder microbial transfer, particularly in healthcare settings, leading to the touch transmission of pathogens such as bacteria and viruses.
Disposable gloves and barriers are designed with hydrophobic materials and non-wetting microtopographies, such as arrays of microposts or patterns of tongues and grooves, to create super-hydrophobic surfaces that reduce microbial attachment and transmission.
The combination of hydrophobic materials and non-wetting microtopographies provides a 1.5-2.5 log reduction in microbial contamination, significantly reducing the transfer of pathogens compared to standard gloves.
Smart Images

Figure US20260215524A1-D00000_ABST
Abstract
Description
CROSS-REFERENCES TO RELATED APPLICATIONS
[0001] This application claims priority to Canadian Patent Application No. 3271494 filed on Apr. 23, 2025, and claims the benefit of U.S. Provisional Patent Application No. 63 / 750,877 filed on Jan. 29, 2025. Each of the aforementioned applications is incorporated herein by reference in its entirety.FIELD
[0002] This document relates to methods and devices for hindering microbial transfer, such as may occur in healthcare settings and may cause the touch transmission of pathogens. More specifically, this document relates to barriers for hindering microbial transfer, for example in the form of disposable gloves, and methods for manufacturing such barriers.BACKGROUND
[0003] U.S. Patent Application Publication No. US20130059113A1 (to Hatton et al.) discloses methods of making and using substrates having raised structures to inhibit adhesion of microorganisms. Raised structures, and methods of using such structures to prevent, inhibit, or reduce the attachment of microorganisms onto substrates, are described. Such raised structures prevent, inhibit, or reduce the attachment of microorganisms on substrates when contacted with contaminated liquids containing a microorganism. The contact can be static due to simple exposure to a contaminated liquid or dynamic, such as contact due to splashing or pouring of the microorganism-containing liquid. Preferably, the adhesion is inhibited or reduced following temporary contact of the contaminated fluid. In certain embodiments, the contact lasts a few milliseconds to a few minutes.SUMMARY
[0004] The following summary is intended to introduce the reader to various aspects of the detailed description, but not to define or delimit any invention.
[0005] Disposable gloves are disclosed. According to some aspects, a disposable glove includes a glove bulk having an interior surface, an exterior surface having a high-touch side and a low-touch side, a palm section, and a plurality of finger sections. On at least the high-touch side, at least some of the finger sections include a respective pad that hinders microbial transfer. Each pad includes a hydrophobic material and a non-wetting microtopography.
[0006] In some examples, each pad provides a contact angle with water of at least about 110 degrees, and / or enables a Cassie-Baxter state of wetting.
[0007] In some examples, the glove bulk includes nitrile, latex, and / or vinyl.
[0008] In some examples, the hydrophobic material includes a polymer. The polymer may be inherently hydrophobic. The polymer may be combined with a surface-modifying additive that renders the material hydrophobic. The polymer may be chemically modified to render the polymer hydrophobic.
[0009] In some examples, the polymer is functionalized with a silane. The polymer may include a UV-cured urethane-acrylate polymer, and the silane may include a trichloro silane.
[0010] In some examples, the non-wetting microtopography includes features having a depth of between 1 about micron and about 1 mm, such as between about 5 microns and about 25 microns.
[0011] In some examples, the non-wetting microtopography includes an array of microposts. The microposts may have a diameter of between about 2.5 microns and about 40 microns and an interpost spacing of between about 4 microns and about 100 microns. The microposts may have a diameter of between about 2.5 microns and about 15 microns and an interpost spacing of between about 5 microns and about 20 microns
[0012] In some examples, the non-wetting microtopography includes a pattern of tongues and grooves. Each tongue may have a tongue width of between about 2.5 microns and about 30 microns, and each groove may have a groove width of between about 5 microns and about 15 microns. Each tongue may have a tongue width of between about 2.5 microns and about 15 microns, and each groove may have a groove width of between about 5 microns and about 10 microns.
[0013] In some examples, each pad has a surface area of at least about 1 square centimeter, or between about 1 square centimeter and about 100 square centimeters. In some examples, each pad has a surface area of between about 2.5 square centimeters and about 3.5 square centimeters.
[0014] In some examples, the pads are on only the high-touch side, and on only the finger sections. In some examples, all of the finger sections comprise a respective one of the pads.
[0015] In some examples, the pads are adhered to the glove bulk. In some examples, the pads are molded to the glove bulk. In some examples, the pads are integrally formed with the glove bulk.
[0016] In some examples, the pads have a thickness of between about 10 microns and about 500 microns. In some examples, the pads have a thickness of between about 50 microns and about 200 microns.
[0017] Disposable barriers for hindering microbial transfer are also disclosed. According to some aspects, a disposable barrier for hindering microbial transfer includes, a flexible and sheet-like bulk material having a high-touch side and a low-touch side. The high-touch side includes at least a first pad that hinders microbial transfer. The first pad includes a hydrophobic material and a non-wetting microtopography.
[0018] In some examples, the first pad provides a contact angle with water of at least about 110 degrees, and / or enables a Cassie-Baxter state of wetting.
[0019] In some examples, the bulk material includes nitrile, latex, and / or vinyl.
[0020] In some examples, the hydrophobic material includes a polymer. The polymer may be inherently hydrophobic. The polymer may be combined with a surface-modifying additive that renders the material hydrophobic. The polymer may be chemically modified to render the polymer hydrophobic.
[0021] In some examples, the polymer is functionalized with a silane. The polymer may include a UV-cured urethane-acrylate polymer, and the silane may include a trichloro silane.
[0022] In some examples, the non-wetting microtopography includes features having a depth of between about 1 micron and about 1 mm. In some examples, the non-wetting microtopography includes features having a depth of between 5 about microns and about 25 microns.
[0023] In some examples, the non-wetting microtopography includes an array of microposts. The microposts may have a diameter of between about 2.5 microns and about 40 microns and an interpost spacing of between about 4 microns and about 100 microns. The microposts may have a diameter of between about 2.5 microns and about 15 microns and an interpost spacing of between about 5 microns and about 20 microns.
[0024] In some examples, the non-wetting microtopography includes a pattern of tongues and grooves. Each tongue may have a tongue width of between about 2.5 microns and about 30 microns, and each groove may have a groove width of between about 5 microns and about 15 microns. Each tongue may have a tongue width of between about 2.5 microns and about 15 microns, and each groove may have a groove width of between about 5 microns and about 10 microns.
[0025] In some examples, each pad has a surface area of at least about 1 square centimeter, or between about 1 square centimeter and about 100 square centimeters. In some examples, each pad has a surface area of between about 2.5 square centimeters and about 3.5 square centimeters.
[0026] In some examples, the pads are adhered to the bulk material. In some examples, the pads are molded to the bulk material. In some examples, the pads are integrally formed with the bulk material.
[0027] In some examples, the pads have a thickness of between about 10 microns and about 500 microns. In some examples, the pads have a thickness of between about 50 microns and about 200 microns.
[0028] In some examples, the bulk material is formed into a glove having an interior surface and an exterior surface, a palm section, and a plurality of finger sections. The exterior surface may include the high-touch side and the low-touch side, and the first pad may be provided on one of the finger sections.
[0029] Methods for manufacturing a disposable glove are disclosed. According to some aspects, a method for manufacturing a disposable glove includes: a. providing a glove bulk having an interior surface, an exterior surface having a high-touch side and a low-touch side, a palm section, and a plurality of finger sections; and b. on at least the high-touch side, providing at least some of the finger sections with a respective pad that hinders microbial transfer. Each pad includes a hydrophobic material and a non-wetting microtopography.
[0030] In some examples, step b. includes forming each pad and then applying each pad to the glove bulk. In some examples, step b. includes molding each pad onto the glove bulk. In some examples, step a. includes forming the glove bulk, and step b. includes integrally forming each pad with the glove bulk.
[0031] In some examples, step b. includes molding each pad from a polymer to yield the non-wetting microtopography. In some examples, the polymer is inherently hydrophobic. In some examples, the method further includes combining the polymer with a surface-modifying additive that renders the material hydrophobic. In some examples, the method further includes chemically modifying the polymer to render the polymer hydrophobic.
[0032] In some examples, the method further includes functionalizing the polymer with a silane to yield the hydrophobic material. The polymer may include a UV-cured urethane-acrylate polymer, and the silane may include a trichloro silane.
[0033] In some examples, step b. includes forming each pad such that the non-wetting microtopography has a depth of between about 5 microns and about 25 microns.
[0034] In some examples, step b. includes forming each pad such that the non-wetting microtopography includes an array of microposts, wherein the microposts have a diameter of between about 2.5 microns and about 40 microns and an interpost spacing of between about 4 microns and about 100 microns. In some examples, step b. includes forming each pad such that the non-wetting microtopography includes an array of microposts, wherein the microposts have a diameter of between about 2.5 microns and about 15 microns and an interpost spacing of between about 5 microns and about 20 microns.
[0035] In some examples, step b. includes forming the pads such that the non-wetting microtopography includes a pattern of tongues and grooves, wherein each tongue has a tongue width of between about 2.5 microns and about 30 microns, and each groove has a groove width of between about 5 microns and about 15 microns. In some examples, step b. includes forming the pads such that the non-wetting microtopography comprises a pattern of tongues and grooves, wherein each tongue has a tongue width of between about 2.5 microns and about 15 microns, and each groove has a groove width of between about 5 microns and about 10 microns.
[0036] In some examples, step b. includes forming the pads such that each pad has a surface area of at least about 1 square centimeter, or between about 1 square centimeter and about 100 square centimeters. In some examples, step b. includes forming the pads such that each pad has a surface area of between about 2.5 square centimeters and about 3.5 square centimeters.
[0037] In some examples, step b. includes providing the pads on only the high-touch side, and on only the finger sections. In some examples, step b. includes providing the pads on all of the finger sections.
[0038] In some examples, step b. includes forming the pads to have a thickness of between about 10 micron and about 500 microns. In some examples step b. includes forming the pads to have a thickness of between about 50 micron and about 200 microns.
[0039] Pads for hindering microbial transfer are disclosed. According to some aspects, a pad for hindering microbial transfer includes a hydrophobic material and a non-wetting microtopography. The pad is affixable to a high-touch surface of a flexible and sheet-like bulk material.
[0040] In some examples, the pad provides a contact angle with water of at least about 110 degrees, and / or enables a Cassie-Baxter state of wetting.
[0041] In some examples, the hydrophobic material includes a polymer. In some examples, the polymer is inherently hydrophobic. In some examples, the polymer is combined with a surface-modifying additive that renders the material hydrophobic. In some examples, the polymer is chemically modified to render the polymer hydrophobic.
[0042] In some examples, the polymer is functionalized with a silane. In some examples, the polymer includes a UV-cured urethane-acrylate polymer, and the silane includes a trichloro silane.
[0043] In some examples, the non-wetting microtopography has a depth of between about 1 micron and about 1 mm. In some examples, the non-wetting microtopography has a depth of between about 5 microns and about 25 microns.
[0044] In some examples, the non-wetting microtopography includes an array of microposts. In some examples, the microposts have a diameter of between about 2.5 microns and about 40 microns and an interpost spacing of between about 4 microns and about 100 microns. In some examples, the microposts have a diameter of between about 2.5 microns and about 15 microns and an interpost spacing of between about 5 microns and about 20 microns.
[0045] In some examples, the non-wetting microtopography includes a pattern of tongues and grooves. In some examples, each tongue has a tongue width of between about 2.5 microns and about 30 microns, and each groove has a groove width of between about 5 microns and about 15 microns. In some examples, each tongue has a tongue width of between about 2.5 microns and about 15 microns, and each groove has a groove width of between about 5 microns and about 10 microns.
[0046] In some examples, the pad has a surface area of at least about 1 square centimeters, or between about 1 square centimeter and about 100 square centimeters. In some examples, the pad has a surface area of between about 2.5 square centimeters and about 3.5 square centimeters.
[0047] In some examples, the pad has a thickness of between about 10 microns and about 500 microns. In some examples, the pad has a thickness of between about 50 microns and about 200 microns.BRIEF DESCRIPTION OF THE DRAWINGS
[0048] The drawings included herewith are for illustrating various examples of articles, methods, and apparatuses of the present specification and are not intended to limit the scope of what is taught in any way. In the drawings:
[0049] FIG. 1 is a perspective view of a first example disposable barrier and a second example disposable barrier, in the form of a first disposable glove and a second disposable glove, respectively.
[0050] FIG. 2A is a top view of a pad of the first disposable glove of FIG. 1, with the encircled portion of the pad shown in enlarged view.
[0051] FIG. 2B is cross-section taken along line B-B in FIG. 2A.
[0052] FIG. 3A is a top view of another example pad, with the encircled portion of the pad shown in enlarged view.
[0053] FIG. 3B is cross-section taken along line B-B in FIG. 3A.
[0054] FIG. 4A is a top view of another example pad, with the encircled portion of the pad shown in enlarged view.
[0055] FIG. 4B is cross-section taken along line B-B in FIG. 4A.
[0056] FIG. 5A is a top view of another example pad, with the encircled portion of the pad shown in enlarged view.
[0057] FIG. 5B is cross-section taken along line B-B in FIG. 5A.
[0058] FIG. 6 (a) The surface of conventional nitrile examination gloves, showing a smooth morphology macroscopically, with microscale roughness and surface features apparent through SEM and surface profilometry. (b) Sequence of surface touch contact transmission events consisting of a ‘pick-up’ and ‘drop-off’ event, each with an associated transfer efficiency (I). (c) Detailed schematic of the mechanism by which both conventional nitrile gloves and the test gloves interact with contaminated surfaces. (d) The surface of a test glove macroscopically (left image), which consists of a non-wetting microtopography shown through SEM (center image) and profilometry (right image).
[0059] FIG. 7 (a) Schematic of the lab-scale simulated touch contact setup where an applied force presses the glove samples down onto a contaminated surface. Each glove sample consists of a nitrile glove wrapped around PDMS to mimic human tissue stiffness. (b) Visualization of the contact and removal phase, showing the contaminant droplet bridging the two surfaces during removal.
[0060] FIG. 8 (a) Surface characteristics of commercially available glove materials through digital profilometry, SEM (scale bar=25 μm), and static contact angles. (b) Bacterial transmission from a contaminated stainless steel coupon (silver bars) to a glove material (orange bars) following a single touch contact event (n=5). (c) Contamination of a nitrile glove with K. pneumoniae following a single contact event.
[0061] FIG. 9 (a) Prototype design of test gloves showing an SEM image of the transition area between the non-wetting microtopography (top) and the native glove roughness (bottom). (b-d) SEM images, design schematics, and measurement of the critical dimensions for each non-wetting microtopography tested (scale bar=10 μm) (e) Representative 3D digital profilometry images of each non-wetting microtopography.
[0062] FIG. 10. Pick-up efficiencies for each test glove from a steel coupon. Sample labels are marked by the shape of the non-wetting microtopography-control both unmodified and functionalized (C and C* respectively), microposts (P), square tongues and grooves (G), and sawtooth tongues and grooves(S). Each number refers to the size of the critical dimension as reported in FIG. 10. Statistical differences noted are for comparisons between the microbial pick-ups of different non wetting microtopographies (orange bars) (n=6).
[0063] FIG. 11 (A) Variations in transmission of S. aureus onto several microtopographies with varying wetting states including plasma treated hydrophilic (P), as-made hydrophobic (M), and functionalized hydrophobic (F). (B) S. aureus transmission under different applied normal forces, showing no increase to the accumulation of cells. (C) (top) Confocal microscopy images of S. aureus following light pressing experiments (1N) indicating the location of cell contamination on each type of microtopography (scale bar=50 μm). (bottom) SEM images showing the location of cells either on the tops of the topographies (post, groove) or at random locations throughout (sawtooth) (scale bar=10 μm).
[0064] FIG. 12. (a) Schematic of sequential touch sequence, with the overall sequence shown by the directions of the red arrows. (b) Microbial transmission results for K. pneumoniae and S. aureus following an 8 surface sequential touch experiment (n=5).
[0065] FIG. 13. Influence of contact time on the attachment of Staphylococcus aureus on various test gloves (n=5) as assessed through CFU plating (left) and fluorescence microscopy (right)—scale bar=10 μm.DETAILED DESCRIPTION
[0066] Various apparatuses or processes or compositions will be described below to provide an example of an embodiment of the claimed subject matter. No embodiment described below limits any claim and any claim may cover processes or apparatuses or compositions that differ from those described below. The claims are not limited to apparatuses or processes or compositions having all of the features of any one apparatus or process or composition described below or to features common to multiple or all of the apparatuses or processes or compositions described below. It is possible that an apparatus or process or composition described below is not an embodiment of any exclusive right granted by issuance of this patent application. Any subject matter described below and for which an exclusive right is not granted by issuance of this patent application may be the subject matter of another protective instrument, for example, a continuing patent application, and the applicants, inventors or owners do not intend to abandon, disclaim or dedicate to the public any such subject matter by its disclosure in this document.
[0067] Numerous specific details are set forth below in order to provide a thorough understanding of the subject matter described herein. However, it will be understood by those of ordinary skill in the art that the subject matter described herein may be practiced without these specific details. In other instances, well-known methods, procedures and components have not been described in detail so as not to obscure the subject matter described herein. The description is not to be considered as limiting the scope of the subject matter described herein.
[0068] As used herein, the wording “and / or” is intended to represent an inclusive-or. That is, “X and / or Y” is intended to mean X or Y or both. As a further example, “X, Y, and / or Z” is intended to mean X or Y or Z or any combination thereof. Furthermore, the phrase “at least one of A and B” is intended to mean only A (i.e. one or multiple of A), only B (i.e. one or multiple of B), or a combination of one or more of A and one or more of B.
[0069] Terms of degree such as “substantially”, “about”, and “approximately” as used herein mean a reasonable amount of deviation of the modified term such that the end result is not significantly changed. These terms of degree may also be construed as including a deviation of the modified term if this deviation would not negate the meaning of the term it modifies.
[0070] Any recitation of numerical ranges by endpoints herein includes all numbers and fractions subsumed within that range (e.g. 1 to 5 includes 1, 1.5, 2, 2.75, 3, 3.90, 4, and 5). It is also to be understood that all numbers and fractions thereof are presumed to be modified by the term “about” which means a variation of up to a certain amount of the number to which reference is being made if the end result is not significantly changed.
[0071] Generally disclosed herein are barriers for hindering microbial transfer. The barriers may be disposable and include a flexible and sheet-like bulk material. For example, the barriers may be in the form of disposable gloves, disposable medical tray liners, disposable stickers (e.g. for bedrail handles), or disposable surgical sheeting.
[0072] As used herein, the term “disposable” indicates that the referenced product is designed to be used for only a brief period of time (e.g. seconds, minutes, or hours), and / or for only a single use (e.g. while interacting with a single patient), and then disposed of. Furthermore, the term “disposable” indicates that the referenced product is not designed to be sterilized via standard sterilization techniques (e.g. steam or chemical sterilization) and / or cannot undergo standard sterilization techniques without destruction.
[0073] As used herein, the term “flexible” indicates that the referenced product can conform to various shapes, such as the shape of a hand or a tray.
[0074] As used herein, the term “sheet-like” indicates that the referenced product generally mimics the dimensions of a sheet, e.g. has a relatively large length and / or width in comparison to its thickness
[0075] The barriers described herein may be particularly useful in healthcare settings, such as in hospitals and / or clinics and / or pharmacies and / or emergency medical service vehicles (e.g. ambulances); however, the barriers may be used in a variety of other settings (e.g. elder care facilities, child care sites, food preparation sites, etc.). The barriers may serve to hinder (i.e. to limit or prevent or minimize or reduce) microbial transfer (i.e. transfer of microbes such as bacteria, viruses, and fungi from one surface to another), and thereby hinder touch transmission of pathogens (e.g. norovirus, Pseudomonas aeruginosa, Acintenobacter baumannii, Candida species (e.g. Candida albicans), Enterococcus faecium, Escherichia coli, Klebsiella pneumoniae, Staphylococcus aureus, methicillin-resistant Staphylococcus aureus (MRSA), and / or Staphylococcus epidermidis). This in turn may hinder the spread of infectious disease.
[0076] The barriers described herein generally include one or more pads that hinder microbial transfer. The pad(s) may be configured to cover all or a majority of the surface area of the barrier, or may cover only a limited portion of the surface area of the barrier. For example, in the case of a medical tray liner, the pad may cover all or a majority of the high-touch side (i.e. the outward facing side) of the medical tray liner. For further example, in the case of medical gloves, pads may be provided on only a high-touch side of each glove (i.e. the palm side as opposed to the side covering the back of the hand), and on only the fingertips of the gloves. Alternatively, a single pad may be provided on the entire high-touch side of each glove.
[0077] The pads may generally include a hydrophobic material and a non-wetting-microtopography (described in further detail below). The combination of the hydrophobic material and the non-wetting microtopography may yield a surface that is “super-hydrophobic”, whereby the non-wetting microtopography enhances the hydrophobicity of the hydrophobic material. As used herein, the term “super-hydrophobic” refers to a surface that provides a contact angle with water of at least about 110 degrees, and / or enables a Cassie-Baxter (C-B) state of wetting. As used herein, the term “Cassie-Baxter state of wetting” refers to a state in which a water interface sits on the top surfaces of the microtopography, resulting in air pockets that are bounded between the pads and the water. This super-hydrophobicity may hinder microbial attachment to the pad, and may thereby hinder touch transmission of pathogens. In particular, the pads described herein may in some examples provide about a 1.5 to 2.5 log reduction in attached cell contamination for disposable gloves as compared to similar disposable gloves that do not include the pads.
[0078] Referring now to FIG. 1, a first example of a disposable barrier is shown. In particular, a first disposable glove 100 and a second disposable glove 102 are shown (whereby each glove forms a respective disposable barrier). The first disposable glove has a glove bulk 104, which is formed from a flexible and sheet-like bulk material such as nitrile, latex, and / or vinyl. The glove bulk 104 has an interior surface 106 and an exterior surface 108. In use, the interior surface 106 is generally in contact with the wearer's skin, and the exterior surface 108 may contact various surfaces that may be contaminated with pathogens or may be susceptible to contamination with pathogens. The exterior surface 108 further has a high-touch side 110, and a low-touch side (not visible). In use, the high-touch side 110 is intended to be worn against the front of the user's hand, and the low touch side is intended to be worn against the back of the user's hand. The glove bulk further has a palm section 112, and a plurality (i.e. five) finger sections 114 (only two of which are labelled). Likewise, the second disposable glove 102 has a glove bulk 116, which has an interior surface 118, an exterior surface 120 having a high-touch side (not visible) and a low-touch side 122, a palm section 124, and a plurality (i.e. five) finger sections 126 (only two of which are labelled).
[0079] Referring still to FIG. 1, and in particular to the first disposable glove 100, on the high-touch 110 side of the exterior surface 108, the finger sections 114 each include a respective pad 128 that hinders microbial transfer. The second glove 102 likewise includes pads that hinder microbial transfer; however, the pads of the second glove are not visible in FIG. 1. As will be described in further detail below, each pad 128 includes a hydrophobic material and a non-wetting microtopography, the combined effects of which serve to hinder microbial attachment to the pads 128, and may thereby hinder touch transmission of pathogens.
[0080] In general, pads 128 may be provided on at least the high-touch side 110 of the exterior surface 108. In the example shown, the pads 128 are provided on only the high-touch side 110 of the exterior surface 108; however in alternative examples, one or more pads 128 may be provided on the low-touch side, or one or more pads 128 may cover both the high-touch 110 side and the low-touch side (e.g. a single pad 128 may extend around and cover an entire finger section 114).
[0081] In general, at least some of the finger sections 114 may include a pad 128. In the example shown, all of the finger sections 114 include one of the pads 128; however, in alternative examples, pads may be provided on only some of the finger sections 114 (e.g. a pad 128 may be omitted on the thumb section).
[0082] In the example shown, the pads 128 are provided on only the finger sections 114, and more specifically, on only the tips of the finger sections 114. In alternative examples, the pads 128 may extend the full length of the finger sections 114, and / or a pad 128 may be provided on the palm section 112. In other words, in the example shown, the pads 128 have a relatively small surface area; however, in alternative examples, the pads 128 may have a relatively large surface area. For example, the surface area of each pad 128 may be at least about 1 square centimeter, or between about 1 square centimeter and about 100 square centimeters, or between about 2.5 square centimeters and about 3.5 square centimeters. The term “surface area” as used herein refers to the surface area of the pads 128 on a macroscopic level (i.e. the term “surface area” does not account for the microtopography described below).
[0083] As mentioned above, each pad 128 includes a hydrophobic material and a non-wetting microtopography. The combination of the hydrophobic material and the non-wetting-microtopography may yield a surface that is “super-hydrophobic”, which may hinder microbial attachment to the pads 128, and may thereby hinder touch transmission of pathogens.
[0084] As used herein, the term “hydrophobic material” refers to any material that has a static contact angle with water (also referred to herein simply as a “contact angle”) of greater than 90 degrees. The hydrophobic material may make up the entirety of each pad 128, or may be provided on only the surface of the pads 128 (e.g. may be provided as surface treatment or a coating on a substrate).
[0085] The hydrophobic material may in some examples include a polymer. Suitable polymers include, but are not limited to, liquid silicone rubber, nitrile rubber, polyurethane (PU), polymethyl methacrylate (PMMA), polystyrene (PS), polypropylene (PP), cyclic olefin copolymers (COC), polyoxymethylene (POM), polyethylene (PE), polyamide (PA), poly ether ether ketone (PEEK), polycarbonate (PC), polybutylene terephthalate (PBT), acrylonitrile butadiene styrene (ABS), polyphenyl ether (PPE), and / or an epoxy. The polymer may be, for example, a thermally curable polymer (e.g. PU or silicone), a UV-curable polymer (e.g. PU or silicone), or a thermoplastic elastomer (like thermoplastic PU).
[0086] In some examples, the polymer is inherently hydrophobic. For example, the polymer may be polytetrafluoroethylene or polyvinylidene fluoride.
[0087] In some examples, the polymer is combined with an additive, such as a surface-modifying additive, that renders the material hydrophobic. For example, the polymer may be combined with an additive, whereby upon curing or cross-linking, a hydrophobic species migrates to the surface of the polymer.
[0088] In some examples, the polymer surface is chemically modified to render the polymer hydrophobic. For example, the polymer may be a UV-cured urethane-acrylate polymer, and may be functionalized with a composite wax or silane (e.g. trichloro silane, methyltrimethoxysilane, vinyltriethoxysilane, and / or propyltrimethoxysilane) to render the polymer hydrophobic.
[0089] In some examples, the hydrophobic material is a non-woven material. In other examples, the hydrophobic material is a woven material.
[0090] As used herein, the term “microtopography” refers to a pattern of micron-scale features (e.g. posts and / or tongues and grooves) on a surface. The term “micron-scale” indicates that the depth and / or diameter (in the case of posts) and / or width (in the case of tongues and grooves) and / or length and / or spacing of the features is less than about 1000 microns. Preferably, the micron-scale features have a diameter or width of between about 20 microns and about 30 microns, and a spacing of between about 20 microns and about 30 microns; while the length may in some cases be larger than about 1000 microns (e.g. in the case of tongues and grooves). The term “non-wetting microtopography” refers to a microtopography applied to a hydrophobic material, whereby the microtopography enhances the hydrophobicity of the hydrophobic material. For example, a given hydrophobic material, without a non-wetting microtopography, may have a contact angle of θ; however, when a non-wetting microtopography is applied to that hydrophobic material, the contact angle will increase to greater than e.
[0091] Referring now to FIGS. 2A and 2B, a first example of a non-wetting microtopography is shown (it will be appreciated that the Figures are not to scale, and in some instances the dimensions of the microtopography have been enhanced for visibility). In the example shown, the non-wetting microtopography includes an array of generally circular microposts 130 (only some of which are labelled). The microposts 130 may, for example, have a diameter 132 of between about 2.5 microns and about 40 microns (e.g. between about 2.5 microns and about 15 microns) and an interpost spacing 134 of between about 4 microns and about 100 microns (e.g. between 5 microns and 20 microns). The microposts 130 may, for example, have a depth 136 of between about 1 micron and about 1 mm (more specifically between about 2.5 microns and about 5 microns).
[0092] Referring now to FIGS. 3A and 3B, a second example of a non-wetting microtopography is shown. In the example shown, the non-wetting microtopography includes an array of generally oblong microposts 138 (only some of which are labelled). The oblong microposts 138 may, for example, have a width 140 of between about 2.5 microns and about 40 microns (e.g. between about 2.5 microns and about 15 microns) and an interpost spacing 142 of between about 4 microns and about 100 microns (e.g. between about 5 microns and about 20 microns). The oblong microposts 138 may, for example, have a depth 144 of between about 1 micron and about 1 mm (e.g. between about 2.5 microns and about 5 microns).
[0093] Referring now to FIGS. 4A and 4B, a third example of a non-wetting microtopography is shown. In the example shown, the non-wetting microtopography includes a pattern of tongues 146 and grooves 148 (only some of which are labelled) that are generally square in cross-section. Each tongue 146 may, for example, have a tongue width 150 of between about 2.5 microns and about 30 microns (e.g. between about 2.5 microns and about 15 microns), and each groove 148 may have, for example, a groove width 152 of between about 5 microns and about 15 microns (e.g. between about 5 microns and about 10 microns). The tongues 146 may, for example, have a depth 154 of between 1 micron and 1 mm (e.g. between about 2.5 microns and about 5 microns).
[0094] Referring now to FIGS. 5A and 5B, a fourth example of a non-wetting microtopography is shown. In the example shown, the non-wetting microtopography includes a pattern of tongues 156 and grooves 158 that are generally sawtooth shaped in cross-section. Each tongue 156 may, for example, have a tongue width 160 (at its tip) of between about 2.5 microns and 30 microns (e.g. between about 2.5 microns and about 15 microns), and each groove 158 may have, for example, a groove width 162 (at its base) of between about 5 microns and about 15 microns (more specifically between about 5 microns and about 10 microns). The tongues 156 may, for example, have a depth 164 of between about 1 micron and about 1 mm (more specifically between about 2.5 microns and about 5 microns).
[0095] The non-wetting microtopography may include various other shapes and patterns. For example, the posts, tongues, and / or grooves may have various other shapes, and may be arranged in various other patterns. In some particular examples, the posts, tongues, and / or grooves may have a re-entrant curvature (e.g. may be mushroom shaped). For further example, the tongues and grooves may all be parallel and non-intersecting as shown in FIGS. 4A and 5A, or the tongues and grooves may be non-parallel and / or may intersect. For further example, the pattern of the features may be regular as shown in FIGS. 2A to 5A, or may be irregular. For further example, the pads may be formed from a woven-material, in which woven nature of the material provides the non-wetting microtopography. That is, woven fibers may provide a non-wetting microtopography in the form of a re-entrant curvature and / or a pattern of tongues and grooves.
[0096] In general, the pads 128 may be relatively thin, in order to minimize changes in haptics as compared to gloves that do not include any such pads 128. For example, the pads 128 may have a thickness 166 (labelled in FIG. 2B) of between about 10 microns and about 500 microns (e.g. between about 50 microns and about 200 microns). In alternative examples, the pads may have a thickness of up to 1 mm.
[0097] In some examples, the pads 128 may be provided separately from the glove bulk 104, and applied to the glove bulk 104 at the point of use. For example, the back face of the pads 128 may be affixable (e.g. using an adhesive) to the high-touch side of the 110 glove bulk 104 via a dispenser at the point of use.
[0098] In some examples, the pads 128 may be provided pre-applied to glove bulk 104. For example, as will be described in further detail below, the pads 128 may be formed and then affixed (e.g. adhered) to the glove bulk 104 at the point of manufacture; molded to the glove bulk 104; or integrally formed with the glove bulk 104.
[0099] In some particular examples, a polymer is molded onto the glove bulk 104, using a mold that imparts the non-wetting microtopography to the polymer. For example, the polymer can be a urethane-acrylate polymer, and can be molded onto the glove bulk 104 and then cured (e.g. via UV curing).
[0100] As described above, in some examples, the polymer is inherently hydrophobic. In other examples, the polymer is combined with a surface-modifying additive that renders the material hydrophobic. In other examples, the polymer can be chemically modified to render the polymer hydrophobic (e.g. the polymer can be functionalized with a silane, such as a trichloro silane).
[0101] As described above, it has been determined that the pads 128 described herein can provide a 1.5-2.5 log reduction in contamination. In particular, with the use of the gloves 100, 102 of FIG. 1, only 1.75-2.41% of microbes may be transferred to secondary surfaces. In comparison, with the use of standard nitrile gloves, 39.1-43.6% of microbes may be transferred to secondary surfaces. It is believed that this reduction in the transfer of microbes is due to the combined effect of the hydrophobic material and non-wetting microtopography. It is further believed that this reduction in the transfer of microbes may in turn hinder touch transmission of pathogens.
[0102] The above description relates to disposable barriers in the form of disposable gloves, and the bulk material of the disposable glove is referred to as a glove bulk. However, as noted above, in alternative examples, the disposable barrier may be in another form, such as a disposable tray liner, disposable surgical sheeting, and the like.EXAMPLES
[0103] Prototype disposable gloves including pads as described above were prepared and tested. The prototypes are referred to below as “test gloves”.Materials & Methods
[0104] Materials: Bacteriological agar (BioShop), LB miller (powder, BioShop), glutaraldehyde (GDA) (Sigma Aldrich), Tween-20 (Sigma, Aldrich), Sytox Green nucleic acid stain (Life Technologies), ethanol (HPLC grade, Sigma Aldrich), Microflex® Supreno SE nitrile examination gloves (Ansell), Dymax Light Weld 4-20508 urethane-acrylate blend UV-curable polymer (Dymax), trichloro (1H, 1H, 2H, 2H-perfluoro octyl silane) (Sigma Aldrich), and Dow Corning Sylgard 184 silicone elastomer kits (Paisely Products of Canada Inc.) were all used as purchased.
[0105] Modification of Prefabricated Disposable Gloves: Test gloves were fabricated by molding a UV-curable polymer onto a flat nitrile glove surface. To simulate the impact of human tissue on the contact mechanics during touch transmission, sections of the test glove were stretched over a silicone rubber. 15 g of a 10:1 ratio of PDMS prepolymer to crosslinker was poured into a 100 mm petri dish (VWR Canada) and cured at 60° C. overnight. 4 cm2 were cut from the cured PDMS and 8 cm2 sections of the nitrile glove material were stretched over the PDMS and fixed using masking tape.
[0106] All non-wetting microtopographies tested were generated initially using photolithography. Sawtooth microtopographies were purchased from FLEXcon USA. Each master mold was exposed to oxygen plasma (Harrick Plasma PDC001) for 3 minutes to prepare for functionalization and molding. Functionalization was carried out under vacuum conditions in a desiccation chamber for 3 h with an open vial containing 50 μL of trichloro silane to impart hydrophobicity. Negative molds of the microtopographies were prepared by pouring a 10:1 ratio of PDMS over the master mold and curing overnight at 60° C. Completed negative molds were detached after curing from the master molds manually. The final microtopographies were molded onto the nitrile surface by applying a 15-20 μL drop of a UV-curable urethane-acrylate polymer (Dymax 4-20508) to the center. Negative molds were pressed over top of the droplet and the polymer was cured (Dymax BlueWave LED DX-1000 Visicure system (405 nm) at full intensity (~800 mW / cm2)) for 200 s. To impart hydrophobicity on the final test gloves, all samples were functionalized by a trichloro silane species as described above.
[0107] Surface Characterization: Each microtopography was imaged through both optical microscopy (Olympus BX63, Tokyo, Japan) and scanning electron microscopy (Thermo Scientific Prisma E SEM). Dimensions of each microtopography are reported as an average of 15 images taken at random locations on the sample. To confirm the functionalization of the non-wetting microtopography, static contact angles were measured using a lab-made goniometer system. 10 μL drops of DI water were applied to the sample surface and contact angles were assessed using ImageJ and the contact angle plugin (Marco Brugnara). All contact angle measurements were repeated ten times. Surface roughness parameters were collected via white light interferometry (Bruker Contour GT-K, Tucson, AZ USA) and non-contact digital microscopy (Keyence VHX-7000).
[0108] Microbial testing: To assess the reduction of microbial transmission of test gloves, several tests with a series of bacterial strains were carried out. The strains used are: Staphylococcus aureus KR3, Staphylococcus epidermidis SE801 (clinical strain), Escherichia coli ATCC 25922, Klebsiella pneumoniae ATCC 13883, Enterococcus faecium #35667, and Candida albicans SC5314. Single colonies of each bacterial strain were isolated from a lysogeny broth (LB) Miller agar media plate grown overnight and mixed into 4 mL LB Miller medium. C. albicans was prepared in a similar method using YPD media. Stock solutions were grown overnight under agitation at 37° C. 1 mL of each stock was centrifuged for 5 min (Galaxy Mini VWR) to remove the media. All pellets were resuspended in 1 mL 1×PBS. Optical densities for each strain were measured through UV-vis spectrometry (Cary 60, Aligent Technologies). Optical densities for each strain were chosen to result in ~105 cells on all control surfaces post-testing and are as follows: E. coli (OD600=0.350), E. faecium (OD600=0.550), K. pneumoniae (OD600=0.450), S. epidermidis, S. aureus (OD600=0.550), and C. albicans (OD600=2.90). 10 μL droplets of each suspension were pipetted onto the contaminated surface. The appropriate glove sample was brought into contact through the methods described in the next section. Post testing, all surfaces and glove samples were placed into a 50 mL centrifuge tube containing 1×PBS after testing. Samples were sonicated at low power for 5 min and vortexed for 10 s to release viable cells. Aliquots were diluted 101 to 105 fold and plated according to the Miles and Misra technique for enumerating viable cells. The number of colonies was counted after incubation for 18 h at 37° C.
[0109] Dip-coater Touch Transmission Testing: To replicate normal touch transmission events, a dip coating system (PTL MM02-200 Dip Coater, MTI Corporation) was modified with a plexiglass upper platform. To measure the applied pressure, a balance (OHAUS Scout Balance Scale) was positioned underneath in line with the plexiglass platform. Surfaces tested for transmission were included: 316 stainless steel (6″ wide shim stock, McMaster-Carr), ABS (McMaster Carr), and glass (plain micro slides, VWR International). Prior to experimentation, each surface was cut into 4 cm2 sections and sterilized with 70% (v / v) ethanol in water.
[0110] Surfaces were lightly fixed to the balance using double sided tape, and glove samples were placed over top of them in-line. Testing proceeded by bringing the plexiglass stage to contact and attach the glove sample through the manual mode at the intended applied pressure for testing. Using the automatic mode, the stage was brought up 70 mm (with the glove fixed to it) and a 10 μL droplet of the bacterial suspension was pipetted onto the lower surface. The stage was then automatically lowered to perform the touch contact event where the glove and contaminated surface remained in contact for 15 s. Cell transmission was measured according to the above antibacterial testing methodologies.
[0111] Fluorescence and confocal microscopy imaging: Visualization of the location of microbes was assessed through fluorescence and confocal microscopy. Post-testing, each sample was allowed to dry for 10 minutes in air. After drying, the bacteria were fixed on the glove surface with 300 μL drop of 4% GDA in 1×PBS. The fixed microbes were then perforated with 300 μL 0.05% Tween-20 in 0.9% NaCl (v / v) solution before being stained with a 100 μL drop of a Sytox Green solution (1 μL in 10 mL 1×PBS) for 30 minutes. Bacterial attachment was assessed through fluorescence microscopy (Olympus BX63, Tokyo, Japan) using a GFP filter ((λex / λem 395 / 470 nm). Location of bacteria on the 3D topography was confirmed through confocal microscopy (Zeiss LSM 880 Super Resolution Confocal).
[0112] Statistical analysis: All experimental counts are plotted as a mean value and an error bar of the standard deviation (+). One-way ANOVA and t-tests with Welch corrections were performed on the results of the glove contamination in each experiment to gauge the statistical difference using GraphPad Prism. All significant differences plotted in the figures are—ns (p≥0.05), * (p between 0.01 to 0.05), ** (p between 0.001 to 0.01), *** (p between 0.0001 to 0.001), or **** (p<0.0001). All data was processed using GraphPad Prism.Results
[0113] Lab-scale simulated touch contact: Within each touch contact event there may be two sub-events occurring—the ‘pick-up’ of contaminants and their subsequent ‘drop-off’ onto secondary surfaces (FIG. 6, panel (b)). In the ‘pick-up’ phase, a sterile glove is contacts a contaminated surface with some microorganisms and organic residue transferring to the glove (FIG. 6 panel (c), contact event). Subsequent contact events will then involve the contaminated glove interacting with potentially sterile secondary surfaces. The test gloves aim to hinder both events. As shown in FIG. 6 panel (a), the surface texture of a standard nitrile glove is irregular with a microscale degree of roughness, allowing for unimpeded fluid interaction and therefore microbial attachment. In contrast, with the test gloves, fluid interaction and microbial attachment is believed to be sequestered to the tips of the features of the non-wetting microtopography.
[0114] Lab-scale replication of touch transfer events was performed using a programmable dip-coating system (FIG. 7). This may allow for accurate application of a normal force as opposed to manual human-operator conditions which may introduce inconsistency during touch contact. Controllable variables on this system include the contact speed, duration during and between contact events, and the number of touch cycles. For measuring the pick-up efficiency, a single pressing cycle for 15 seconds at the maximum speed (200 mm / min) was implemented; this may mirror the scenario in which a health care interacts with several fomites during a care task. Pressure monitoring was enabled through using a microbalance aligned with the test setup, with experimental forces ranging from those typical of resting a finger on a surface (~1 N) up to pressing firmly or gripping objects (1-9 N).
[0115] Contamination of Control Gloves: To assess the physical properties of commercially available gloves as they relate to microbial contamination, three materials were tested—nitrile, latex, and vinyl. Physical characterization was performed through wettability analysis and surface characterization techniques. All glove materials tested exhibited slightly hydrophobic behaviour (Table 1) with static contact angles between 90-102°, indicating that fluid contact can spread over the entirety of the fingertip during touch events. Surface roughness measurements were performed through standard profilometry (white light interferometry) and digital microscopy, and revealed that all gloves tested have an average roughness (Ra) or root mean square roughness (RRMS) of between 1.2 to 6.2 μm. Apparent on all glove surfaces was the presence of small surface pores or depressions (FIG. 8, panel (a)), confirmed by all maximum profile heights (Rt) values exceeding 6 μm. Sites such as these, which are capable of wetting, can act as a preferential site for the pooling of fluid contaminants and subsequently bacterial contamination. This is evident in FIG. 8, panel (c), where contamination of a nitrile glove with K. pneumoniae following the simulated touch contact leads to widespread attachment of cells to the glove surface, with a large majority pooling in a depression within the glove surface.TABLE 1Physical properties of commercially available gloves.ContactSurface roughness parameters (mm)GloveAnglesProfilometryTypeAvg ± SD (°)methodRaRRMSRtLatex94 ± 6.5WLIa4.0 ± 0.85.1 ± 0.7 101 ± 14.9DMb1.5 ± 0.51.5 ± 0.56.0 ± 1.4Nitrile90 ± 3.9WLI6.2 ± 1.87.9 ± 2.2 120 ± 33.4DM1.9 ± 1.14.3 ± 1.79.2 ± 4.6Vinyl102 ± 4.2 WLI1.8 ± 0.22.3 ± 0.362.5 ± 23.9DM1.2 ± 0.41.4 ± 0.56.5 ± 2.0aWhite light interferometry (WLI) measurement of parameters using a Contour GT-3D Bruker profilometer;bDigitial Microscopy (DM) measurement of parameters using a Keyence VHX 7000.
[0116] Simulated touch contact experiments performed with contaminant suspensions of E. coli, K. pneumoniae, S. aureus, and S. epidermidis fouled on stainless steel found no significant difference in the transfer of all microbial species between all three glove materials (FIG. 8, panel (b)). All glove materials show a high degree of transmission following touch contact.
[0117] Test Gloves: Test gloves including pads were prepared as shown in FIG. 9, panel (a). Non-wetting microtopographies imparted to the pads include tongues and grooves having a sawtooth shape (periodic triangular prisms with a curved apex) and square shape (raised wall structures), and posts having a circular shape and oblong shape. Scanning electron microscopy (SEM) images are shown in FIG. 4, panels (b) to (d). Variations in these structures will affect the mechanical stability under applied pressures, as well as the available surface area for microbial interaction; it is expected that although groove or sawtooth designs may increase the available surface area, they may be more durable under sustained touch contact scenarios.
[0118] All pads were functionalized to impart hydrophobicity, which was evaluated by measuring the static water contact angle (Table 2). Commercial nitrile gloves have a slightly hydrophobic nature (90±3.9°) which is not altered significantly post-functionalization (100±1.3)°. In contrast, all non-wetting microtopographies show an increase in their hydrophobicity when fluorinated, with contact angles ranging between 115 to 153°. Ranges in the contact angles are believed to be due to the difference in topography shapes and curvatures, with the curved widely spaced linear features of sawtooth shaped tongues and grooves showing the lowest contact angles. Furthermore, all non-wetting microtopographies other than the large sawtooth design (S30) exhibited droplet mobility; should a droplet be pinned between surface features, accumulation of contaminated fluid can occur, leading to a higher incidence of microbial contamination.TABLE 2Static contact angles on each non-wetting microtopography. All valuesare reported as the mean and standard deviation of 10 counts.As MadeFunctionalizedSample IDCA (°)(a)CA (°)Nitrile glove 90 ± 3.9100 ± 1.310 mm post (P10)122 ± 3.3138 ± 0.625 mm post (P25)147 ± 3.1153 ± 0.32.5 mm groove (G2.5) 99 ± 3.9138 ± 0.815 mm groove (G15)100 ± 2.8129 ± 0.820 mm groove (G20)115 ± 2.8134 ± 3.325 mm groove (G25)110 ± 3.8123 ± 1.56 mm pitch sawtooth (S6) 97 ± 4.3115 ± 1.230 mm sawtooth (S30)110 ± 1.5 117 ± 3.5(b)(a)Plasma treated contact angles were not reported as all samples showed full wetting (q < 5°).(b)When functionalized, this was the only sample for which the droplet was immobile and pinned to the surface during tilting.
[0119] Final test designs included a nitrile glove wrapped around a polydimethylsiloxane (PDMS) surrogate to mimic human finger tissue stiffness. Pads were applied to these samples through the molding of a small volume of a UV curable polymer (Dymax 4-20508) using a PDMS negative. Each pad occupied a circular area with a diameter of 1.25-1.5 cm on a 4 cm2 glove sample (FIG. 6, panel d).
[0120] Microbial attachment to test gloves: The pick-up efficiency of the pads was tested when lightly pressed against a fluid contaminated stainless steel coupon. Stainless steel was chosen due to its prevalence and contamination potential in hospital environments. Six representative microbial species were utilized based on their strong association with healthcare associate infections or presence in skin microflora—Escherichia coli, Enterococcus faecium, Klebsiella pneumoniae, Staphylococcus aureus, Staphylococcus epidermidis, and Candida albicans. Each contact event included a 15 s press at 1 N of force onto a droplet contaminated stainless steel coupon, after which all samples were suspended in buffer. All viable cell populations were enumerated using standard colony forming unit (CFU) plating techniques for both the test glove sample and stainless steel after contact.
[0121] The results of these simulated touch contact tests are shown in FIG. 10. For all tested microbial strains, it was noted that no significant difference in pick-up efficiency existed between a control nitrile glove and one which is functionalized to impart hydrophobicity, meaning that hydrophobicity alone is not enough to alter microbial attachment. In contrast, all non-wetting microtopographies showed a reduction in microbial pick-up of between 1-2.5 log. Specifically, the maximum reductions achieved for each strain compared to a control nitrile glove were—2.0 log for E. coli (G2.5), 2.5 log for E. faecium (G2.5), 2.1 log for K. pneumoniae (G2.5), 1.5 log for S. aureus (P10), 1.5 log for S. epidermidis (P25), and 1.5 log for C. albicans (P25). Differences in these reductions are believed to be due to the strain-dependent kinetics of attachment such as surface chemistry, bacterial motility, bacterial hydrophobicity, and cell-cell interactions. Minor increases to pick-up were noted for the sawtooth designs (S6 and S30) which is hypothesized to be due to droplet pinning to the topography, which increases the surface area for microbial attachment.
[0122] Variations in the surface chemistry and applied pressing force were tested for a representative microtopography of each shape. Surface chemistry was altered through plasma treating the surfaces, rendering them hydrophilic and susceptible to full wetting. When the wettability of these microtopographies was altered to either hydrophilic or slightly hydrophobic (without functionalization), the pick-up efficiencies were comparable for the post and groove structures to a control nitrile glove (see FIG. 11). It was also shown that the reductions achieved for the microtopographies remained stable under 9 N of pressing force, as opposed to the initial 1 N, which indicates stability in reducing microbial pick-up during higher pressure activities such as object gripping.
[0123] Visualization of the microbial cell locations to each microtopography was performed through confocal microscopy and SEM. For microtopographies (FIG. 11, panel (c)), the surfaces behaved as previously described for the C-B state, where cells were isolated to the tips of the features. This is evident through the repeated nature of the fluorescent intensity signals in either defined lines (for groove structures) or in a circular array (for post structures). However, the sawtooth shaped tongues and grooves showed an accumulation of cells at the base of the substrate between the ‘teeth’, indicating that the surface is not C-B stable. This is further evidenced in the pick-up efficiency data (FIG. 10), where the large sawtooth pattern (S30) exhibited slightly higher contamination compared to all other groove and post patterns.
[0124] Sequential touching of fomite surfaces-‘drop-off’ efficiencies: The ability of a glove to deposit contaminants onto subsequently touched surfaces is referred to as the drop-off efficiency. Based on the information gained from the pick-up efficiency testing, these experiments were performed with a test glove having pads with candidate non-wetting microtopographies, including a micropost array and a square tongue and groove pattern, both of which could maintain C-B state wettability following a single contact event. Following the initial touch event, a sterile coupon of stainless steel was placed in the same location as the initially contaminated surface. After a short pause in the automated stage (which simulates a health care worker moving elsewhere in a patient room), the contaminated glove contacted this sterile secondary surface. This sequence continued for a total of 8 steel samples, shown schematically in FIG. 12, panel (a).
[0125] The results of these sequential touch experiments are shown in FIG. 12, panel (b) for K. pneumoniae and S. aureus. For a control nitrile glove, the number of cells transferred to subsequent surfaces remains relatively high (>1000 CFUs) for the first four to five surfaces touched before slowly decaying to a low degree of transmission (<100 CFUs). In contrast, the test gloves deposited 1.5-2 log less bacteria onto the first contacted surface. Following the first or second surface transfer, all subsequent surfaces exhibited a low degree of transmission; the large error bars for each of these CFU values is associated with some surfaces exhibiting no transmission of cells during the touch event. Compared to the control nitrile transmission, this resulted in between 1-3 log less bacteria transferred to the second to sixth / seventh surfaces. At the end of the experimental cycle, the number of viable cells remaining on the gloves were assessed. Overall, both the test gloves and control gloves were fouled with a significant portion of the microbial cells, with the test gloves having <1 log less CFUs on their surface.
[0126] To further quantify the decrease in both the pick-up and drop-off efficiencies resulting from the use of the test gloves, the overall transfer efficiencies were calculated from the data in FIG. 12. The transfer efficiency (I) is defined as the overall percentage of cells transferred to a recipient surface (glove) compared to the cell population initially present on a donor surface (contaminated steel coupon prior to touch event). In the simulated sequential touch network tested in FIG. 12, the recipient surface cell count was defined as the sum of all cells transferred to subsequent surfaces as well as the cells remaining on the glove after the sequence. For a control glove, the transfer efficiency was found to be 38.6% and 43.6% for K. pneumoniae and S. aureus, respectively. For the test gloves, these efficiencies reduced to between 1.33-1.79%, representing a significant decrease in the amount of potentially pathogenic cells which are transferred by the hands of healthcare workers.TABLE 3Transfer efficiencies following sequential contact testing.Non-wetting Microtopography of PadControlMicropostGrooveMicrobial Transmission(None)(P10)(G15)Components%%%Transfer efficiency (I)43.61.791.75% cells transferred to73.419.523.9subsequent surfaces% cells attached to the26.680.576.1glove after touch sequenceTransfer efficiency (I)38.61.331.64% cells transferred to78.315.225.0subsequent surfaces% cells attached to the21.784.875.0glove after touch sequence
[0127] For each of these transfer efficiencies, the mode of transfer can be further broken down into the percentage of cells transferred to subsequently touched fomites and the percentage of cells which attach to the glove but are not transferred. The majority of cells (73.4-78.3%) initially “picked-up” by a control nitrile glove are transferred to other surfaces, with a smaller population of cells (21.7-26.6%) remaining attached to the glove. For the test gloves, the opposite was found to be true, where most cells picked up remain attached to the test glove (75.0-84.8%) following the sequential contact experiment. When considering the practical applicability of glove to reduce transmission, the ability for gloves to “trap” microbial cells is believed to be preferable over transfer to other surfaces.
[0128] Mechanism of test gloves in preventing microbial transmission: The extent to which wettability dictates the observed reductions was characterized, and the stability of the C-B state was investigated. As evidenced macroscopically in all experiments performed in this work, the extent of fluid transfer occurring during a touch transfer event was significantly different between all control surfaces and the various microtopographies. Macroscopically, all control surfaces following a touch event appeared wet, with a thin film of contaminant fluid coating the entire surface; in contrast, no fluid was observed on the test glove surfaces. To quantify this transfer, the weight gain associated with a single touch event was measured using a microbalance. These results (see Table 4) agreed with the macroscopic observations, with significantly larger amounts of fluid transferring to a control nitrile glove (31% of droplet weight) compared to a test glove (tongue and groove, G15, 3%) (micropost, P10, 1%). By extension, this also reduced the number of microbial cells transferred from the contaminant surface, which are contained and mobile within the fluid.TABLE 4Fluid transfer to gloves during single touch contact events.Glove TypeTest Glove(Large SquareTest GloveFluid transferTongue and Groove(Micropostto glovesControl(G15))(P10))Contact time% of droplet weight A60 seconds3131300 seconds (5 min) 3275600 seconds (10 min)3174A Initial droplet is 10 μm with a weight of ~0.01 g.
[0129] The stability of the various non-wetting microtopographies was assessed. When the C-B state becomes unstable, a transition to the Wenzel state will occur, which will allow for wetting of the entire surface area. To assess the stability of the various non-wetting microtopographies, a single contact event between a contaminated stainless steel coupon and a pad having a given non-wetting microtopography (tongue and groove (G2.5, G15) or post (P10)) design was performed, with increasing contact durations from an initial 15 seconds up to 10 minutes. Results are shown in FIG. 13.
[0130] For the pad with the posts, small increases to the amount of CFUs transferred were observed, though overall were considered non-significant. Through visualization with fluorescence microscopy, it was confirmed that this non-wetting microtopography remained C-B stable after 10 minutes of contact; had there been a transition to the Wenzel state, cells would have been apparent outside of the well-defined post areas. Increases to the cell counts were instead confined to the post tips, with each tip showing an increased cell density after longer contact durations.
[0131] For pads with the two tongue and groove designs, significant increases to the CFU counts were observed with increasing time. For the larger tongue and groove (G15), a significant increase of attached cells occurred after 1 minute of contact. Fluorescence imaging indicated this is due to the microtopography occupying a mixed wettability state, where some areas of the groove sample show either C-B or Wenzel state wetting. In areas where the droplet has pinned into the Wenzel state, large clusters of cells were observed both on the top and bottom aspects of the microtopography. A similar phenomenon was observed for the smaller tongue and groove (G2.5), though to a lesser extent. This is believed to be due to the reduced width of both the top and lower surfaces, which disrupt attachment.
[0132] While the above description provides examples of one or more processes or apparatuses or compositions, it will be appreciated that other processes or apparatuses or compositions may be within the scope of the accompanying claims.
[0133] To the extent any amendments, characterizations, or other assertions previously made (in this or in any related patent applications or patents, including any parent, sibling, or child) with respect to any art, prior or otherwise, could be construed as a disclaimer of any subject matter supported by the present disclosure of this application, Applicant hereby rescinds and retracts such disclaimer. Applicant also respectfully submits that any prior art previously considered in any related patent applications or patents, including any parent, sibling, or child, may need to be re-visited.
Claims
1. A disposable glove comprising:a glove bulk having an interior surface, an exterior surface having a high-touch side and a low-touch side, a palm section, and a plurality of finger sections;wherein on at least the high-touch side, at least some of the finger sections comprise a respective pad that hinders microbial transfer, each pad comprising a hydrophobic material and a non-wetting microtopography.
2. The disposable glove of claim 1, wherein each pad provides a contact angle with water of at least 110 degrees, and / or enables a Cassie-Baxter state of wetting.
3. The disposable glove of claim 1, wherein the glove bulk comprises nitrile, latex, and / or vinyl.
4. The disposable glove of claim 1, wherein the hydrophobic material comprises a polymer, whereinthe polymer is inherently hydrophobic;the polymer is combined with a surface-modifying additive that renders the material hydrophobic; and / orthe polymer is chemically modified to render the polymer hydrophobic.
5. The disposable glove of claim 4, wherein the polymer is functionalized with a silane.
6. The disposable glove of claim 5, wherein the polymer comprises a UV-cured urethane-acrylate polymer, and the silane comprises a trichloro silane.
7. The disposable glove of claim 1, wherein the non-wetting microtopography comprises an array of microposts and / or a pattern of tongues and grooves.
8. The disposable glove of claim 1, wherein the pads are on only the high-touch side, and on only the finger sections.
9. The disposable glove of claim 1, wherein all of the finger sections comprise a respective one of the pads.
10. The disposable glove of claim 1, wherein the pads are adhered to the glove bulk, molded to the glove bulk, or integrally formed with the glove bulk.
11. A method for manufacturing a disposable glove comprising:a. providing a glove bulk having an interior surface, an exterior surface having a high-touch side and a low-touch side, a palm section, and a plurality of finger sections; andb. on at least the high-touch side, providing at least some of the finger sections with a respective pad that hinders microbial transfer, each pad comprising a hydrophobic material and a non-wetting microtopography.
12. The method of claim 11, wherein step b. comprises forming each pad and then applying each pad to the glove bulk.
13. The method of claim 11, wherein step b. comprises molding each pad onto the glove bulk.
14. The method of claim 11, wherein step a. comprises forming the glove bulk, and step b. comprises integrally forming each pad with the glove bulk.
15. The method of claim 11, wherein step b. comprises molding each pad from a polymer to yield the non-wetting microtopography, wherein:the polymer is inherently hydrophobic;the method further comprises combining the polymer with a surface-modifying additive that renders the material hydrophobic; and / orthe method further comprises chemically modifying the polymer to render the polymer hydrophobic.
16. The method of claim 15, wherein the method further comprises functionalizing the polymer with a silane to yield the hydrophobic material.
17. The method of claim 11, wherein step b. comprises forming each pad such that the non-wetting microtopography comprises an array of microposts, wherein the microposts have a diameter of between about 2.5 microns and about 40 microns and an interpost spacing of between about 4 microns and about 100 microns.
18. The method of claim 11, wherein step b. comprises forming the pads such that the non-wetting microtopography comprises a pattern of tongues and grooves, wherein each tongue has a tongue width of between about 2.5 microns and about 30 microns, and each groove has a groove width of between about 5 microns and about 15 microns.
19. The method of claim 11, wherein step b. comprises providing the pads on only the high-touch side, and on only the finger sections.
20. The method of claim 11, wherein step b. comprises providing the pads on all of the finger sections.