Method of manufacturing microneedle structures using soft lithography and photolithography
First Claim
1. A method for fabricating microneedles, said method comprising:
- (a) providing a substrate that includes a plurality of microstructures;
(b) coating said substrate with a layer of a first moldable material that takes the negative form of said plurality of microstructures, and hardening said first moldable material;
(c) separating said hardened first moldable material from said substrate, thereby creating a micromold from said hardened first moldable material containing said plurality of microstructures; and
(d) applying a second moldable material onto said micromold, allowing said second moldable material to harden using a soft lithography procedure, then separating said hardened second moldable material from said micromold, thereby creating a microneedle structure from said hardened second moldable material having the three-dimensional negative form of said plurality of microstructures of the patterned micromold;
wherein said microneedle structure comprises one of;
(a) a plurality of solid protrusions, (b) a plurality of hollow protrusions forming through-holes, (c) a plurality of hollow protrusions forming microcups that do not extend entirely through said hardened second moldable material, or (d) a plurality of solid protrusions, each having at least one surface external channel.
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Accused Products
Abstract
A method for manufacturing microneedle structures is disclosed using soft lithography and photolithography, in which micromold structures made of a photoresist material or PDMS are created. The micromold manufacturing occurs quite quickly, using inexpensive materials and processes. Once the molds are available, using moldable materials such as polymers, microneedle arrays can be molded or embossed in relatively fast procedures. In some cases a sacrificial layer is provided between the forming micromold and its substrate layer, for ease of separation. The microneedles themselves can be solid projections, hollow “microtubes,” or shallow “microcups.” Electrodes can be formed on the microneedle arrays, including individual electrodes per hollow microtube.
254 Citations
7 Claims
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1. A method for fabricating microneedles, said method comprising:
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(a) providing a substrate that includes a plurality of microstructures;
(b) coating said substrate with a layer of a first moldable material that takes the negative form of said plurality of microstructures, and hardening said first moldable material;
(c) separating said hardened first moldable material from said substrate, thereby creating a micromold from said hardened first moldable material containing said plurality of microstructures; and
(d) applying a second moldable material onto said micromold, allowing said second moldable material to harden using a soft lithography procedure, then separating said hardened second moldable material from said micromold, thereby creating a microneedle structure from said hardened second moldable material having the three-dimensional negative form of said plurality of microstructures of the patterned micromold;
wherein said microneedle structure comprises one of;
(a) a plurality of solid protrusions, (b) a plurality of hollow protrusions forming through-holes, (c) a plurality of hollow protrusions forming microcups that do not extend entirely through said hardened second moldable material, or (d) a plurality of solid protrusions, each having at least one surface external channel.- View Dependent Claims (2, 3, 4)
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5. A method for fabricating microneedles, said method comprising:
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(a) providing a substrate that includes a plurality of microstructures;
(b) coating said substrate with a layer of a first moldable material that takes the negative form of said plurality of microstructures, and hardening said first moldable material;
(c) separating said hardened first moldable material from said substrate, thereby creating a micromold from said hardened first moldable material containing said plurality of microstructures;
(d) applying a second moldable material onto said micromold, allowing said second moldable material to harden using a soft lithography procedure, then separating said hardened second moldable material from said micromold, thereby creating a microneedle structure from said hardened second moldable material having the three-dimensional negative form of said plurality of microstructures of the patterned micromold;
(e) providing a second substrate that includes a second plurality of microstructures, wherein said second plurality of microstructures is substantially complementary in shape as compared to said first plurality of microstructures;
(f) coating said second substrate with a layer of a third moldable material that takes the negative form of said second plurality of microstructures, and hardening said third moldable material;
(g) separating said hardened third moldable material from said second substrate, thereby creating a second micromold from said hardened third moldable material containing said second plurality of microstructures;
(h) applying a fourth moldable material onto said second micromold, allowing said fourth moldable material to harden using a soft lithography procedure, then separating said hardened fourth moldable material from said second micromold, thereby creating a second microneedle structure from said hardened fourth moldable material having the three-dimensional negative form of said second plurality of microstructures of the patterned second micromold; and
(i) applying a layer of a fifth moldable material upon one of said first or second microneedle structures, placing said first and second microneedle structure into a face-to-face relationship to thereby sandwich said layer of fifth moldable material therebetween, allowing said layer of fifth moldable material to harden using a soft lithography procedure, then separating said hardened fifth moldable material from both said first and second microneedle structures, thereby creating a third microneedle structure from said hardened fifth moldable material having the three-dimensional negative form of both said first and second microneedle structures. - View Dependent Claims (6)
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7. A method for fabricating microneedles, said method comprising:
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(a) providing a substrate that includes a plurality of microstructures;
(b) coating said substrate with a layer of a first moldable material that takes the negative form of said plurality of microstructures, and hardening said first moldable material;
(c) separating said hardened first moldable material from said substrate, thereby creating a micromold from said hardened first moldable material containing said plurality of microstructures; and
(d) applying a second moldable material onto said micromold, allowing said second moldable material to harden using a soft lithography procedure, then separating said hardened second moldable material from said micromold, thereby creating a microneedle structure from said hardened second moldable material having the three-dimensional negative form of said plurality of microstructures of the patterned micromold;
wherein said first moldable material after hardening exhibits a flexibility characteristic and, therefore, can be deformed to a predetermined extent without breaking; and
further comprising;
after creating said micromold from said hardened, flexible first moldable material, deforming said micromold during the step of applying the second moldable material onto said micromold, thereby creating either a concave or convex micromold.
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Specification