# US 12,599,757 B2 · Fabrication method for complex, re-entrant 3D microscale structures

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- Number: US 12,599,757 B2
- Document ID: US12599757B2
- Status: Granted
- Kind: B2
- Application number: 18/431,205
- Filed: 2024-02-02
- Published: 2024-06-06
- Granted: 2026-04-14
- Earliest claimed: 2021-07-02
- Assignees: The Charles Stark Draper Laboratory, Inc.
- Applicants: The Charles Stark Draper Laboratory, Inc.
- Inventors: Daniel Frederick King; David J. Carter; Corin Williams; Stephanie Lynne Golmon
- Web page: https://patentgrep.com/patent/US12599757B2

## CPC

- A61M 37/0015: {by using microneedles}
- A61M 2037/0046: {Solid microneedles}
- A61M 2037/0053: {Methods for producing microneedles}
- A61M 2207/10: Device therefor
- A61M: DEVICES FOR INTRODUCING MEDIA INTO, OR ONTO, THE BODY (introducing media into or onto the bodies of animals A61D7/00; means for inserting tampons A61F13/26; devices for administering food or medicines orally A61J; containers for collecting, storing or administering blood or medical fluids A61J1/05); DEVICES FOR TRANSDUCING BODY MEDIA OR FOR TAKING MEDIA FROM THE BODY (surgery A61B; chemical aspects of surgical articles A61L); DEVICES FOR PRODUCING OR ENDING SLEEP OR STUPOR {(Electrotherapy, e.g. producing anaesthesia by the use of alternating or intermittent currents A61N1/36021)}

## Abstract

A bilayer mold for forming polymer microstructures is provided. The bilayer mold includes a rigid plastic cylinder having slots defined along an outer periphery of the rigid plastic cylinder; and a layer of plastic elastic polymer material disposed within the slots and having indents defined therethrough and in the rigid plastic cylinder. The indents have a first profile extending through the layer of plastic elastic polymer and terminating within the rigid plastic cylinder. A metal polymer structure profile is also provided using laser-etching of a desired shape for the features of the microstructures in a metallic foil, followed by further refining of the features. The polymer and metal microstructures can be formed on the surface of a stent to facilitate retention of the stent.

## Claims

### Claim 1

A bilayer mold for forming polymer microstructures, the bilayer mold comprising:
a rigid plastic cylinder having slots defined along an outer periphery of the rigid plastic cylinder;
a layer of plastic elastic polymer material disposed within the slots and having indents defined therethrough and in the rigid plastic cylinder,
wherein the indents have a first profile which extends through the layer of plastic elastic polymer and terminates within the rigid plastic cylinder.

### Claim 2 (depends on 1)

The bilayer mold of claim 1, wherein the indents have a second profile in the rigid plastic cylinder, different from the first profile.

### Claim 3 (depends on 2)

The bilayer mold of claim 2, wherein the first profile is narrower than the second profile to form a re-entrant mold.

### Claim 4 (depends on 1)

The bilayer mold for claim 1, wherein the rigid plastic cylinder is formed of wax.

### Claim 5 (depends on 3)

The bilayer mold of claim 3, wherein the wax is machinist's wax.

### Claim 6 (depends on 1)

The bilayer mold of claim 1, wherein the layer of plastic elastic polymer material is polyethylene.