ORS11-1632
Anti-Adhesive 3D-Printed Photopolymer Molds for Hydrogel Microneedle Fabrication
Topic
S11. PMSE–PSK50 Anniversary Symposium: Advancing Polymer Science for a Sustainable and Intelligent Future
When and Where
Sep 30, 2026
11:35 - 11:50
Room 110
Session Chairs
Tae Hee HAN
Presenter(s)
CHAN HO PARK (Gachon University)
Co-Author(s)
Abstract
Hydrogel microneedle arrays require a fabrication route that is customizable, repeatable, and capable of preserving sharp microscale tips. While 3D printing is well suited for generating customized mold geometries, direct printing of every microneedle array becomes inefficient as production moves beyond prototyping. We therefore focus on a direct single-mold strategy, in which a 3D-printed negative mold is used as a reusable casting interface for hydrogel microneedles. The central obstacle is interfacial adhesion between the cured hydrogel and the printed photopolymer mold, which can cause incomplete release, tip deformation, and loss of array fidelity.
Here, we show that anti-adhesive molecular surface programming enables clean demolding of hydrogel microneedle arrays directly from 3D-printed photopolymer molds. The printed mold surface was modified with an octadecylsilane-based molecular layer to reduce hydrogel-mold adhesion while preserving the microscale cavity geometry. Surface modification was verified by Fourier-transform infrared spectroscopy and wetting analysis, and interfacial adhesion was quantified by mechanical testing. Silanization increased the water contact angle and reduced the interfacial adhesion force by up to 80%, enabling hydrogel microneedle arrays to be released without a secondary PDMS replica.
To further evaluate whether the single-mold process preserves the intended needle geometry, we introduce a quantitative tip-definition method based on geometric contour analysis. This method defines the microneedle apex and curvature region using fixed geometric criteria, reducing operator-dependent variation in tip-radius measurement. Together, the anti-adhesive single-mold fabrication process and quantitative tip verification establish a streamlined fabrication-and-characterization workflow for hydrogel microneedle arrays produced from surface-engineered 3D-printed photopolymer molds.
Here, we show that anti-adhesive molecular surface programming enables clean demolding of hydrogel microneedle arrays directly from 3D-printed photopolymer molds. The printed mold surface was modified with an octadecylsilane-based molecular layer to reduce hydrogel-mold adhesion while preserving the microscale cavity geometry. Surface modification was verified by Fourier-transform infrared spectroscopy and wetting analysis, and interfacial adhesion was quantified by mechanical testing. Silanization increased the water contact angle and reduced the interfacial adhesion force by up to 80%, enabling hydrogel microneedle arrays to be released without a secondary PDMS replica.
To further evaluate whether the single-mold process preserves the intended needle geometry, we introduce a quantitative tip-definition method based on geometric contour analysis. This method defines the microneedle apex and curvature region using fixed geometric criteria, reducing operator-dependent variation in tip-radius measurement. Together, the anti-adhesive single-mold fabrication process and quantitative tip verification establish a streamlined fabrication-and-characterization workflow for hydrogel microneedle arrays produced from surface-engineered 3D-printed photopolymer molds.
