Fabrication techniques for thin-walled silicone ocular implants using parylene-C coated 3D-printed molds.

Abstract

Silicone drug delivery implants are widely used, but their fabrication often relies on non‑standardized, empirically tuned protocols that limit reproducibility and transfer across labs. Here, we present a reproducible and generalizable fabrication workflow that brings together design rules, process settings, and validation for rapid fabrication of complex thin-walled biocompatible silicone implants. We outline mold design choices, including vents and micro refill-valve/filter placement, and post‑processing to make smooth inner surfaces, and we compare molds using an applied release agent (mold‑release chemical) versus molds coated with a parylene‑C barrier. Contact angle, Fourier transform infrared spectroscopy (FT-IR), and residue analyses show that parylene‑C prevents cure inhibition and enables clean demolding. We then link spin‑coating variables to membrane thickness and use rheology to guide material selection for pattern fidelity. We also correlate the curing time with network formation and extractable content. Device-level cross-sectional analyses and cytocompatibility assays are also conducted, with the assays indicating excellent compatibility with cells. Taken together, this work provides practical, transferable practice guidance and a reference workflow that other laboratories can adopt to make consistent silicone drug delivery implants and move the field toward standardization.

Supplementary information: The online version contains supplementary material available at https://doi.org/10.1007/s44347-026-00063-7.