PVA-Coated 3D-Printed Molds for Rapid Prototyping of PDMS Microdevices for Stem Cell Culture

3D printing has emerged as a versatile approach for fabricating molds used in PDMS-based microdevices. However, residual photoinitiators from photocurable resins often inhibit PDMS curing, while layer-by-layer printing induces surface roughness that hampers device performance in cell culture applications. Here, we present a facile surface modification strategy using PVA dip coating to enhance the compatibility of 3D-printed molds with PDMS replication. Systematic characterization revealed that PVA concentration governs film viscosity and thickness, with the 3–18% (w/w) range yielding uniform and reproducible coatings. PVA-coated molds effectively suppressed PDMS curing inhibition and reduced surface roughness by up to 80%, enabling high-fidelity replication of microstructures. Furthermore, PDMS microwell arrays fabricated from PVA-coated molds supported efficient and uniform embryoid body (EB) formation from human iPS cells, with a significantly increased frequency of single EB per well compared to uncoated molds. These findings demonstrate that PVA coating provides a facile, biocompatible, and geometry-preserving post-treatment to overcome key limitations of 3D-printed molds. The proposed method offers a robust and accessible pathway for the rapid prototyping of PDMS-based microdevices for stem cell culture and broader biomedical applications.