3D Printed Molds for Organ-on-a-Chip and Fluidics: PDMS-Based Rapid and Accessible Prototyping

The ability to rapidly fabricate custom polydimethylsiloxane (PDMS) devices is central to advancing organ-on-a-chip (OoC) technologies and other biological microplatforms. However, traditional photolithography and the surface roughness of directly 3D printed molds limit their accessibility and scalability of PDMS-based systems. Photolithographic workflows are limited by their dependence on specialized equipment, technical expertise, dedicated fabrication infrastructure, and are typically restricted to planar geometries and microscale features, limiting their use for millifluidic or complex 3D device features. To address these challenges, we present a modular workflow for the robust fabrication of PDMS-based devices using stereolithography (SLA) or fused deposition modeling (FDM) printing combined with optimized epoxy coatings. Acetone-thinned epoxy formulations dramatically improve SLA printed mold smoothness, eliminate tearing during demolding, and yield PDMS replicas with clean, well-defined structural features. For FDM printed molds, a two-step epoxy coating strategy restores mold quality sufficient for robust replica molding. The resulting PDMS devices support irreversible glass bonding, fluid containment, and cell culture applications, validated using normal mammary epithelial and cancer cell lines. We further demonstrate the formation of perfusable tissue aggregates within 3D matrices and introduce a low-cost 3D printed imaging platform for parallel live-cell imaging across four PDMS devices, showcasing its use for monitoring 20 OoC channels under gravity- or pump-driven flow. This versatile and reproducible method lowers the barrier to entry for soft lithography, allowing researchers without prior microfabrication expertise to rapidly prototype functional PDMS devices for diverse biological applications. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=102 SRC="FIGDIR/small/645830v1_ufig1.gif" ALT="Figure 1"> View larger version (44K): org.highwire.dtl.DTLVardef@bbf403org.highwire.dtl.DTLVardef@191249forg.highwire.dtl.DTLVardef@1fb7bf2org.highwire.dtl.DTLVardef@1865e4c_HPS_FORMAT_FIGEXP M_FIG C_FIG