Among other 3D printing methods DLP printing has gained signifi cant interest for rapid prototyping of lab- and organ-on-a-chip devic es, because of its fabrication speed and high resolution. Compared to conventional chip fabrication methods it streamlines the process from design to finished product, eliminating labor-intensive steps such as photolithography, casting, and bonding [1]. Despite its benefits, the resin materials used in DLP printing rely mainly on radical photo-initiator-based polymerization, which cannot achieve complete polymerization, particularly in bulk materials. Cy totoxic monomers, crosslinkers and photo initiators may remain in the material and leach out over time, negatively affecting the microphysi ological systems [2]. Therefore, we aim to develop a streamlined process to rapidly as sess the suitability of resins for use in microfluidic cell culture. The first step involves identifying the optimal post-processing condition through the evaluation of (1) the degree of curing using Raman spec troscopy on both the surface and inside the bulk material, and (2) the leaching of potentially cytotoxic components into cell culture medium via HPLC. The second phase assesses material compatibility on a bio logical level by performing a 24-hour cell viability assay with human fibroblasts comparing the optimal condition to the uncured material as proof of concept. Finally, the optimized parameters are applied in long-term on-chip studies with dynamic cell culture to evaluate cell stress, adhesion, and leaching via PCR markers and HPLC. Unlike previous studies, this approach emphasizes the long-term evaluation of leaching, coupled with molecular-biological assessments [1]. First results show that polymerization efficiency is influenced by an interplay of material thickness, washing, UV and heat treatment steps which all affect leaching of compounds. Preliminary cell studies in dicate viable fibroblast cultures with optimized post-processing over five days. In conclusion, this approach highlights the necessity to evaluate DLP-printed materials for microfluidic cell culture as fabrication pa rameters need optimization to minimize adverse effects on MPS. The process could also be adapted for assessing material reusability, pro viding a sustainable method for rapid prototyping. References [1] Fritschen, A., Bell, A., Königstein, I. et al. (2022). Biomater Sci 8, 1981-1994. doi:10.1039/D1BM01794B [2] Bagheri, A. and Jin, J. (2019). ACS Appl Polym Mater 1, 593-611. doi:10.1021/acsapm.8b00165 Presentation: Poster