Photoinitiator Release of Photoprinted SLA Resins for Lab-on-a-chip Applications

3D printing with SLA resins is a very useful manufacturing process to build microfluidic devices (lab-on-a-chip). These photoresin-based methods are especially interesting, as they allow to obtain quickly and accurately high precise designs. However, commercial photoresins have some limitations for cell culture due to its composition. In this sense, photoinitiators used for curing these resins are commonly cytotoxic. Although curing and cleaning protocols are used to remove these components from printed pieces, they could still remain in enough quantity to compromise cell culture on lab-on-a-chips. For this reason, a continuous phase in a solid-liquid extraction has been studied using two media (IPA and PBS) to determine the photoinitiator release of two different resins (Clear and BioMedClear) along 16 days. So, detection, identification and quantification of the released compounds were done by UV-Vis spectroscopy each two days during this period. Results show spectra of TPO and PPO photoinitiators. Additionally, curing and cleaning protocols do not fully remove these toxic compounds, but IPA provides better solvent properties to release these photoinitiator molecules than PBS. In conclusion, lab-on-a-chip applications of SLA resins require specific post-processing to minimize toxicity due to release of photoinitiators.