BioPuSL: Material & Process Optimization

Abstract

Stereolithography is an advantages bioprinting technique that can be used to develop 3 dimensional printed structures. In the field, prints of structures with cells seeded after the printing process has completed has shown to generate high cell viability [ Hang Lin]. Currently, a technique is needed to print with cells already in the resin so that the cells print inside the structures as the layers are curing. For this to occur, the resin and the parameters of the printing process need to print high-resolution structures while still able to achieve high cell viability. This technique can have significant impact many biological fields like tissue and drug application studies. In this study, various concentrations of Poly (ethylene glycol) diacrylate (PEGDa) and Gelatin Methacryloyl (GelMA) are used as prepolymers with the photoinitiator Lithium phenyl- 2,4,6-trimethylbenzoylphosphinate (LAP) at 1% weight concentration is used in the resin. The mechanical properties, biocompatibility, and impacts of the parameters are tested. From this study we were able to conclude that the amount of PEGDa makes a significant impact on storage modulus of the gel. Likewise, the various amounts of PEGDa, when printing, will affect the amount of polymerization that occurs. Therefore, if less than the needed amount of PEGDa is used when printing, the 3D structure will not fully form or form at all. Also, when studying various GelMa concentrations in resin, the study resulted in the amount of GelMa is directly proportional to cell variability. These results will help determine the concentration of PEGDa and GelMa that can be tested in future studies to ultimately print cells in 3D structures with high cell viability.