Development of Photocrosslinkable/Photodynamically Bactericidal Methacrylated Chitosan/Silk Fibroin (Cs/Sf) Composites for 3d Bio-Printing Applications

Aseptic operation techniques are of great importance to ensure the success of tissue cell culturing. The objective of this study is to develop photocrosslinkable and photodynamically bactericidal hydrogel systems for 3D bioprinting applications. The degummed silk cocoons are first dissolved in a (CaCh • 2H2O/C2H5OH/H2O) solution, and then silk fibroin (SF) is harvested by a non-dialysis silk fibroin regeneration process patented by Taipei Medical University. Various compositions of water soluble chitosan/silk fibroin (WSC/SF) mixtures are turned into photocrosslinkable by methacrylation according to Michael addition reaction. The resulted photocrosslinkable M-WSC/SF composites can be used as a cell delivery system for filling irregular neural tissue defects. By incorporating M-WSC/SF with toluidine blue O (TBO), in situ gelling and photodynamically bactericidal effects are expected to occur simultaneously under UV light radiation. The major challenge of this project is to establish UV dose dependence of photocrosslinking and photodynamically bactericidal effects of these M-WSC/SF/TBO hydrogel systems. Then the MC3T3 E1 cells will be used as the model scaffold system for 3D bioprinting processes. The dependence of 3D bioprinting operation parameters on the cell encapsulation, cell viability, and the bactericidal effects on the M-WSC/SF/TBO/MC3T3 E1 scaffolds will be investigated. It will shed some light on the future development of high-end photocrosslinkable and photodynamically bactericidal biomaterial for 3D bioprinting applications.