O103 Digital light processing 3D printed collagen/PEGDA hydrogel for regenerative medicine

Abstract

Abstract Introduction Digital light processing represents a rapid approach to constructing 3D structures with superior resolution. However, it imposes demanding requirements on the properties of bioink. Methacrylated gelatin has long been the major option but results in limited mechanical properties. The development of collagen-based bioinks provides a wider stiffness tuning range, native bioactivities, and versatility in regenerative medicine applications. Methods Purified collagen solution was obtained via enzymolysis and ultrafiltration, then went through methacrylation. The photo-crosslinkable bioink comprises methacrylated collagen, PEGDA, acetic acid, yellow food dye, and photoinitiator LAP. The 3D structures were fabricated utilising a commercial digital light processing printer with 405 nm visible light. Results The collagen/PEGDA bioink showed translucent and low viscosity suitable for digital light processing printing. The printed scaffolds reached a compressive modulus of ∼100 kPa with 0.6 wt% collagen. Sharp-edged and fine structures (∼250 μm) were obtained via printing. The hydrogels show tuneable mechanical properties and flexibility in post processing. A series of structures were fabricated to test the printability, including ear, nose, osteons, microfluidic pads, and porous scaffolds. Aligned micro structures (∼50 μm) of dehydrated scaffold were also achieved via directional freezing. Moreover, the scaffolds could be further stiffened by immersing into the mineralisation solution, to mimic nanocomposite ECM of native bone. The hydrogels exhibited low cytotoxicity and supported the attachment and proliferation of 3T3 fibroblasts. Conclusion The collagen/PEGDA bioink was fabricated for the digital light processing technique. It is capable of being printed into high-resolution structures with tuneable properties for various tissue regeneration applications.