Bioactive Nanocomposite Bioink with Selfassembled Chitosan/Gelatin Nanofibrous Aggregates for Bone Tissue Engineering

Abstract

The potential of chitosan-based thermosensitive bioink as a viable option for bone tissue engineering lies in its remarkable biocompatibility and the ability to form a gel without the need for a crosslinker at physiological temperature. However, certain limitations, including low mechanical strength, poor printability, and low cell viability post-printing, hinder its efficacy. To address these concerns, this study focused on enhancing the printability, mechanical properties, post-printing cell viability, and proliferation of chitosan-based bioinks by incorporating self-assembled nanofibrous aggregates of chitosan and gelatin. In this study, optimal concentration of nanohydroxyapatite was determined and the potential of the resulting nanocomposite bioink through physicochemical, mechanical, and in vitro characterizations was evaluated. The bioink demonstrated optimal printability at a 10% nanohydroxyapatite concentration, with cell viability above 88%. Moreover, the composite bioink exhibited a low water uptake capacity (2.5%) and degraded within three weeks in the presence of lysozyme. Mechanical characterization revealed an elastic modulus of approximately 15.5 kPa, while storage modulus indicated efficient sol-gel transition of the bioink samples at 37℃. Notably, the scaffold culture in osteogenic media exhibited an ALP activity and collagen estimation of 36.830 ± 3.095 units/ ml and OD of 0.4 ± 0.03, respectively in 14 days culture, signifying excellent osteogenic potential of the bioink. Overall, these findings suggest that the incorporation of osteogenic nanohydroxyapatite and nanofibrous aggregates significantly enhances the osteogenic and physicochemical potential of the thermosensitive bioink