An approach for mechanical property optimization of cell-laden alginate-gelatin composite bioink with bioactive glass nanoparticles.

Alginate-gelatin (Alg-Gel) composite hydrogel is extensively used in extrusion-based bioprinting. Although Alg-Gel blends possess excellent biocompatibility and printability, poor mechanical properties have hindered its further clinical applications. In this study, a series of design by incorporating bioactive glass nanoparticles (BG) (particle size of 12 and 25 nm) into Alg-Gel hydrogel have been considered for optimizing the mechanical and biological properties. The composite Alg-Gel-BG bioink was biophysically characterized by mechanical tests and bioprinting practice. Biocompatibility of Alg-Gel-BG bioink was then investigated by bioprinting mouse dermal fibroblasts. Mechanical tests showed enhanced stiffness with increasing concentration of incorporated BG. But the maximum concentration of BG was determined 1.0 wt% before blends became too viscous to print. Meanwhile, the incorporation of BG did not affect the highly porous structure and biodegradation of Alg-Gel hydrogel, while the mechanical strength and printability were enhanced. In addition, the cellular proliferation and adhesion in the bioprinted constructs were significantly enhanced by BG (12 nm), while extension was not affected. Therefore, our strategy of incorporating BG in Alg-Gel composite hydrogel represents an easy-to-use approach to the mechanical reinforcement of cell-laden bioink, thus demonstrating their suitability for future applications in extrusion-based bioprinting.