Nanofibrous polyelectrolyte complex incorporated BSA-alginate composite bioink for 3D bioprinting of bone mimicking constructs.

Although several bioinks have been developed for 3D bioprinting applications, the lack of optimal printability, mechanical properties, and adequate cell response has limited their practical applicability. Therefore, this work reports the development of a composite bioink consisting of bovine serum albumin (BSA), alginate, and self-assembled nanofibrous polyelectrolyte complex aggregates of gelatin and chitosan (PEC-GC). The nanofibrous PEC-GC aggregates were prepared and incorporated into the bioink in varying concentrations (0 % to 3 %). The bioink samples were bioprinted and crosslinked post-printing by calcium chloride. The average nanofiber diameter of PEC-GC was 62 ± 15 nm. It was demonstrated that PEC-GC improves the printability and cellular adhesion of the developed bioink and modulates the swelling ratio, degradation rate, and mechanical properties of the fabricated scaffold. The in vitro results revealed that the bioink with 2 % PEC-GC had the best post-printing cell viability of the encapsulated MG63 osteosarcoma cells and well oragnized stress fibers, indicating enhanced cell adhesion. The cell viability was >90 %, as observed from the MTT assay. The composite bioink also showed osteogenic potential, as confirmed by the estimation of alkaline phosphatase activity and collagen synthesis assay. This study successfully fabricated a high-shape fidelity bioink with potential in bone tissue engineering.