Highly Methacrylated Gelatin Bioink for Bone Tissue Engineering.

Methacrylated gelatin (Gel-MA) is a commonly used biomaterial in bioprinting applications. The Gel-MA synthesis procedure is inadequate and needs to be improved, particularly from the point of optimization and efficacy. We report a significantly faster (by 5 min) and effective method to controllably synthesize Gel-MA using microwave energy (Mw at 1000 W power) with ≥90% degree of methacrylation (DM) even with the use of a very low concentration of methacrylic anhydride (MA). Rheological and mechanical analyses indicated that Gel-MA synthesized by Mw-assisted methacrylation enabled the formation of hydrogels that are more elastic and stronger and have a lower degradation rate (∼27% at 35 days) than Gel-MA synthesized by the conventional method. The viscosity values of the Gel-MA bioink were in the range applicable for use in 3D bioprinters. Additionally, Mw-assisted methacrylated Gel-MA hydrogels that have mechanically superior properties significantly enhanced the viability, attachment, proliferation, alkaline phosphatase (ALP) activity, mineral deposition, and mRNA expression levels of osteogenic genes of MC3T3-E1 preosteoblastic cells.