An antibacterial ε-poly-L-lysine-derived bioink for 3D bioprinting applications

The limited availability of bioinks has hindered the application of 3D bioprinting to tissue engineering, and bacterial infection is a serious threat to these applications. Aiming to solve this problem, a novel ε-poly-L-lysine (EPL)-derived antibacterial bioink has been developed for 3D bioprinting and tissue-engineering applications. Three glycidyl methacrylate (GMA)-modified EPL products, EPLGMA-1, EPLGMA-2, and EPLGMA-3, were prepared by reacting 3, 4, and 5 mL GMA with 5 g EPL, respectively. EPLGMA-1, EPLGMA-2, and EPLGMA-3 were photocurable and their corresponding photo-crosslinked hydrogels, EPLGMA-1H, EPLGMA-2H, and EPLGMA-3H, all exhibited very high antibacterial rates, good biocompatibility, good degradability, and promising mechanical properties. After EPLGMA-1H, EPLGMA-2H, and EPLGMA-3H with encapsulated chondrocytes were incubated for 4 weeks, EPLGMA-3H was the best one among them for tissue-engineering applications due to its most efficient tissue regeneration. Carrying chondrocytes, the EPLGMA-3 solution was printed into hydrogel products with high-fidelity shapes and high cell viability using a projection-based 3D bioprinter. Following the implantation of chondrocyte-loaded EPLGMA-3H samples into nude mice for 4 weeks, cartilage-like tissue was regenerated, suggesting that EPLGMA-3 is a promising antibacterial bioink for 3D bioprinting and tissue-engineering applications.