A Ti3C2Tx-based nanosystem triggers in situ nitric oxide release to boost the antibacterial capability of scaffolds

Transplant-associated bacterial infections, especially the formation of bacterial biofilms, frequently lead to persistent infections and even transplant failure. Herein, a near-infrared laser-triggered nanosystem with antibacterial and anti-biofilm activities is constructed by loading S-nitrosothiols (RSNO) onto Ti 3 C 2 T x nanosheets, which are then mixed with poly-L-lactic acid (PLLA) powders to prepare porous PLLA/Ti 3 C 2 T x -SNO scaffolds. Especially, the excellent photothermal property of the scaffold is expected not only to eliminate bacterial biofilms but also to trigger RSNO molecules to in situ release nitric oxide (NO) gas under near-infrared laser irradiation. Moreover, the removal of the biofilms facilitates more NO to enter and kill the deep bacteria through nitridation damage, thus realizing the synergistic antibacterial capabilities of photothermal and NO gas therapies. The experimental results showed that the photothermal conversion efficiency of the scaffold reached 39 %. Combining with the in situ NO release, the scaffold presented excellent anti-biofilm and antibacterial activities, with antibacterial rates of 93.6 % and 94.9 % against E. coli and S. aureus , respectively. This work is expected to solve the dilemma of treating bacterial infections in deep tissues, providing reference for the clinical treatment of transplant-associated bacterial infections and even extending to the treatment of other deep refractory infections. • The Ti 3 C 2 T x -SNO nanosystem was successfully constructed by loading S-nitrosothiols to the Ti 3 C 2 T x nanosheets. • The Ti 3 C 2 T x -SNO nanosystem was mixed with PLLA to fabricate porous scaffolds by selective laser sintering. • The superior photothermal property of PLLA/Ti 3 C 2 T x -SNO scaffold effectively triggered the release of NO gas. • The Ti 3 C 2 T x -SNO nanosystem extremely enhanced the antibacterial rates of scaffold.