Near-Infrared Light-Responsive Multifunctional Photothermal/Photodynamic Titanium Diboride Nanocomposites for the Treatment of Antibiotic-Resistant Bacterial Infections.

Diseases caused by bacterial infection have resulted in serious harm to human health. It is crucial to develop a multifunctional antibiotic-independent antibacterial platform for combating drug-resistant bacteria. Herein, titanium diboride (TiB 2 ) nanosheets integrated with quaternized chitosan (QCS) and indocyanine green (ICG) were successfully prepared as a synergetic photothermal/photodynamic antibacterial nanoplatform (TiB 2 -QCS-ICG). The TiB 2 -QCS-ICG nanocomposites exhibit effective photothermal conversion efficiency (24.92%) and excellent singlet oxygen ( 1 O 2 ) production capacity simultaneously under 808 nm near-infrared irradiation. QCS improved TiB 2 stability and dispersion, while also enhancing adhesion to bacteria and further accelerating the destruction of bacteria by heat and 1 O 2 . In vitro experiments indicated that TiB 2 -QCS-ICG had excellent antibacterial properties with an inhibition rate of 99.99% against Escherichia coli ( E. coli ) and methicillin-resistant Staphylococcus aureus (MRSA), respectively. More importantly, in vivo studies revealed that the nanoplatform can effectively inhibit bacterial infection and accelerate wound healing. The effective wound healing rate in the TiB 2 -QCS-ICG treatment group was 99.6% which was much higher than control groups. Taken together, the as-developed TiB 2 -QCS-ICG nanocomposite provides more possibilities to develop metal borides for antibacterial infection applications.