Versatile self-assembled MXene-Au nanocomposites for SERS detection of bacteria, antibacterial and photothermal sterilization

The emergence of antibiotic-resistant bacterial strains has caused bacterial infections to become a more serious worldwide health problem. The development of multi-functional platform that can quickly and sensitively detect bacteria and effectively inhibit or kill bacterial is important and urgent. Herein, a novel versatile MXene-Au nanocomposite was successfully synthesized by self-assembly method for rapid detection of bacteria and photothermal sterilization. The typical gram-negative Escherichia coli (E. coli) and the gram-positive Bacillus subtilis (B. subtilis) were used as models to perform label-free, rapid and sensitive detection of bacteria based on SERS method. The antibacterial performance of the material was proved by the colony counting method, and the survival rates of E. coli and B. subtilis were as low as 8.05% and 0.06%, respectively. The Ti3C2Tx-Au nanoparticles (NPs) irradiated with 808 nm light showed significant antibacterial effect within only 6 min, and the germicidal rates for E. coli and B. subtilis were 99.25% and 100%, respectively. The photothermal conversion efficiency reached as high as 43.40%. Accordingly, this multi-functional nanocomposite material can not only detect bacteria sensitively, but also has antibacterial and photothermal sterilization effects, which provides a greatly promising countermeasure for clinical treatment of diseases caused by multi-drug resistant bacteria.