Ultrathin TiS2@N,S-Doped Carbon Hybrid Nanosheets as Highly Efficient Photoresponsive Antibacterial Agents

Nanobactericides are employed as a promising class of nanomaterials for eradicating microbial infections, considering the rapid resistance risks of conventional antibiotics. Herein, we present a pioneering approach, reporting the synthesis of two-dimensional titanium disulfide nanosheets coated by nitrogen/sulfur-codoped carbon nanosheets (2D-TiS₂@NSC_LAA hybrid NSs) using a rapid l-ascorbic acid-assisted sulfurization of Ti₃C₂T_x-MXene to achieve efficient alternative bactericides. The as-developed materials were systematically characterized using a suite of different spectroscopy and microscopy techniques, in which the X-ray diffraction/Raman spectroscopy/X-ray photoelectron spectroscopy data confirm the existence of TiS₂ and C, while the morphological investigation reveals single- to few-layered TiS₂ NSs confined by N,S-doped C, suggesting the successful synthesis of the ultrathin hybrid NSs. From in vitro evaluation, the resultant product demonstrates impressive bactericidal potential against both Gram-positive Staphylococcus aureus and Gram-negative Escherichia coli bacteria, achieving a substantial decrease in the bacterial viability under a 1.2 J dose of visible-light irradiation at the lowest concentration of 5 μg·mL^-1 compared to Ti₃C₂T_x (15 μg·mL^-1), TiS₂-C (10 μg·mL^-1), and standard antibiotic ciprofloxacin (15 μg·mL^-1), respectively. The enhanced degradation efficiency is attributed to the ultrathin TiS₂ NSs encapsulated within heteroatom N,S-doped C, facilitating effective photogenerated charge-carrier separation that generates multiple reactive oxygen species (ROS) and induced physical stress as well as piercing action due to its ultrathin structure, resulting in multimechanistic cytotoxicity and damage to bacterial cells. Furthermore, the obtained results from molecular docking studies conducted via computational simulation (in silico) of the as-synthesized materials against selected proteins (β-lactamas^{E. coli}/DNA-Gyras^{E. coli}) are well-consistent with the in vitro antibacterial results, providing strong and consistent validation. Thus, this sophisticated study presents a simple and effective synthesis technique for the structural engineering of metal sulfide-based hybrids as functionalized synthetic bactericides.