Phase-Dependent MoS₂ Nanoflowers for Light-Driven Antibacterial Application

Abstract

The metallic phase of 1T-MoS2 nanoflowers (NFs) and the semiconducting phase of 2H-MoS2 NFs were prepared by a facile solvothermal and combustion method. The antibacterial activities, reactive oxygen species (ROS) generation, and light-driven antibacterial mechanism of metallic 1T-MoS2 NFs and semiconducting 2H-MoS2 NFs were demonstrated with the bacterium Escherichia coli (E. coli) under light irradiation. Results of the bacterial growth curve and ROS generation analyses revealed higher light-driven antibacterial activity of metallic 1T-MoS2 NFs compared to semiconducting 2H-MoS2 NFs. Electron paramagnetic resonance (EPR) spectroscopy demonstrated that the ROS of the superoxide anion radical •O2 – was generated due to the incubation of 1T-MoS2 NFs and E. coli with light irradiation. Furthermore, E. coli incubated with metallic 1T-MoS2 NFs exhibited significant damage to the bacterial cell walls, complete bacterial destruction, and abnormal elongation after light irradiation. The light-driven antibacterial mechanism of metallic 1T-MoS2 NFs was examined, and we found that, under light irradiation, photoinduced electrons were generated by metallic 1T-MoS2 NFs, and then the photoinduced electrons reacted with oxygen to generate superoxide anion radical which induced bacterial death. For semiconducting 2H-MoS2 NFs, photoinduced electrons and holes rapidly recombined resulting in a decrease in ROS generation which diminished the light-driven antibacterial activity.

Gold Nanorod-Decorated Metallic MoS2 Nanosheets for Synergistic Photothermal and Photodynamic Antibacterial Therapy

“…As shown in Figure 6a, the relative ROS levels of 1T-MoS2 NSs with NIR laser (2 min), visible light (1 min), and both NIR laser (2 min) and visible light (1 min) irradiation were respectively 1.23-, 4.25-, and 5.43-fold higher compared to that of no irradiation. The results could be because metallic 1T-MoS2 NSs with photocatalytic activity induced the ROS generation under visible light [46]. However, for the AuNRs, with NIR laser, visible light, and both NIR laser and visible light irradiation, there were no significant increases in ROS production, as shown in Fig- ure 6b.…”

“…NSs of 1T-MoS 2 were prepared according to a solvothermal method with some modifications [46]. Typically, a precursor solution (40 mL) containing thiourea (12.5 mM) and molybdic acid (5 mM) was prepared with stirring.…”

“…Various light-activated nanomaterials are popularly applied as antibacterial agents based on photodynamic therapy [39][40][41][42][43][44][45]. For example, metallic molybdenum disulfide (1T-MoS 2 ) and semiconducting molybdenum disulfide (2H-MoS 2 ) nanoflowers were validated to have bactericidal effects due to their light-driven ROS production [46]. A nanocomposite of iron disulfide nanoparticles (NPs) conjugated with titanium dioxide NPs was designed as a photodynamic antibacterial agent with broad absorption from the visible (Vis) to NIR region [47].…”

Cost-Effective 1T-MoS2 Grown on Graphite Cathode Materials for High-Temperature Rechargeable Aluminum Ion Batteries and Hydrogen Evolution in Water Splitting

“…Figure 1a shows the X-ray diffraction (XRD) patterns of 1T-MoS 2 /SP-1. The peaks at 2θ~9.30 • , 18.26 • , and 32.80 • were indexed to (002), (004), and (100) planes of 1T-MoS 2 crystal structure, respectively [19,22]. The peak at 2θ~26.70 • was indexed to the (002) plane of graphite.…”

“…Molybdenum disulfide (MoS 2 ) has been established as an excellent energy-storage material owing to its layer structure and high active sites similar to those of graphene [19][20][21][22]. However, the performance of MoS 2 is not adequate, thereby limiting its applications in AIBs [23,24].…”