*2.5. Characterization*

Ultraviolet-visible (UV–vis) absorption spectra were recorded by UV–vis spectroscopy (model S-3100, Scinco Co., Daejeon, Korea). Fluorescence spectra of MoS2-Van-FITC NPs were recorded by fluorescence spectrophotometry (model RF-5301PC, Shimadzu Corp., Kyoto, Japan). Fourier transform infrared (FT-IR) spectroscopy was performed with an FT-IR spectrometer (model Nicolette is50, Thermo Fisher Scientific, Waltham, MA, USA). The ultrastructural characteristics of synthesized MoS2 were observed via scanning electron microscopy (SEM; model S-4800, Hitachi, Tokyo, Japan). The Brookhaven Zeta Pals instrument was used to obtain zeta potential measurements and to characterize the optical properties of MoS2-Van-FITC (Brookhaven Instruments Corp., Holtsville, NY, USA). NPs of different concentrations were illuminated by using NIR irradiation at 808 nm at different power densities for 15 min, and the temperature was detected with an infrared camera with an accuracy of 0.1 ◦C [36,37].

#### *2.6. In Vitro Antibacterial Assays*

The minimum inhibitory concentration (MIC) of MoS2-Van-FITC NPs was determined using the 96-well microtitration plate dilution method. In brief, 100 μL of LB medium was added to each well of a sterile 96-well plate, and 100 μL of the drug solution was added to the first well, mixed, and diluted in multiples until the last well was mixed. Thereafter, 100 μL of the mixture was discarded, followed by the addition of 100 μL of the bacterial diluent to each well (final density of bacteria, 1 × 10<sup>6</sup> CFU/mL). The positive controls were kanamycin and ampicillin. The cells of the NIR group were NIR irradiated (1.5 W/cm2) for 6 min and cultured at 37 ◦C for 12 h. The OD value was measured with a microplate reader [38]. The three independent measurements were averaged, and each treatment group had three wells.

Log-phase *S. aureus* cultures were inoculated (1:40) into medium containing MoS2- Van-FITC (100 μg/mL) or MoS2 (100 μg/mL) and incubated in a shaking incubator at 37 ◦C for 12 h. The irradiation power densities were 0.5 W/cm2, 1 W/cm2, and 1.5 W/cm2, and the irradiation times were 0 s, 150 s, and 300 s. Thereafter, the cells were coated on solid medium. The number of live bacteria was calculated using the CFU counting method.

## *2.7. Cellular Uptake Assays*

To confirm the effect of Van in capturing *S. aureus* cells, we performed cellular uptake assays. Log-phase *S. aureus* cultures were incubated with different concentrations (15, 30, 45 μg/mL) of MoS2-Van-FITC NPs for 12 h. The cells treated with PBS served as the control. *S. aureus* cells were harvested and stained with 4-6-diamidino-2-phenylindole (DAPI; concentration, 5 μg/mL) for 15 min. Thereafter, the cells were washed twice with PBS, and the red and blue channels were examined under a fluorescence microscope.
