*2.1. Materials*

Raw MoS2 (99.5%), FITC (90%, mixture of 5- and 6-isomers), CS (≥99.8%), and Van HCL were purchased from Aladdin Chemical Reagent Co., Ltd. (Shanghai, China). The beef extract peptone agar medium, *Staphylococcus aureus* ATCC 25,923 cells (*S. aureus*, Grampositive), and *Escherichia coli* ATCC 11,303 cells (*E. coli*, Gram-negative) were obtained from Anhui Polytechnic University.

#### *2.2. Synthesis of MoS2 Nanosheets*

MoS2 nanosheets were synthesized by liquid ultrasonic stripping [29–32]. In brief, 0.5 g of MoS2 was combined with 50 mL of 45% ethanol to form the dispersion system of MoS2 (concentration, 10 μg/mL), which was sonicated in a water bath for 12 h. The solution was centrifuged at 12,000 rpm for 15 min, and the supernatant was collected and processed by a rotary evaporator to yield a thin film. The film was weighed, and MoS2 was resuspended in deionized water to form the MoS2 nanosheet aqueous solution.

## *2.3. Synthesis of MoS2-Van-FITC*

Van is a heptapeptide-containing glycopeptide antibiotic with a primary amine moiety that binds covalently to FITC [33]. In brief, 4 mL of the MoS2 nanosheet aqueous solution (concentration, 0.002 g/mL) was aliquoted, 0.2 mg of Van was added to the solution, and the volume was adjusted to 20 mL. The solution was mixed on a magnetic stirrer at 250 rpm for 6 h and centrifuged at 12,000 rpm for 15 min. The precipitate was resuspended in 20 mL of pure water, and 1 mL of FITC was added. The solution was further mixed for 12 h. MoS2-Van-FITC was obtained by centrifugation.

#### *2.4. Synthesis of the MoS2-Van-FITC@CS Hydrogel*

To prepare the hydrogel, 300 mg of CS was added to 18 mL of 0.1 mol HCl solution and mixed on a magnetic stirrer until the CS solution was clarified. Thereafter, 2 mg of sodium β-glycerophosphate was added to 2 mL of 0.001 g/mL MoS2-Van-FITC solution, dissolved completely, and mixed for 4 h [27,34,35]. The MoS2-Van-FITC@CS hydrogel was obtained by heating in a water bath at 37 ◦C for 1 h.
