NIH3T3 cells (RRID: CVCL_M025) were cultured in a medium supplemented with 10% fetal bovine serum and 1% penicillin-streptomycin solution (HyClone) in a humidified atmosphere of 5% CO2 at 37°C, and the medium was changed every 2 days. Cell cytotoxicity was measured using the MTT assay. Before the MTT assay, all samples were prepared in 48-well plates. The cells were seeded onto the MNs in the 48-well plates. After culturing for 1, 3, and 7 days, 400 μl of MTT solution (5 μg/ml) was added to each well, and the cells were incubated at 37°C for 4 hours. After the medium was removed, 400 μl of dimethyl sulfoxide was added to each well, and the plates were shaken for 15 min on a shaking table. The supernatant fluid was assessed using a SpectraMax i3 platform (Molecular Devices, CA, USA). To align with the antimicrobial experimental protocol, all the MN samples used in the in vitro cell experiments were also exposed to ultrasound stimulation (1.0 MHz, 1.5 W cm−2, and 50% duty cycle) for 15 min on the day 1 of cell culture and the culture continued until day 7. The cell viability was assessed on days 1, 3, and 7 by MTT assay. At day 1, the cells were washed thrice with PBS (pH 7.4), fixed in 4% formaldehyde solution for 10 min at room temperature, and rinsed thoroughly with PBS. Afterward, the samples were stained with fluorescein isothiocyanate–phalloidin (YiSen, Shanghai) at room temperature in darkness for 30 min and further stained with 4′,6-diamidino-2-phenylindole (YiSen, Shanghai) for 30 s in darkness. The cell morphology of different samples was examined using an IFM (Olympus, IX73). For the transcriptome sequencing test and qRT-PCR analysis, 2 ml of NIH3T3 cell suspensions (1 × 105 cells/ml) was cultured in six-well plates with different samples for 72 hours. The cell lysates were then stored at −80°C before sequencing using a triazolo reagent (Beyotime Biotechnology). RNA sequencing was performed using Illumina HiSeq X10 (Illumina, USA). The value of the gene expression was converted to log10 (transcript per million readings + 1). The data were analyzed by the online Majorbio cloud platform. The qRT-PCR primer sequences are listed in table S2. For the ELISA assay, the concentrations of cytokines in cell growth medium and cells were measured by an ELISA assay kit (Shanghai Jianglai Biotechnology Co. Ltd., Shanghai Enzyme-linked Biotechnology Co. Ltd.).