We used E. coli MG1655 as a model bacterium to evaluate the antibacterial activity of MoS2 nanosheets (MSNs), and the strain was kindly provided by the group of Prof. Guoqiang Chen (School of Life Sciences, Tsinghua University, China). E. coli was maintained on Luria Bertani (LB) liquid medium containing 10 g/L tryptone (OXIOD, UK), 5 g/L yeast extract (OXIOD, UK) and 5 g/L NaCl, with pH set to 7.0, at 37°C under constant orbital shaking at 220 rpm for up to 12 h. The LB liquid medium was supplemented with MSNs at concentrations of 0, 1, 10, 100 and 1000 μg/mL. For fermentation, 5% v/v aliquots of seed culture were used to inoculate 50 mL fermentation media containing 10 g/L tryptone, 5 g/L yeast extract, 10 g/L NaCl and 15 g/L glucose, which were subsequently incubated at 37°C under constant orbital shaking at 220 rpm for a further 12 h.