Polycotton fabrics coated with two-dimensional nanosheets of a light-responsive material show promise in filtering out and killing airborne pathogens, and could potentially be used to provide better protection against the novel coronavirus1.
The nanosheets made of molybdenum disulfide, a material that can absorb sunlight and generate enough heat to kill pathogens on the surface of the fabrics, a team of researchers from the Indian Institute of Technology in Mandi has shown in experiments.
The modified fabrics retain antibacterial property even after repeated washing, making them suitable for reusable surgical face masks, the researchers say.
Currently used surgical and other face masks only filter out viruses and bacteria. They don’t kill the pathogens. In contrast, the nanosheet-coated polycotton fabrics show efficiency to kill bacteria such as Escherichia coli and Staphylococcus aureus , according to the IIT Mandi scientists.
The nanosheets act as nanoknives or nanoscissors. Their sharp edges and corners puncture the cell membranes of the bacteria, eventually killing them. A three-minute exposure to sunlight increased the surface temperature of the modified fabrics, allowing complete self-disinfection without washing.
The modified fabrics exhibited excellent antibacterial activity even after 60 cycles of washing, says lead researcher Amit Jaiswal.
The researchers found that the three-layered surgical masks, repurposed by incorporating the modified fabrics as an additional layer, could filter out around 97% of 200 nm particles and 96% of 100 nm particles. This makes them potentially useful for preventing the spread of coronaviruses which are around 120 nm in diameter, the researchers note.
1. Kumar, P. et al. Reusable MoS2‑modified antibacterial fabrics with photothermal disinfection properties for repurposing of personal protective masks. ACS. Appl. Mater. Interfaces. 13, 12912-12927 (2021)