Gels made from cosmetic ingredients could trap respiratory droplets and aerosols, say scientists at Northwestern University (Chem 2021, DOI: 10.1016/j.chempr.2021.05.017). Jiaxing Huang and his team hope the gels could be put on walls, windows, cloth, and plexiglass barriers to make buildings healthier and stop the spread of infections. Small respiratory droplets and aerosols that bacteria and viruses use to hop from person to person are surprisingly “bouncy,” Huang says, so protections like the plexiglass shields that have become widespread during the COVID-19 pandemic can actually end up keeping aerosols in the air between a person and the barrier. Huang’s team decided that physically trapping or destroying the aerosols could be better than just blocking them. The group eventually settled on poly(acrylamide-co-dialkyl dimethyl ammonium dichloride), a transparent gel found in cosmetics and hair conditioners, as its main component. The researchers added the gel to surfaces, at which they fired aerosols and droplets of salty water. They found the coating absorbs water-based droplets into its matrix and can also be functionalized with copper ions to help with disinfection. Still, Huang says, more work is needed to show if the approach can prevent disease spread.