Pathogens found in the air and on surfaces present a massive global health challenge, threating human health and food security. With the increased prevalence of antibiotic-resistant bacteria and the use of harmful chemicals in typical decontamination processes, there is a need for new technologies that are greener and more efficient.

Philip Demokritou's lab at the Harvard TH Chan School of Public Health has developed a nanotechnology-based approach to improving hand hygiene, helping to limit the spread of infectious diseases. Engineered Water Nanostructures (EWNS) are nano-size water particles that contain reactive oxygen species and can deliver nature-inspired antimicrobials to inactivate microorganisms on surfaces and in the air. Only pico- to nano-gram amounts of active ingredients (e.g. ROS, hydrogen peroxide, citric acid, lysozyme) are required for decontamination. Using an aerosol delivery approach, EWNS are applied as a dry deposition. Recent work has shown that a 0.5 min exposure to EWNS-based nanosanitizers reduced Escherichia coli, Staphylococcus aureus, and bacteriophage MS2 by ∼3, 1, and 2 log, respectively.

This highly efficient technology has numerous impactful applications:

• Hand sanitation

• Surface sanitation (e.g. in hospital and clinical settings)

• Food safety and food spoilage (farm, transportation and storage, retail display, home appliances)

This work was highlighted in the Harvard Gazette and has been published in ACS Sustainable Chemistry & Engineering, Scientific Reports, Environmental Science & Technology, and Nanomedicine: Nanotechnology, Biology and Medicine