Department Seminars: A Nature Inspired, Nano-carrier Platform for the Targeted Delivery of Antimicrobials using Engineered Water Nanostructures: Food Safety Applications and beyond

Speaker Dr Philip Demokritou (Host: A/Prof Leong Tai Wei, David)

Host Department of Chemical and Biomolecular Engineering

Date/Time 17 Nov - 17 Nov, 2.00PM

Venue E5-02-32 , Faculty of Engineering, National University of Singapore


   Despite advances in public health, infectious diseases continue to affect millions of people, often with serious outcomes. The toll of airborne infectious disease is further complicated through the evolution of antibiotic-resistant bacteria, while the constant antigenic shift of influenza viruses creates difficulties for vaccine development. Similarly, microbial contamination is a leading cause of foodborne illnesses and food waste in the US with the annual cost exceeding 15 billion USD. Control of these infections remains a challenge and currently relies on interventions that have significant shortcomings, including health risks. Air disinfection for the interruption of transmission relies on UV-A radiation, HEPA filtration and biocidal gasses while for food disinfection chemical and thermal methods are widely used and create many inefficiencies and environmental health implications. New, innovative, effective, low cost, ‘green’ antimicrobial technologies, possessing fewer drawbacks than the existing ones, are urgently in need in the battle against infections.

   The development and assessment of a ‘dry’, green, nano-carrier platform for the targeted delivery of nature inspired antimicrobial agents for food safety applications and beyond will be presented. This method takes an aqueous suspension of a naturally occurring antimicrobial and encapsulates it into an Engineered Water Nanostructure (EWNS) by combining a novel electrospraying-ionization platform. This synthesized EWNS possess unique physico-chemical properties, have extensive surface per volume ratio, are highly mobile due to their nanoscale size, contain the encapsulated antimicrobial and reactive oxygen species generated from aqueous phase and can be targeted to surfaces using their electric charges where they interact and inactivate microorganisms. The effectiveness on inactivation of microorganisms on surfaces and air of the developed EWNS based nano-sanitizers using nature inspired antimicrobials such as citric acid, lysozyme and hydrogen peroxide will be discussed. Applications of the developed nano-sanitizers across the Farm-to-Fork chain for enhanced food safety will also be presented. The main advantage of this approach is the precise and targeted delivery of antimicrobials in minute quantities (pico-to-nanogram level). As a result, sensory characteristics of foods remain unaffected while chemical residues are miniscule. These breakthrough results are pointing to a dry, green, game-changing disinfection approach that is safer for products, consumers and the environment. (Disclaimer: Funding for the development and characterization of EWNS platform was provided by the US National Institutes of Health (NIH) and United States Department of Agriculture (USDA))


Dr Demokritou’s research interests are primarily in the areas of nano-aerosol science and technology with emphasis on the elucidation of particle health effects. His particle research spans across the exposure- disease continuum and includes the development of personal PM monitoring systems for use in exposure assessment and epidemiological studies, methods for the physico-chemical and in-vitro/in-vivo toxicological characterization of nanoparticles and environmental nanotechnology applications. Such novel methods linking particle exposures to toxicology and adverse health effects have been widely used by scientists in the field and also adopted as reference methods by scientists at US EPA, Environment Canada and other PM exposure assessors around the world and helped in advancing the field of particle health effect research. His current research focuses on nanosafety and nano-bio interactions related to engineered nanomaterials (ENMS) and the role of ENM structure on bioactivity. His nanosafety research has involved development of in-vitro screening approaches for nano-specific effects (DNA damage, epigenetics, translocation of ENMs across biological barriers, etc), “safer by design” approaches for families of ENMs, development of advanced tools and framework approaches for in-vitro/in-vivo dosimetry, life cycle specific risk assessment studies for nano-enabled products (NEPs) and environmental nanotechnology applications for pathogen inactivation. Dr Demokritou is currently the Director of two interdisciplinary research Centers at Harvard University: Harvard-NIEHS Nanosafety Research Center and the Center for Nanotechnology and Nanotoxicology at ( He served as a co-PI of the Harvard-EPA PM Health Effect Center (1999-2010, US EPA star grant) and as the Director of Harvard-Cyprus International Institute for the Environment and Public Health from 2005-2008 and participated in the development of graduate level degree programs in the area of Environmental Health. He served as PI, co-PI or co-investigator on several grants funded by NIH, EPA, NIOSH, NSF, USDA/NIFA, CPSC and EU research framework (FP7). He holds 7 international/US patents and inventions. He is a co-author of two books, numerous book chapters and hundreds of articles in leading journals and conference proceedings in nanoscience, particle health effect and aerosol engineering fields. Dr. Demokritou’s innovative research was highlighted in major mainstream media and online magazines including articles published in the Economist, NanoWerk, Chemistry world, The Scientist, ACS C&En News, MIT News, Harvard Gazette, NBR news. Dr Demokritou is currently an Associate Professor at Harvard School of Public and a founding co-Editor in Chief of NanoImpact, a journal that focuses on all aspects of nanosafety research (Elsevier).