Bacteriophages as a New Biomatrix for Engineered Nanoparticles: What We Have Learned So Far

Abstract: Nanotechnology has rapidly expanded with applications in electronics, contaminant remediation, toy manufacturing, drug delivery, and food processing. The unrestricted entry of engineered nanoparticles (ENPs) into the environment has been a concern for several years. In general, the toxicity of some ENPs inactivate, or destroy, microorganisms and negatively impacts microbial and eukaryotic ecology. For example, silver ENPs (AgNPs) effectively suppress nitrifying bacteria populations, which can lead to elevated nutrient conditions in aquatic systems and reduced effectiveness of the activated sludge process in wastewater treatment. Bacteriophages, viruses that infect bacteria, make up the majority of organisms on earth and have a profound impact on prokaryotic life everywhere, tempering microbial populations and promoting biodiversity though predation and gene transfer. Despite the immense diversity of bacteriophages and their proven role in controlling microbial diversity, absolutely nothing was known, prior to this study about how ENPs interact with bacteriophages at a mechanistic level. More recently, Dr. Goel's lab showed using tools from nanotechnology and synthetic biology about how silver ENPs negatively affected certain phages and did not affect other types. Effects included 96% reductions in post-infection phage yield in terms of plaque forming units (PFUs) after phages were incubated with silver nanoparticles and 28% to 43% reductions from the presence of Ag+ alone. The degree of reduction also depended on the type of phage. The coatings on ENPs had also profound negative impact on phage growth cycle. For example, when Klebsiella pneumonia phage KL and Salmonella typhimurium phage Det7 were exposed to silver nanoparticles coated with poly-N-vinyl-2 pyrrolidone (PVP), an increase in final phage yield by as much as 250% was observed compared with the same phage not incubated with nanoparticles Currently, more experiments are underway with other types of ENPs and a more in depth understanding on interactions between phages and ENPs. This research has several positive other implications apart from just understanding the interactions between phages and ENPs. The results could be significant in designing new ENP based tools against human viruses for example and/or designing phage mediated nano drug deliveries.

Bio: Dr. Ramesh Goel is a professor of environmental engineering in Civil & Environmental Engineering at the University of Utah, Salt Lake City. He obtained his PhD from South Carolina and Post Doctoral training from the University of Wisconsin, Madison. He researches in environmental microbiology with specific applications in engineered bioreactors (anammox, granular sludge processes and leachate treatment), surface water quality (harmful algal blooms and tipping point), emerging environmental issues (such as PFAS and microplastics) and bacteriophages. He employs whole community metagenomics and metatranscriptomics to study microbial ecology and ecophysiology in different systems. His research is funded by USEPA, NSF, EREF, DOD, US Department of Interior, State of Utah and several other local utilities. He is past awardee of the [prestigious NSF CAREER award, ASM's professorship to India, best mentor and best teacher awards in the Department at several occasions. Cooking is his hobby and he plays harmonium towards his music interests.