Optimization of a nanotechnology based antimicrobial platform for food safety applications using Engineered Water Nanostructures (EWNS)

Abstract

A chemical free, nanotechnology-based, antimicrobial platform using Engineered Water Nanostructures (EWNS) was recently developed. EWNS have high surface charge, are loaded with reactive oxygen species (ROS), and can interact-with, and inactivate an array of microorganisms, including foodborne pathogens. Here, it was demonstrated that their properties during synthesis can be fine tuned and optimized to further enhance their antimicrobial potential. A lab based EWNS platform was developed to enable fine-tuning of EWNS properties by modifying synthesis parameters. Characterization of EWNS properties (charge, size and ROS content) was performed using state-of-the art analytical methods. Further their microbial inactivation potential was evaluated with food related microorganisms such as Escherichia coli, Salmonella enterica, Listeria innocua, Mycobacterium parafortuitum, and Saccharomyces cerevisiae inoculated onto the surface of organic grape tomatoes. The results presented here indicate that EWNS properties can be fine-tuned during synthesis resulting in a multifold increase of the inactivation efficacy. More specifically, the surface charge quadrupled and the ROS content increased. Microbial removal rates were microorganism dependent and ranged between 1.0 to 3.8 logs after 45 mins of exposure to an EWNS aerosol dose of 40,000 #/cm3.

Review on water electro-sprays and applications of charged drops with focus on the corona-assisted cone-jet mode for High Efficiency Air Filtration by wet electro-scrubbing of aerosols

“…Electro-spray in the steady cone-jet mode is, to date, mainly used for materials production, with a particular interest for composite materials such as coated powders and porous membranes deposited on surfaces. Indeed, powder production starting from ES of water based solutions and suspensions of nanoparticles is already used in numerous domains of applications from food flavoring and conservation (Pyrgiotakis et al, 2016), to new materials and bio-applications (Sweet ML et al, 2014). With highly charged droplets, ES is well adapted for electric field driven applications, either for deposition on grounded electrodes, in grounded liquids or for coagulation with opposite polarity species in suspension.…”

Nanotechnology to the rescue: using nano-enabled approaches in microbiological food safety and quality

“…Ag,[19] ZnO,[20] and the photocatalytic ability of TiO 2 ,[21] nano-enabled sensors that can very rapidly detect the presence of pathogens or other substances,[22,23] ‘active/intelligent’ food packaging with improved food protection properties and biodegrading abilities [14] and as surface disinfection methods. [24] Table 1 summarizes nano-enabled intervention approaches explored for food safety and quality. [25,26]…”

“…This method relies on generating engineered water nano-structures (EWNS) using water by combining two different processes, electrospraying and ionization. [24,81,82] The synthesized EWNS possess a unique set of physicochemical and biological properties: they are highly charged, contain Reactive Oxygen Species (ROS), are highly mobile, can remain airborne for hours, and interact and inactivate microorganisms on surfaces and in the air by delivering the ROS payload. [82] Their high surface charge makes possible the targeted delivery of the EWNS on the surface of interest, maximizing their efficiency.…”

“…[82] Their high surface charge makes possible the targeted delivery of the EWNS on the surface of interest, maximizing their efficiency. [24,83] In recent studies their antimicrobial potential was assessed on a representative panel of food-related microorganisms reaching inactivations up to 4 logs (99.99% reduction) without affecting sensory quality of food or leaving chemical traces making it an ideal technology for chemical free applications. [83] In addition, it has very low power demands and has been shown by an acute inhalation toxicological study to possess no apparent health effects to humans when EWNS are inhaled.…”

How to avoid interfering electrochemical reactions in ESI‐MS analysis

“…The combination the well‐known principles of current coupling in a wasted flow stream with an electrically insulated liquid feed system results in an electrospray setup in which the sprayed analyte solution is reliably unaffected by electrochemical reactions under properly chosen flow splitting conditions. The pressure driven liquid feed, as shown in Figure , is an established liquid supply concept and can easily be operated as an electrically insulated system. The flow splitting as realized by the two outflow capillaries instead of a T‐connector leads additionally to an easy to clean zero dead volume setup.…”