Continuous preparation of hydro-alcoholic gel with antimicrobial complex nanoparticles via cascaded reactive confined impinging jets micromixing

Abstract

Hand hygiene was crucial for suppressing a spread of infectious diseases. A gel hand sanitizer (GHS) can be used in circumstances of a water shortage and suitable for outdoor usages. A hydro-alcoholic gel formation required mixing a viscous aqueous solution of a thickener with an alcohol solution of a gelling reagent. The homogeneity of the mixing and the gelling reaction dominantly affected the product quality and the expiration period. Moreover, a GHS was typically only able to kill the pathogens rather than also to inhibit a successive pathogen growth. To overcome this mixing issue as well as prolong antimicrobial persistence, this study employed a confined impinging jets (CIJ) microreactor to generate a GHS with suspending antimicrobial nanoparticles of carboxymethyl chitosan (CMC)/Zn(II)/proanthocyanidins (PAC) via the reactive flash nanoprecipitation (RFNP), intensifying shear thinning in turbulent mixing. The pressure drops and the energy consumption of the CIJ micromixing were theoretically analyzed. The developed process was continuous, effective and energy-saving and the device was compact but capable of massively producing the GHS, enabling a distributed production and beneficial to infection controls in undeveloped areas.