Sustainable and effective antimicrobial surface based on cellulose thin films

TL;DR

This study presents a sustainable, scalable, and effective cellulose-based thin film that rapidly inactivates viruses, inhibits bacteria, and reduces liquid transfer, offering a green solution for antimicrobial surfaces.

Contribution

Developed a novel, plant-based cellulose thin film with tunable properties that provides rapid antiviral and antibacterial effects, suitable for practical daily use and scalable application.

Findings

Rapid inactivation of SARS-CoV-2 within 5 minutes

Over 90% reduction in liquid contact transfer

Effective inhibition of E.coli and S.epidermidis growth

Abstract

In the present work, we developed a sustainable and effective antimicrobial surface film based on Micro-Fibrillated Cellulose. The resulting porous cellulose thin film is barely noticeable to human eyes due to its sub-micron thickness, of which the coverage, porosity and microstructure can be modulated by the formulations developed. Using goniometers and a quartz crystal microbalance (QCM), we observed a threefold reduction in water contact angles and accelerated (more than 50% faster) water evaporation kinetics on the cellulose film. The thin film exhibits not only a rapid inactivation effect against SARS-CoV-2 in 5 minutes, following deposition of the virus loaded droplets, but also an exceptional ability to reduce contact transfer of liquid, e.g. respiratory droplets, onto surfaces such as artificial skin by more than 90%. It also exhibits excellent antimicrobial performance in inhibiting the growth of both gram-negative and gram-positive bacteria (E.coli and S.epidermidis) due to the excellent porosity and hydrophilicity. Additionally, the cellulose film shows nearly 100% resistance to skin scraping in dry condition thanks to its strong attachment to the substrate, whilst good removability once wetted, suggesting its practical suitability for daily use. Importantly, the coating can be formed on solid substrates readily by spraying and requires solely a simple formulation of a plant-based cellulose material with no additives, rendering it a scalable, affordable and green solution for antimicrobial surfaces. Implementing such cellulose films could thus play a significant role in controlling future pan- and epidemics, in particularly during the first phase when appropriate medication needs to be developed.