Demonstrating the In Vitro and In Situ Antimicrobial Activity of Oxide Mineral Microspheres: An Innovative Technology to Be Incorporated into Porous and Nonporous Materials

Abstract

The antimicrobial activity of surfaces treated with zinc and/or magnesium mineral oxide microspheres is a patented technology that has been demonstrated in vitro against bacteria and viruses. This study aims to evaluate the efficiency and sustainability of the technology in vitro, under simulation-of-use conditions, and in situ. The tests were undertaken in vitro according to the ISO 22196:2011, ISO 20473:2013, and NF S90-700:2019 standards with adapted parameters. Simulation-of-use tests evaluated the robustness of the activity under worst-case scenarios. The in situ tests were conducted on high-touch surfaces. The in vitro results show efficient antimicrobial activity against referenced strains with a log reduction of >2. The sustainability of this effect was time-dependent and detected at lower temperatures (20 ± 2.5 °C) and humidity (46%) conditions for variable inoculum concentrations and contact times. The simulation of use proved the microsphere’s efficiency under harsh mechanical and chemical tests. The in situ studies showed a higher than 90% reduction in CFU/25 cm2 per treated surface versus the untreated surfaces, reaching a targeted value of <50 CFU/cm2. Mineral oxide microspheres can be incorporated into unlimited surface types, including medical devices, to efficiently and sustainably prevent microbial contamination.

Advancing Antimicrobial Textiles: A Comprehensive Study on Combating ESKAPE Pathogens and Ensuring User Safety

“…Advanced porous materials, such as mesoporous silica nanoparticles, porous silicon nanoparticles, metal-organic frameworks, covalent-organic frameworks, hydrogen-bonded organic frameworks, and porous carbon materials, have also emerged as promising alternatives due to their low cost of production, high biocompatibility, adjustable porous structure, large surface area, and easy surface functionalization [14]. These materials have shown great potential as nanotools for antimicrobial treatment, although only a few examples have been currently described in the literature [15][16][17]. Additionally, the current progress towards the design of these advanced porous materials for antimicrobial treatment is mainly focused on in vitro antimicrobial evaluation, with only a few in vivo examples reported so far.…”