Photo-activated antimicrobial textiles and paper using non-covalently adsorbed zinc phthalocyanines

Abstract

Effective personal protective equipment (PPE) and operational clothing and equipment (OCE) are essential to protect healthcare workers and the population at large from infectious microbes, as highlighted by the COVID-19 pandemic. The demand for effective and technologically advanced PPE/OCE is high due to the threat of new viral pandemics and growing antibiotic resistance. PPE and OCE typically act as physical barriers to respiratory droplets and other body fluids and thus are limited in their ability to protect users. Here we sought to develop PPE/OCE materials that actively kill bacteria and inactivate viruses upon contact. Photoactivatable metallophthalocyanines (PcMs) have antimicrobial properties and are more cost-effective and less toxic than metals and nanoparticles as surface treatments. We identified several PcMs with strong in-solution activity for both Gram-positive and Gram-negative bacterial pathogens and diverse viral pathogens. These PcMs were used to dye textiles and paper under mild conditions. Upon photoactivation cotton and paper dyed with the water-soluble PcM RLP068/OTf produce a 5–6-log₁₀ reduction in viable Gram-positive bacteria, a 3-log₁₀ reduction in Gram-negative bacteria, and a 1–2-log₁₀ reduction in active enveloped viruses. A combination of RLP068/OTf and the water-insoluble PcM 4BuImid/OTf produced a 4–5-log₁₀ reduction in both Gram-positive and Gram-negative bacteria. Leaching of these compounds into the surrounding medium is minimal, suggesting their microbicidal activity results from direct contact. The self-sterilizing textiles identified here are promising raw materials for low-cost PPE and OPE in preparation for pandemics and for everyday protection in sectors at high risk from pathogen transmission.