The
medicinal applications of noble metal nanomaterials are of
considerable interest due to the unique properties they possess. The
following contribution will showcase one of these properties, the
photothermal effect produced by silver nanoparticles (AgNPs), and
show how AgNPs can serve as potential viricidal materials for PPE
(i.e., personal protective equipment) disinfection. In the context
of the COVID-19 global pandemic, PPE disinfection is critical for
addressing the shortfalls in the supply chains that ensure rapid and
reliable sources of PPE for both medical professionals and the public.
Two AgNP composites were prepared using both photochemical and pulsed
laser ablation in liquid techniques. Then, to improve the durability
of the NPs’ coating, they were mixed in a commercially available
tent protectant solution or with a chitosan suspension. Transmission
electron microscopy and spectroscopic analyses of the AgNP/protectant
composites present mostly monodisperse, spherical particles of ∼5–10
nm in diameter, dependent on the route of nanoparticle synthesis.
Blue light-emitting diodes (LEDs) were utilized to activate the surface
plasmon resonance effects of the AgNP-coated materials at ∼400
nm. The resultant photothermal activation produced elevated surface
temperatures on the fabrics, up to 150 °C, approaching the ignition
temperature of the fabric samples, and well above the threshold required
to deactivate the SARS-CoV-2 virus responsible for the COVID-19 pandemic.
Photothermal heating was found to be largely dependent on both proximity
of the coated sample surface to the LED source and illumination intensity.
Furthermore, the rate of temperature increase was determined to be
considerably faster than traditional or photothermal heating studies
conducted on aqueous nanoparticle colloids, illustrating the efficiency
of this methodology. Finally, durability studies of the AgNP/protectant
coatings were examined and were found to maintain photothermal activity
over long durations of exposure and after a 3-month storage timeframe.
A marginal decrease in heating can be noticed following laundering
with traditional detergent cleaners, mainly during the first washing
cycle. The coating resistance to washing could be improved by the
cross linkage of a biodegradable polymer, chitosan.