Analysis of the sensitivity of microorganisms contaminating museums and archives to silver nanoparticles

The results of microbial contamination analysis of air and surfaces in six different museums and archives in Poland are presented. It was shown that the level of microbial contamination of the air ranged from 1.5 × 102 to 7.0 × 103 cfu m−3; contamination of the surfaces was 1.4 × 102 to 1.7 × 104 cfu 100 cm−2. The most common fungi contaminating museums and archives were Aspergillus, Penicillium, Cladosporium, Alternaria, Mucor, Rhizopus, Trichoderma, Paeciliomyces, Aureobasidium, Botrytis and Chrysonila; and from bacteria Bacillus. Some potentially allergenic and toxic species were diagnosed: Aspergillus fumigatus, Aspergillus flavus, Aspergillus ochraceus, Aspergillus parasiticus, Aspergillus versicolor, Staphylococcus aureus. For 32 strains of bacteria and fungi with the highest occurring frequency in the analyzed areas and for 6 strains of ATCC collection, MIC and MBC for the preparation of nanosilver were determined. A concentration of nanosilver with a particle size 10–100 nm at the level of 90 ppm is effective in removing the microorganisms present on the surface of objects, while a concentration of 45 ppm removed 94% of all microorganisms except for the resistant Bacillus subtilis and Staphylococcus xylosus. It was shown that a preparation of silver nanoparticles can be used as a disinfectant for the surface of historical objects and archival documents.

► A nanosilver concentration (90 ppm) is effective for all microorganisms.
► A concentration of 45 ppm removed 94% of all microorganisms.
► We observed the sensitivity difference among collection and environmental strains.
► A nanosilver preparation is effective for historical objects disinfection.