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Flow cytometry was evaluated for the first time for the microbiological characterisation of samples collected from the surfaces of stone and mortar sculptures. The study was carried out on outdoor sculptures located in the district of Porto (Portugal), from which samples were collected using swabs and poly(2-hydroxyethylmethacrylate) (poly(HEMA)) cryogels as non-invasive sampling methods. The use of poly(HEMA) cryogels was tested as an alternative to swabbing due to the difficulties often encountered in sampling stone surfaces and retrieving microorganisms from swab fibres. The quantification of the microorganisms collected by the two sampling methods and the determination of their cell viability were performed using a combination of the fluorochromes thiazole orange (TO) and propidium iodide (PI). Both methods were effective to collect samples for analysis by flow cytometry, which proved to be a technique of interest and potential use for biodeterioration studies of cultural heritage (CH). Data visualisation of viable and non-viable microbial cells was clearer with cryogels, although higher concentrations of total microorganisms were achieved with swabs. Our results show that swab sampling is a more adequate method, although poly(HEMA) cryogels can be an option to consider for specific microbial viability analyses for biodeterioration evaluation of stone artworks. [ABSTRACT FROM AUTHOR]

Outdoor sculptures are part of the sociocultural identity of cities, but are extremely vulnerable to deterioration due to exposure to harsh environmental conditions and climate change. Furthermore, deterioration by micro-organisms renders urgent the need to design protective coatings. This research proposes an integrated methodology for the development of innovative and sustainable nanofilms for applications in the area of art conservation, very specifically in the preventive conservation of outdoor sculptures. Gathering objective data for the characterization of the surface microbiota is important in order to design strategies that make use of bio or nanotechnology innovative coatings. Methodologies for the characterization of the microbiota present in a granite outdoor sculpture, followed by preliminary results on the application of protective antimicrobial coatings for surfaces of cultural objects are described. [ABSTRACT FROM AUTHOR]