CONICET | Buscador de Institutos y Recursos Humanos

Antimicrobial surfaces are required to obtain more hygienic indoor environments. There are biogenic compounds like terpenic ones with potential antimicrobial properties and nano-clays are promising vehicles for these. The aim of this research was to assess modified nano-clays with terpenic compounds to be used as bioactive component for antimicrobial coatings.An organic surfactant such as soybean lecithin was used as an organic modifier of the clay mineral. The modified nano-clay (Nc) was obtained by exchange of a montmorillonite (Mt) from Rio Negro (Argentina) with soy lecithin (Sl) in ethanol / water (2:1), at pH 2.3 in a ratio of 1:033 (Mt/Sl).The assessment of the antifungal activity of three commercial terpenic compounds: linalol, citronellol (Col) and citral was carried out against fungal strains, Chaetomium globosum (KU936228) and Alternaria alternata (KU936229), from biodeteriorated indoor coatings. The more active compound which inhibited the 100% of growth of both fungal strains with the lowest concentrations was Col. Therefore, modified clays were obtained incorporating different concentrations of Col suspensions in 1:1 distilled water/ethanol (2.5, 5, 10, 20 and 40 wt. %) to the clay samples (Mt and Nc). Finally, the products were separated by centrifugation and vacuum dried. Additionally, a sample was prepared mixing the components in a different sequence, where the lecithin and Col suspensions (40% wt.) were incorporated at the same time at the synthesis mix. The modified clays were characterized by physical-chemical tests (x-ray diffraction, Z-potential and infrared spectrum) and microbiological test (agar diffusion). Mt modified with LS and Col showed a higher antifungal activity especially when both organic compounds were added at the same time. This was confirmed with Staphylococcus aureus (ATCC 6538) a bacterial strain. In a next stage, we will proceed to formulate and elaborate coatings that integrate the corresponding nano-clays.