Papel de parede líquido revestido com nanopartículas de prata

Abstract

The application of nanotechnology aimed at containing pathogenic agents is increasingly necessary in society, especially after the pandemic resulting from the new SARS-COV-2 coronavirus, which emerged in 2019 with rumors that reverberate until the present moment (2023). Silver nanoparticles are constantly highlighted in the literature for presenting antimicrobial activity. In this sense, the synthesis by chemical reduction of silver nanoparticles (AgNPs) based on silver nitrate (AgNO3) and tribasic sodium citrate (TSC) was carried out, aiming at the application of the colloidal solution on the surface of liquid wallpaper based on natural compounds (ecopaper), in order to create an antimicrobial surface. The analysis of the surface of materials subject to intense contact with people, such as wallpaper, deserves special attention in the search for treatments with nanotechnology aimed at prolonging the life cycle of the material and containing the proliferation of microorganisms harmful to health. The characterization of solutions of 10, 20, 30 and 40% of nanoparticles was carried out through rheological analysis, together with the isolated reagents. The colloidal solution as well as the isolated reagents were classified as non-Newtonian, time-dependent and thixotropic fluid. The investigation of the coating material, ecopaper, with and without the application of AgNPs in 40% was carried out through scanning electron microscopy (SEM), infrared spectroscopy (FTIR) and thermogravimetric analysis (TGA). By SEM it was possible to observe the nanoparticles formed on a scale of 10 μm. The infrared spectra showed that the nanosilver interacted with the functional groups present in the “white” echopaper. TGA pointed out that nanosilver helps to stabilize the material based on cotton and silk up to an approximate range of 400 ºC. The verification of the antimicrobial activity took place for different isolated colloidal solutions with 10, 20, 30 and 40% of nanoparticles, as well as for the liquid wallpaper coated with the solutions, by the technique of perforation in agar, being verified the inhibitory capacity of nanosilver for 4 (four) bacterial strains, between gram-positive and gram-negative, through the diameter of the inhibition halo. For Streptococcus pyogenes, halos reaching up to 10.0 mm of inhibition of the solution with 20% concentration were verified, and halos with 4.0mm of inhibition of the wallpaper coated with AgNPs at 40%. The analyzed gram-negative bacteria showed lower inhibition in relation to the gram-positive ones in question, a fact related to the thick cellular layer of the pathogens, making it impossible to interact with the nanosilver.