Avaliação da atividade antimicrobiana de máscaras cirúrgicas revestidas com silano e tio2

Abstract

The use of the surgical mask as we know it today began in Germany in 1897 and its effectiveness as a microbial barrier is recognized. However, there are some factors that can compromise the protective effect of a surgical mask, and this effect is only maintained when the surface layer of the mask is hydrophobic and dry. In this context, there is a need to replace masks that are wet from prolonged use or that have been contaminated with blood or other secretions with clean masks, which cannot always be done immediately during emergency procedures. In addition, the hands of healthcare workers can be contaminated during the removal of surgical masks. The coating of surfaces by different metals can give these coated materials antimicrobial activity. In this context, titanium dioxide (TiO2) has known antimicrobial activity and is used in a wide variety of biological applications. In addition, coatings made up of silica particles, TiO2 or other oxides to modify the roughness of surfaces in order to make them hydrophobic. The sol-gel method can be applied to obtain a hydrophobic coating and this method involves the hydrolysis of a silica precursor source, such as tetraethyl orthosilicate (SiO2), with alcohol at low temperatures. Therefore, the present dissertation aims to develop a coverage with antimicrobial properties, based on the preparation of particles (Ps) of TiO2 with SiO2, on the textile composition of 100% polypropylene (PP) used for making surgical masks. The study was carried out through the following treatments: (a) immersion of tissue in tetraethylorthosilicate (SIO2) solution, PP/SIO2 sample; (b) immersion of tissue in SIO2 solution and after curing, sample PP/SiO2-curing; (c) immersing the tissue in SIO2 solution and after curing the tissue is immersed in titanium isopropoxide solution, sample PP/SIO2- curing-TiO2; (d) immersion of tissue in SiO2 solution, followed by immersion in titanium isopropoxide solution and finally curing, sample PP/SiO2-TiO2-curing. The microcrystalline structure and morphology of the samples were analyzed by X-ray diffraction (XRD) and electron microscopy (SEM). The degree of hydrophobicity of the surface was evaluated by measuring the contact angle. Antimicrobial activity was evaluated by the bacterial growth inhibition technique. The data obtained by XRD confirmed the crystalline pattern of the PP tissue in all analyzed samples. The amorphous SiO2 diffraction peak was only observed in the PP/SiO2-Cure and PP/SiO2-TiO2-Cure samples. TiO2 diffraction peaks were only observed in the PP/SiO2-TiO2-cure sample. The SEM showed in all analyzed samples the PP non-woven, formed by 18.5 m wide interwoven microfibers. The SEM-EDS showed the low incorporation of TiO2 in the PP non-woven. The contact angle showed the highest degree of hydrophobicity 11 in the PP/SiO2-curing sample. There was no inhibition of bacterial growth in Kirby Bauer, however, in the biofilm analysis, the PP + TiO2 + SiO2 + Cura sample showed a decrease in bacterial biomass.