Nanoestrutura plasmônica de ouro e sua aplicação em nanobiotecnologia têxtil: avaliação antimicrobiana e de citotoxicidade

Abstract

Several studies reported on the development of functional textile materials using metallic nanoparticles. These particles exhibit high reactivity and characteristic properties of nanometer-scale materials. The main characteristic of gold nanoparticles (NPAu) is the effect of plasmon resonance, which is a phenomenon that occurs as a consequence of the size and morphology of nanomaterials. In this work, a functional textile material of biodegradable fibers of soybean and bamboo was developed, modified with chitosan and functionalized with NPAu in different concentrations. The objective was to give the substrates bioactive properties, such as antimicrobial action, and to verify the degree of cytotoxicity in fibroblasts in vitro. Initially, the soybean and bamboo knitted fabrics were targeted and later modified with chitosan at varied concentrations in order to obtain the best NPAu depletion result in the substrates, by K/S result (Kubelka-Munk). Afterwords, the NPAu were incorporated in the samples through an experimental design 23, aiming to obtain the highest concentration of nanomaterials in the fibres. The synthesized NPAu were characterized by UV/Vis spectroscopy, zeta potential, DLS, MET and AFM, techniques that demonstrated characteristic peaks of absorbance, mean size, morphology and surface charge of gold nanoparticles. The bioactive samples were evaluated using SEM/EDS, TG and XRF techniques, which determine the incorporation of NPAu on the surface of the fabrics in study. In addition, the NPAu adsorption isotherm was studied in the substrates, as well as the influence of wash fastness and colorimetric values (L * a * b *) in order to verify the color and chroma variations (ΔE) of the samples before and after successive washes. In addition, the bioactive properties of the fabrics were verified by quantitative and qualitative antimicrobial analysis for gram-positive (Staphylococcus aureus) and gram-negative (Klebsiella pneumoniae), bacterias measuring the immediate quantitative inhibition and/or contact (0 hour) of 89.38% and inhibition over time (24 hours) of 98.22% for S. aureus and 74.14% inhibition (0 hour) and 96.45% inhibition (24 hours) for K. pneumoniae. Finally, the cellular viability was studied through NPAu cytotoxicity analysis at 115 μg/ml, where there was a non-significant reduction in fibroblasts viability (12.55%). According to established analysis, it can be demonstrated that the functional tissues developed, have a greater potential for technological and biomedical applications.