Polyurethane Gel with Silver Nanoparticles for the Treatment of Skin Diseases

Abstract

The aim of this study was focused on the bactericide test of Silver nanoparticles with an average diameter of 6 nm, over Escherichia coli, Staphylococcus aureus and Candida albicans and the treatment of a dermatosis of unknown etiology with a poly(hydroxy urethane-acrylate) gel (PHU) with a concentration of approximately 10 ppm Ag-NPs and a ratio-NHCOO-:RGD (Arg-Gly-Asp) on the macromolecular chain of 200:1. The gel was obtained at the room temperature in sterile conditions, in a reactor with stirring facilities and a cushion of nitrogen purified by traces of oxygen, with several different silver (Ag 0) concentrations (10.907, 15.96, 31.92, 39.5, respectively) and 56.88 ppm Ag-NPs ppm for the anti-germs tests, while for the treatment of a dermatosis of unknown etiology we used the gel with the smallest silver concentration. For the gel with the highest metallic silver concentration of 56.88 ppm, after 48 hours at 37 o C, no one of the germs E. coli, S. aureus or C. albicans resisted. Candida albicans fungus showed an increased sensitivity to metallic silver, as it was eradicated after only 24 h. Probably, in the biological processes Ag 0-cell, the poly(hydroxy urethane-acrylate), also intervenes, as this might facilitate the accumulation of nanometric silver on the extracellular matrix (ECM). Thus, the microorganism might accumulate faster the amount of silver, which stops its vital functions, such as the permeability and breathe. The developed gel with the smallest silver concentration, of 10.907 ppm Ag-NPs, lead to very good results in the treatment of a dermatosis of unknown etiology, after 78 days of treatment.

Novel Waterborne Polyurethane Adhesives Based on Ag@SiO2Nanocomposites

“…Some authors [12,13,[25][26][27] have referred to the fact that nanometric silver is not ''free'' in the polyurethane matrix, as it forms several complex structure polyurethane-Ag-polyurethane through C = O, CN, NH groups, which could explain the changes in the FTIR spectrum of the polyurethane containing silver nanoparticles (WPU-100AgNPs). In the case of the Ag@SiO 2 nanocomposites, the silica could avoid the chemical interactions of the silver with the polyurethane matrix.…”