A novel antibacterial and biocompatible wound cover made of gelatin/chitosan with silver nanoparticles of green synthesis

A dressing material based on the combination of gelatine, chitosan and silver nanoparticles with a suitable proportion has been developed and can be successfully applied in biomedical fields. The new gelatin/chitosan membranes were prepared using the chitosan suspension mixed with gelatin and silver nanoparticles (AgNPs), resulting in a biocompatible and antibacterial product. AgNPs were obtained by the reduction of silver nitrate with chitosan solution and added to chitosan/gelatin (GCs) blend solutions to obtain membranes by the casting method. Thus, membranes with three different AgNPs concentrations were produced: 30 mM, 20 mM and 10 mM AgNPs. To evaluate the characteristics of the membranes, physicochemical and morphological tests were carried out, such as infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and transmission (TEM), and in vitro cytotoxicity and bacterial assays. The formation of AgNPs was confirmed by Visible Ultraviolet to Ultraviolet to Visible (UV-vis) and TEM, where the nanoparticles were observed by the formation of the peak spectrum at a wavelength at 560 nm. According to the TEM images, polymorphic nanoparticles with an average size of 30 nm were obtained. Furthermore, the results of scanning electron microscopy (SEM) with energy dispersive spectroscopy (EDS) indicated the presence of silver evenly distributed within the membranes. The results obtained by (FTIR) showed spectral peaks characteristic of the membrane materials, that is, typical spectra of gelatin, chitosan and silver. These results could be explained by addition of free -OH, -NH2 and -NHOCOCH3 groups of the amorphous chitosan in the blends and a network structure through electrostatic interactions between the ammonium ions (-NH3+) of the chitosan and the carboxylate ions (-COO-) of the gelatin. The concentrations of AgNPs 30 mM and 20 mM in the membranes attributed to them a high hydration rate and high water vapor permeability (WVP). Membranes with 30 mM AgNPs showed bacterial effect against Staphylococcus aureus and Pseudomonas aeruginosa, concentrations of 20 mM AgNPs and 10 mM AgNPs, bacteriostatic effect against Staphylococcus aureus and bacterial effect against Pseudomonas aeruginosa. In the results of the in vitro assays, 10 mM AgNPs membranes were not cytotoxic. With the results obtained, GC membranes with up to 10 mM AgNPs are candidates for use in the fields of biomaterials and biomedicine.