The present study aims to develop thermosensitive membranes with an intelligent mechanism of adhesion/release and potent antimicrobial action for the treatment of wounds. The membranes were prepared by electrosynthesis of the thermosensitive hydrogel poly (N-isopropylacrylamide) (PNIPAm) in the presence of chitosan (CHI). The material obtained is constituted by a semi-interpenetrating polymer network (sIPN) of CHI and PNIPAm. The chitosan is a natural biopolymer with activity bactericidal, anti-inflammatory and healing action. The commercial chitosan used was previously characterized in terms of its average molar mass (0.9312 * 105 g mol-1) by viscosimetric method and degree of deacetylation (86.23%), through conductometric titration. The PNIPAm hydrogel was incorporated to CHI polymer chain by electrochemical method using cyclic voltammetry technique. The sIPN CHI-PNIPAm membrane obtained was characterized by Fourier Transform Infrared Spectroscopy using the Attenuated Total Reflectance (FTIR-ATR), differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). FTIR-ATR spectra confirmed the polymerization of PNIPAm in the presence of CHI. TGA curve showed that sIPN membrane obtained has a composition of 33% chitosan and 55% PNIPAm. DSC thermal analysis showed a lower Tg of sIPN CHI-PNIPAm membrane compared to Tg of PNIPAm hydrogel. The phase transition temperature (LCST) of the sIPN CHI-PNIPAm membrane was determined by Ultaviolet-visible spectroscopy (UV-vis) the value found was 32 ° C.

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In this paper, we report the synthesis and evaluation of a poly(vinyl alcohol)/poly(glycerol) dendrimer hydrogel incorporated with green synthesized silver nanoparticles (PVA/PGLD-AgNPs) using Cinnamomum verum extract as the reducting agent (Cz-extract). The Cz-extract was prepared using ultrasonic technique. UV-visible (UV-vis) spectra of Cz-extract confirmed the presence of cinnamaldehyde. PVA/PGLD-AgNPs films were prepared using 5, 10 and 20 mL of Cz-extract and characterized by UV-vis, Fourier transform infrared spectroscopy, Thermogravimetric analysis and X-ray diffraction (XRD). The surface plasmon resonance band in the UV-vis spectra confirmed the formation of AgNPs. XRD pattern confirmed the presence of silver, with average crystallite sizes calculated by Scherrer equal to 13.64 nm, 16.63nm and 20.27 nm for AgNPs prepared with 5 mL, 10 mL and 20 mL of Cz-extract, respectively. AgNPs release kinetic was studied by Korsmeyer-Peppas model. The antimicrobial results revealed that the PVA/PGLD-AgNPs hydrogels showed good antibacterial activity behavior against Escherichia coli.

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