Electrochemical synthesis and characterization of poly(vinyl alcohol)/graphene nanocomposites with silver nanoparticles

Cilj ove doktorske disertacije je dobijanje srebro/polivinil-alkohol (Ag/PVA) i srebro/polivinil-alkohol/grafen (Ag/PVA/Gr) nanokompozita elektrohemijskom sintezom nanočestica srebra u PVA rastvoru, odnosno PVA/Gr koloidnoj disperziji. Elektrohemijska reakcija izvodi se pri galvanostatskim uslovima, pri čemu je količinu, oblik i veličinu nanočestica srebra (AgNPs) moguće kontrolisati izborom vrednosti gustine struje i vremena sinteze, te je međusobna zavisnost ovih parametara detaljno ispitana u ovom radu. Svojstva nanokompozita dobijenih u vidu koloidnih disperzija, filmova i hidrogelova ispitane su u cilju potencijalne biomedicinske primene...The goal of this doctoral dissertation is to obtain silver/poly(vinyl alcohol) (Ag/PVA) and silver/poly(vinyl alcohol)/graphene (Ag/PVA/Gr) nanocomposites by electrochemical synthesis of silver nanoparticles (AgNPs) in the PVA solution, or PVA/Gr colloidal dispersion. The electrochemical reaction is performed under galvanostatic conditions, whereby the quantity, shape and size of the silver nanoparticles can be controlled by selecting the value of the current density and the time of the synthesis, and the relation between these parameters is thoroughly examined in this paper. The properties of the nanocomposites obtained in the form of colloidal dispersions, films and hydrogels were examined for potential biomedical application..

Electrochemical synthesis and characterization of poly(vinyl alcohol)/graphene nanocomposites with silver nanoparticles

Cilj ove doktorske disertacije je dobijanje srebro/polivinil-alkohol (Ag/PVA) i srebro/polivinil-alkohol/grafen (Ag/PVA/Gr) nanokompozita elektrohemijskom sintezom nanočestica srebra u PVA rastvoru, odnosno PVA/Gr koloidnoj disperziji. Elektrohemijska reakcija izvodi se pri galvanostatskim uslovima, pri čemu je količinu, oblik i veličinu nanočestica srebra (AgNPs) moguće kontrolisati izborom vrednosti gustine struje i vremena sinteze, te je međusobna zavisnost ovih parametara detaljno ispitana u ovom radu. Svojstva nanokompozita dobijenih u vidu koloidnih disperzija, filmova i hidrogelova ispitane su u cilju potencijalne biomedicinske primene...The goal of this doctoral dissertation is to obtain silver/poly(vinyl alcohol) (Ag/PVA) and silver/poly(vinyl alcohol)/graphene (Ag/PVA/Gr) nanocomposites by electrochemical synthesis of silver nanoparticles (AgNPs) in the PVA solution, or PVA/Gr colloidal dispersion. The electrochemical reaction is performed under galvanostatic conditions, whereby the quantity, shape and size of the silver nanoparticles can be controlled by selecting the value of the current density and the time of the synthesis, and the relation between these parameters is thoroughly examined in this paper. The properties of the nanocomposites obtained in the form of colloidal dispersions, films and hydrogels were examined for potential biomedical application..

Elektrohemijska karakterizacija nesinterovane biokeramičke hidroksiapatit/lignin prevlake na titanu

The bioceramic hydroxyapatite/lignin (HAP/Lig) coatings were obtained from ethanol suspension by electrophoretic deposition on titanium. The aim of this work was to investigate the corrosion stability of non-sintered HAP/Lig coatings in simulated body fluid (SBF). Using the open circuit potential-time measurements and electrochemical impedance spectroscopy, it was shown that investigated nonsintered HAP/Lig coating on titanium exhibited good protective properties during immersion in SBF solution.Dobijanje biokeramičke prevlake hidroksiapatit/lignin (HAP/Lig) na titanu iz etanolske suspenzije vršeno je postupkom elektroforetskog taloženja. Cilj rada je ispitivanje korozione stabilnosti nesinterovanie HAP/Lig prevlake u simuliranom telesnom fluidu. Korišćene su metode registrovanja vremenske promene potencijala otvorenog kola i spektroskopije elektrohemijske impedancije. Nesinterovana HAP/Lig prevlaka na titanu pokazala je dobra zaštitna svojstva u ispitanom rastvoru

Electrochemical synthesis of silver nanoparticles in poly(vinyl alcohol) solution

In this work silver/poly(vinyl alcohol), Ag/PVA, colloid dispersions were obtained by electrochemical reduction of Ag+ ions. The electrochemical synthesis of silver nanoparticles in the aqueous solutions of 5 and 10 wt. % PVA, containing 0.1 M KNO3 and 3.9 mM AgNO3, was performed at constant current density of 25 mA cm-2, and during synthesis time of 10 min. The presence of silver nanoparticles was confirmed by UV-vis spectroscopy. Cyclic voltammetry analysis and FTIR spectroscopy indicated the interactions between silver nanoparticles and PVA molecules. TEM analysis confirmed spherical shape of the obtained silver nanoparticles, with the mean diameter of 15 ± 9 nm. [Projekat Ministarstva nauke Republike Srbije, br. III 45019 and Eureka E!6749

Elektrohemijska sinteza nanočestica srebra u rastvoru poli(vinil alkohola)

In this work, silver/poly(vinyl alcohol), Ag/PVA, colloidal dispersions were obtained by electrochemical reduction of Ag+. The electrochemical synthesis of silver nanoparticles in aqueous solutions of 5 and 10 wt. % PVA, containing 0.1 M KNO3 and 3.9 mM AgNO3, was performed at a constant current density of 25 mA cm-2 for a synthesis time of 10 min. The presence of silver nanoparticles was confirmed by UV-Vis spectroscopy. Cyclic voltammetry analysis and FT-IR spectroscopy indicated interactions between the silver nanoparticles and the PVA molecules. TEM analysis confirmed the spherical shape of the obtained silver nanoparticles, with a mean diameter of 15±9 nm. .U ovom radu pokazano je dobijanje koloidnih disperzija srebro/poli(vinil alkohol), Ag/PVA, elektrohemijskom redukcijom Ag+. Elektrohemijska sinteza nanočestica srebra u vodenim rastvorima poli(vinil alkohola) sa 5 i 10 mas. % PVA, koji su sadržali 0,1 M KNO3 i 3,9 mM AgNO3, vršena je pri konstantnoj gustini struje od 25 mA×cm-2 u trajanju od 10 min. Prisustvo nanočestica srebra potvrđeno je ultraljubičastom i vidljivom spektroskopijom. Cikličnom voltametrijom i infracrvenom spektroskopijom pokazana je interakcija između nanočestica srebra i molekula poli(vinil alkohola). Analizom transmisione elektronske mikroskopije je potvrđeno da su dobijene nanočestice srebra sfernog oblika, prečnika 15±9 nm.

Optimization of the electrochemical synthesis of silver nanoparticles in poly(vinyl alcohol) colloid solutions

This work focuses on the optimization of electrochemical synthesis of silver nanoparticles in poly(vinyl alcohol) colloid solutions, films and hydrogel discs with the ability for immobilization of silver nanoparticles and their progressive release, as a new, prospective generation of medical wound dressings. Incorporation of silver nanoparticles into polyvinyl alcohol and polyvinyl alcohol/graphene matrices, with the aim to determine the effect of silver and graphene, was achieved by the electrochemical synthesis at different values of constant current density between 10 and 40 mA cm(-2) and for different time between 10 and 75 min, followed by drying (to obtain films) or freezing-thawing method (to obtain hydrogels). Synthesized nanocomposites were characterized by UV-Visible spectroscopy (UV-Vis), transmission electron microscopy (TEM), cyclic voltammetry (CV), Fourier transform infrared spectroscopy (FT-IR), Raman spectroscopy and atomic absorption spectroscopy (AAS). Additionally, antibacterial activity of thus prepared samples was evaluated against pathogenic bacteria strains Staphylococcus aureus and Escherichia coli using agar diffusion test. The results indicated that both silver/polyvinyl alcohol and silver polyvinyl alcohol/graphene nanocomposites are excellent candidates for soft tissue implants and wound dressings

Silver Nanoparticles-Loaded Poly(Vinyl Alcohol)/Chitosan/Graphene Hydrogels Obtained by Electrochemical Synthesis

Recent advances in biomaterials science are increasingly focused on (re)search for next-generation soft tissue regeneration solutions. Hydrogel-based materials are becoming a focal point to address many tissue engineering requirements, possessing exceptional biocompatibility, with tailorable shape, structure and mechanical properties, as well as infinite possibilities drug delivery. The widespread antibiotics use has led to aggravated resistance issues in many bacterial strains, so the focus is increasingly shifted towards alternative antibacterial solutions such as silver nanoparticles (AgNPs). In this work, we have developed novel composite materials based on poly(vinyl alcohol)/chitosan (PVA/CHI) and poly(vinyl alcohol)/ chitosan/graphene (PVA/CHI/Gr) hydrogels with silver nanoparticles obtained through green in situ constant-voltage electrochemical synthesis. The obtained AgNPs’ properties, sizes and size distributions were examined using UV-visible spectroscopy, dynamic light scattering and transmission electron microscopy. In vitro swelling and silver release kinetics were monitored in the simulated physiological conditions (pH7.4, 37 C). The obtained release and swelling isotherms were fitted with several theoretical models that helped discern the mechanisms of these processes. Tensile testing was carried out to examine the composites’ mechanical behavior and elasticity – important properties for soft tissue engineering materials. Finally, the excellent antibacterial activity of the obtained silver/ poly(vinyl alcohol)/chitosan (Ag/PVA/CHI) and silver/poly(vinyl alcohol)/chitosan/graphene (Ag/PVA/CHI/Gr) hydrogels against Staphylococcus aureus and Escherichia coli was confirmed quantitatively by colony counting method, and their non-toxicity was verified towards two model fibroblast cell lines (MRC-5 and L929) utilizing the MTT assay. Through thorough characterization, the obtained nanocomposite hydrogel materials were identified as strong candidates for active antibacterial soft tissue engineering materials.Book of Abstracts / 6th World Congress - TERMIS 2021, 15-19 November 2021, Maastricht, The Netherland

Physico-chemical and mechanical properties and antibacterial activity of silver/poly(vinyl alcohol)/graphene nanocomposites obtained by electrochemical method

Silver/poly(vinyl alcohol) and silver/poly(vinyl alcohol)/graphene nanocomposites in different forms (colloid dispersion, thin films and hydrogel discs) were synthesized by electrochemical reduction of Ag+ ions at constant current density. CV, Raman, XRD, FT-IR, and XPS analyses were used to characterize the interactions between silver nanoparticles, PVA molecules, and graphene. Ag/PVA/Gr nanocomposites had better mechanical and thermal properties and higher antibacterial activity against Staphylococcus aureus and Escherichia coli than Ag/PVA nanocomposites. Slow silver release, as well as a high remaining silver content (76%) after 28 days in simulated body fluid confirmed that both Ag/PVA and Ag/PVA/Gr nanocomposites are capable of maintaining sterility over time