Antibacterial polymeric nanocomposites synthesized by in-situ photoreduction of silver ions without additives inside biocompatible hydrogel matrices based on N-isopropylacrylamide and derivatives

Abstract

Abstract. Synthesis of antibacterial nanocomposite obtained by in-situ photoreduction of Ag+ ions impregnated inside a biocompatible hydrogel matrix is described. Hydrogel matrixes based on N-isopropylacrylamide (PNIPAM) and copolymers are synthesized by free radical polymerization in aqueous medium. The hydrogels are loaded with Ag + ions and then silver nanoparticles (Ag-NPs) are obtained in-situ by application of UV light without using additives. Ag-NPs formation inside hydrogels is confirmed by UV-visible spectroscopy, scanning electronic microscopy (SEM) and transmission electronic microscopy (TEM). An extensive characterization of nanocomposites is performed by determining the partition coefficient of Ag + ions before photoreduction, the Ag-NPs mass loaded per gram of hydrogel as a function of irradiation time, swelling capacity and volume phase transition temperature. Fourier Transform Infrared (FTIR) spectra indicate the loss of some functional groups of the polymer backbone during reduction of Ag + ions whereas 13 C NMR spectra do not show any change in the main carbon chain. Nanocomposites show antibacterial activity against Pseudomonas aeruginosas by release of Ag + ions while Ag-NPs remain inside matrix. Reducing/stabilizing character of hydrogel and antibacterial activity of nanocomposite depend on the chemical composition of the matrix.

Acid hydrogel matrixes as reducing/stabilizing agent for the in-situ synthesis of Ag-nanocomposites by UV irradiation: pH effect

“…PNIPAM-co-2%AMPS was an exceptional case with a behavior similar to previously reported work [26]. Possibly, lower Pc value at pH 2 than pH 7 is related to the low swelling capacity of matrix at that pH or with the absence of anionic groups to interact with Ag + ions.…”

“…In this work, acidic hydrogels obtained by copolymerization of N-isopropylacrylamide (NIPAM) and methacrylic acid (MAA) monomers were proposed as matrixes generator of Ag-nanocomposites. Biocompatibility of matrixes based on NIPAM [27,28] and the antibacterial effect of Ag-nanocomposites based on these matrixes were previously demonstrated [26].…”

“…However, this usually requires using reducing agents and/or harmful solvents to environmental and biological systems, such as sodium borohydride, hydrazine, and dimethylformamide [25]. Previously, the synthesis of Ag-NPs inside hydrogel by in situ photoreduction of Ag + ions was proposed as a new alternative to avoid the use of strong reducing agents not compatible with biomedical applications [26]. It was shown that hydrogels made of crosslinked acrylamides are able to photoreducing Ag + ions by absorption of UV irradiation avoiding the presence of toxic chemical reactive and generating antibacterial nanocomposites.…”

Biosynthesized Nanosilver from Alginate Dialdehyde: An In Vitro Evaluation

“…The UV-Vis spectra of both AgNO 3 solution and Borax added-AgNO 3 solution showed a peak corresponding to Ag + ions at 300 nm [42] (black arrow) (Figure 2 A). But, this peak was not observed in the spectrum of ADA-AgNO 3 solution.…”

Novel electrospun polyvinylidene fluoride-graphene oxide-silver nanocomposite membranes with protein and bacterial antifouling characteristics

“…However, PVDF-Ag and PVDF-GO-Ag membranes can inhibit bacteria from attaching to the membrane surfaces by releasing Ag + ions. Very recently, Monerris et al [79] reported that hydrogel nanocomposites loaded with AgNPs show antibacterial activity by releasing Ag + ions from AgNPs reside in the matrix. Figure 11a shows the agar plate cultured with Gramnegative E. coli and then contacted directly with pure Figure 10.…”