Synthesis and characterization of hydrogel‐silver nanoparticle‐curcumin composites for wound dressing and antibacterial application

Hydrogel silver nanocomposites are found to be excellent materials for antibacterial applications. To enhance their applicability novel hydrogel‐silver nanoparticle‐curcumin composites have been developed. For developing, these composites, the hydrogel matrices are synthesized first by polymerizing acrylamide in the presence of poly(vinyl sulfonic acid sodium salt) and a trifunctional crosslinker (2,4,6‐triallyloxy 1,3,5‐triazine, TA) using redox initiating system (ammonium persulphate/TMEDA). Silver nanoparticles are generated throughout the hydrogel networks using in situ method by incorporating the silver ions and subsequent reduction with sodium borohydride. Curcumin loading into hydrogel‐silver nanoparticles composite is achieved by diffusion mechanism. A series of hydrogel‐silver nanoparticle‐curcumin composites are developed and are characterized by using Fourier transform infrared (FTIR) and UV–visible (UV–vis) spectroscopy, X‐ray diffraction, thermal analyses, as well as scanning and transmission electron microscopic (SEM/TEM) methods. An interesting arrangement of silver nanoparticles i.e., a shining sun shape (ball) (～ 5 nm) with apparent smaller grown nanoparticles (～ 1 nm) is observed by TEM. The curcumin loading and release characteristics are performed for various hydrogel composite systems. A comparative antimicrobial study is performed for hydrogel‐silver nanocomposites and hydrogel‐silver nanoparticle‐curcumin composites. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

In vitro and in vivo investigational studies of a nanocomposite‐hydrogel‐based dressing with a silver‐coated chitosan wafer for full‐thickness skin wounds

A nanocomposite reservoir‐type hydrogel dressing of poly vinyl alcohol (PVA) was fabricated by a freeze–thaw method and loaded with silver‐nanoparticle‐coated chitosan wafers (Ag–CHWs). The Ag–CHWs were synthesized by a sonication technique with silver nitrate (AgNO₃) and chitosan powder. Scanning electron microscopy images showed silver nanoparticles (AgNPs) with a size range of 10 ± 4 nm on the surface of the chitosan wafers, and the antibacterial efficacy (minimum inhibitory concentration) of the Ag–CHWs was measured against Pseudomonas aeruginosa (32 µg/mL), Staphylococcus aureus, (30 µg/mL) and Escherichia coli (32 µg/mL). The antimicrobial PVA hydrogel showed an improved tensile strength (～0.28 MPa) and gel content (～92%) in comparison with the blank hydrogels. Full‐thickness‐excision wound studies of the nanocomposite dressing on Wistar rats revealed enhanced wound contraction, improved inflammation response, re‐epithelization rate, neoangiogenesis, and granulation tissue formation in comparison to the control group. A flexible, biocompatible, nanocomposite reservoir dressing not only established the chitosan as a stabilizer but also proved the efficacious and safe utility of AgNPs toward chronic wound management. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43472.     

Construction of chitosan-carboxymethyl β-cyclodextrin silver nanocomposite hydrogel to improve antibacterial activity

Silver nanoparticles (AgNPs) are widely used in various fields but their physical and chemical instability have limited their applications. The present work demonstrates a novel approach for the synthesis and stabilising of AgNPs. Chitosan and carboxymethyl β-cyclodextrin were used to prepare a polymeric hydrogel with glutaraldehyde as cross-linker. As a result, AgNPs were formed with very high dispersion and stability in the hydrogel structure. It is possible to create nanoreactors to produce AgNPs by adding CM-βCD to the structure of the hydrogel. Fourier transform infrared (FTIR) analysis was employed to characterise the Cs-CM-βCD hydrogel. The morphologies of pure Cs-CM-βCD hydrogel and silver nanocomposite were observed by scanning electron microscopy. Moreover, UV–VIS spectroscopy and X-ray diffraction were used to characterise the prepared silver nanocomposite. In addition, the antibacterial properties of these silver nanocomposite hydrogels were investigated against Staphylococcus aureus (Gram positive) and Escherichia coli (Gram negative).     

Breathing‐in/breathing‐out approach to preparing nanosilver‐loaded hydrogels: Highly efficient antibacterial nanocomposites

The key objective of developing novel materials for hygienic living conditions is to lower the risk of transmitting diseases and biofouling. To this end, a number of silver–hydrogel nanocomposite systems are under development. In this study, we attempted a unique strategy to prepare silver‐nanoparticle‐loaded poly(acrylamide‐co‐N‐vinyl‐2‐pyrolidone) hydrogel composites. To load nanosilver particles into such a nonionic hydrogel, a novel breathing‐in/breathing‐out (BI–BO) approach was employed. As the number of BI–BO cycles increased, the amount of the silver nanoparticles loaded into these hydrogels also increased. This behavior was obvious and was confirmed by ultraviolet–visible spectroscopy and thermal analysis. Furthermore, the hydrogel–silver‐nanoparticle composites were confirmed with Fourier transform infrared spectroscopy and transmission electron microscopy studies. Antibacterial studies of these hydrogel–silver nanocomposites showed excellent results against Escherichia coli. The antibacterial activity increased with the number of BI–BO cycles, and samples that underwent three BI–BO cycles showed optimal bactericidal activity. The degree of crosslinking and the silver content had a great influence on the antibacterial efficacy. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Preparation and characterization of acrylic acid/itaconic acid hydrogel coatings containing silver nanoparticles

Hydrogel silver nanocomposites have been used in applications with excellent antibacterial performance. Acrylic acid (AA)/itaconic acid (IA) hydrogels silver nanocomposites were prepared and applied as a coating on a textile substrate. Hydrogel matrices were synthesized first by the polymerization of an AA/IA aqueous (80/20 v/v) solution and mixed with 2‐2‐azobis(2‐methylpropionamide) diclorohydrate and N,N′‐methylene bisacrylamide until the hydrogel was formed. Silver nanoparticles were generated throughout the hydrogel networks with an in situ method via the incorporation of the silver ions and subsequent reduction with sodium borohydride. Cotton (C) and cotton/polyester (CP) textile fibers were then coated with these hydrogel silver nanocomposites. The influence of these nanocomposite hydrogels on the properties of the textile fiber were investigated by infrared spectroscopy (attenuated total reflectance), scanning electron microscopy, energy‐dispersive X‐ray spectroscopy, and antibacterial tests against Pseudomona aeruginosa and Staphylococcus aureus. The better conditions, in which no serious aggregation of the silver nanoparticles occurred, were determined. It was proven that the textiles coated with hydrogels containing nanosilver had an excellent antibacterial abilities. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 2713–2721, 2013     

Fabrication of Au and Ag Bi-metallic nanocomposite for antimicrobial applications

Hydrogel silver nanocomposites have shown immense potential in many biomedical applications, specifically wound healing. The combination of bi-metallic (Ag, Au) hydrogel nanocomposites are developed to enhance their antimicrobial activity. This paper presents the fabrication of bi-metallic nanocomposites obtained from the synthesis of acrylamide (AM) and 2-acrylamido-2-methyl-1-propanesulfonic acid (AMPS) based hydrogels for antimicrobial applications. The nanocomposite formation was confirmed by scanning electron microscopy (SEM), thermal analysis (TGA/DSC), as well as X-ray diffraction (XRD) methods. The bi-metallic nanocomposite hydrogel has shown significant antibacterial activity on bacillus. Therefore, these bi-metallic antibacterial materials are promising candidates for a wide range of biomedical applications. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Preparation of modified sodium lignosulfonate hydrogel–silver nanocomposites

In this article, modified sodium lignosulfonate (MSLS) hydrogel particles were prepared using sodium lignosulfonate as starting material. The hydrogel particles exhibit a reversible property transformed between the two states of macrohydrogel and microhydrogel by ultrasonic dispersion and vacuum drying. Using this property, highly stable and uniformly dispersed silver nanoparticles (AgNPs) have been prepared via in situ reduction of silver ions (silver nitrate) in the microhydrogel aqueous dispersion with sodium borhydride. The hybrid microhydrogel with AgNPs was transformed into MSLS hydrogel–silver nanocomposites by drying under vacuum at 40°C. X‐ray diffraction, ultraviolet–visible (UV–vis) spectrophotometry, Fourier transform infrared spectra, atomic absorption spectroscopy, transmission electron microscopy, and scanning electron microscopy were used to characterize the composite system. The results show that the size of spherical silver nanoparticles incorporated in the hydrogel framework is about 10 nm. POLYM. COMPOS., 34:860–866, 2013. © 2013 Society of Plastics Engineers     

Antibacterial activity and cytotoxicity of hydrogel–nanosilver composites based on copolymers from 2‐acrylamido‐2‐methylpropanesulfonate sodium

In this research, we contributed to the search for potential hydrogel–silver dressings by generating hydrogel–silver nanoparticles (AgNPs) composites prepared by the dipping of the crosslinked hydrogel poly(N‐vinylpyrrolidone‐co‐2‐acrylamido‐2‐methylpropanesulfonate sodium) (1:1) and poly(acrylamide‐co‐2‐acrylamido‐2‐methylpropanesulfonate sodium) (1:1) into an aqueous suspension of citrate‐stabilized AgNPs. The composites obtained were evaluated by an antibacterial activity assay on Staphylococcus aureus and Escherichia coli and subjected to an in vitro cytotoxicity assay for human fibroblasts. The composite formed from the hydrogel poly(N‐vinylpyrrolidone‐co‐2‐acrylamido‐2‐methylpropanesulfonate sodium) with 3 mol % N,N‐methylene bisacrylamide showed the highest antibacterial activity and the least cytotoxicity among the composites tested; this makes it an excellent alternative as a potential dressing for the treatment of deep and exudative wounds. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 39644.     

Chitosan–poly(aminopropyl/phenylsilsesquioxane) hybrid nanocomposite membranes for antibacterial and drug delivery applications

We fabricated hybrid (CSSQ) membranes from chitosan and poly(aminopropyl/phenylsilsesquioxane) (PAPSQ) blends via a sol–gel reaction and solution casting followed by crosslinking with glutaraldehyde. The CSSQ membranes were then used for loading of 5‐fluorouracil (5‐FU) as an anticancer drug as well as templates for the production of silver nanoparticles (AgNPs). The physicochemical properties of the CSSQ membranes were examined using UV‐visible spectroscopy, Fourier transform infrared spectroscopy, X‐ray diffraction, thermogravimetric analysis and scanning electron microscopy (SEM). SEM results showed the controllable formation of AgNPs around PAPSQ. CSSQ–Ag nanocomposite membranes exhibited good antibacterial activity towards both Escherichia coli and Bacillus subtilis, while the CSSQ membranes worked as good carriers for controlled release of 5‐FU as model drug. The results suggest that both CSSQ and CSSQ–Ag nanocomposite membranes can be potentially applied for biomedical applications such as controlled release carriers as well as antibacterial wound dressing materials. © 2014 Society of Chemical Industry     

Development of Gelatin Based Inorganic Nanocomposite Hydrogels for Inactivation of Bacteria

In this investigation, silver nanocomposite hydrogels were developed by using acrylamide and biodegradable gelatin. Silver nanoparticles were generated throughout the hydrogel networks using in situ method by incorporating Ag⁺ ions and the subsequent treatment with sodium borohydride. The effect of gelatin on the swelling studies was investigated. The hydrogel synthesized silver nanocomposites were characterized by using Fourier transform infrared, UV–Visible spectroscopy, X-ray diffraction, thermogravimetric analysis, scanning electron and transmission electron microscopy techniques. The biodegradable gelatin-based silver nanocomposite hydrogels were tested for antibacterial properties. The results indicate that these biodegradable silver nanocomposite hydrogels can be useful in medical applications, as antibacterial agents.     

Physicochemical properties and antimicrobial activity of biocompatible carboxymethylcellulose‐silver nanoparticle hybrids for wound dressing and epidermal repair

Skin loss can be caused by accident, burn, trauma, chronic wounds, and diseases, which is severely aggravated by multidrug‐resistant bacterial infections. Soft hybrids based on biopolymers combined with silver nanoparticles (AgNPs) have potential applications as wound dressing supports and skin tissue repair. Thus, our study focused on the design, green synthesis, and comprehensive characterization of carboxymethyl cellulose (CMC–AgNP) nanocomposites for producing hydrogel membranes, with tunable physicochemical properties, cytocompatibility, and biocidal activity for potential application as wound dressing and skin repair. These nanocomposites were prepared using CMC with two degrees of carboxymethylation, distinct concentrations of citric acid (CA) crosslinker, and AgNPs by in situ chemical reduction, forming hybrid membranes by the solvent casting method. The results demonstrated that superabsorbent hydrogels were produced with swelling and degradation behaviors dependent on the concentration of CA crosslinker, degree of carboxymethylation of CMC, and content of AgNP in the matrices. Moreover, the Fourier transform infrared spectroscopy analysis evidenced that the CMC functional groups (e.g., ? COOH and ? OH) were directly involved in the chemical reactions for the formation of AgNPs and hydrogel crosslinking pathway. These nanocomposites were cytocompatible using in vitro 3‐(4,5‐dimethyl‐2‐thiazolyl)‐2,5‐diphenyltetrazolium bromide cell viability assay with of human embryonic kidney cells. Conclusively, the CMC–AgNP nanohybrids demonstrated to be simultaneously non‐toxic combined with highly effective antibacterial activity against gram‐positive multi‐resistant wound/skin pathogens (Staphylococcus aureus) and moderate effect towards gram‐negative strains (Escherichia coli and Pseudomonas aeruginosa). © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 45812.     

Functionalized polymeric silver nanoparticle hybrid network as a dual antimicrobe: Synthesis,characterization, and antibacterial application

The present work describes a novel method for the synthesis of silver polymer nanocomposite for the delivery of amoxicillin (AMO). Silver nanoparticles (AgNPs) were synthesized with chitosan and silver nitrate. The reaction parameters were optimized. Three‐dimensional polymeric networks were synthesized by simple free‐radical graft copolymerization. UV–visible spectroscopy, Fourier transform infrared spectroscopy, X‐ray diffraction, SEM, atomic force microscopy, dynamic light scattering, and zeta potential analysis were used for the complete characterization of the samples. Swelling studies and swelling factors were evaluated. In vitro release of AMO and AgNPs at physiological pHs was analyzed using the Peppas kinetic model to explain the drug delivery mechanism. Cytotoxicity, free‐radical scavenging, and antibacterial activities were analyzed. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43479.     

Facile synthesis and antibacterial evaluation of poly(acrylamide‐co‐(β‐cyclodextrin))/silver nanocomposite

Hydrogel/silver nanocomposites have shown immense potential in many biological applications. In this article, a facile method to synthesize poly(acrylamide‐co‐(β‐cyclodextrin))/silver nanocomposites is reported. The silver nanoparticles were in situ synthesized accompanying with the formation of poly(acrylamide‐co‐(β‐cyclodextrin)) hydrogel by gamma irradiation without additional reducing and stabilizing agents. In addition, the nanocomposites were prepared under ambient conditions. The formation of silver nanoparticles was confirmed by ultraviolet used to characterize the structure and composition of the synthetic nanocomposites. Transmission electron microscope verified the formation and homogeneous distribution of silver nanoparticles in the hydrogel matrix. The hybrid hydrogel exhibited excellent water‐swelling properties, which could be controlled by varying the mass ratio of acrylamide (AM) to β‐cyclodextrin (β‐CD) in the hydrogel. Furthermore, the poly(acrylamide‐co‐(β‐cyclodextrin))/silver nanocomposites were found to be effective in inhibiting the growth of both Gram‐negative Escherichia coli and Gram‐positive Staphylococcus aureus. POLYM. COMPOS., 37:1480–1487, 2016. © 2014 Society of Plastics Engineers     

Development of microbial protective Kolliphor‐based nanocomposite hydrogels

In this scientific work, a novel class of antimicrobial nanocomposite hydrogels were designed and synthesized by chemical and environmentally bioprocess using Kolliphor, acrylamide, and mint leafs in order to achieve antiseptic property for wound applications. In the bioprocess approach, silver nitrate and gold chloride were nucleated with mint leafs in order to obtain effective free individual nano‐inorganic compounds to provide superior antibacterial assets. The formations of dual inorganic nanoparticles were confirmed by transmission electron microscopy, which indicated the size of nanoparticles in the range of approximately 3 ± 2 nm and without agglomeration. The formations of biomaterials were characterized using Fourier transform infrared spectroscopy, thermogravimetric analysis, scanning electron microscopic–energy dispersive spectrometric studies and their swelling properties were determined. Furthermore, the pure hydrogel and the dual inorganic nanocomposite hydrogels developed were tested for antibacterial activities. When compared with the neat hydrogel, the nanocomposite hydrogels significantly improved their anti‐bacterial activities on Bacillus bacterium. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42781.     

Radiation synthesis and characterization of poly(vinyl alcohol)/poly(N-vinyl-2-pyrrolidone) based hydrogels containing silver nanoparticles

A series of PVA/PVP based hydrogels at different compositions were prepared by gamma irradiation. The gel fraction degree of swelling were investigated. Highly stable and uniformly distributed silver nanoparticles have been obtained onto hydrogel networks. The morphology and structure of (PVA/PVP) hydrogel and dispersion of the silver nanoparticles in the polymeric matrix were examined by scanning electron microscopy (SEM) and infrared spectroscopy (FT-IR), respectively. The formation of silver nanoparticles has been confirmed by ultraviolet visible (UV–vis) spectroscopy. A strong characteristic absorption peak was found to be around 420 nm for the silver nanoparticles in the hydrogel nanocomposite. The X-ray diffraction pattern confirmed the formation of silver nanoparticles with average particle size of 12 nm. The diameter distribution of silver nanoparticles was determined by dynamic light scattering DLS. Transmission electron microscope (TEM) showed almost spherical and uniform distribution of silver nanoparticles through the hydrogel network and the mean size of silver nanoparticles ranging is 23 nm. The good swelling properties and antibacterial of PVA/PVP-Ag hydrogel suggest that it can be a good candidate as wound dressing.     

Preparation and antibacterial effects of PVA‐PVP hydrogels containing silver nanoparticles

The poly(vinyl alcohol)/poly(N‐vinyl pyrrolidone) (PVA–PVP) hydrogels containing silver nanoparticles were prepared by repeated freezing–thawing treatment. The silver content in the solid composition was in the range of 0.1–1.0 wt %, the silver particle size was from 20 to 100 nm, and the weight ratio of PVA to PVP was 70 : 30. The influence of silver nanoparticles on the properties of PVA–PVP matrix was investigated by differential scanning calorimeter, infrared spectroscopy and UV–vis spectroscopy, using PVA–PVP films containing silver particles as a model. The morphology of freeze‐dried PVA–PVP hydrogel matrix and dispersion of the silver nanoparticles in the matrix was examined by scanning electron microscopy. It was found that a three‐dimensional structure was formed during the process of freezing–thawing treatment and no serious aggregation of the silver nanoparticles occurred. Water absorption properties, release of silver ions from the hydrogels and the antibacterial effects of the hydrogels against Escherichia coli and Staphylococcus aureus were examined too. It was proved that the nanosilver‐containing hydrogels had an excellent antibacterial ability. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 125–133, 2007     

Silver/poly(N‐vinyl‐2‐pyrrolidone) hydrogel nanocomposites obtained by electrochemical synthesis of silver nanoparticles inside the polymer hydrogel aimed for biomedical applications

Silver nanoparticles were produced inside a poly(N‐vinyl‐2‐pyrrolidone) hydrogel (PVP) by an innovative method based on the electrochemical reduction of Ag⁺ ions within the swollen PVP hydrogel. UV‐visible spectroscopy showed the highest value of the absorbance intensity and the lowest values of the wavelength of the absorbance maximum and the full width at the half‐maximum absorbance for the Ag/PVP nanocomposite obtained at 200 V during 4 min. Cyclic voltammetry results suggested an adequate entrapment of the silver nanoparticles. The mechanical properties under bioreactor conditions of the Ag/PVP nanocomposite suggested the possibility of wound dressing application. Silver release from Ag/PVP nanocomposites was confirmed under static conditions as well as by their antimicrobial activity against Staphylococcus aureus. POLYM. COMPOS., 35:217–226, 2014. © 2013 Society of Plastics Engineers     

Polypropylene oxide/polyethylene oxide-cellulose hybrid nanocomposite hydrogels as drug delivery vehicle

This article deals with the synthesis of hybrid nanocomposite hydrogels through the combination of cellulose (C), polypropylene oxide/poly ethylene oxide (PPO/PEO), and silver nanoparticles (AgNPs) by in situ polymerization technique for the in vitro release of ornidazole drugs. The structure of the resulted materials is identified using SEM, XRD, FTIR, XPS, and TGA spectroscopic techniques. The resulting structure, morphology, thermo responsive property, water retention, and swelling behavior of hydrogels are investigated. The rheological measurement is studied to establish the enhancement of the viscoelasticity and stiffness of hydrogels. The antibacterial activity of the biodegradable silver hybrid nanocomposite hydrogel is investigated by inhibition zone method against gram positive and negative bacteria. Maximum drug release of 96.4% is recorded at 7.4 pH in 5 h. The biocompatibility and cytotoxicity of the hybrid nanocomposite hydrogel are verified using mouse fibroblast cell line L-929 (ATCC CCL-1) cells for their possible use as controlled drug delivery vehicles. The nontoxic nature makes the materials more biocompatible and suitable to apply in the biological systems. Therefore, nontoxic and biocompatible natures of present materials with improved thermal and rheological properties support for their possible uses as drug delivery vehicles.     

Innovative preparation of bacterial cellulose/silver nanocomposite hydrogels: In situ green synthesis,characterization, and antibacterial properties

In this study, an innovative in situ green strategy was applied to prepare bacterial cellulose/silver nanocomposites using green tea as a substrate for the fermentation of Acetobacter xylinum bacteria and a reducing agent for the in situ synthesis of silver nanoparticles. The samples were analyzed by different characterization tests including field emission scanning electron microscopy (FESEM), X-ray diffraction analysis (XRD), UV–vis spectroscopy, atomic absorption spectroscopy, and ATR. The results indicated the excellent antibacterial activities with 100% bacterial reduction percentage and inhibition zones of 2.6 and 2.8 cm against S. aureus and E. coli, respectively. Moreover, water absorption percentage and vertical wicking measurements supported the hydrogel properties of the prepared bio-cellulose/silver nanocomposites. Finding of this research suggested the potential of the proposed green route for preparing antibacterial BC which can be regarded as a candidate for future wound healing applications.     

Physicochemical evaluation of nanocomposite hydrogels with covalently incorporated poly(vinyl alcohol) functionalized graphene oxide

To avoid the negative effect of graphene oxide (GO) nanosheets aggregation in aqueous solutions on physicochemical properties of GO incorporated nanocomposite hydrogels, poly(vinyl alcohol)-functionalized GO (GO-es-PVA) are synthesized and are used for preparation of nanocomposite hydrogels. By graft copolymerization of GO-es-PVA with poly(AA-co-AAm) chains, the nanocomposite hydrogel samples with covalently incorporated GO-es-PVA are achieved. FTIR spectroscopy, XRD analysis, and SEM and EDAX techniques confirm successful synthesis process. It is clear that GO-es-PVA content has significant effect on physicochemical properties of nanocomposite hydrogels, such as improvement of the water uptake properties, porosity, and gel strength. The hydrogel sample with 1:80 mass ratio of GO-es-PVA/AAm has the best physicochemical properties due to the optimum amount of GO-es-PVA, which gives the hydrogel proper viscoelasticity as well as fine porosity and water uptake rate. Interpenetration of PVA chains into the polymeric networks makes the movement of the polymer chains easier, which leads to softer polymeric networks. This phenomenon is called plasticizing effect. The plasticizing nature of PVA and its high hydrophilicity are the main reasons for the fine physicochemical properties. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 48025.