Hydrogel–silver nanoparticle composites: A new generation of antimicrobials

Design of consistant and eco‐friendly methods for the synthesis of silver nanoparticles (AgNPs) is a significant forward direction in the field of application of antibacterial bionanotechnology. One among the available options is hydrogel templates, which are highly useful to achieve this goal. This investigation involves the development of poly(acrylamide)/poly(vinyl alcohol) hydrogel–silver nanocomposites (HSNCs) to achieve AgNPs of ～2–3 nm size in gel networks. The nanocomposite synthesis process is quite convenient, direct, and very fast, and the obtained hydrogel AgNP composites can be used for antibacterial and wound dressing applications. All the nanocomposite aqueous solutions have shown absorption peaks at 420 nm in UV–visible absorption spectrum corresponding to the Plasmon absorbance of AgNPs. X‐ray diffraction spectrum of the HSNC exhibited 2θ values matching with silver nanocrystals. Transmission electron microscopy images of nanocomposites represent discrete AgNPs throughout the gel networks in the range of 2–3 nm. The developed nanocomposites were evaluated for antibacterial application on E. coli. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Toxicity of a polymer-graphene oxide composite against bacterial planktonic cells, biofilms, and mammalian cells

It is critical to develop highly effective antimicrobial agents that are not harmful to humans and do not present adverse effects on the environment. Although antimicrobial studies of graphene-based nanomaterials are still quite limited, some researchers have paid particular attention to such nanocomposites as promising candidates for the next generation of antimicrobial agents. The polyvinyl-N-carbazole (PVK)-graphene oxide (GO) nanocomposite (PVK-GO), which contains only 3 wt% of GO well-dispersed in a 97 wt% PVK matrix, presents excellent antibacterial properties without significant cytotoxicity to mammalian cells. The high polymer content in this nanocomposite makes future large-scale material manufacturing possible in a high-yield process of adiabatic bulk polymerization. In this study, the toxicity of PVK-GO was assessed with planktonic microbial cells, biofilms, and NIH 3T3 fibroblast cells. The antibacterial effects were evaluated against two Gram-negative bacteria: Escherichia coli and Cupriavidus metallidurans; and two Gram-positive bacteria: Bacillus subtilis and Rhodococcus opacus. The results show that the PVK-GO nanocomposite presents higher antimicrobial effects than the pristine GO. The effectiveness of the PVK-GO in solution was demonstrated as the nanocomposite "encapsulated" the bacterial cells, which led to reduced microbial metabolic activity and cell death. The fact that the PVK-GO did not present significant cytotoxicity to fibroblast cells offers a great opportunity for potential applications in important biomedical and industrial fields.     

Low-temperature assembling of naturally driven copper ferrite starch nanocomposites hydrogel with magnetic and antibacterial activities

Most hydrogels are prepared with using synthetic polymers that are nonecofriendly materials. Also, hydrogel nanocomposites are mostly prepared in the multi-step processing through costly techniques. Here, starch as a natural, biodegradable, hydrophilic, and inexpensive material was used for fabrication of a copper ferrite starch nanocomposites hydrogel. This was synthesized using alkali starch solution along with copper and iron salts through coprecipitation method at low-temperature led to the one-step gelatinization and retrogradation. The various characteristics of the nanocomposites hydrogel were examined including morphology and chemical structure besides magnetic, antimicrobial, and swelling behaviors. Further, the remaining ashes were considered as a simple method to estimate organic matter and inorganic nanoparticles content of hydrogel nanocomposite. The results indicated successful fabrication of a green hydrogel with magnetic and antibacterial features through a very simple method. The obtained ecofriendly hydrogel can be used in various applications such as controlled drug delivery, cancer hyperthermia, waste-water treatment, and many others. © 2020 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020 , 137, 48961.     

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.     

Bioactive Carboxymethyl Starch-Based Hydrogels Decorated with CuO Nanoparticles: Antioxidant and Antimicrobial Properties and Accelerated Wound Healing In Vivo

In this study, nanocomposite hydrogels composed of sodium carboxymethylated starch (CMS)-containing CuO nanoparticles (CMS@CuO) were synthesized and used as experimental wound healing materials. The hydrogels were fabricated by a solution-casting technique using citric acid as a crosslinking agent. They were characterized by Fourier-transform infrared spectroscopy (FTIR), energy-dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), and thermogravimetric analysis (TGA) to evaluate their physicochemical properties. In addition, swelling, antibacterial activities, antioxidant activities, cytotoxicity, and in vivo wound healing were investigated to evaluate the wound healing potential of the CMS@CuO nanocomposite hydrogels. Growth inhibition of the Gram-positive and Gram-negative pathogens, antioxidant activity, and swelling were observed in the CMS@CuO nanocomposite hydrogels containing 2 wt.% and 4 wt.% CuO nanoparticles. The hydrogel containing 2 wt.% CuO nanoparticles displayed low toxicity to human fibroblasts and exhibited good biocompatibility. Wounds created in rats and treated with the CMS@2%CuO nanocomposite hydrogel healed within 13 days, whereas wounds were still present when treated for the same time-period with CMS only. The impact of antibacterial and antioxidant activities on accelerating wound healing could be ascribed to the antibacterial and antioxidant activities of the nanocomposite hydrogel. Incorporation of CuO nanoparticles in the hydrogel improved its antibacterial properties, antioxidant activity, and degree of swelling. The present nanocomposite hydrogel has the potential to be used clinically as a novel wound healing material.     

Chitosan modified MMT‐poly(AMPS) nanocomposite hydrogel: Heating effect on swelling and rheological behavior

Vulnerability of hydrogels against thermal circumstances may be substantially eliminated via incorporating nanoclay to prepare nanocomposite hydrogels. In this research, chitosan‐intercalated montmorillonite (ChitoMMT) was used as a bionanoclay to yield novel nanocomposite hydrogels based on 2‐acrylamido‐2‐methylpropanesulfonic acid. The bionanoclay is suitable especially for preparing biomaterials used in biomedical, food, and pharmaceutical applications, unlike conventional commercial nanoclays (alkyl ammonium‐intercalated MMT) which are not appropriate for bio‐applications due to toxicity of the intercalant particularly where the clay content is high. Two different crosslinkers (i.e., methylene bisacrylamide, and polyethyleneglycol dimethacrylate) were employed to synthesize the nanocomposites. The variations in swelling, rheological and thermal properties of the hydrogels were essentially attributed to thermally induced crosslink cleavage/formation depending upon the crosslinker nature. The nanocomposites comprised superior thermal properties in comparison with the clay‐free hydrogel counterpart. They can preserve substantially their swelling ability for longer heating periods. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Preparation, characterization, and antibacterial properties of pH-responsive P(MMA-co-MAA)/silver nanocomposite hydrogels

A pH-responsive copolymer hydrogel was synthesized based on methyl methacrylate (MMA) and methacrylic acid (MAA) as monomers, and was adopted as a nanoreactor for assembling Ag nanoparticles. Fourier transform infrared spectroscope (FTIR), scanning electron microscopy (SEM), transmission electron microscope (TEM), UV-visible spectroscopy (UV-Vis) and thermogravimetric analysis (TGA) were used to fully characterize the formation of silver nanoparticles in P(MMA-co-MAA) hydrogels. The experimental results showed that the P(MMA-co-MAA) hydrogels assume a three-networks architecture in morphologies, and that nearly spherical Ag nanoparticles are formed in these hydrogel networks; the size of these Ag nanoparticles varies with the system composition. The swelling kinetics investigations demonstrated that the equilibrium swelling ratio (ESR) of the P(MMA-co-MAA)/Ag hydrogels depended on the content of the MAA and pH of the buffer solutions, and the ESR values were reduced with increasing MAA contents. The antibacterial properties against both S. aureus and B. subtilis bacteria demonstrated that the P(MMA-co-MAA)/silver nanocomposite hydrogels had higher antimicrobial efficacy than the pure P(MMA-co-MAA) counterparts. Therefore, the nanocomposite hydrogels turned out to be a potentially smart material in the range of applications of antibacterial activity.     

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     

Hybrid Nanocomposites of Hydroxyapatite,Eu2O3, Graphene Oxide Via Ultrasonic Power: Microstructure,Morphology Design and Antibacterial for Biomedical Applications

Post-implantation infections are regarded as a major issue in the biomedical field. Further, many investigations are continuous towards developing antibacterial biocompatible materials. In this regard, hydroxyapatite (HAP), erbium oxide (Eu₂O₃), and graphene oxide (GO) were introduced in nanocomposites combinations, including single, dual, and triple constituents. The nanoparticles of HAP, Eu₂O₃, and nanosheets of GO are synthesized separately, while dispersed in the nanocomposites simultaneously. The morphological investigation showed that HAP was configured in a rod-like shape while the nano ellipsoidal shape of Eu₂O₃ was confirmed. The particle size of the ternary nanocomposite containing HAP/Eu₂O₃/GO reached the length of 40 nm for the rods of HAP and around 28 nm for the length axis of ellipsoidal Eu₂O₃ nanoparticles. The roughness average increased to be about 54.7 nm for HAP/GO and decreased to 37.9 nm for the ternary nanocomposite. Furthermore, the maximum valley depth (R_v) increased from HAP to the ternary nanocomposite from 188.9 to 189.8 nm. Moreover, the antibacterial activity was measured, whereas the inhibition zone of HAP/Eu₂O₃/GO reached 13.2?±?1.1 mm for Escherichia coli and 11.4?±?0.8 mm for Staphylococcus aureus. The cell viability of the human osteoblast cell lines was evaluated to be 98.5?±?3% for the ternary composition from 96.8?±?4% for the pure HAP. The existence of antibacterial activity without showing cytotoxicity against mammalian cells indicates the compatibility of nanocomposites with biomedical applications.

     

The release of cefazolin from chitosan/polyvinyl alcohol/sepiolite nanocomposite hydrogel films

Films of chitosan/polyvinyl alcohol (PVA)/sepiolite nanocomposite were prepared by a simple and “green” route through solution mixing; followed by freezing–thawing cycles. The structures of nanocomposites were characterized by transmission electron microscopy (TEM), scanning electron microscopy (SEM), thermogravimetric analysis, X-ray diffractometry, and Fourier transform infrared spectroscopy. The SEM and TEM micrographs confirmed a needle-type dispersion of sepiolite nanoclay in the hydrogel nanocomposites. The effects of sepiolite and chitosan/PVA weight ratio on the swelling of nanocomposites were investigated. The water absorbency of nanocomposites was decreased by introducing sepiolite nanoclay. The nanocomposites with high content of chitosan showed high swelling capacity. The nanocomposite films showed pH-dependent swelling behavior with a maximum water absorbency under acidic pH. The cefazolin with a broad-spectrum activity toward gram-positive and gram-negative bacteria was loaded in hydrogels. The release of cefazolin from nanocomposites was evaluated at pH 7.4. The content of released drug was affected by both sepiolite amount and chitosan/PVA weight ratio. The nanocomposites films released more cefazolin than the neat hydrogel film. Cefazolin-loaded nanocomposites showed the antibacterial activity with a large zone of inhibition against gram-positive Bacillus cereus bacterium.     

Controlled synthesis of (CuO-Cu2O)Cu/ZnO multi oxide nanocomposites by facile combustion route: A potential photocatalytic,antimicrobial and anticancer activity

Photocatalytic activity of (CuO-Cu₂O)Cu/ZnO hetero-junction nanocomposites along with their luminescent, biological applications in the progress of anticancer and antibacterial agents is investigated. The Cu and Zn bi-components modified (CuO-Cu₂O)Cu/ZnO nanocomposites were synthesized via facile combustion route in the presence of controlled fuel to oxidizer ratio and were characterized by X-Ray Diffraction (XRD) patterns, Transmission electron microscopy (TEM), High resolution Transmission electron microscopy (HRTEM), Scanning Electron Microscopy (SEM), X-ray photoelectron Spectroscopy (XPS), Fourier transform infrared spectroscopy (FTIR), photoluminescence (PL) and energy dispersive X-ray (EDX) analysis. The PL and UV–Visible diffused reflectance spectral (UV–Vis-DRS) techniques were used to measure the optical sensitivity and tuning of band gap in the samples. The excellent photocatalytic degradation of Methylene Blue and industrial waste water under Sunlight irradiation depends on the mass ratios of Cu/Zn. The findings show that the addition of a certain proportion of CuO, Cu₂O, ZnO, and Cu can promote efficiency in Sunlight harvesting and separation of charge carriers. Process parameters namely catalyst quantity, dye concentration and a proposal for the mechanism of degradation pathway, experiments for trapping and enhancer are investigated. The study of photoluminescence, CIE and CCT calculations suggests that the present nanocomposite may find applications as phosphor material in warm white LEDs. The second segment of this study deals with the investigation of antibacterial performance of composites upon Gram-negative and Gram-positive bacteria. The results indicate that nanocomposites can be used in antibacterial control systems and as an important growth inhibitor in various microorganisms. The cytotoxic effect of the (CuO-Cu₂O)Cu/ZnO (CCCZ11) nanocomposite was determined by colorimetric and flow cytometric cell cycle analysis. Our experimental results show that the nanocomposite can induce apoptosis and suppress the proliferation of HeLa cells. The applications of nanocomposites based on Cu, an abundant and inexpensive metal has created much interest in various multifunctional applications.     

Polymer-Metal Nanocomposites Containing Dual-Function Metal Nanoparticles: Ion-Exchange Materials Modified with Catalytically-Active and Bactericide Silver Nanoparticles

This work reports the results obtained by the development of two types of nanocomposite membranes containing metal nanoparticles prepared by applying the Intermatrix Synthesis technique for the synthesis of silver nanoparticles in the ion-exchange matrices of sulfonated polyethersulfone-Cardo and Nafion membranes. The stability (in terms of silver nanoparticles loss) of the polymer-metal nanocomposites was evaluated by using both ultrasonic and thermostatic baths and appeared to be appropriate for their practical applications. The dual-function nanocomposites were characterized in batch tests, first, by monitoring their catalytic activity in the reduction of p-nitrophenol to p-aminophenol and second, by evaluating their antibacterial efficiency towards E. coli. The results of the catalytic tests have shown that polymer-silver nanocomposites demonstrate remarkably better activity in comparison with their polymer-palladium nanocomposite analogues. The same nanocomposites have been shown to permit the complete disinfection of E. coli containing water within a short period of time.     

Preparation and characterization of cotton fibers coated with AA-IA hydrogel containing silver/graphene or graphene oxide nanoparticles

This study presents the fabrication and characterization of cotton textile fibers coated with hydrogels containing silver and Graphene or Graphene Oxide nanoparticles using 1-hexyl-3-methyl-imidazolium (HMIMPF6) ionic liquid (IL) as carbon filler dispersant. Acrylic acid/Itaconic acid (AA-IA) hydrogels are synthesized by polymerizing an acrylic acid-itaconic acid aqueous (80/20 v/v) solution and mixed with 2-2-Azobis (2-methylpropionamide) diclorohydrate, and N,N´-methylenbis (acrylamide). Then silver nanoparticles are generated throughout the hydrogel networks using in situ method by incorporating the silver ions and subsequent reduction with sodium borohydride. Then a cotton textile fiber substrate was coated with this hydrogel. Finally, graphene or graphene oxide was added to the textile substrate already impregnated with hydrogel and silver nanoparticles. In order to favor the dispersion of the carbon nano-structures in the system, an IL was used. The influence of these nanocomposite hydrogels on the properties of textile fiber were investigated by infrared spectroscopy (ATR), scanning electron microscopy (SEM), inductively coupled plasma mass spectroscopy (ICP) and antibacterial tests against Staphylococcus aureus (Gram positive) and Escherichia coli (Gram negative). The effect of each and combined fillers dispersion on antimicrobial properties were determined. Cotton fibers coated with hydrogel containing silver nanoparticles and graphene showed better results when the ionic liquid was used. Graphene showed greater antimicrobial efficiency than graphene oxide. It was proved that the textiles coated with hydrogels containing these fillers had an excellent antibacterial ability and are a good option to be used for medical applications such as wounds and burns dressing.     

Optimized synthesis,characterization, and antibacterial activity of an alginate–cupric oxide bionanocomposite

In this research, the structural features and optimal conditions for the synthesis of an alginate–CuO nanocomposite with the highest antibacterial activity were investigated. CuO nanoparticles (NPs) and the alginate biopolymer were synthesized chemically and biologically, respectively. Nine nanocomposite compounds were produced on the basis of the Taguchi method with different levels of CuO NPs and the alginate biopolymer nanocomposite with different stirring times. Fourier transform infrared spectroscopy, high‐resolution field emission scanning electron microscopy, and energy‐dispersive X‐ray spectroscopy analysis confirmed the formation of the nanocomposites. The nanocomposite synthesized with 8 mg/mL copper oxide NPs and 2 mg/mL alginate biopolymer with 60 min of stirring time showed the highest antibacterial activity. The results of two colony forming units and disk‐diffusion methods indicated a stronger antibacterial activity of the alginate–CuO nanocomposite compared with those of its components. The alginate–CuO nanocomposite showed the potential ability to act as an antimicrobial agent against Gram‐negative and Gram‐positive bacteria. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 45682.     

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     

In situ synthesized chitosan–gelatin/ZnO nanocomposite scaffold with drug delivery properties: Higher antibacterial and lower cytotoxicity effects

In this work, chitosan–gelatin/zinc oxide nanocomposite hydrogel scaffolds (CS–GEL/nZnO) were prepared via in situ synthesis of ZnO nanoparticles (nZnO) to reach a scaffold with both inherent antibacterial and drug delivery properties. The prepared nanocomposite hydrogel scaffolds were characterized using scanning electron microscopy, transmission electron microscopy, atomic absorption spectrometer, Fourier transform infrared spectroscopy, and X-ray diffraction. In addition, swelling, biodegradation, antibacterial, cytocompatibility, and cell attachment of the scaffolds were evaluated. The results showed that the prepared scaffolds had high porosity with a pore size of 50–400 μm and nZnO were well distributed without any agglomeration on the CS–GEL matrix. In addition, the nanocomposite scaffolds showed enhanced swelling, biodegradation, and antibacterial properties. Moreover, the drug delivery studies using naproxen showed that nZnO could control naproxen release. Cytocompatibility of the samples was proved using normal human dermal fibroblast cells (HFF2). In comparison to the previous reports which nZnO were simply added to the matrix of the scaffold, in situ synthesis of nZnO was led to higher antibacterial and lower cytotoxicity effects as a result of well distribution of nZnO in this method. According to the findings, the in situ synthesized CS–GEL/nZnO is strongly recommended for biomedical applications especially skin tissue engineering. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47590.     

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     

Poly(vinyl alcohol)/chitosan/honey/clay responsive nanocomposite hydrogel wound dressing

Many efforts have been made to develop modern wound dressings to overcome limitations of traditional ones. Smart nanocomposite hydrogels are appropriate candidates. In this work, a novel responsive nanocomposite hydrogel based on poly(vinyl alcohol)/chitosan/honey/clay was developed and evaluated as a novel wound dressing. The morphology and properties of synthesized nanocomposite hydrogels loaded with honey as a drug model were investigated. The exfoliated morphology of nanocomposite was confirmed by X‐ray diffractometry. Swelling studies were performed at 20 and 37 °C at various pH. The results showed that swelling increased as a result of temperature rise and maximum swelling occurred at a pH of 2. In vitro release of honey was also studied at the same conditions. Corresponding results indicated faster honey release rate at higher pH values. MTT results exhibited no cytotoxicity in nanocomposite hydrogel system. Investigation of antibacterial activity revealed more than 99% antibacterial activity for proposed system. In vivo results confirmed the wound healing ability of developed system. Generally, appropriate properties of proposed system made it ideal in wound dressing applications. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46311.     

Radiation synthesis and characterization of polyvinyl alcohol/chitosan/silver nanocomposite membranes: antimicrobial and blood compatibility studies

Polyvinyl alcohol/chitosan/silver (PVA/CS/Ag) nanocomposite membranes were synthesized by γ-radiation with promising antimicrobial and biomedical applications. The nanocomposite membranes were prepared by mixing PVA and CS solutions with different copolymer compositions in the presence of silver nitrate (AgNO₃) and glutaraldehyde as cross-linker, followed by in situ reduction with γ-radiation at different doses. The nanocomposite membranes were characterized by ultraviolet spectroscopy (UV), Fourier transform infrared, X-ray diffraction (XRD) and transmission electron microscopy (TEM). UV studies showed a strong peak around λ _max at 430 nm due to surface plasmon resonance of silver nanoparticles formed during irradiation. As the irradiation dose increased from 25 to 75 kGy, the plasmon band is shifted from 430 to 418 nm with high intensity, indicating the formation of smaller particles. TEM investigation showed uniform distribution of silver nanoparticles (AgNPs) in the membranes with mean diameter of 32–19 nm. XRD results confirmed that the mean diameter of AgNPs estimated from the Debye–Scherrer formula was in the range of 27.5–12.8 nm which confirms the TEM results. The PVA/CS/Ag nanocomposite membranes exhibited good antibacterial activity and were found to cause significant reduction in microbial growth. The nanocomposite membranes showed non-thrombogenicity effect and slightly haemolytic potential, suggesting their promising use in biomedical applications.     

The Impact of Graphite Oxide Nanocomposites on the Antibacterial Activity of Serum

Nanoparticles can interact with the complement system and modulate the inflammatory response. The effect of these interactions on the complement activity strongly depends on physicochemical properties of nanoparticles. The interactions of silver nanoparticles with serum proteins (particularly with the complement system components) have the potential to significantly affect the antibacterial activity of serum, with serious implications for human health. The aim of the study was to assess the influence of graphite oxide (GO) nanocomposites (GO, GO-PcZr(Lys)₂-Ag, GO-Ag, GO-PcZr(Lys)₂) on the antibacterial activity of normal human serum (NHS), serum activity against bacteria isolated from alveoli treated with nanocomposites, and nanocomposite sensitivity of bacteria exposed to serum in vitro (using normal human serum). Additionally, the in vivo cytotoxic effect of the GO compounds was determined with application of a Galleria mellonella larvae model. GO-PcZr(Lys)₂, without IR irradiation enhance the antimicrobial efficacy of the human serum. IR irradiation enhances bactericidal activity of serum in the case of the GO-PcZr(Lys)₂-Ag sample. Bacteria exposed to nanocomposites become more sensitive to the action of serum. Bacteria exposed to serum become more sensitive to the GO-Ag sample. None of the tested GO nanocomposites displayed a cytotoxicity towards larvae.