Chitosan-silver Nanocomposites Research Articles

Chemical synthesis and characterization of chitosan/silver nanocomposites films and their potential antibacterial activity

This study provides the optimum preparation parameters for functional chitosan silver nanocomposite (CSN) films with promising antibacterial efficacy though prepared with very low silver nitrate (AgNO3) concentration. Chitosan nano‑silver composites were fabricated by In-situ chemical method utilizing the reducing ability of sodium borohydride (NaBH4) and afterward casted into films. Utilization of response surface methodology, NCSS, and SigmaPlot for the optimization of CSN and their predicted antibacterial efficacy assessment of the selected bacterial strains (standard and clinical) was the essential part of the study. The cumulative silver ions released from the CSN films was examined by AAS and was found pH dependent. The developed nanocomposite films exhibited strong antibacterial activity against ATCC strains of Gram-positive Staphylococcus aureus, Gram-negative bacteria (Pseudomonas aeruginosa) and clinically isolated strains of MRSA. The antibacterial activity CSN films were compared with three commercially available dressings (Aquacel Ag®, Bactigras®, and Kaltostat®) and Quench cream. Statistical analysis of the results indicated that the developed CSN films were equally or even more effective than commercial products. Thus the fabricated CSN films may act as a potential candidate to overcome the emerging antibiotic resistance particularly in hospital-acquired skin infections caused by MRSA.

Production of Well-Dispersed Aqueous Cross-Linked Chitosan-Based Nanomaterials as Alternative Antimicrobial Approach

In the current study, chitosan was extracted by deacetylation of chitin, which is extracted from shrimp shell. chitosan nanoparticles (CSNPs) were prepared by ionotropic gelation technique. chitosan/tripolyphosphate ratio (CS:TPP) was kept at 3:1 to prepare CSNPs. chitosan/silver nanocomposite (CS/AgNCs) were prepared by incorporating silver nanoparticles into CSNPs. The quality of the prepared nanocomposite was evaluated by infrared spectroscopy, UV–Vis spectroscopy, transmission electron microscopy, and antibacterial activity. Results showed that chitosan/silver nanocomposite in which, both chitosan and silver are in nanoscale was successfully prepared for the first time in a well-dispersed aqueous form. Whereas CSNPs act as a host material to form the nanocomposite unlike the previously prepared forms of chitosan–silver nanocomposites, that used chitosan bulk as host materials and the dispersion medium was slightly acidic. Moreover, results revealed that the antibacterial activity of CSNPs was significantly enhanced after incorporating trace amount of silver nanoparticles (0.535% w/w AgNPs/CSNPs).

Comparative pot studies of chitosan and chitosan-metal nanocomposites as nano-agrochemicals against fusarium wilt of chickpea ( Cicer arietinum L.)

Abstract Fusarium wilt is a seed borne and soil borne disease of chickpea caused by Fusarium oxysporum f. sp. ciceri (FOC). In this work, chitosan and their nanocomposites were evaluated as antifungal agents against FOC, in vitro as well as in vivo. Among these, chitosan copper oxide nanocomposites (Ch-CuO) and chitosan-zinc oxides nanocomposites (Ch-ZnO) were found to be the most effective against FOC at all recommended concentrations i.e. 50, 100 and 200 µg/ml. Chitosan nanoparticles (Ch) and chitosan-silver nanocomposites (Ch-Ag) were found to be moderately effective but more efficient than standard fungicide i.e. copper-oxy-chloride (CuOCl). Based on in vitro results, 100 µg/ml concentration of all nanoformulations (NFs) was selected for in vivo studies in potted plants. The highest wilt disease reduction was observed in Ch-CuO (46.67%) followed by plants treated with Ch-ZnO (40%) as moderately effective, while Ch-Ag and Ch caused only 33.33% reduction in wilt incidence as less effective. All nanoformulations showed good antifungal efficacy and inhibited the pathogen as well as found to promote the growth of chickpea plants as compared to untreated plants.

Wound Healing Activity of the Formulated Silver Chitosan Nanocomposite Cream against Alloxan-Induced Diabetic Wounded Animal Model

Wound Healing Activity of the Formulated Silver Chitosan Nanocomposite Cream against Alloxan-Induced Diabetic Wounded Animal Model

Chitosan-silver nanocomposites in goldfish aquaria: A new perspective in Lernaea cyprinacea control

Nanomedicine is a promising new research area in human and veterinary science. Metal nanoparticles have shown high biocidal activity against bacteria, fungi and viruses, few studies have focused on antiparasitic action. Therefore, this study aims to investigate the influence of chitosan-silver nanocomposites on the fish crustacean parasite Lernaea cyprinacea. The disease was detected in goldfish (Carassius auratus) aquaria during the spring. Molecular and morphometric characterizations of the parasite were performed using polymerase chain reaction for rRNA and scanning electron microscopy. Chitosan-silver nanocomposites were characterized using transmission electron microscopy and Zetasizer. Probit analysis of parasite mortality versus the logarithmic concentrations of the composites indicated that the 1h/LC50 was 5.495ppm. Parasites exposed to the chitosan-silver nanocomposites showed severe pathological alterations and adsorbed the composite particles on their cuticles. After aqueous exposure of the infected fish to the compound at its LC50 for 24h, the female lernaeids were completely dislodged. Moreover, the pathological findings indicated rapid skin wound healing and renewal at the parasitic injury site. Therefore, we concluded that chitosan-silver nanocomposites are potential parasitic control agents for ornamental glass aquaria, as they have detrimental effects on aquatic predators, such as copepods.

Extraction and Characterization of Chitin and Chitosan from Aspergillus niger, Synthesis of Silver-Chitosan Nanocomposites and Evaluation of their Antimicrobial Potential

The fungal species such as Aspergillus niger are the rich source of antimicrobial compounds. The chitin which is the cell wall component are being isolated and used as potential source of antimicrobial along with its derivates. In the present study, the chitin and chitosan were purified from the mycelial mat of the A. niger. By using the chitosan isolated from the fungi, the chitosan-silver nanocomposite was synthesized under lab conditions. The comparative antibacterial potential of chitin, chitosan and nanocomposites were screened against Bacillus subtilis and Bacillus cereus, which are infecting mulberry silkworm (Bombyx mori) and humans respectively. The in vitro inhibition study results revealed that, Nanocomposites showed more inhibition of pathogens in comparison with other treatments along with positive control. Further, the highest antibacterial activity of chitosan-silver nanocomposites may be due to presence of two potential antimicrobial compounds in combination. Based on the results of the present study, chitosan based nanocomposites can be used for the management of the bacterial diseases of silkworm. The nanocomposite derived in the present work can be used for management of medically important pathogens infecting humans.

Preparation, Characterization, and Antimicrobial Properties of Chitosan-Silver Nanocomposites Films Against Fish Pathogenic Bacteria and Fungi.

Development of nanostructured films using natural polymers and metals has become a considerable interest in various biomedical applications. Objective of the present study was to develop silver nano particles (AgNPs) embedded chitosan films with antimicrobial properties. Based on the Ag content, two types of chitosan silver nano films, named as CAgNfs-12 (12mM) and CAgNfs-52 (52mM) were prepared and characterized. Field emission scanning electron microscope(FE-SEM) images of two CAgNfs showed the circular AgNPs, which were uniformly embedded and distributed in the matrix of chitosan films. Antimicrobial experiment results clearly indicated that CAgNfs can inhibit the growth of fish pathogenic bacteria Vibrio (Allivibrio) salmonicida, V. tapetis, Edwardsiella tarda and fungi Fusarium oxysporum. Moreover, CAgNfs significantly reduced the experimentally exposed V. salmonicida levels in artificial seawater, suggesting that these CAgNfs could be used to develop antimicrobial filters/membranes for water purifying units to eliminate the pathogenic microbes.

Comparative study on antifungal activities of chitosan nanoparticles and chitosan silver nano composites against Fusarium oxysporum species complex

Though the metal nanoparticles (NPs) have been shown favorable results against fungal diseases, erratic environmental toxicity of NPs have raised serious concerns against their applications. Hence, it is vital to modify antifungal compounds into safe substitutes over synthetic chemicals. In this study, antifungal effects of chitosan nanoparticles (CNPs) and chitosan silver nanocomposites (CAgNCs) were compared against Fusarium oxysporum species complex. CNPs and CAgNCs were synthesized, characterized and compared based on the transmission electron microscope, X-ray diffraction, UV–vis absorbance spectra, particle size distribution, zeta potential and thermal stability analysis. Ultra-structural analysis on mycelium membrane of treated F. oxysporum showed that CNPs and CAgNCs could induce a pronounced membrane damage and disruption of the mycelium surface, increase the membrane permeability, and even cell disintegration. CAgNCs showed a significantly higher radial growth inhibition than CNPs in all the tested concentrations. Both CNPs and CAgNCs were not only effective in reducing the fungal growth, but also caused morphological and ultrastructural changes in the pathogen, thereby suggesting its usage as an antifungal dispersion system to control F. oxysporum. Additionally, CNPs and CAgNCs therapy reduced the F. oxysporum infection in zebrafish. Data demonstrates biologically active CNPs and CAgNCs are promising antifungal agents against F. oxysporum.

Metagenomics analysis of gut microbiota and immune modulation in zebrafish (Danio rerio) fed chitosan silver nanocomposites

In this study, we evaluated the effects of chitosan silver nanocomposites (CAgNCs) supplemented diet on gut microbial community, goblet cell density, gut morphometry and mRNA expression of immune related and mucin encoding genes in zebrafish. Zebrafish gut microbiota analysis results clearly showed the reduction of phylum Proteobacteria. However, they remained as the major bacterial group in gut with CAgNCs supplemented diet, while the abundance of phylum Fusobacteria and phylum Bacteroidetes were increased notably compared to the control diet fed fish. Total goblet cell density was significantly increased at 30 and 60 days in CAgNCs supplemented group (1.6–fold and 2.0-fold, respectively) compared to the control group indicating enhanced immune function in the gut. CAgNCs supplementation has also increased villi height significantly in the zebrafish mid gut at the end of 30 (95.5 ± 3.7 μm) and 60 days (144.40 ± 4.8 μm) compared to control diet fed fish at 30 (86.90 ± 3.7 μm) and 60 days (96.2 ± 4.8 μm). Furthermore, mRNA expression of immune related genes such as TNF-α (6.2-fold), IL-10 (5.0-fold), IL-12 (9.2-fold), IRF-1 (5.2-fold), Defbl1 (3-fold), Lyz (5.1-fold) and mucin encoding genes were significantly upregulated (above 2-fold) compared to that of control group. The current study revealed that CAgNCs supplemented diet engenders promising effects on fish gut immunity by enhancing beneficial microbial populations, goblet cell density, villi length, and transcriptional regulation of immune related and mucin encoding genes.

Chitosan–silver nanocomposites: New functional biomaterial for health-care applications

ABSTRACTChitosan–silver nanocomposites (CS-HDA-AgNCs) was prepared using chitosan, biogenic silver nanocomposites, and crosslinker, hexamethylene 1,6-di(amino carboxysulfonate) (HDA). The film is flexible and transparent. Its physical, mechanical, thermal, hydrophilicity, and swelling properties were improved by HDA (2.5%). The antimicrobial activity of CS-HDA-AgNCs were not displayed any remarkable zone of inhibition but showed toxic effect in the presence of normal 3T3 fibroblasts and cancer HeLa cells. It decreases to ca. 5–7% for both cell lines. In conclusion, it can be mentioned that the CS-HDA-AgNCs, a kind of new functional biomaterial, could be useful for health-care applications.

Development of noncytotoxic silver-chitosan nanocomposites for efficient control of biofilm forming microbes.

Severe bacterial and fungal infections have become a major clinical and public health concern. Nowadays, additional efforts are needed to develop effective antimicrobial materials that are not harmful to human cells. This work describes the synthesis and characterization of chitosan-ascorbic acid-silver nanocomposites as films exhibiting high antimicrobial activity and non-cytotoxicity towards human cells. The reductive and stabilizing activity of both the biocompatible polymer chitosan and ascorbic acid were used in the synthesis of silver nanoparticles (AgNPs). Herein, we propose an improved composite synthesis based on medium average molecular weight chitosan with a high deacetylation degree, that together with ascorbic acid gave films with a uniform distribution of small AgNPs (<10 nm) exhibiting high antimicrobial activity against biofilm forming bacterial and fungal strains of Staphylococcus aureus, Pseudomonas aeruginosa, Escherichia coli and Candida albicans. At the same time, the resulting solid nanocomposites showed, at the same doses, reduced or totally excluded cytotoxicity on mammalian somatic and tumoral cells. Data obtained in the present study suggest that adequately designed chitosan-silver nanocomposites are powerful and promising materials for reducing pathogenic microorganism-associated infections without harmful effects towards mammalian cells.

Synthesis and Characterization of Chitosan-Silver Nanocomposite Film

Chitosan is termed as one of the useful carbohydrate oligosaccharides derived from chitin, which can be used to improve film packaging by hybridizing with silver due to their advantages of flexibility, easy scale up and low cost methods. Design of packaging material with non-toxic property becomes key issue. The objective of this work is to synthesize and characterize chitosan-silver nanocomposite film for effective packaging. The nanocomposite was synthesized using in-situ, co-mixing chemical method and air drying method. The morphology integrity of the nanohybrid was confirmed using UV-Visible Spectrophotometer, Transmission Electron Microscope (TEM) and X-ray Diffraction (XRD). TEM analysis revealed the cap shaped spherical morphology with no agglomeration and uniform size distribution of the nanoparticles within the range of 20.00 nm. UV-visible analysis showed Plasmon resonance band at 275 nm and 435 nm indicating the presence of chitosan and silver with no observable peak and an increase in intensity of chitozan. XRD confirmed the order and crystalline peak located at 2θ = 35ᵒ, 64ᵒ and 77ᵒwhich have been keenly indexed as face centred cubic Silver nanocrystals.Thus, the nanocomposite film produced serves as an effective packaging material.

Chitosan silver nanocomposite (CAgNC) as an antifungal agent againstCandida albicans

Due to limited numbers of antifungal drugs and emergence of drug resistance have directed to develop nonconventional therapeutic agents against fungal pathogen Candida albicans. In this study, anticandidal activity of chitosan silver nanocomposite (CAgNC) was tested against C. albicans Minimum inhibitory concentration (MIC) and minimum fungicidal concentration (MFC) of CAgNC were determined as 25 and 100μg/ml, respectively. Electron microscopic image results confirmed the ultrastructural cell wall deformities and injuries caused by CAgNC. Propidium iodide (PI) penetration into the CAgNC treated cells could be considered as an evidence for loss of cell membrane integrity and cell death at MFC. Level of intracellular reactive oxygen species (ROS) was increased, while cell viability was decreased with the increased of CAgNC concentrations. In our protein profile results, several induced proteins were observed under CAgNC treatment, and they could be related to multidrug and stress resistant proteins such as CDR1 (55kDa) and CaHSP70 based on the protein band size. CAgNC mediated cell wall damage, loss of cell membrane integrity, elevated ROS level, and associated oxidative stress have been identified as the main causative factors for the anticandidal activity. Overall results from our study indicated that CAgNC could affect negatively on physiological and biochemical functions of C. albicans suggesting CAgNC as a potential alternative for antifungal chemotherapy.

Physicochemical investigations of biogenic chitosan-silver nanocomposite as antimicrobial and anticancer agent

Chitosan (CS), a seaweed polysaccharide is a natural macromolecule which is widely being used in medical applications because of its distinctive antimicrobial and anticancer properties. Silver, a noble metal, is also receiving wide attention for its potential usage in antimicrobial and anticancer therapeutics. In this study, an effective way of reduction of silver using chitosan at varying reaction temperatures and an optimised concentration of silver were performed. The optical, structural, spectral, morphological and elemental studies of the biosynthesized chitosan-silver (CS-Ag) nanocomposites were characterized by several techniques. The synthesized CS-Ag nanocomposites exhibit particle size around 20nm and were further exploited for potent biological applications in nanomedicine due to their nanometric sizes and biocompatibility of chitosan. The antimicrobial activity of the biosynthesized CS-Ag nanocomposites exhibits zone of inhibition ranged between 09.666±0.577 and 19.000±1.000 (mm). The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) were from 8 to 128μgmL−1 and 16 to 256μgmL−1 respectively, with the highest antimicrobial activity shown against Gram-negative Salmonella sp. The synergistic effect of chitosan and silver as a composite in nanometric size revealed significant IC50 value of 29.35μgmL−1 and a maximum of 95.56% inhibition at 100μgmL−1 against A549 lung cancer cell line, resulting in potent anticancer effect.

Comparative study of preparation, characterization and anticandidal activities of a chitosan silver nanocomposite (CAgNC) compared with low molecular weight chitosan (LMW-chitosan)

A chitosan-silver nanocomposite (CAgNC) was synthesized in a green manner using low molecular weight chitosan (LMW-chitosan) and silver nitrate without applying external chemical reducing agents.

Effect of glycerol on mechanical and physical properties of silver-chitosan nanocomposite films

The effect of using glycerol as plasticizer on mechanical and physical properties of silver-chitosan nanocomposite films have been studied. The nanocomposite films were prepared via three steps consisting of silver-chitosan colloidal nanocomposites preparation, adding of glycerol to colloids and silver-chitosan nanocomposites films formation. During the first step, silver ions were reduced by glucose and accelerated by sodium hydroxide (NaOH). Chitosan of 1% (v/v) act as stabilizing agent. Glycerol with volume variation of 0.2, 0.4, 0.6, 8 and 1.0 mL was added colloidal nanocomposites of 60 mL on the second step. On the third step, colloidal nanocomposites were cast on the polypropylene plate and dried at room temperature. The as-prepared films were then neutralized by NaOH and rinsed with distilled water until the filtrate reached the pH of 7. The colloidal nanocomposites were characterized by UV-Vis spectroscopy and transmission electron microscopy (TEM). The film were characterized by X-ray diffraction (XRD) and thermogravimetric analysis (TGA). The mechanical properties, swelling capacity, water vapor permeability (WVP) of the films were also studied. The results indicated that the addition of different amounts of glycerol on colloidal nanocomposites effects on mechanical and physical properties of the resulted nanocomposite films. The elongation and tensile strength were gradually increased as the glycerol amount. Meanwhile, the swelling capacity, WVP, and crystallinity of the film also showed enhancement at increasing glycerol amount. However, the thermal stability decreased.

Microwave assisted antibacterial chitosan–silver nanocomposite films

In the current approach, antibacterial chitosan-silver nanocomposite films were fabricated through microwave irradiation. During the process, by utilizing chitosan as reducing agent, silver nanoparticles were synthesized within 11min by microwave irradiation. Further, films were fabricated within 90min. It involved an energy consumption of just 0.146kWh to synthesize silver nanoparticles. This is many times less than the energy consumed during conventional methods. The silver nanoparticles were examined through UV–vis spectrum and transmission electron microscopy (TEM). The fabricated films were characterized by using scanning electron microscopy coupled with an energy dispersive spectrometer (SEM–EDS), Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), and contact angle (CA) measurements. The films exhibited antibacterial properties against both Gram-negative micro-organisms (Escherichia coli; E. coli) and Gram-positive micro-organisms (Staphylococcus aureus; S. aureus). In overall, the procedure adopted for fabricating these antibacterial films is environmental friendly, time-saving and energy-saving.

A versatile effect of chitosan-silver nanocomposite for surface plasmonic photocatalytic and antibacterial activity

Chitosan-silver (CS-Ag) nanocomposite was green synthesised without the aid of any external chemical-reducing agents. The synthesised nanocomposite was characterised by UV–visible spectroscopy, X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), thermo-gravimetric analysis (TGA), differential scanning calorimetry (DSC), field emission scanning electron microscopy (FE-SEM), energy dispersive X-ray spectroscopy (EDX), atomic force microscopy (AFM), high-resolution transmission electron microscopy (HR-TEM) with selected area electron diffraction (SAED), X-ray photoelectron spectroscopy (XPS), and zeta potential analyser. The particle size of the synthesised CS-Ag nanocomposite was around 20nm and was found to be thermally stable in comparison with pure chitosan. The prepared nanocomposite acts as a photocatalyst for dye decolourisation, with a maximum of 81% of methyl orange (MO) decolourisation that occurred under visible light irradiation. The kinetics was found to follow pseudo-first-order according to Langmuir–Hinshelwood (L–H) model. The nanocomposite also proved to be an excellent antimicrobial agent against both Gram-positive and Gram-negative bacteria, possessing a broad spectrum of antimicrobial activity. The zone of inhibition ranged between 16.000±1.000 and 19.333±1.155 (mm), proving its high susceptibility than chitosan itself. The minimum inhibitory concentration (MIC) values were from 8 to 64μg/mL, whereas the minimum bactericidal concentration (MBC) values ranged from 16 to 128μg/mL, with the highest antibacterial activity shown against Gram-positive Staphlococcus aureus. This report illustrates the eco-friendly approach for the reduction of silver using chitosan as a reducing agent, and its potential to dye decay and microbial contaminants.

Antimicrobial effects of chitosan silver nano composites (CAgNCs) on fish pathogenic Aliivibrio (Vibrio) salmonicida

Chitosan is one of the promising bio-degradable natural products which can be applied in nano forms in disease prevention, and treatment measures in aquaculture. The aim of this study was to develop and investigate the antibacterial function of chitosan-silver nano composites (CAgNCs) against fish pathogenic Aliivibrio salmonicida. Zeta potential and average size of synthesized CAgNCs were +32.1mV and 281nm, respectively. The Ag content of the CAgNCs was 0.643±0.012% (w/w). Antibacterial results revealed that CAgNCs could inhibit the A. salmonicida growth which indicates minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) at 50μg/mL and 100μg/mL, respectively. We confirmed the attachment of AgNPs on the surface of A. salmonicida which indicates the interaction of CAgNCs with the bacterium. Propidium iodide (PI) uptake results suggested that CAgNCs has affected to permeability of cell membrane of A. salmonicida. Also, CAgNCs induced the level of reactive oxygen species (ROS) in concentration and time dependent manner (up to 3h) suggesting that it may generate oxidative stress leading to bacterial cell death. Also, the level of protein was decreased in A. salmonicida cells after CAgNCs (50μg/mL) treatment. DNA fragmentation assay results confirmed that CAgNCs can cause extensive DNA degradation of A. salmonicida which may inhibit the expression and production of bacterial proteins. Toxicity and safety results prove that CAgNCs is not toxic to zebrafish (Danio rerio) at 12.5mg/kg of body weight/day as a feed ingredient and rock bream (Oplegnathus fasciatus) testis cells up to 50μg/μL. Overall results from this study suggest that CAgNCs is potential antibacterial agent to control fish pathogenic bacteria. Statement of relevanceThe fisheries and aquaculture industry can be optimized by using biodegradable nano materials such as chitosan for disease detection, control as well as delivery system of drugs such as hormones, vaccines and nutrients.Aquaculture can be optimized by using biodegradable nano materials such as chitosan for disease detection, control as well as delivery system of drugs such as hormones, vaccines and nutrients.Application of biodegradable nano materials in aquaculture

Synthesis of Silver-Chitosan Nanocomposites Colloidal by Glucose as Reducing Agent

Silver-chitosan nanocomposites colloidal was successfully performed by chemical reduction method at room temperature using glucose as reducing agent, sodium hydroxide (NaOH) as accelerator reagent, silver nitrate (AgNO3) as metal precursor and chitosan as stabilizing agent. Compared to other synthetic methods, this work is green and simple. The effect of the amount of NaOH, molar ratio of AgNO3 to glucose and AgNO3 concentration towards Localized Surface Plasmon Resonance (LSPR) absorption band of silver nanoparticles was investigated using UV-Vis spectrophotometer. The stability of the colloid was also studied for the first 16 weeks of storage at ambient temperature. The formation of silver nanoparticles was confirmed by the appearance of LSPR absorption peak at 402.4–414.5 nm. It is also shown that the absorption peak of LSPR were affected by NaOH amount, ratio molar AgNO3/glucose and concentration of AgNO3. The produced silver nanoparticles were spherical with dominant size range of 6 to 18 nm as shown by TEM images. All colloidals were stable without any aggregation for 16 weeks after preparation. The newly prepared silver-chitosan nanocomposites colloidal may have potential for antibacterial applications.