Chitosan aerogel containing silver nanoparticles: From metal-chitosan powder to porous material

The work presents a synthetic approach that combines methods of metal vapor synthesis (MVS), gelation and supercritical drying in order to obtain chitosan aerogels containing silver nanoparticles. On the first stage, two types of silver organosols were prepared via the eco-sustainable MVS method. Then the prepared silver organosols were used to modify chitosan powders for producing metal-chitosan powder composites. Gelation of the powder composites was performed in oxalic acid at elevated temperatures. Supercritical drying of the gels was implemented in order to preserve the formed porous structures. Thus, the chitosan powders modified with MVS-produced silver nanoparticles were used to prepare metal-chitosan aerogels. Characterization of the structure and the morphology of both powder and aerogel silver-chitosan composites was conducted by means of low temperature nitrogen adsorption, X-ray photoelectron spectroscopy, X-ray powder diffraction, small-angle X-ray scattering, SEM and TEM. Changes in the structure and morphology of silver nanoparticles between powder and aerogel composites were analyzed.     

Silver Nanoparticles in Polyacrylamide and Hyperbranched Polyamine Matrix

Silver nanoparticles have been prepared in a polyacrylamide (PA) matrix, as well as in the presence of a hyperbranched polyamine/polyacrylamide combined system (HB‐PA) by using a reductive technique. The stability of colloidal solution of silver nanoparticles is higher (5 months) in combined matrix compared to PA alone (4 months). The prepared silver nanoparticles were characterized by different spectroscopic and analytical techniques such as FTIR, UV‐visible, X‐ray diffraction, TEM etc. TEM and XRD studies confirmed the formation of well‐dispersed nanoparticles with an average size of 9.91 nm and 8.5 nm for PA and HB‐PA matrices, respectively. The antibacterial activity of silver nanoparticles in both the matrices was tested against Bacillus Subtilis bacteria by using the diffusion disc technique. The result shows that the antibacterial activity of the active agent, Ag(0) is a little higher in the case of HB‐PA system. The dielectric constant of the matrices decreases with an increase in frequency, but the values increase with an increase of concentration of silver nanoparticles in PA matrix.     

Preparation of colloidal stable fluoroalkyl end‐capped oligomer/silver nanocomposites––application to the surface modification of traditional organic polymers with these nanocomposites

A variety of fluoroalkyl end‐capped oligomers/silver nanocomposites were prepared by the reactions of silver ions with poly(methylhydrosiloxane) in the presence of fluoroalkyl end‐capped N,N‐dimethylacrylamide oligomer, N‐(1,1‐dimethyl‐3‐oxobutyl)acrylamide oligomer, N,N‐dimethylacrylamide cooligomer containing poly(dimethylsiloxane) segments in organic media such as toluene and 1,2‐ dichloroethane. These fluorinated oligomers/silver nanocomposites thus obtained were found to exhibit clear plasmon absorption bands around 420 nm related to the formation of silver nanoparticles. In particular, these composites could display narrow plasmon absorptions around 420 nm in toluene by the addition of trioctylamine (TOA). On the other hand, the corresponding non‐fluorinated N‐(1,1‐ dimethyl‐3‐oxobutyl)acrylamide oligomer was not able to afford such a plasmon absorption under similar conditions. These fluorinated oligomers/silver nanocomposites in organic media have been found to be stable for more than 10 days. Transmission electron microscopy (TEM) and dynamic light scattering (DLS) measurements showed that silver nanoparticles could be effectively encapsulated into fluorinated oligomeric aggregate cores to afford colloidal stable fluorinated oligomers/silver nanocomposites. Fluorinated oligomers/silver nanocomposites were also applied to the surface modification of traditional organic polymers such as polystyrene (PSt) and poly(methyl methacrylate) (PMMA) to exhibit not only a good oleophobicity imparted by fluorine but also a higher surface antibacterial activity related to the silver nanoparticles on their surface. Copyright © 2007 John Wiley & Sons, Ltd.     

Full polysaccharide chitosan‐CMC membrane and silver nanocomposite: synthesis,characterization, and antibacterial behaviors

Chitosan‐carboxymethyl cellulose (CMC) full polysaccharide membrane was prepared by cross‐linking of chitosan with CMC dialdehyde and subsequent reductive amination. CMC dialdehyde molecule was prepared by periodate oxidation of CMC and then applied as a cross‐linking agent to form a new membrane network. The properties of oxidized CMC were investigated by various methods such as Fourier transform infrared (FT‐IR) spectroscopy, ¹H NMR spectroscopy, and viscosity test. Then, novel chitosan‐CMC silver nanocomposite was prepared using chitosan‐CMC as a carrier. The structure of the chitosan‐CMC membrane and the silver nanocomposite were confirmed by FT‐IR spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM), and thermogravimetric analysis (TGA). TEM images indicate that the chitosan‐CMC nanocomposite comprises silver nanoparticles with diameters in the range of about 5–20 nm. The antibacterial studies of the nanocomposite were also evaluated. The chitosan‐CMC silver nanocomposite demonstrates good antibacterial activity against Staphylococcus aureus, Pseudomonas aeruginosa, and Escherichia coli. Copyright © 2016 John Wiley & Sons, Ltd.     

Preparation and synthesis a new chemotherapeutic drug of silver nanoparticle-chitosan composite; Chemical characterization and analysis of their antioxidant,cytotoxicity, and anti-acute myeloid leukemia effects in comparison to Daunorubicin in a leukemic mouse model

Nanoparticles usually have better outcomes than the bulk samples of the same element because they possess a higher specificity level than the larger particles. This is also true for silver nanoparticles, and little amount of these materials has high remedial effects. Silver nanoparticles are used as a therapeutic tool for the treatment of several diseases such as cancer. In this study, silver nanoparticles using chitosan (AgNPs-chitosan composite) are reported for the first time to exert a dietary therapeutic potential compared to Daunorubicin in an animal model of acute myeloid leukemia. The synthesized AgNPs-chitosan composite was characterized using different techniques including ultraviolet–visible spectroscopy, fourier-transform infrared spectroscopy, energy dispersive X-ray spectrometry, scanning electron microscopy, and transmission electron microscopy. FTIR findings suggested antioxidant compounds in the nanoparticles were the sources of reducing power, reducing silver ions to AgNPs. SEM and TEM images exhibited a uniform spherical morphology and average diameters of 30 nm for the nanoparticles. Then, 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical scavenging test was done to evaluate the antioxidant potentials of Daunorubicin, AgNO₃, chitosan, and AgNPs-chitosan composite. DPPH test revealed similar antioxidant potentials for Daunorubicin and AgNPs-chitosan composite. For the analyzing of cytotoxicity effects of Daunorubicin, AgNO₃, chitosan, and AgNPs, 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromidefor (MTT) assay was used on HUVEC, 32D-FLT3-ITD, and Murine C1498 cell lines. AgNPs-chitosan composite similar to Daunorubicin had low cell viability dose-dependently against 32D-FLT3-ITD and Murine C1498 cell lines without any cytotoxicity on HUVEC cell line. In vivo design, induction of acute myeloid leukemia was done by 7,12-Dimethylbenz[a]anthracene in 50 mice. Then, the animals were randomly divided into six subgroups, including control, untreated, Daunorubicin, AgNO₃, chitosan, and AgNPs-chitosan composite. Similar to Daunorubicin, AgNPs-chitosan composite significantly (P ≤ .01) decreased the weight of the body, the pro-inflammatory cytokines, and the total white blood cells, blast, neutrophil, monocyte, eosinophil, and basophil counts and increased the anti-inflammatory cytokines and the lymphocyte, platelet, and red blood cell parameters as compared to the untreated mice. These results show that the inclusion of chitosan improves the therapeutic properties of AgNPs-chitosan composite, which led to a significant enhancement in the antioxidant, cytotoxicity, and anti-acute myeloid leukemia activities of the nanoparticles. It appears that AgNPs-chitosan composite can be used as a chemotherapeutic drug for the treatment of acute myeloid leukemia in the clinical trial.     

Microwave-Assisted Green Synthesis of Non-Cytotoxic Silver Nanoparticles Using the Aqueous Extract of Rosa santana (rose) Petals and Their Antimicrobial Activity

Green methods using biological extracts, in particular plant-based solutions, have shown great potential for silver nanoparticle synthesis. A microwave-assisted single-step phytosynthesis of silver nanoparticles is described in the present study. The aqueous extract obtained from the Rosa santana (rose) petals was used for the first time in the synthesis. The synthesized nanoparticles obtained after optimized microwave conditions for time and temperature were analyzed by ultraviolet–visible spectroscopy (UV–Vis), Fourier-transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), transmission electron microscopy (TEM), and Zeta-size analysis. The results obtained from the characterization studies showed that the synthesized nanoparticles were nearly spherical in shape with sizes from 6.52?nm to 25.24?nm with an average particle size of 14.48?nm with a face-centered cubic structure. The antibacterial activities of the synthesized nanoparticles were evaluated and revealed that the silver nanoparticles displayed good inhibition against both Gram-negative and Gram-positive bacteria. Also, the cytotoxic effect of the silver nanoparticles on a mouse fibroblast cell line (L929) was studied by a cell viability assay. The results showed that phytosynthesized silver nanoparticles were nontoxic to the healthy normal cell line at all tested concentrations.     

Antibacterial cotton fabrics with in situ generated silver and copper bimetallic nanoparticles using red sanders powder extract as reducing agent

Using aqueous extraction of red sanders powder as a reducing agent, silver and copper bimetallic nanoparticles were in situ generated in cotton fabrics. Silver and copper nanoparticles were also generated separately for comparison. The resulted nanocomposite cotton fabrics (NCFs) were characterized by Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), X-ray diffraction (XRD), thermogravimetric analysis (TGA), and antibacterial tests. SEM analysis indicated the generation of more number of nanoparticles when bimetallic source solutions were used. Further, the size range of the generated bimetallic nanoparticles was found to be lower than when individual metal nanoparticles were generated in NCFs. XRD analysis confirmed the in situ generation of silver and copper nanoparticles when equimolar bimetallic salt source solutions were utilized. The NCFs with bimetallic nanoparticles exhibited higher antibacterial activity against both Gram-negative and Gram-positive bacteria and hence can be considered for applications as antibacterial bed and dressing materials.     

Durable antibacterial Ag/polyacrylonitrile (Ag/PAN) hybrid nanofibers prepared by atmospheric plasma treatment and electrospinning

Durable antibacterial Ag/polyacrylonitrile (Ag/PAN) hybrid nanofibers were prepared by atmospheric plasma treatment and electrospinning. Atmospheric helium plasma treatment was first used to reduce the AgNO₃ precursor in pre-electrospinning solutions into metallic silver nanoparticles, followed by electrospinning into continuous and smooth nanofibers with Ag nanoparticles embedded in the matrix. SEM, TEM, and EDX spectra were used to study the structure and surface elemental composition of the nanofibers. Silver nanoparticles, with diameters ranging between 3 and 6 nm, were found to be uniformly dispersed in the nanofiber matrix. The Ag/PAN nanofibers exhibited slow and long-lasting silver ion release, which provided robust antibacterial activity against both Gram-positive Bacillus cereus and Gram-negative Escherichia coli microorganisms.     

Biosynthesis and characterization of Dillenia indica-mediated silver nanoparticles and their biological activity

Dillenia indica L. is a traditional medicinal plant well known for its ability to cure various human diseases. In the current study, silver nanoparticles have been synthesized by simple and eco-friendly method using Dillenia indica extract. The green synthesized nanoparticles were characterized by Fourier transform infrared (FTIR), UV–visible spectroscopy, Atomic force microscopy (AFM), High-resolution transmission electron microscopy (HR-TEM), Zeta Potential and Size Distribution. UV–visible and FTIR spectra, AFM, HR-TEM and Zeta Potential readings and size distribution conformed that the synthesized silver particles were in the size of nano. The green synthesized silver nanoparticles were subjected for antibacterial activity against Gram-positive bacteria Enterococcus faecalis and Gram-negative bacteria Escherichia coli by agar well diffusion method. The synthesized AgNPs exhibited significant inhibition of 27 and 16 mm against the test bacteria at 0.25 mg/ml. Further the antibacterial activity was confirmed by live and dead cell assay by fluorescence microscopy and morphological changes of bacteria were studied by Scanning electron microscope (SEM). The study recommends that the synthesized silver nanoparticles using Dillenia indica extract have potential application in inhibition of bacteria owing to their potent antibacterial activity.     

Nanocomposites based on polyethylene and nanosilver particles produced by metallocenic “in situ” polymerization: synthesis, characterization, and antimicrobial behavior

Polyethylene nanocomposites containing silver nanoparticles with antimicrobial properties were produced via in situ polymerization. The silver nanoparticles were added together with the catalytic system (metallocene catalyst and methylaluminoxane, MAO, as cocatalyst) directly to the reactor. The polymerization activity did not present significant changes with the incorporation of the silver nanoparticles in comparison to the homopolymerization without filler. The effect of various silver nanoparticle contents on silver ion release and antimicrobial efficacy against Escherichia Coli were studied. Nanocomposites containing higher nanosilver concentrations (5 wt.%) showed the highest silver ion release, and after 24 h reached 99.99% of efficacy against the bacteria compared with the neat PE. Transmission electron microscopy (TEM) images showed that the nanospheres were well dispersed throughout the polyethylene matrix.     

Phytofabrication of silver nanoparticles from Limonia acidissima leaf extract and their antimicrobial,antioxidant and its anticancer prophecy

Green synthesis of nanoparticles by eco-friendly methods is a recent technique which draws the attention of researchers because of the reward over many conventional chemical methods. The present work focuses on aqueous Limonia acidissima leaf extract in synthesizing silver nanoparticles and its applications in a simple way. The silver nanoparticles formed were characterized by Infrared, Ultra violet-visible, X-ray diffraction, transmission electron microscopic, and atomic force microscopic techniques. The powder X-ray diffraction studies and transmission electron microscopic images reveal that the silver nanoparticles synthesized were approximately 10–40 nm and have a spherical structure. The nanoparticles were assayed for their antibacterial, antifungal and antioxidant activity. The antimicrobial studies for the silver nanoparticles show a maximum zone of inhibition of 8.8 mm for Bacillus subtilis bacteria and 8.5 mm for Candida albicans fungi at 3 and 1 μg/mL respectively. In-silico ADMET studies reveal that the toxicity, bioactivity, pharmacokinetics and drug-likeness properties of Limonia acidissima leaf extract is good. The molecular docking studies show that the microbial activity is high for Bacillus subtilis and Candida albicans showing the coincidence of the in silico and in vitro studies as expected. The free radical scavenging activity of nanoparticles is 80 for 100 μg/mL. The 50% of inhibition of silver nanoparticles against human breast cancer cell lines is 18 μg/mL. It is evident that silver nanoparticles would be helpful in treating cancer cell lines and have great perspectives in the biomedical sector.     

Water Saturated with Pressurized CO2 as a Tool to Create Various 3D Morphologies of Composites Based on Chitosan and Copper Nanoparticles

Methods for creating various 3D morphologies of composites based on chitosan and copper nanoparticles stabilized by it in carbonic acid solutions formed under high pressure of saturating CO₂ were developed. This work includes a comprehensive analysis of the regularities of copper nanoparticles stabilization and reduction with chitosan, studied by IR and UV-vis spectroscopies, XPS, TEM and rheology. Chitosan can partially reduce Cu²⁺ ions in aqueous solutions to small-sized, spherical copper nanoparticles with a low degree of polydispersity; the process is accompanied by the formation of an elastic polymer hydrogel. The resulting composites demonstrate antimicrobial activity against both fungi and bacteria. Exposing the hydrogels to the mixture of He or H₂ gases and CO₂ fluid under high pressure makes it possible to increase the porosity of hydrogels significantly, as well as decrease their pore size. Composite capsules show sufficient resistance to various conditions and reusable catalytic activity in the reduction of nitrobenzene to aniline reaction. The relative simplicity of the proposed method and at the same time its profound advantages (such as environmental friendliness, extra purity) indicate an interesting role of this study for various applications of materials based on chitosan and metals.     

Preparation and Antibacterial Effect of Bamboo Charcoal/Ag on Staphylococcus Aureus and Pseudomonas Aeruginosa

Bamboo charcoal supporting silver (BC/Ag) was prepared by activation and chemical reduction. The BC/Ag composites were characterized by silver particle size and distribution, silver ion (Ag⁺) release and antibacterial properties. Scanning and transmission electron microscopy (SEM and TEM) showed that the Ag particles were distributed uniformly on the BC matrix. The Ag particle size was found to be less than 150 nm based on TEM. The Ag⁺ release increased initially which was followed by a marginal increase between the 8th and 24th hour. Composites contained higher amounts of silver exhibited a further rise in Ag⁺ release from the 24‐hours of storage in water. The antibacterial effects of the BC/Ag composite powders against Pseudomonas aeruginosa and Staphylococcus aureus were assessed from the minimum inhibitory concentrations (MICs) and minimum bactericidal concentrations (MBCs) method, and an excellent antibacterial performance was discovered.     

Green synthesis of chitosan-stabilized silver-colloidal nanoparticles immobilized on white-silica-gel beads and the antibacterial activities in a simulated-air-filter

This study explored the green synthesis and immobilization of colloidal silver nanoparticles (AgNPs) on a solid compatible support. Its antibacterial properties in reusable air filters are also discussed. The chitosan stabilized colloidal AgNPs (chi-AgNPs) were prepared using visible light irradiation in methanol. The UV–Vis, FTIR spectra, and TEM confirmed the chi-AgNPs formation. The immobilization technique of chi-AgNPs on the surface of white-silica-gel beads, which was previously coated chitosan (chi-SiG), was effective. The immobilized silver particles (AgNPs-[chi-SiG]) were solid, stable, dispersed, and nano-size. Both AgNPs-[chi-SiG] and chi-SiG exhibited antibacterial properties and prevented the growth of Gram-positive (Staphylococcus aureus) and Gram-negative (Escherichia coli) bacteria in agar media. Air filter containing the AgNPs-[chi-SiG] showed high antibacterial activity against Bacillus subtilis in the air.     

Oxidative stress induced antimicrobial efficacy of chitosan and silver nanoparticles coated Gutta-percha for endodontic applications

Root canal treatment is the most effective treatment for irreversible pulpal damage. However, it suffers the risk of failure due to micro-leakage at the Gutta-percha-sealer-tooth interface. Concerning the issue, it is important to enhance the antimicrobial properties of Gutta-percha. The current study describes a novel coating of the Gutta-percha with chitosan and silver nanoparticles to increase their antimicrobial efficacy. They were coated with chitosan and silver nanoparticles with concentrations of 1%, 2% using chemical methodology. Coated Gutta-percha were evaluated for their antimicrobial efficacy against E. faecalis, which is frequently isolated microorganism in failed endodontic cases using standard microbiological methods like growth curve analysis. Detailed analysis of the antimicrobial activity was performed by live-dead analysis with the help of flow cytometry and fluorescent microscopy. Although, the experimental analysis showed concentration-dependent antibacterial activity by both chitosan and silver NP coated Gutta-percha, the silver NP coating exhibited higher antibacterial activity compared to the Gutta percha coated with chitosan nanoparticles. Mechanistic evaluation unveiled the cause of antibacterial activates due to action of induced oxidative stress and membrane damage to the bacteria by coated nanoparticles. The information will be useful for the endodontist to have an alternative filling material with higher antibacterial potency for higher success rate of root canal therapies in clinical procedures.     

Norvancomycin-capped silver nanoparticles: Synthesis and antibacterial activities against E. coli

The synthesis of norvancomycin (NVan)-capped silver nanoparticles (Ag@NVan) and their notable in vitro antibacterial activities against E. coli, a Gram-negative bacterial strain (GNB), are reported here. Mercaptoacetic acid-stabilized spherical silver nanoparticles with a diameter of 16±4 nm are prepared by a simple chemical reaction. The formation process of the silver nanoparticles is investigated by UV-visible (UV-vis) spectroscopy and transmission electron microscopy (TEM). NVan is then grafted to the terminal carboxyl of the mercaptoacetic acid in the presence of N-(3-Dimethylaminopropyl)-N′-ethylcarbodiimide hydrochloride (EDAC). The TEM images of single bacteria treated with Ag@NVan show that plenty of Ag@NVan aggregate in the cell wall of E. coli. A possible antibacterial mechanism is proposed that silver nanoparticles may help destroy the stability of the outer membrane of E. coli, which makes NVan easier to bind to the nether part of the peptidoglycan structure. The antibacterial activities of silver nanoparticles on their own, together with the rigid polyvalent interaction between Ag@NVan and cell wall, enables Ag@NVan to be an effective inhibitor of GNB. This kind of bionanocomposites might be used as novel bactericidal materials and we also provide an effective synthesis method for preparing functional bioconjugated nanoparticles here. Supported by the National Natural Science Foundation of China (Grant No. 50373036) and Fok Ying Tung Education Foundation (Grant No. J20040212)     

XPS study of silver and copper nanoparticles demonstrated selective anticancer,proapoptotic, and antibacterial properties

Silver and copper nanoparticles were produced by an ecologically safe metal vapor synthesis (MVS) method using acetone as an organic dispersion medium. Transmission electron microscopy (TEM) showed that the specimens are spherical and polydisperse, and their average size is 2.5 nm for silver nanoparticles (Ag NPs) and 2.6 nm for copper nanoparticles (Cu NPs). X-ray photoelectron spectroscopy analyses showed that the state of silver in the nanoparticles is close to that of silver in the Ag⁰ state, whereas copper black contains two oxidized states of the metal—Cu⁺ and Cu²⁺. Biological in vitro studies demonstrated that the nanoparticles have antibacterial activity against Gram-positive and Gram-negative bacterial species. Cu NPs exhibited more prominent antibacterial effects and induced significant growth inhibition of Bacillus cereus and Escherichia coli. Both types of nanoparticles showed anticancer properties in vitro. Cu NPs induced intense cytotoxicity in cancer and normal fibroblasts in vitro cultures, but their inhibitory effect against noncancerous cells was milder compared with cancer cell lines. Ag NPs demonstrated selective cytotoxicity against human lung and cervical adenocarcinoma cell lines. Further in vitro studies indicated that the mechanism of Ag NPs and Cu NPs anticancer effects involves induction of apoptosis. The present study describes a green synthesis approach for production of biologically active silver and copper nanoparticles and highlights their potential for medical application.     

Antimicrobial activity of sulfur nanoparticles: Effect of preparation methods

Sulfur nanoparticles (SNPs) were synthesized using elemental sulfur and sodium sulfide, capped with chitosan as a stabilizer (SNP_ES), and their properties were compared to SNPs prepared by acidification of sodium thiosulfate (SNP_STS). The SNPs were characterized using UV–visible spectroscopy, EDS, TEM, XRD, and TGA, and their antimicrobial activity was tested using the disk diffusion method and minimum inhibitory concentration (MIC)/minimum bactericidal concentration (MBC) analysis. The SNP_ES showed a rod-shaped morphology with an average length of 87 nm, while SNP_STS exhibited a spherical shape with an average particle size of 17 nm. The rod-shaped SNP_ES showed higher thermal stability than the spherical SNP_STS. Both types of SNPs did not show significant antibacterial activity against Gram-negative (E. coli) bacteria but showed significant antibacterial activity against Gram-positive (L. monocytogenes) bacteria. Between the SNPs, SNP_ES showed higher growth-inhibiting activity against L. monocytogenes than SNP_STS.     

Cinnamon zeylanicum bark extract and powder mediated green synthesis of nano-crystalline silver particles and its bactericidal activity

The exploitation of various plant materials for the biosynthesis of nanoparticles is considered a green technology as it does not involve any harmful chemicals. The present study reports the synthesis of silver (Ag) nanoparticles from silver precursor using the bark extract and powder of novel Cinnamon zeylanicum. Water-soluble organics present in the plant materials were mainly responsible for the reduction of silver ions to nano-sized Ag particles. TEM and XRD results confirmed the presence of nano-crystalline Ag particles. The pH played a major role in size control of the particles. Bark extract produced more Ag nanoparticles than the powder did, which was attributed to the large availability of the reducing agents in the extract. Zeta potential studies showed that the surface charge of the formed nanoparticles was highly negative. The EC₅₀ value of the synthesized nanoparticles against Escherichia coli BL-21 strain was 11 ± 1.72 mg/L. ThusC. zeylanicum bark extract and powder are a good bio-resource/biomaterial for the synthesis of Ag nanoparticles with antimicrobial activity.     

Modification of natural fibers from Thespesia lampas plant by in situ generation of silver nanoparticles in single-step hydrothermal method

Ligno-cellulosic fibers have a great market and propose higher value addition and options to develop various products but they do not have inherent antimicrobial properties. In this study, a simple hydrothermal method was applied to build up antimicrobial properties to natural fibers by in situ-generating silver nanoparticles (AgNPs) in them. Herein, the ligno-cellulosic Thespesia lampas natural fibers were selected to develop antimicrobial activity using silver nitrate (AgNO₃) solution by hydrothermal method. The modified fibers were characterized by SEM, FTIR, XRD, TGA, and antibacterial activity tests. The modified fibers had spherical AgNPs with an average size of 95?nm. The thermal stability of the modified fibers was higher than that of the unmodified fibers. The modified fibers exhibited good antibacterial activity against both the Gram negative and Gram positive bacteria. These modified fibers can be considered as fillers in polymer matrices to make antibacterial composites.