Antibacterial effect of silver nanoparticles prepared in bipolymers at moderate temperature

The purpose of this study was to investigate the antibacterial effect of silver nanoparticles in chitosan–poly(ethylene glycol) suspension. The silver nanoparticles (AgNPs) were prepared by use of an environmentally benign method from chitosan (Cts) and poly(ethylene glycol) (PEG) at moderate temperature and with stirring for different times. Silver nitrate (AgNO3) was used as the metal precursor and Cts and PEG were used as solid support and polymeric stabilizer, respectively. The antibacterial activity of silver–chitosan–poly(ethylene glycol) nanocomposites (Ag–Cts–PEG NCs) against Staphylococcus aureus, Micrococcus luteum, Pseudomonas aeruginosa, and Escherichia coli was tested by use of the Mueller–Hinton agar disk-diffusion method. Formation of AgNPs was determined by UV–visible spectroscopy; surface plasmon absorption maxima were observed at 415–430 nm in the UV–visible spectrum. The peaks in the XRD pattern confirmed that the AgNPs had a face-centered cubic structure; peaks of contaminated crystalline phases were not observed. Transmission electron microscopy (TEM) revealed that the AgNPs synthesized were spherical. The optimum stirring time for synthesis of the smallest particle size (mean diameter 5.50 nm) was 12 h. The AgNPs in Cts–PEG were effective against all the bacteria tested. Higher antibacterial activity was observed for AgNPs with smaller size. These results suggest that AgNPs can be used as an effective inhibitor of bacteria and can be used in medical applications. These results also suggest that AgNPs were successfully synthesized in Cts–PEG suspension at moderate temperature with different stirring times

Synthesis of silver nanoparticles in chitosan, gelatin and chitosan/gelatin bionanocomposites by a chemical reducing agent and their characterization

In this research, silver nanoparticles (AgNPs) were synthesized in chitosan (Cts), Cts/gelatin and gelatin suspensions using a chemical reducing agent. Cts and gelatin were used as natural stabilizers and solid support, whereas AgNO3 was used as the silver precursor. Sodium borohydride (NaBH4) was used as the reducing agent. The properties of AgNPs in Cts, Cts/gelatin and gelatin bionanocomposites (BNCs) were studied in terms of their surface plasmon resonance, crystalline structure, average diameter size, particle distributions, surface topography and functional groups. All the samples were characterized by UV-visible spectroscopy, powder X-ray diffraction, transmission electron microscopy, atomic force microscopy and Fourier transform infrared spectroscopy

Green Synthesis and Characterization of Silver/Chitosan/Polyethylene Glycol Nanocomposites without any Reducing Agent

This paper presents the green synthesis of silver nanoparticles (Ag NPs) in aqueous medium. This method was performed by reducing AgNO3 in different stirring times of reaction at a moderate temperature using green agents, chitosan (Cts) and polyethylene glycol (PEG). In this work, silver nitrate (AgNO3) was used as the silver precursor while Cts and PEG were used as the solid support and polymeric stabilizer. The properties of Ag/Cts/PEG nanocomposites (NCs) were studied under different stirring times of reaction. The developed Ag/Cts/PEG NCs were then characterized by the ultraviolet-visible (UV-Vis) spectroscopy, X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM) and Fourier transform infrared (FTIR) spectroscopy

Preparation and characterization of silver/chitosan/gelatin bionanocomposites by chemical reducing method and their antibacterial activities

The aim of this study is to investigate the functions of polymers and size of nanoparticles on the antibacterial activity of silver bionanocomposites (Ag BNCs). In this research, silver nanoparticles (Ag NPs) were incorporated into biodegradable polymers, which are chitosan (Cts), gelatin and both polymers via chemical reduction method in solvent in order to produce Ag BNCs. Silver nitrate and sodium borohydride were employed as a metal precursor and reducing agent respectively. In addition, chitosan and gelatin were added as both polymeric matrix and stabilizer. The properties of Ag BNCs were studied based on function of the polymer weight ratio in relation to the use of chitosan and gelatin. These prepared Ag NPs were very stable over a long period (i.e. 4 months) in an aqueous solution without any sign of precipitants. The UV-vis spectra shown maximum absorbance bands for Ag BNCs were detected at 408, 416, 414, 413, and 414 nm, respectively. From the FTIR spectra, the vibrational band of Ag BNCs detected at ~1395 cm−1 could indicate the interaction between Ag NPs with chitosan and gelatin. The morphology of the Ag BNCs films and the distribution of the Ag NPs were characterized using Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM). From the SEM image, Ag/Cts BNCs shown layered surfaces with small flakes, Ag/Cts/gelatin BNCs showed smooth layered surfaces and Ag/gelatin BNCs showed porous layered surfaces. In addition, the EDX spectra for Ag BNCs had confirmed the presence of elemental compounds in the Cts, gelatin and Ag NPs without any impurity peaks. From the TEM images, the results of average diameters of the Ag NPs in different weight composition of polymers were in the range of 2.90-11.25 nm. However, the TEM results also shown that aggregation of Ag NPs where there is an overlap of particles and larger particle size in chitosan only which contributed to the size of 11.25 nm compared with others samples which are 2.90 nm-4.38 nm. With the aid of XRD pattern, Ag BNCs films confirmed the face-centered cubic (FCC) type crystallographic planes of the Ag crystal. The XRD peaks at 2θ with value of around 38°, 44°, 64°, and 77° are well recognized to the 111, 200, 220, and 311 crystallographic planes of the FCC Ag crystals, respectively. The antibacterial activities of the Ag BNC films were examined against Gram-negative bacteria (E. coli and P. aeruginosa) and Gram-positive (S. aureus and M. luteus). The silver ions released from the Ag BNCs and their antibacterial activities were scrutinized. From TEM analysis and the result of antibacterial activity, Ag/Cts/gelatin BNCs exhibited better particle distribution as well as having high antibacterial activity. A simple way to prepare Ag/Cts/gelatin bionnanocomposites had been employed as previously there is no research on investigating the antibacterial activities of silver into both chitosan and gelatin