الفهرس 
Aim of the work
Assessment of the antibacterial activityOnly 14 pages are availabe for public view
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Abstract
The present work was devoted to investigate the development of stabilized and densely dispersed
chitosan-silver hybrid nanoparticles (CS-Ag NPs) using a new eco-friendly “green” approach based on
electrochemical oxidation/complexation process followed by UV irradiation reduction. The synthesized
CS-Ag NPs were characterized using transmission electron microscopy (TEM), X-ray diffraction
(XRD), elemental analysis, atomic absorption, energy dispersive X-ray (EDX), Fourier transform
infrared (FTIR), differential thermogravimetric analysis (DTGA, DSC), zeta potential (ZP) and UV–Vis
spectroscopy. These characterizations were carried out to specify the functional groups, crystalline
structure, average size and size distribution, surface charge and surface plasmon resonance of the
developed CS-Ag NPs. Formation of the CS-Ag NPs was confirmed from the appearance of surface
plasmon absorption maxima around 420 nm in the UV-Vis spectra.
The obtained CS-Ag NPs were uniform and spherical with average size in the range of 2 to 34 nm.
The CS-Ag NPs synthesized in the present study also demonstrated a relatively strong antibacterial
activity against Gram-positive (B. thuringiensis) and Gram-negative (P. aeruginosa) bacteria as
compared to that of control (CS) by using the nutrient agar disc diffusion method with determination of
the inhibition zones (mm). This antibacterial activity increased with increasing the concentration of the
CS-Ag NPs. The obtained results revealed that the CS-Ag NPs developed in this study could be useful in
various biological and biomedical applications, such as surgical devices and drug delivery vehicles.
Dielectric studies a powerful scientific technique in the interpretation of the effect of dative bond on
the dielectric properties. The frequency dependence part of dielectric parameters (dielectric constant,
dissipation factor and real part of electric modulus) is non-Debye type. The temperature dependence part
of dielectric parameters is a very usefully representated in the glass transition temperature determination.
The dielectric spectra of the investigated samples showed that the dielectric constant decreases with
increasing frequency. The relaxation time and its associated activation energy were also determined from
the loss factor spectra.