While in the derivative (Fig. 2b), the most characteristic peaks were 3438 cm−1

(axial O–H stretching), 2913 cm−1 and 2853 cm−1 (symmetric or http://www.selleckchem.com/products/epacadostat-incb024360.html asymmetric CH3 stretching vibration), 1636 cm−1 (CO carbonyl group vibration), 1381 cm−1 (C–C stretching vibration and asymmetric C–H bending of CH2 group) and 1057 cm−1 (interaction between silver nanoparticles and amino group of chitosan).14, 15, 16 and 17 The X-ray Diffraction (XRD) is used to confirm the nature of crystal structure of the formed chitosan/silver nanocomposites (Fig. 3). Pure chitosan showed weak reflection at 2θ of 10.96° and strong reflection at 2θ of 20.06° which match well with literature values.6, 18 and 19 For Ag/Cts NCs, the XRD peaks at 2θ of 37.91°, 43.71°, 64.06° and 76.98° were OTX015 ic50 characteristics to the (111), (200), (220), and (311) planes of the face-centered cubic (fcc) of Ag NPs, respectively.20 The peaks showed that the main composition of nanoparticles was chitosan/silver and no other peaks present as impurities were found in the XRD patterns. Therefore, this gives clear evidence for the presence of chitosan embedded Ag NPs. The surface morphology

of synthesized chitosan/silver was analyzed using the HRSEM technique. The micrograph of nanocomposite shows the porous nature of the film which is embedded with the silver nanoparticles (Fig. 4a). The HRSEM image of silver nanoparticles shows spherical from shaped particles (Fig. 4b). The size of the particles is seen within 20–50 nm. The synthesized particles are in the form of aggregates. The reduction of agglomeration is seen to occur when the chitosan is allowed to dissolve for a longer duration of time, followed by the dispersion of silver nanoparticles in the chitosan solution for about an hour before the process of reduction. The inhibitory zone of CSNC film was shown in Fig. 5. In terms of surrounding

clearing zone, CSNC film showed a very clear inhibitory effect against Gram-negative and Gram-positive bacteria chitosan film alone didn’t show any positive results. The inhibitory effect of silver on microorganisms tested is effected via two possible mechanisms First, is the electrostatic attraction between the negatively charged cell membrane of the microorganisms and the positively charged Ag, and second, is the formation of ‘pits’ in the cell wall of bacteria related to Ag concentration.21 In this study, since the zero valent metal nanoparticles were obtained by chemical reduction of metal salts, it seems the latter mechanism would have been mooted. Moreover, results showed that Gram-negative bacteria were more sensitive to nanocomposites. It was probably resulted from the different characteristics of the cell surfaces.