Optical and Structural Study of Biocompatible Silver-Chitosan Colloids

Nontoxic and biocompatible silver-chitosan colloids were prepared by direct chemical reduction. The Ag-chitosan colloids are drop cast on a glass slide and left to dry to obtain uniform, homogeneous films. The presence of chitosan prevented the growth of silver nanoparticles from agglomeration. The occurrence of localized surface plasmon resonance (LSPR) at ~ 400 nm in the optical absorption spectra indicated the formation of Ag nanoparticles which is the characteristic property of metal nanoparticles. The -prepared colloidal Ag nanoparticles are chemically stable and remain colloidal even after aging. The estimated average particle size is about 14nm and the face-centered cubic phase was observed in the XRD pattern. SEM images clearly showed the homogeneous distribution of silver nanoparticles.