Fabrication and Characterization of Polyoxometalate based Nano-hybrids: Evaluation of their role in Biological Activity.

Polyoxometalates are a class of stable metal-oxide clusters with great molecular diversity having significant biological applications. Firstly, europium substituted polyoxometalate K₄H[Eu(α -SiW₁₁O₃₉)-(H₂O)₂].17H₂O (Eu-Si-POM) was synthesized and Eu-Si-POM was encapsulated into biocompatible chitosan (CS), through ionotropic gelation technique thus synthesizing a nano-hybrid (CS-Eu-Si-POM). CS-Eu-Si-POM retained the fluorescence property even after encapsulation. The nano-hybrid CS-Eu-Si-POM was characterized using FT-IR, UV-Vis spectra, fluorescence spectra, scanning electron microscopy (SEM), atomic force microscopy (AFM) and dynamic light scattering (DLS). Eu-Si-POM was further characterized by inductively coupled plasma (ICP) technique. These characterization techniques reveal the successful encapsulation of Eu-Si-POM within CS matrix by electrostatic interaction between cationic CS and anionic Eu-Si-POM. CS-Eu-Si-POM was applied as a fluorescent probe in A549 cell lines fluorescence imaging. The antibacterial activity of (CS-Eu-Si-POM), CS and Eu-Si-POM have been tested against bacterial strains of B. subtilis gram (+) ve and P. aeruginosa gram (-) ve. The (CS-Eu-Si-POM) showed enhanced antibacterial activity as compared to bare POM and CS. [ABSTRACT FROM AUTHOR]