Enhanced biological activity and biosorption performance of trimethyl chitosan-loaded cerium oxide particles

Nano ceria is considered to be an antioxidative agent due to its fast oxido-reductive capability and there has been a number of studies that deal with the non-toxic nature of cerium oxide; however, the antioxidative capacity is mostly influenced by the presence of Ce3+/Ce4+ in the sample. We studied for the first time the oxidative nature of CeO2 nanoparticles (NPs) on in vitro systems and we hypothesized that if the oxido-reductive behavior of Ce is not well utilized which may lead to adverse toxic effects. Since, we have been interested to combine the oxido-reductive potential of nano ceria with that of the antimicrobial, antioxidative, and biosorption properties of trimethyl chitosan (TMC). We hypothesize that such a design will not only modulate the oxidant activity of CeO2 NPs, but also will help to provide enhanced antimicrobial, antioxidative, and adsorption properties. We present here the synthesis, characterization, biological activity and biosorption performance of the TMC-CeO2 composite and its efficiency was tested by comparing the results with that of other materials (pure CeO2, pure chitosan, and pure TMC). The polymer composite formation was thoroughly analyzed by means of UV-vis, FTIR, zeta potential, powdered XRD, and XPS studies. Further, the in vitro antibacterial and antioxidative assays proved that the coating of CeO2 with TMC biopolymer significantly enhances its biological efficiency by increasing the interaction of the CeO2 composite with that of bacterial cell wall, and also serving as the free radical scavenger. In addition to bioactivity, we also observed some enhanced biosorption performance towards the removal of phenolic compounds (phenol, 2-chlorophenol, and 4-chlorophenol) by the TMC-CeO2 composite, thereby supporting its role during the waste water treatment. (C) 2016 The Korean Society of Industrial and Engineering Chemistry. Published by Elsevier B.V. All rights reserved.