Chitosan as a peroxidase mimic: Paper based sensor for the detection of hydrogen peroxide

In the present communication, a unique peroxidase mimicking catalytic property of chitosan was observed and investigated for its analytical application through deployment of a paper based colorimetric sensor for the detection of H2O2. Chitosan in the presence of H2O2 catalyze the oxidation of TMB to a colored complex proportional to the concentration of H2O2. Linearity of the chitosan based assay was found to be in the range of 10 mu M to 10mM with a limit of detection and limit of quantification of 1.55 and 1.74 mu M, respectively. Analytical performance of chitosan in the form of a paper based sensor demonstrated its potential for point of care applications in determining hydrogen peroxide in a series of analytes. We hypothesize the origin of unusual peroxidase catalytic activity from chitosan with the help of antioxidants and depolymerizing agents. Chitosan breaks H2O2 leading to the formation of highly unstable oxidative species such as hydroxyl ions and free radicals. Catalytic activity of chitosan will overcome the complexity of assays and boost its application in the fabrication of colorimetric diagnostic test kits and in-vivo diagnostics which requires an inexpensive and biocompatible material.