Chitozyme: First Peroxidase-like Activity of Chitosan for Multiplexed Visual Detection of H2O2, Glucose and Lactate on Paper-based Device

Abstract

Visual read-out diagnostics tools are promising candidates for field applicable medical devices. Current colorimetric biosensors require introduction of natural enzymes or nanozymes, which has some serious drawbacks for practical applications. Chitosan, a natural polymer, provides safe and efficient compound in medical and pharmaceutical technology. Herein, we report on a simple, cost-efficient, field-portable, environmental friendly and ultra-sensitive multiplex detection platform based on peroxidase-like activity of chitosan in the presence of 3,3,5,5-Tetramethylbenzidine (TMBZ) and H2O2. This straight forward signal amplification strategy was successfully applied to detect H2O2, glucose and lactate with the limit of detection (LOD) of 2.64 pM, 0.104 M and 2.8 nM respectively, represents the lowest LOD of H2O2, glucose and lactate with visual read-out. The chitosan-based assay performance was also retained in complex biological media for glucose and lactate detection. Furthermore, the proposed assay was successfully demonstrated as a paper-based colorimetric biosensor. Most importantly, the simplicity, biocompatibility and sensitivity of the proposed assay will open new doors for instrument free naked eye visual detection of H2O2, glucose and lactate detection.