3.1.2.1. Electrochemical biosensor:
Chitosan is often used in the construction of electrochemical biosensors due to its solubility in moderately acidic aqueous solutions and simplicity of usage under physiological settings (Bhatnagar et al., 2018; Baranwal et al., 2018; Kashish et al., 2017). Chitin requires partly deacetylated chitin’s amine and hydroxyl functionalities, as well as glyoxal, carbodiimide, or epichlorohydrin to cross-link individual chitin chains and bind enzymes to chitin networks. For electrostatic immobilization of enzymes, thin chitin or chitin dispersed in carbon/platinum paste are acceptable matrices (Kittle et al., 2012). Chitosan to show electrical conductivity, combine with nanoparticles like graphene, multiwall carbon nanotubes, polypyrrole, polyaniline to enhance its electrical properties for sensing applications.
The glucose oxidase-loaded chitin films are used for quantifying the pH, oxygen and hydrogen peroxide changes in traditional glucose sensors. Lou et al. (2020) developed electrochemical biosensor for amlodipine identification for pharmaceutical applications using nickel molybdate nanosheets chitosan nanocomposite. Another application of chitosan-based electrochemical biosensor with graphene was reported by Shen et al. (2020) and for the detection of dopamine by exhibiting good sensitivity with a low detection limit of 0.29 μM.