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.