Electrochemical sensing of glucose using conjugated polymer/chitosan/mwcnt architecture

Özel, Hande
In this thesis an amperometric biosensor consisting of a conjugated polymer, chitosan and multi-walled carbon nanotubes constructed for the detection of glucose. Conjugated polymers have opened a new era for the development of biosensing platforms with their unique electronic properties, high stabilities and processabilities. They serve both as immobilization matrices for biorecognition elements and as transducers in biosensing devices. As an additional modification material, chitosan was participated in the construction of the proposed biosensor due to its promising properties such as excellent film formability, biocompatibility, biodegradability, and nontoxicity. Chitosan served as a great immobilization matrix together with the conjugated polymer and improved the stability and sensitivity of the biosensor. Multiwalled carbon nanotubes have also extensively used in electrochemical sensing devices since they improve the response performances of biosensors due to their superior electrochemical properties. Furthermore, they are also promising as supporting matrix materials while preserving the catalytic activity and stability of enzymes. From this point of view, by modifying a graphite electrode with a monomer via electropolymerization followed by casting with CHIT/MWCNTs solution, the proposed biosensor was fabricated having a good linear response for glucose between 0.01-0.75 mM with a detection limit of 0.032 mM and the sensitivity value of 63.76 µAmM-1cm-2. Moreover, the biosensor presented promising kinetic parameters with the KMapp value of 0.05 mM. For investigating the surface modifications, cyclic voltammetry and SEM techniques were utilized. Besides, in order to prove the applicability of the proposed biosensor, the system was tested with a commercial beverage sample.