Production of carbonized conductive electrode material from biomass and its use in bioelectronic applications

Biosensors and fuel cells are used in many applications, especially in the determination of biomarkers. Enzymatic biosensors and enzymatic fuel cells, on the other hand, stand out due to the ability of enzymes to work under physiological conditions, their high specificity, and their miniature design possibilities. This study aims to produce conductive electrode materials using different biomass sources via carbonization and to examine the performance of this carbonized material in bioelectronic applications. First, conductive carbonized materials were obtained from typha tassel (TT) and pussy willow (PW) using the carbonization method (CTT and CPW). The carbonized materials obtained were characterized by physical, chemical, and electrochemical methods, coated on screen-printed carbon electrodes and the glucose oxidase enzyme was immobilized on modified surfaces. The most suitable enzyme immobilization method was determined and the biosensor working potential, applied enzyme, and mediator amounts were optimized. The reproducibility, shelf life, interference effects, linear operating ranges, and detection limits (LOD and LOQ) of the prepared electrodes were determined, and real sample tests were carried out. Then, these electrodes were combined with the cathode developed with platinum black, and fuel cell tests were carried out. The relative standard deviation values of the repeatability of CTT and CPW-modified electrodes at 5 mM glucose concentration were calculated as 6.67% and 12.85%, respectively, and the current change at the end of 30 days was found to be 12.33% and 19.56%, respectively. When the biosensor was tested in the presence of uric acid, ascorbic acid, and insulin, no significant interference effect was observed against the glucose response. The linear operating range of the sensor is determined as 0 – 10 mM for both materials, the LOD values for CTT and CPW are 0.45 mM and 0.31 mM, respectively, and the LOQ values are 1.35 mM and 0.93 mM, respectively. The applicability of biosensors for glucose determination has been demonstrated by real sample (strawberry, cherry, and apricot jam) tests. Finally, maximum power density values obtained from fuel cells prepared with CTT and CPW are 3.54 µW/cm2 and 3.31 µW/cm2,respectively.