Development of single fiber electrodes modified with 2D nanomaterial derived polydopamine for application in non-invasive electrochemical (bio)sensors

Analytical devices based on pyrolyzed biomass have gained increasing attention in analytical chemistry due to their low cost, high electrical conductivity, intrinsic filtration capability, and high sensitivity. However, they still exhibit significant variations in electrochemical responses, both faradaic and capacitive, which are mainly attributed to the structural heterogeneity of fibrous substrates. These materials consist of multiple fibers with distinct properties in terms of conductivity, surface chemistry, porosity, and wettability, ultimately compromising analytical reproducibility. In this context, the use of a single fiber emerges as a promising strategy to minimize these limitations and to enable a deeper understanding of the underlying electronic and electrochemical phenomena. Thus, this project proposes the development of electrodes based on a single pyrolyzed bamboo fiber, modified with pyrolyzed polydopamine (PDA), for application in electrochemical (bio)sensors. The monofiber approach allows for improved control over electrical and electrochemical properties compared to conventional multifiber systems. Initially, delignification and isolation of individual bamboo fibers will be performed, followed by thermal treatment under an inert atmosphere to obtain conductive carbonaceous structures. Subsequently, dopamine polymerization will be carried out, followed by pyrolysis of the resulting film, leading to the formation of a functionalized two-dimensional (2D) material on the fiber surface. The chemical, structural, and morphological properties will be investigated using microscopic and spectroscopic techniques, while the electrical and electrochemical properties will be evaluated through electrical measurements and electroanalytical methods. As a proof of concept, an electrochemical biosensor will be developed based on the immobilization of oxidases and redox mediators, aiming at the detection of glucose, uric acid, and cholesterol in non-invasive biological samples. The results are expected to contribute to advancing knowledge on individual biomass-derived fibers, while promoting the development of miniaturized, sustainable, and high-performance analytical devices.