(BIO)ELECTROCHEMICAL TOOLS FOR INTEGRATION OF BIOLOGICAL SYSTEMS AND ELECTRONIC COMPONENTS (BIONIC)
This thesis develops biocompatible interfaces for cell-based sensing platforms using microalgae and neuronal cells, focusing on direct and indirect electrochemical communication for toxin detection and environmental monitoring. Chapter 1 reviews state-of-the-art bioelectrodes, highlighting direct extracellular electron transfer (DEET) and mediated electron transfer mechanisms, and the need for cost-effective, portable toxin detection systems compared to lab-based methods like patch clamping. It outlines requirements for cell immobilization and efficient electron transfer using biocompatible materials.
Chapter 2 details a composite matrix of poly(3,4-ethylenedioxythiophene) (PEDOT) and poly(3-aminophenylboronic acid) (PAPBA) doped with graphene quantum dots (GQDs), enabling DEET from Raphidocelis subcapitata. The matrix, formed via layer-by-layer electropolymerization on gold electrodes, supports cell adhesion and electron transfer. Chronoamperometry at 50 mV showed photocurrent increases of 36–57 µA/cm² (53–73%) under light stimuli, with a 10-fold enhancement (501–767 µA/cm²) after one week of dark storage, indicating a robust platform for mediator-free biosensing of environmental toxins like heavy metals.
Chapter 3 extends toxin detection to neuronal cells for health risk assessment, using Neuro-2a (N2a) cells on indium tin oxide (ITO) substrates. These substrates enabled simultaneous microscopy and electrophysiological measurements, with extracellular field potentials (EFPs) and patch clamping confirming TTX detection. An impedimetric biosensor, using redox polymer-modified ITO, detected TTX from 6–300 nM, offering a portable, cost-effective alternative to traditional methods.
This work advances bioelectrochemical interfaces for real-time, sensitive detection of toxins, leveraging microalgae and neuronal cells. It supports applications in environmental monitoring and health risk assessment, addressing challenges in portability and cost while elucidating cellular responses to toxins.
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