Electrochemical Neurotransmitter Detection with Parylene-C Neural Probes

Catecholamines are a focus of extensive research due to their crucial role in the brain's reward system, yet their precise function remains elusive. Quantifying catecholamines including dopamine is essential for regulating cognitive processes, aiding in early detection, diagnosis, monitoring, and therapeutic interventions for intricate neural disorders.<br/>Implantable neural interfaces are indispensable for advancing practical applications of clinical neurotechnologies. Electrochemical sensors, known for high sensitivity, selectivity, rapid response time, minimal sample preparation, non-invasiveness, and portability, play a key role in catecholamine measurement.<br/>Parylene C is chemically inert and features a low Young’s modulus (∼2-3 GPa), aligning closely with the mechanical properties of biological tissue. We propose the use of a label-free Pt electrode known for durability during long-term implantation using Parylene C. The electrodes are constructed using thin-film Parylene C, a biocompatible polymer classified as USP class VI. The flexibility of parylene is pivotal as it allows implanted devices to adapt to the brain or muscle shape, ensuring movement without harming surrounding tissue. To achieve the detection of dopamine at low concentrations, we applied gold-palladium nanoparticles and a graphene oxide, poly(3,4-ethylenedioxythiophene)/ poly(styrene sulfonate) (PEDOT/PSS) electrode coating and optimized square wave voltammetry (SWV) waveform for selective dopamine measurement.<br/>Our approach holds promise for prolonged, reliable in vivo sensing. The introduction of parylene electrodes is crucial for understanding the context of our work. Our electrodes are crafted through a process involving the integration of gold-palladium nanoparticles and a graphene oxide PEDOT: PSS film onto flexible parylene C sensors. This novel combination aims to enhance sensitivity and durability for precise catecholamine determination in vivo.<br/>The novelty of our work lies in the development of a modified sensor with improved sensitivity and durability for in vivo catecholamine determination. This modification involves the strategic use of gold-palladium nanoparticles and a graphene oxide PEDOT:PSS film on a flexible parylene C sensor. This innovative approach addresses challenges related to biofouling and degradation, ensuring a prolonged sensor lifespan during long-term implantation.