Flexible Electrochemical Neural Probes for In Vivo Recording of Neurotransmitters

Catecholamines are a significant focus in research because they play a critical role in the brain's "reward" system, although their precise function is not yet fully comprehended. The quantification of catecholamines are vital as they regulate all cognitive processes in the brain and<br/>can aid in early detection, diagnosis, monitoring, and therapeutic interventions for complex neural disorders. Implantable neural interfaces are essential in expediting progress in neuroscience research and the practical application of clinical neurotechnologies. Electrochemical<br/>sensors offer several advantages for measuring catecholamines, including high sensitivity and selectivity, rapid response time, minimal sample preparation, non-invasiveness, and portability.<br/>The proposed design will be used to create the sensor. It includes a working electrode and a reference electrode with a reference membrane. The reference electrode is shared between the platinum electrodes and will be formed on a parylene C substrate that is 10-20 μM thick. The<br/>platinum electrodes have a 100-200 μM radius and a thickness of approximately 200 nm. The sensing membrane will be applied to<br/>the circular area of the platinum contact using drop-casting.<br/>For in vivo recording, parylene's flexibility is essential because it enables implanted devices to adapt<br/>to the shape of the brain or muscles and move with it without harming the surrounding tissue. While many in &lt;div&gt;vitro catecholamine sensing electrodes utilize coatings made of enzymes, aptamers, and antibodies to increase their sensitivity, these &lt;/div&gt; &lt;div&gt;coatings are prone to biofouling and quick degradation, reducing the sensor's lifespan in vivo. As a result, we are using a label-free surface-modified Pt electrode, which has been shown to be durable during long-term implantation, Figure 1. The<br/>expected peaks potential for different catecholamines are: Epinephrine (EP): around 0.1-0.3 V, Norepinephrine (NE): around 0.1-0.2 V, Dopamine (DA): around 0.2-0.4 V. We utilize cyclic voltammetry and square wave voltammetry for direct electrochemical detection of catecholamines.<br/>We are depositing a sensing membrane comprising an ionophore on the working electrode for acetylcholine and pH. &lt;/div&gt;