SiC-C fiber electrode for biological sensing

Microelectrodes implanted in the brain can act as transducers for the neuronal impulses. In this work a composite fiber (SiC-C) electrode was studied for neuronal activity sensing and for biochemical detection of electroactive neurotransmitters. An electrolytic etching technique was also developed for fabricating electrode tips from SiC-C composite fiber. SEM was used to study different tip geometries and shapes. Cyclic voltammetry and electrochemical impedance spectroscopy were used for the electrochemical characterization and modeling. Almost square voltammograms showed that the current generated was due to the charging and discharging of the capacitive double layer without any significant redox reaction. The electrodes showed capacitive interaction with the surrounding electrolyte solution which is highly desirable for safe charge transfer. Biochemical sensing of neurotransmitters including dopamine hydrochloride and vitamin C was done with the SiC-C composite electrodes and oxidation currents were found to vary linearly with concentration. In vivo action potential recordings from anesthetized rat's brain with very high signal to noise ratio were obtained.