Investigating the electroactivity of short chain fatty acids on carbon fiber microelectrodes using fast scan cyclic voltammetry

Short-chain fatty acids (SCFAs), specifically acetic acid, propionic acid, and butyric acid, are the most abundant metabolites produced by gut bacteria and play a significant role in brain health and neurochemistry. There is a great deal of interest in measuring how much SCFAs cross into the brain and how they directly affect neurotransmission in a dose-dependent manner. Here we utilize fast scan cyclic voltammetry at carbon fiber microelectrodes to investigate the electroactivity of these SCFAs. Our findings demonstrate that these gut metabolites display a single cathodic and two anodic peaks in the cyclic voltammograms. Two of these peaks (one oxidation, one reduction) respond to changes in scan rate in a manner characteristic of faradaic processes. We varied the holding and switching potentials as well as utilized butyrate analogs to understand the nature of the peaks further. While future optimization will be needed to create SCFA-selective sensors, this work demonstrate the potential for in situ electrochemical detection of these gut metabolites.