Developing fast scan cyclic voltammetry at carbon fiber microelectrodes toward quantifying in situ short chain fatty acid dynamics

It has been largely hypothesized that the beneficial effects of dietary fibers are through the actions of short chain fatty acids (SCFAs) such as acetic acid, propionic acid, and butyric acid, which are fermentation byproducts produced by bacteria in the gut. Recent research has shown, however, that the concentrations of these fatty acids in the cecum and in fecal samples do not correlate with the beneficial effects of dietary fiber. Rather, it is hypothesized that the fluxes of SCFAs are the primary driver of dietary fiber effects in the gut and other tissues. Measuring these fluxes, however, is challenging. Here, we describe the development of fast scan cyclic voltammetry (FSCV) at carbon fiber microelectrodes (CFMs) to measure these rapid SCFA dynamics. We have extensively characterized the cyclic voltammograms of each SCFAs, including effects of holding potentials, switching potentials, and scan rates on different peaks. We identified 2-4 faradaic peaks for each fatty acid that are responsive to concentration changes. Our work here sets the groundwork for the development of FSCV at CFMs to selectively measure each fatty acid in the future.