Advancements in sensors for rapid detection of short-chain fatty acids (SCFAs): Applications and limitations in gut health and the microbiota-gut-brain axis

Short-chain fatty acids (SCFAs) have emerged as an important family of microbial metabolites for metabolic health and gut-brain communication. Quick detection of SCFAs in body fluids such as blood, urine, or stool samples could allow for the monitoring of disease status and progression over time. However, their detection methods are still very complex and expensive. In this review, we summarised the available literature on (bio)sensors for the rapid detection of different SCFAs. They were divided into electrochemical, optical, and genetically modified cell-based sensors. Optical sensors were shown to be the most sensitive, achieving limits of detection in the ranges needed for SCFA levels in body fluids, however, to date, they have mostly focused on the detection of acetate without interferences other than ions. Electrochemical and cell-based detection was typically too complex, variable, and not sufficiently sensitive. Further developments in this exciting field could address the need for rapid evaluation of SCFA concentrations in body fluids.