Microfluidic models of the gastrointestinal (GI) tract, known as gut-on-a-chip devices, mimic the structural, absorptive, pathophysiological and microbial environment of the human gut. They have potential to revolutionize drug delivery testing and replace animal testing to improve efficacy. However, current models lack methods for quantitative assessment of molecular cues that determine biological function, limiting their ability to discern the efficacy of treatments on diseases. Team BioCHIPS developed a polydimethylsiloxane (PDMS) gut-on-a-chip model lined with Caco-2 intestinal epithelial cells, with the novel incorporation of catechol-chitosan biomolecular sensors. This is the first instance of in situ assembled biomolecular sensors that provide direct electrical connectivity and assessment of glucose level in real time. These sensors enable quantifying changes in the physiological conditions due to alterations in glucose concentration, to monitor effects of treatments on their respective GI diseases.