Gelatin-Enabled Microsensor for Pancreatic Trypsin Sensing

Abstract

Digestive health is critically dependent on the secretion of enzymes from the exocrine pancreas to the duodenum via the pancreatic duct. Specifically, pancreatic trypsin is a major protease responsible for breaking down proteins for absorption in the small intestine. Gelatin-based hydrogels, deposited in the form of thin films, have been studied as potential sensor substrates that hydrolyze in the presence of trypsin. In this work, we (1) investigate gelatin as a sensing material; (2) develop a fabrication strategy for coating sensor surfaces; and (3) implement a miniaturized impedance platform for measuring activity levels of pancreatic trypsin. Using impedance spectroscopy, we evaluate gelatin’s specificity and rate of degradation when exposed to a combination of pancreatic enzymes in neutral solution representative of the macromolecular heterogeneity present in the duodenal environment. Our findings suggest gelatin’s preferential degradation to trypsin compared to enzymes such as lipase and amylase. We further observe their interference with trypsin behavior in equivalent concentrations, reducing film digestion by as much as 83% and 77%, respectively. We achieve film patterns in thicknesses ranging from 300–700 nm, which we coat over interdigitated finger electrode sensors. Finally, we test our sensors over several concentrations to emulate the range of pancreatic secretions. Ultimately, our microsensor will serve as the foundation for developing in situ sensors toward diagnosing pancreatic pathologies.