The broader impact/commercial potential of this I-Corps project is advancement of sensing technology for health, food safety, and diagnostics, and taps into the rapidly growing global market for sensors. Colorimetric sensors are a family of compounds that undergo a conversion between two different colored states upon exposure to a stimulus and are validated in real-world applications such as blood-glucose monitoring and early pregnancy tests. This project focuses on the development and deployment of simple and cost effective colorimetric indicators for use in applications such as detection of food spoilage, detection of contaminants in water, detection of pharmaceutical residues, monitoring wounds for the onset of infection, and tracking solid phase peptide and peptoid synthesis. The initial focus area applies to the large market, where these indicators can be used to determine the freshness of meat and seafood, and can help address the problems of food waste and food-borne illnesses.<br/><br/>This I-Corps project is based on a growing interest in smart materials ? compounds that change properties or state as a result of an external input. In particular, this research is based on the development of a portable and inexpensive colorimetric sensor capable of detecting sub-ppm levels of amine in the presence of thiols and alcohols, and prepared from low-cost, commercially available starting materials. The reaction between an activated furan and these low levels of amines, in solution or when incorporated onto solid supports, produces a vibrant pink color under ambient conditions that is distinguishable by the naked eye or by using the digital camera of a smartphone. Analysis of the kinetics of these reactions in solution and the quantification of the levels of detectable amine show excellent sensitivity and selectivity. In application, activated furan solutions were used as a colorimetric assay for solid-phase synthesis of peptides and peptoids and were adsorbed onto nylon filters and used to monitor the real-time release of amines from decaying fish samples.