||Per- and polyfluoroalkyl substances (PFAS) are a family of over 4,000 man-made chemicals that have been released into the environment for decades. Because they are extremely difficult to break down in natural environments, PFAS are also called the “forever chemicals”. PFAS have been detected in the blood samples of 97% Americans and considered an urgent concern for human health. One of the major routes for human exposure to PFAS is via drinking tap water. For this reason, a growing number of states across the US are regulating PFAS in drinking water. To alert people of PFAS contamination in tap water, fast, cheap, and onsite detection of PFAS is required, which, unfortunately, cannot be fulfilled by the current grab-sampling and laboratory-based analytical methods. The overall goal of this project is to develop an innovative sensor for inexpensive and rapid PFAS analysis in drinking water supplies. To achieve this goal, hollow molecules that can strongly and selectively bind with PFAS will be used to enrich PFAS onto the sensor surface via “lock-and-key” interactions. Subsequently, the sensor will generate light signals that contain the identity and concentration information of PFAS. How the background molecules in tap water affect PFAS detection will also be carefully investigated. The sensor developed in this project could be deployed in field to monitor the spatial and temporal fluctuation of PFAS concentrations in drinking water supplies and provide guidance for data-driven action plans for PFAS contamination and for reducing human exposure to PFAS.