Directional movement of cells in response to environmental cues (e.g. chemotaxis) is essential throughout biology, and the membrane receptors that initiate cell migration offer a key opportunity for modulation by synthetic biologists. The design of chemotactic receptor biosensors for metastatic markers has the potential to expand the immune system’s spectrum of actions. Metastatic cancers are extremely lethal, and tumor cells that escape to seed a secondary tumor in a distant organ often escape immunosurveillance. Extensive studies on metastasis have identified soluble secreted factors that promote the initial escape of tumor cells, their intravasation into circulation, and extravasation into metastatic niches where they can proliferate and form new malignant tumors. We will employ a host of computational design techniques developed in the Barth Lab to build novel biosensors that will elicit chemotactic responses towards molecular indicators of metastatic cells at various key points during their journey to secondary sites when they are vulnerable to engineered cytotoxic immune (T and NK) cells. By harnessing the migratory potency of a chemokine receptor scaffold, we will design several novel chemotactic receptors sensing molecules of increasing complexity to ultimately build and validate a general computation-based platform for rational biosensor design. At a fundamental level, engineering membrane receptors that can respond to a diversity of molecules is a stringent test of our biophysical understanding of protein structure and function, but also has far-reaching applications in basic and translational research with immediate relevance and impact for cancer therapeutics.