The ideal molecular sensor will be sensitive, versatile, small enough to hold in your hand, and selective enough to work even when faced with complex samples, such as whole blood. Given the affinity and specificity with which biomolecules (proteins, DNA, RNA) recognize their targets, “biosensors” have been widely touted as a potential solution to these challenges. To date, however, the translation of biomolecular recognition into convenient, highly selective sensors has proven difficult. Stealing several tricks from nature, we have solved this problem to create a new sensing technology that appears ideally suited for diagnostics at the point of care and in the developing world. Refreshments provided. summer.ucsb.edu/grit