Detecting Ricin with Engineered Sensor Switches

OrthoSystems, Inc. creates switchable molecular sensors for bioterror agents and other targets. In this project our OrthoSwitchTM technology platform will be used to develop a rapid diagnostic device for detecting ricin in solution. OrthoSwitchesTM are custom designed molecular sensors that function in the absence of a separation step or attachment to a solid-support. In contrast to antibody-based alternatives, highly selective sensors based on nucleic acids can be engineered to switch between two forms. In Phase I, a bi-stable Ricin OrthoSwitchTM will be tested and improved. This switch will be quenched (dark) in the absence of the ricin, and fluorescent (bright) in its presence; it will be set to trigger from dark to light at a low threshold concentration of ricin. Only the bright form of the switch will present a sequence that is known to have very high affinity for ricin. The described ricin switch will be tested for high sensitivity, selectivity and response time using conventional fluorophore/quencher (FRET) signaling. This ricin switch will then be tested in a prototype detection device developed with technology partners. Commercial applications of our technology lie in rapid detection of biowarfare agents, environmental contaminants, and discovering and evaluating potential antidotes to toxic agents.