Ricin toxin chain A (RTA), a byproduct of the production of castor oil from castor bean plants, is a hazardous toxin that inhibits the cellular production of proteins once it enters the body. This toxin, whether ingested, inhaled, or injected, can be lethal, and treatment is difficult as there are currently no known antidotes for ricin. Detection of RTA prior to exposure is thus important, and it is necessary to expand the methods that can be used for this detection, as current methods are not time-sensitive. In this project, we have designed and tested an electrochemical biosensor that is capable of-- and sensitive enough-- to detect small, bio-medically relevant concentrations of RTA. This biosensor was designed based on an existing oligonucleotide aptamers that have been previously shown to bind to the hydrolase protein in ricin toxin. One of these aptamers was then used as the basis of a rationally designed DNA oligonucleotide biosensor scaffold that allows the coupling of RTA binding to a conformational change in the oligonucleotide. Ultimately, this biosensor design allows voltammetric interrogation to detect RTA concentration in complex media (such as coffee, blood, and river water). Additionally, this biosensor is convenient and collects real-time data, offering beneficial applications to the monitoring processes of areas involved in castor oil production. Furthermore, it may possess diagnostic potential in assessing ricin exposure. Electrochemical DNA biosensors have the potential to be used in numerous different situations, and this project shows a strategy for how they may be expanded to the detection and quantification of hazardous toxins.

Expanding electrochemical DNA biosensors to detect ricin

249th National Meeting (2015)

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