The National Heart, Lung, and Blood Institute (NHLBI) awarded DBC a Phase I SBIR to pursue the real-time, continuous detection of chemotherapeutic drug doxorubicin in the blood stream. The sensor resulting from this project will provide continuous feedback on systemic levels of doxorubicin, or other drugs, to determine individual metabolism of a compound. The ultimate goal of this product is to monitor individuals for exposure to drugs, particularly for cases in which drug levels vary significantly between individuals or for which lifetime exposure of a drug should be limited to prevent toxicity. In the case of doxorubicin, too high an exposure may cause cardiotoxicity. Currently, blood drug level is measured only at a few time points, resulting in an imcomplete and potentially inaccurate profile of a patient's exposure to the drug.