|Abstract||Early detection is the key to successful treatment of most diseases and is imperative for the treatment of many types of cancer. The most commonly used techniques are imaging modalities such as MRI, PET, and CT and are optimal for understanding the physical structure of the disease. However, these can be performed only once every four to six weeks due to the use of imaging agents and overall cost. With this in mind, the development of "point of care" techniques such as biosensors, which evaluate the stage of disease and/or efficacy of treatment in the clinician's office in a timely manner, would revolutionize treatment protocols. As a means to developing ferrocene based biosensors, we have produced a library of ferrocene-biotin bioconjugates that have been evaluated for a change in redox activity in the presence of avidin. We have shown that our molecules show an electrochemical response specific for the biomarker of interest, in this case avidin. The next phase of this project is to immobilize the complexes on an electrode surface. This will impart stability, portability, and allow access to commercialization.