Directly fast detection of digoxin in the serum sample by the synthetic receptor sensor

A novel biosensor (the synthetic receptor sensor) employing the molecular imprinted technology for the digoxin analysis is investigated. The molecularly imprinted polymer (MIP) modified electrode can specifically bind to the analyte in the sample without sample pretreatment. The digoxin analyzed by the MIP sensor was carried out in 1 mM K3Fe(CN)6 solution with the cyclic voltammetry. In the system, the K3Fe(CN)63−/Fe2(CN)64− redox couple was taking place. When the solution contains the digoxin, the MIP on the electrode will bind the digoxin. Further the redox system is interrupted and the peak current is decreased according to the digoxin concentration increasing. Digoxin is a glycosylated steroid-like drug. It is important for the heart disease treatment. However, since the digoxin toxic level is low, the drug remains in the blood sample must be monitored frequently. The device possesses many advantages, such as high specific recognition properties, good chemical and mechanical stability, simplicity and low cost of preparation, sensitive and label free determination. The reproducibility is good (CV < 5). The linear relationship between the digoxin concentration and the current is 1.28–128 nM, and a detection limit of 1.28 nM is achieved. The detection time is less than 5 min.