Use of Over-oxidized Molecularly Imprinted Polypyrrole for the Sensitive Detection of Dopamine in Human Serum

Low concentrations of dopamine in the central nervous system cause several neurological diseases, such as schizophrenia and Parkinson's disease. A simple electrochemical sensor for dopamine detection, based on molecularly imprinted and electropolymerized over-oxidized polypyrrole (OPPy) is designed. It is based on the electropolymerization of pyrrole in the presence of the template molecule, dopamine (DA). The square wave voltammetry (SWV) is used for the detection of dopamine in a buffer solution. A molecularly imprinted polymer (MIP) is formed in the presence of a target molecule and, after extraction, a complementary cavity is formed, with a chemical affinity for the target molecule which favors its adsorption. The current peak obtained at the MIP electrode was proportional to the logarithm of the DA concentration in the range of 10-11 to 5x10-8 M and a detection limit of 10-11 M is obtained. The proposed sensor was used for the detection of DA in spiked blood serum, satisfactory results were obtained, showing the possible application of this dopamine sensor in biological fluids. MIP-OPPy has demonstrated high sensitivity compared to published dopamine electrochemical sensors based on polypyrole. This sensor can be easily manufactured at low cost and can be applied for the determination of dopamine in human serum.