Electrochemical genosensor for detection of human mammaglobin in polymerase chain reaction amplification products of breast cancer patients.

Human mammaglobin (MG) has been found to be the most specific molecular marker for the hematogenous spread of breast cancer cells. In our study, an electrochemical impedance spectroscopic DNA biosensor was established for the detection of MG in breast cancer patients. The working conditions for the biosensor, such as immobilization time, rinse process, and hybridization process, were optimized. Under the optimal conditions, the charge transfer resistance of the proposed DNA biosensor shows excellent correlation with the amount of the complementary oligonucleotides in the range from 1.0 × 10(-9) to 2.0 × 10(-8) M. The detection limit is 5.0 × 10(-10) M. The proposed biosensor was used to detect the polymerase chain reaction amplification products of actual clinical breast cancer samples. The results were compared with that obtained by conventional gel electrophoresis. The results indicate that the electrochemical impedance spectroscopic assay is significantly sensitive and time-saving. The simple strategy described here is expected to be used in clinical application for early diagnosis of breast cancer.