Development of a DNA Microelectrochemical Biosensor for CEACAM5 Detection

An electrochemical DNA biosensor for the detection of carcinoembryonic antigen-related cell adhesion molecule (CEACAM5), a specific tumor marker for colorectal cancer, is presented. The biosensor based on microelectronicmechanical systems (MEMS) technology, consists of a three electrode configuration where the working electrode is a gold thin-film. The immobilization of the previously designed DNA capture probe is performed by self-assembled monolayer (SAM) technique, and it is hybridized with the complementary target. The formation of the biorecognition surface (SAM) and the detection of the hybridization event are characterized by two different electrochemical techniques: Electrochemical Impedance Spectroscopy (EIS) and Cyclic Voltammetry (CV), using potassium ferricyanide/ferrocyanide as redox couple. The differences in the charge transfer resistance (R
_ct
), capacitance (C), and in the redox signals of the potassium ferricyanide/ferrocyanide upon the hybridization, show that the biosensor presented is a rapid, low-cost, and effective tool for CEACAM5 detection. Moreover, the specificity in the hybridization event is demonstrated by exposing the biorecognition surface to a noncomplementary target.