Electrochemical immuno-biosensors for the detection of the tumor marker alpha-fetoprotein: A review.

Alpha-fetoprotein (AFP) is a glycoprotein that has many important physiological functions, including transportation, immunosuppression, and induction of apoptosis by T lymphocytes. AFP is closely related to the development of hepatocellular carcinoma and many kinds of tumors, all of which can show high concentrations, so it is used as a positive test indicator for many kinds of tumors. This paper reviews recent advances in the detection of the tumor marker AFP based on three immuno-biosensors: electrochemical (EC), photoelectrochemical (PEC), and electrochemical luminescence (ECL). The electrodes are modified by different materials or homemade composites, different signaling molecules are selected as single probes or dual probes for the detection of AFP. The detection limit was as low as 3 fg/mL, which indicated that the AFP immunosensor had achieved highly sensitive detection. In addition, we also reviewed and summarized the current development status and application prospect of AFP immunoelectrochemical sensors. There are not too many researches on immunosensors based on dual-signal ratios, and the commonly used probes are methylene blue (MB) and ferrocene (Fc). It would be more innovative to have more novel signaling molecules as probes to prepare dual-signal ratio sensors. This paper reviews recent advances in the detection of the tumor marker AFP in recent years based on three different types of electrochemical biosensors: electrochemical (EC) immunosensors, photoelectrochemical (PEC) sensors, and electrochemical luminescence (ECL) sensors. Among them, EC sensors are classified as single-probe and dual-probe. [Display omitted] • This manuscript reviews recent research on the detection of AFP. • The review describes three immunobiosensors: EC, PEC and ECL. • A comprehensive summary and comparison of three sensors for AFP detection. • This review provides guidelines for future research on immunobiosensors. [ABSTRACT FROM AUTHOR]