Polymer-functionalized carbon nanotubes prepared via ring-opening polymerization for electrochemical detection of carcinoembryonic antigen

Carcinoembryonic antigen (CEA) is regarded as the most common tumor biomarker, the precise and sensitive measurement of which has great significance for the cancer diagnosis, treatment, and prognosis. Herein, for the first time, we construct a novel sandwich-type electrochemical aptasensor for CEA detection based on polymerfunctionalized carbon nanotubes (CNTs) composites prepared by ring-opening polymerization (ROP). CEA-aptamer 1 (Apt 1) is self-assembled on a gold electrode surface and used as a probe for CEA capture. CNTs are used as the substrates for polymer chain growth to prepare poly(ferrocenyl glycidyl ether)-grafted CNTs (PFcGE-CNTs) composites by ROP. Due to the efficient polymerization and good biocompatibility of ROP technology, PFcGE-CNTs composites can provide a hydrophilic-biocompatible nanoplatform for CEA-aptamer 2 (Apt 2) capture and serve as a signal amplifier. Remarkably, PFcGE-CNTs composites feature the characteristics of good conductivity and abundant ferrocene derivatives, which significantly amplify the electrochemical signal. Under optimized conditions, the fabricated aptasensor shows a wide detection range of 1 x 10(15) -1 x 10(-8) g mL(-1) and a limit of detection (LOD) down to 2.8 x 10(-16) g mL(-1), which are superior to those of most reported electrochemical methods. Furthermore, the proposed aptasensor exhibits excellent applicability for CEA detection in practical sample analysis, which is of promising application potential for the early diagnosis and monitoring of cancer.