The Sensitive and Selective Electrochemical Detection of Carcinoembryonic Antigen Using a NanoMIPs-Aptamer Sandwich Assay

Carcinoembryonic antigen (CEA) is a well-established cancer biomarker that plays a crucial role in cancer diagnosis, treatment monitoring, and recurrence detection. This study presents the development of a highly sensitive and selective electrochemical sensor based on molecularly imprinted polymer nanoparticles (nanoMIPs) for CEA detection. CEA-specific nanoMIPs were synthesized and immobilized onto a screen-printed carbon electrode, providing selective recognition sites for CEA binding. The electrochemical signal probe was constructed using a metal organic framework, UiO-66-NH₂, which served as the substrate for lead ion (Pb²⁺) adsorption and aptamer functionalization. A nanoMIPs-aptamer sandwich assay was used for CEA detection. Square wave anodic stripping voltammetry was used to measure the electrochemical response of Pb²⁺, which correlates with the amount of CEA captured on the electrode surface. The sensor demonstrated an excellent linear CEA detection range at concentrations between 1–1,000 ng/mL. The limit of detection was determined to be 1.4 ng/mL, which is below the clinical cut-off value for CEA. The proposed sandwich assay offers several advantages, including low cost, high sensitivity, good reproducibility, and excellent selectivity. When applied to CEA-spiked human serum samples with the appropriate pretreatment, the sensor achieved satisfactory recovery rates ranging from 98.12–103.24%, highlighting its applicability for clinical diagnostics.