Magnesium-based micromotors for the detection of carcinoembryonic antigen in whole blood

The rapid and accurate detection of tumor marker carcinoembryonic antigen (CEA) is of great significance for the early diagnosis of cancer. Here, we design an electrochemical detection platform based on zwitterionic surface modification, nanomotor and magnetic separation technology. Specifically, magnesium-based micromotors (magnesium/ferroferric oxide/poly(carboxybetaine methacrylate)/ carcinoembryonic antigen antibody, Mg/Fe 3 O 4 /PCBMA/anti-C) were firstly prepared using asymmetric surface modification technology, which could react with water to form active motion to promote the capture of the target detection substance CEA. Furthermore, after the Mg-based micromotor was completely consumed in the test solution, a self-made funnel device was used to collect the magnetic nanoparticles that captured CEA onto the surface of the magnetic electrode. Then, the electrochemical testing was performed. When CEA bound with anti-CEA, the resulting immune complex hindered the electrochemical probe Fe(CN)₆³⁻/⁴⁻ from reaching the electrode surface, thereby causing a decrease in the electrochemical signal. By measuring the change in the electrochemical signal, the concentration of CEA could be quantitatively determined. The experimental results indicate that Mg-based micromotors display good blood compatibility and could actively capture CEA in whole blood. This detection platform was very sensitive for CEA detection, with a detection range from 0.001   ng   mL -1 to 100   ng   mL -1 and a detection limit of 2.58×10 -4   ng   mL -1 . This multi-technology composite application of whole blood antigen detection is expected to provide a new technological platform for early diagnosis of cancer.