Ratiometric electrochemiluminescence biosensor based on red blood cell membrane as an efficient antifouling interface...

Electrochemiluminescence (ECL) biosensors are suitable for trace detection of serum biomarkers due to their high sensitivity and rapid response. However, human serum contains many interfering biomolecules that affect the output signals and operating life of biosensors. On this basis, a highly bioactive ECL sensing platform based on red blood cell membrane (RBCM) as an antifouling interface was developed for sensitive and accurate detection of circulating tumor cells (CTCs). Specifically, RBCM exhibited excellent antifouling performance due to its superhydrophilicity and low content of membrane proteins, and its good biocompatibility avoided the adverse effects of chemical antifouling coatings on the activity of biosensors. At the same time, the electropolymerized polyaniline nanowires (PANI NWs) were inserted into RBCM, which enhanced its stability and conductivity, thus expanding the potential application of antifouling cell membranes in ECL analysis. In addition, C₃N₄ was modified as an internal standard to eliminate background signals and external interferences, thereby improving detection accuracy. According to these strategies, the constructed ECL antifouling biosensor achieved ultrasensitive CTCs detection in human serum, with a wide linear range (10-5 × 10⁶ cells mL^-1) and a detection limit as low as 3 cells mL^-1 (3δ/k). This study provides positive insights for bioanalysis application of antifouling cell membranes and trace detection of serum biomarkers.