Self-enhanced biohybrid frameworks as novel ECL emitters for sensitive detection of CA15-3

Early screening for breast cancer can be effective in reducing cancer mortality; therefore, accurate detection of breast cancer marker carbohydrate antigen 15-3 (CA15-3) is of great importance. In this study, a highly sensitive sandwich-type electrochemiluminescence (ECL) biosensor based on an electron transfer quenching mechanism was developed for the ultrasensitive detection of the CA15-3. The self-assembled biohybrid framework through hydrogen bonding between the amino groups (-NH₂) of bovine serum albumin (BSA) and the carboxylic acid groups (-COOH) of perylene tetracarboxylic acid (PTCA) was used as a luminophore. The aggregation-caused quenching (ACQ) effect was effectively suppressed by framework spatial arrangement preventing PTCA aggregation and enhancing ECL emission. Simultaneously, introduction of Au NCs with BSA as a protective ligand catalyzed the production of more SO₄^•- radicals from S₂O₈^2- to enhance ECL emission intensity. Cu₂O@MnO₂ with matched energy level can be used as an electron transfer quencher to construct sandwich-type ECL biosensors. ECL signals was quenched by target response via the electron transfer (ET) pathway. The sensor achieves sensitive detection of CA15-3 under optimal conditions with a wide response range (0.001-100 U/mL) and a low limit of detection (LOD) (0.00014 U/mL), and has sufficient practical analytical performance. This study provides a high-precision analytical platform for the sensitive detection of CA15-3 and offers more possibilities for the development of ECL systems based on novel biohybridisation frameworks.