A chemiluminescence immunosensor for biomarker detection based on boronic acid-modified magnetic composite microspheres

High-sensitivity detection of biomarkers in biological samples is crucial for the early diagnosis and treatment of diseases. In this paper, a versatile and flexible immobilization technique based on the specific affinity interaction between boronic acid and cis-diol groups of antibodies was developed for biomarker detection. As a model, the boronic acid-modified immunomagnetic beads were used for facile and quick immobilization of the alpha-fetoprotein (AFP) antibody due to the specific affinity interactions. Based on this new class of immunomagnetic beads, the chemiluminescence immunosensor could efficiently detect the biomarker of AFP. Under optimal conditions, the limit of detection (LOD) is as low as 8 fM (S/N = 3), showcasing superior sensitivity and detection specificity for AFP. Subsequently, the system was successfully applied to the detection of AFP in fetal bovine serum samples, and the average recovery rate is greater than 95%. Its performance surpassed that of commercial immunomagnetic beads, showcasing the potential application of this new strategy for bioanalysis and clinical diagnosis.