Construction of Boronate-Affinity Magnetic Immunity SERS Sensor and Detection of Alpha-Fetoprotein (AFP) in Human Serum

Abstract

Abstract According to its characteristics, borate can recognize and adsorb target glycoproteins and specific binding properties of antigens and antibodies. This article introduces a preparation method for a magnetic immune SERS sensor, and it is used for the specific identification and detection of trace AFP in human serum. The test used AFP as the target protein and 4-mercaptophenylboronic acid (4-MPBA) modified gold-coated silver nanoparticles (Ag@AuNPs) as the signal factor. After the AFP antibody was grafted on the boric acid group, the SERS detection probe (Ag@Au@4-MPBA@Anti-AFP) was obtained. On the surface of boric acid-functionalized (-P) magnetic silica particles, AFP antibody was modified, and the particles were used as magnetic immunocapture probes (Fe3O4@SiO2-P@Anti-AFP). Finally, the sandwich structure complex of “detection probe-target protein-capture probe” was successfully constructed. The prepared magnetic immune SERS sensor exhibits excellent selectivity and high sensitivity for AFP detection; based on the signal-to-noise ratio S/N = 3, the detection limit can reach 1.0 ng/mL; by performing a spike test on AFP in human serum, the sensor can be used to detect AFP in actual samples. The recovery rate was between 85.8% and 105.7%, and the RSD distribution was ≤3.52%. The sensor was easy to prepare, required no complex processing of samples and can achieve rapid detection, so that it is expected to become a new strategy for clinical detection of AFP.