The early diagnosis of
liver cancer by target
biomarkers is of great significance for improving the survival rate of
cancer patients. However, it is still a challenging task to sensitively detect circulating
protein biomarkers due to decreased binding activity of
antibodies originating from uncontrolled orientation of immobilization on the surface of a solid matrix. In this work, a novel immunoaffinity probe, Fe3O4@TpBD-DSS-Ab-MEG, based on magnetic COFs with ordered arrangement of anchored
antibodies has been developed and applied for the first time to detection of a
cancer biomarker,
heat shock protein 90alpha (Hsp90α). The fabricated composites possess favorable features from magnetic cores and COF shells, including strong magnetic responses (7.96 emu g-1), ordered active groups, a large amount of
immobilized antibodies (111.7 μg/mg), good
solvent and thermal stability. Fe3O4@TpBD-DSS-Ab-MEG demonstrated low detection limit (50 pg/mL), high selectivity (Hsp90α:BSA = 1:1000), desirable repeatability and good stability for Hsp90α immunocapture. Compared with other immunoprobes, our materials showed higher selectivity and sensitivity, which were mainly attributed to regular arrays of surface
antibodies. Furthermore, samples containing Hsp90α at the concentration of 1 µg/mL in human plasma were used to test our immunoprobe, and 2
peptides of Hsp90α were successfully observed. The proposed non-invasive immunoassay strategy offers enhanced ability to control the orientation of
immobilized antibodies and great promise for accurate analysis of the
liver cancer biomarker Hsp90α in a complicated
biological matrix. In addition, the facile preparation of magnetic COFs support and the satisfactory analytical performance made the newly developed immunoprobe a potential tool for sensitive detection of other
cancer biomarkers in clinical diagnosis.