Magnetic hydrophilic polymer-based apta-sensing probe for sensitive detection of fetuin-A in serum

A new apta-sensing probe based on magnetic hydrophilic polymer (MHP) was proposed for simple and sensitive detection of fetuin-A in serum matrix. Briefly, MHP was the hydrophilic polymer modified magnetic nanoparticles , which was synthesized through free radical polymerization method with hydrophilic monomers and magnetic nanoparticles. Then, aptamer against fetuin-A first selected through capillary electrophoresis-SELEX was hybridized with FAM-labeled aptamer complementary sequence (CS) to form duplex structure, which was finally conjugated on MHP to form MHP apta-sensing probe (MHPA). In this probe, MHP with hydrophilic property was employed as separation carrier, aptamer was used for fetuin-A binding and FAM-labeled CS as signal probe . With the presence of fetuin-A, CS escaped and could be detected because of the competitive binding between fetuin-A-aptamer and aptamer-CS. Because of the synergistic effect of specific affinity of aptamer on protein and hydrophilic property of the polymer, MHPA exhibited sensitive and selective detection for fetuin-A. Under optimal conditions, the linear range was 5.0 nM-4.0 μM with the detection limit of 4.4 nM. What’s more, MHPA engaged with good stability and selectivity had been successfully applied in the detection of fetuin-A in serum samples. The as prepared hydrophilic polymer assistant apta-sensing probe with facile and sensitive properties, provides novel explication for efficient protein detection.