Bioreceptor multi-walled carbon nanotubes@Fe3O4@SiO2–surface molecular imprinted polymer in an ultrasensitive chemiluminescent biosensor for bovine hemoglobin

Abstract

An ultrasensitive chemiluminescent biosensor with a high selectivity, based on a bioreceptor surface molecular imprinted polymer (SMIP) that used core–shell Fe₃O₄@SiO₂–multi-walled carbon nanotube nanostructures (Fe₃O₄@SiO₂/MWCNTs) as the backbone material, for bovine hemoglobin (BHb) determination was proposed. The Fe₃O₄@SiO₂/MWCNTs were synthesized with a new method, and then were characterized using SEM, FTIR and XRD techniques. The adsorption ability of Fe₃O₄@SiO₂/MWCNTs–SMIP was evaluated to be 91 mg g⁻¹ following the Langmuir isotherm equation and it demonstrated an excellent recognition and adsorption ability for the imprinted sites located on the surface or near the surface of the Fe₃O₄@SiO₂/MWCNTs. Under optimum conditions of CL, the detection range of BHb was from 5.0 × 10⁻¹⁰ to 7.0 × 10⁻⁷ mg mL⁻¹ with a detection limit of 1.5 × 10⁻¹⁰ mg mL⁻¹ (3δ). The proposed biosensor was successfully applied in the determination of BHb in real samples with high selectivity and sensitivity, and the recoveries were excellent and varied from 92% to 106%. Finally, the possible CL mechanism of the BHb in amplifying the CL signal of the luminol–NaOH–H₂O₂ system was discussed.