An ultrasensitive chemiluminescence aptasensor for indirect hemin detection based on aptamer recognition materials

Abstract

In this work, an ultrasensitive chemiluminescence (CL) aptasensor was prepared for indirect hemin detection based on hemin aptamer modified magnetic graphene oxide polymers (MGO@H-Atp@Co-PP). First, magnetic graphene oxide (MGO) was prepared, and MGO has a large specific surface area and easy separation characteristics. GO and MGO were characterized using scanning electron microscopy (SEM), X-ray powder diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR). Then, the hemin aptamer (H-Atp) was immobilized on the surface of the MGO, followed by cobalt porphyrin (Co-PP) being modified on its surface by the charge attracting effect between H-Atp and Co-PP. The immobilization properties of MGO to H-Atp and the adsorption properties of MGO@H-Atp to Co-PP were researched through the curves of kinetics and the curves of thermodynamics. When hemin existed in solution, Co-PP was removed from the surface of MGO@H-Atp@Co-PP due to the specific recognition ability between hemin and H-Atp while MGO@H-Atp@hemin was separated by a magnet, and Co-PP caused changes to the CL signal. So under optimized CL conditions, hemin could be assayed indirectly within the linear concentration range from 8.0 × 10⁻¹¹–4.8 × 10⁻⁸ mol L⁻¹, and the detection limit was 3.9 × 10⁻¹² mol L⁻¹ (3δ) with the relative standard deviation (RSD) of 3.6%. The CL aptasensor was finally used for the determination of hemin in practical serum samples, and recoveries ranged from 97% to 105%. The satisfactory results revealed the potential applications of the MGO@H-Atp@Co-PP-CL aptasensor for hemin detection in monitoring of drugs and diagnosis of diseases.