An ultrasensitive and ultraselective chemiluminescence aptasensor for dopamine detection based on aptamers modified magnetic mesoporous silica @ graphite oxide polymers

Abstract

In this work, an ultrasensitive and ultraselective chemiluminescence (CL) aptasensor was prepared for dopamine (DA) detection based on aptamers modified magnetic mesoporous silica @ graphite oxide polymers (Fe3O4·mSiO2·nSiO2@GO). Firstly, Fe3O4·mSiO2·nSiO2@GO and Au nanoparticles (AuNPs) were prepared and characterizated by transmission electron microscopy (TEM), scanning electron microscope (SEM), fourier transform infrared (FTIR), X-ray powder diffraction (XRD) and others. Then, dopamine aptamer (D-Apt) was immobilized on the surface of Fe3O4·mSiO2·nSiO2@GO while AuNPs was modified by ssDNA (a single stranded DNA partially complementary to D-Apt). The immobilization properties of Fe3O4·mSiO2·nSiO2@GO to D-Apt and the adsorption properties of Fe3O4·mSiO2·nSiO2@GO@D-Apt to AuNPs@ssDNA were researched sequentially. When DA existed, AuNPs@ssDNA was desorbed from the surface of Fe3O4·mSiO2·nSiO2@GO@D-Atp and catalyzed luminescence. After that, under optimized CL conditions, DA could be measured with the linear concentration range of 2.5×10−13 to 2.0×10−9mol/L. The detection limit was 3.9×10−14mol/L (3δ) while the relative standard deviation (RSD) was 2.6%. Finally, the Fe3O4·mSiO2·nSiO2@GO@D-Apt/AuNPs@ssDNA − CL aptasensor was used for the determination of DA in practical samples and recoveries ranged from 98.0% to 102.0%. Those satisfactory results clarified the proposed CL aptasensor achieved ultraselective, ultrasensitive and reliable detection of DA and revealed potential application in monitoring and diagnosis of human neurological diseases.