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

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 center dot mSiO(2)center dot nSiO(2)@GO). Firstly, Fe3O4 center dot mSiO(2)center dot nSiO(2)@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 center dot mSiO(2)center dot nSiO(2)@GO while AuNPs was modified by ssDNA (a single stranded DNA partially complementary to D-Apt). The immobilization properties of Fe3O4 center dot mSiO(2)center dot nSiO(2)@GO to D-Apt and the adsorption properties of Fe3O4 center dot mSiO(2)center dot nSiO(2)@GO@D-Apt to AuNPs@ssDNA were researched sequentially. When DA existed, AuNPs@ssDNA was desorbed from the surface of Fe3O4 center dot mSiO(2)center dot nSiO(2)@GO@D-Atp and catalyzed luminescence. After that, under optimized CL conditions, DA could be measured with the linear concentration range of 2.5 x 10(-13) to 2.0 x 10(-9) mol/L. The detection limit was 3.9 x 10(-14) mol/L (3 delta) while the relative standard deviation (RSD) was 2.6%. Finally, the Fe3O4 center dot mSiO(2)center dot nSiO(2)@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. (c) 2017 Elsevier B.V. All rights reserved.