Abstract: A specific detection approach for platelet-derived growth factor(PDGF) via the competitive reaction between Aptamer-DNA and Aptamer-protein was established. In the paper, SiO2-MB nanocomposite was synthesized by reverse microemulsion method. For this proposed aptasensor, aptamer was immobilized on the magnetic nanoparticles, and the complementary oligonucleotide was labeled with SiO2-MB nanocomposite, Through the hybridization between the aptamer and its complementary oligonucleotide, a certain amount of SiO2-MB nanocomposite was gathered onto the magnetic nanoparticles. In the presence of PDGF, the aptamer was in a conformational equilibrium between Aptamer-DNA and Aptamer-protein, the aptamer prefers to bind with PDGF, resulting in a significant decrease of the electrochemical signal of MB. Upon this, we were able to detect the binding events between the aptamer and the protein. The assay was highly sensitive for PDGF, and is interference from other proteins such as IgG, thrombin and lysozyme. The linear range of the PDGF is 5.51×10-17 ～1.01×10-15mol/L with a detection limit of 1.31×10-17mol/L.

Key words: aptamer, PDGF, specific recognition