Preparation of Label-free Aptasensor for the Detection of Platelet-derived Growth Factor

Gold nanoparticles immobilized upon mesoporous silica (Au-MSN) were synthesized. In the presence of chitosan (CHIT), Au-MSN were immobilized on the surface of glassy carbon electrode. Then, the thiolated platelet-derived growth factor (PDGF) aptamer was immobilized on the electrode surface via self-assembled technology. Using methylene blue as electroactive intercalator,, the quantitative determination of PDGF was carried out based on the increase of electrical signal of methylene blue after the combination of aptamer with target PDGF. The effects of the pH of buffer, incubation time etc. on the signal of the electrode were investigated. The results showed that the biosensor exhibits excellent linear response to PDGF in the range of 0. 1 mu g/mL-1 mu g/mL with a detection limit of 0. 03 pg/mL. This electrochemical aptasensor showed simplicity, low cost, high sensitivity and stability.