The Chemiluminescence Aptasensor Based on Magnetic Separation and Double-Functionalized AuNPs for the Detection of Human Thrombin

The Aptasensors are a new kind of biosensors using aptamers as biorecognition elements, and they have been broadly applied in the detection of all kinds of targets. Chemiluminescence method has the advantages such as high sensitivity, wide linear dynamic range, simplified operation, and easy automation. Therefore, chemiluminescence aptasensor has attracted increasing attention and has become an important branch of the aptasensors. In this work, a chemiluminescence aptasensor based on magnetic separation and double-functionalized AuNPs for rapid and efficient detection of human thrombin has been developed. Fe₃O₄@SiO₂@Au composite nanoparticles were used to immobilize human thrombin-specific aptamer for rapid magnetic separation, but Fe₃O₄ nanoparticles have a masking effect on chemiluminescence. The detection signal could be amplified by double-functionalized AuNPs, which could bind with alkaline phosphatase (ALP) labeled streptavidin to catalyze the chemiluminescence of 3-(2'-spiroadamantane)-4-methoxy-4-(3"-phosphoryloxy)-phenyl-1,2-dioxetane (AMPPD) and avoid the masking effect of Fe₃O₄ nanoparticles on chemiluminescence. The results showed that there was a linear relationship between the chemiluminescent (CL) intensity and the concentration of human thrombin in the range of 1 ∼ 100 ng/mL, and a low detection limit of 0.1 ng/mL, as well as a good specificity. This chemiluminescence aptasensor based on magnetic separation and double-functionalized AuNPs could be widely applied in the field of detection.