Electrochemical aptasensor based on proximity binding-induced DNA networked for enzyme-free and ultrasensitive detection of thrombin

The abnormal change of thrombin concentration is closely related with various diseases. By using proximity binding-induced DNA network assembled by nonlinear hybridization chain reaction (HCR), we here developed an enzyme-free and ultrasensitive electrochemical strategy for analyzing thrombin in human serums. The binding of the two different aptamers to a thrombin enhanced the local concentration of the aptamers and facilitates the formation of an intact strand. Subsequently, the formed strand caused nonlinear HCR, forming DNA network. The DNA network bound to the capture probes (CP)-modified electrode, producing electrochemical signal of MB. Benefiting from the proximity binding-induced DNA network, the proposed biosensor exhibited a wide linear range from 1.0 pM to 1.0 nM with a low detection limit of 0.56 pM and high specificity. More importantly, the developed enzyme-free electrochemical biosensor has been used to detect thrombin in serum samples with good performance. This makes such a strategy possess potential promise in the application of clinical diagnosis.

Automated summary

The article introduces an enzyme-free electrochemical strategy for analyzing thrombin concentration in human serum using a DNA network assembled by nonlinear hybridization chain reaction. The strategy has high sensitivity and specificity, and performs well in detecting thrombin in serum samples.