In situ construction of oriented Au/PPy nanorod arrays-based aptasensor for fast and ultrasensitive determination of thrombin

Abstract

The dynamic changes in coagulation function indicators provide important references for early warning, disease progression, and prognosis evaluation of clinical cardio-cerebrovascular disease (CCVD) patients. However, current assay methods, such as enzyme-linked immunosorbent assay (ELISA), fluorescence immunoassay and colorimetry, are time-consuming, require bulky equipment, tedious operations, and long analytical period, which are difficult in achieving an on-site and rapid detection. To address above issues, we proposed an ultrasensitive and fast-responded aptasensor for the detection of a typical coagulation function indicator (Thrombin, Tob) through constructing a unique oriented Au/polypyrrole (PPy) nanorod arrays. This architecture has provided both high electrocatalysis and abundant active sites as the signal transfer and DNA carrier. Meanwhile, through the specific DNA-binding representative design, we also designed a target-induced chain release strategy based on the competitive interaction between Tob and cDNA, which remarkably accelerated the Tob recognition process. This aptasensor enables to present an ultralow detection limit of 3 fg/mL and fast detection time of 20 min in real human serum samples, together with the favorable repeatability, stability and anti-interference ability for early warning and prognosis prediction of CCVD. It is promising that this aptasensor can be extended to analyze more disease markers through the change of different bases sequence of the applied DNA stands, which will provide an on-site and convenient technique and device for clinical disease diagnosis.