A team led by Prof. WU Zhengyan from Institute of Intelligent Machines, Hefei Institutes of Physical Science developed a high-sensitivity electrochemical aptasensor to detection of thrombin in serum.
The paper was published in Biosensors & Bioelectronics.
Thrombin, a proteolytic enzyme, catalyzes the conversion of fibrinogen to fibrin and promotes blood clotting. It is closely related to leukemia, thrombotic disease, vascular wall inflammation, Alzheimer's disease and many other diseases. Thrombin is not present in the blood of human and other animals under normal circumstances. It is converted from prothrombin during coagulation. Therefore, the accurate detection of low concentration thrombin is a great significance for the diagnosis, treatment of related diseases and the evaluation of drug efficacy.
In this research, the team developed an ultrasensitive electrochemical aptasensor for picomolar thrombin detection. What they used is called synchronous coordination of triple signal amplification strategy.
When designing the sensor, scientists chose a Ti3C2Tx MXene multilevel pore structure framework as the sensing material and a metallic nanoprobe as the signal amplifier. The pore structure has the more electronic transport channels and the nanoprobe has an advantage of high electrocatalytic effect, which help to promote the response signal of sensor.
YANG Pengqi, a PhD student who conducted the research, further explained the process. Under the exsistence of picomolar-level thrombin, catalytic hairpin assembly reactions of DNA were triggered to bridge thionine labelled Au nanorob or hollow Cu-Pt alloy nanoprobes on the hierarchically porous Ti3C2Tx MXene framework with controllablly scondary pore structures. The sandwich-typed aptasensor showed an excellent performance with a wide linear range from 2 pM to 10 nM for thrombin, and a low limit of detection of 0.67 pM.
When researchers applied the sensor to the detection of a low concentration thrombin in blood, they found that it could not only detect thrombin at picomolar concentration, but also showed the excellent anti-interference and stability for various physiological substances.
"The sensing platform established in this study can be customized to analyze other biological or environmental substances," said YANG, "what's required is to rationally design the DNA sequences of target-binding aptamer."
This research was supported by the University Synergy Innovation Program of Anhui Province, the Special Project of Central Government for Local Science and Technology Development of Shandong Province, and the Open Research Fund of Key Laboratory of Environmental Toxicology and Pollution Control Technology of Anhui Province.
Schematic illustration of detection mechanism based on self-prepared aptasensor. (Image by YANG Pengqi)