An aptasensor based on heparin-mimicking hyperbranched polyester with anti-biofouling interface for sensitive thrombin detection.

In this paper, novel heparin-mimicking hyperbranched polyester nanoparticles (HBPE-SO3 NPs) with abundant of sulfonated acid functional groups were synthesized, and their antithrombogenicities were further evaluated. Further, a label-free electrochemical aptamer biosensor (aptasensor) based on HBPE-SO3 NPs modified electrode was developed for thrombin (TB) detection in whole blood. Meanwhile, the anti-biofouling properties of different modified electrodes were studied by whole blood and platelet adhesion test, hemolysis assay and morphological changes of red blood cells in vitro. Besides, the thrombin-binding aptamer was selected as receptor for the proposed aptasensor, which has excellent binding affinity and selectivity for TB. When binding to TB, the electron transfer taking place at the modified electrode interface was inhibited that can attribute to the stereo-hindrance effect, resulting in the decreased current response. This aptasensor showed excellent electrochemical properties with a wide detection range and a low detection limit of 0.031pM (S/N = 3), and provided high selectivity, long-term stability and good reproducibility. Finally, the sensitively detection of TB in whole blood samples directly was achieved by this aptasensor we proposed, which suggested its great potential for TB detection in the clinic.