Hierarchical Porous Fluorinated Graphene Oxide@Metal-Organic Gel Composite: Label-Free Electrochemical Aptasensor for Selective Detection of Thrombin.

Current research effort aims at developing and designing new sensing platform architectures for effectively assaying biological targets that are significantly important for human healthcare and medical diagnosis. Here, we proposed a novel nanostructured sensor based on the combination of fluorinated graphene oxide and iron-based metal-organic gel (FGO@Fe-MOG). The unique properties including hierarchical porosity along with excellent electron transfer behavior make it an ideal candidate for electrochemical sensing of thrombin with superior detection limits compared to other (electrochemical, fluorescence, and colorimetric) strategies. Specifically, thrombin-binding aptamer was immobilized onto FGO@Fe-MOG through strong electrostatic interaction without any special modification or labeling, and the electrochemical impedance spectroscopy was used as the analyzing tool. The introduced aptasensor revealed high selectivity and reproducibility toward thrombin with the detection limit of 58 pM. The effectiveness, reliability, and real applicability of the proposed FGO@Fe-MOG nanohybrid were also confirmed by the determination of thrombin in a complex biological matrix represented by human serum. Taking into account the superior detection limit, high selectivity, reproducibility, and precision, the developed scalable and label-free aptasensor meets the essential requirements for clinical diagnosis of thrombin.