An enzyme-free signal amplified strategy based on hollow platinum nanochains catalyzed oxidation of uric acid for electrochemical aptasensor construction

Abstract This work designed an enzyme-free aptasensor for thrombin detection using hollow platinum nanochains (HPtNCs) to catalyze uric acid oxidation as signal amplification strategy and Au-Pt nanoflowers (Au-PtNFs) functionalized C 60 nanoparticles (nano-C 60 ) as interface. Firstly, the nano-C 60 was coated on the bare electrode and then the Au-Pt nanoflowers (Au-PtNFs) were decorated on the resultant electrode by electrodepositing method to obtain the Au-PtNFs/nano-C 60 interface. Subsequently, the thrombin primary aptamer (TBA I) was immobilized on the modified electrode through interaction between Au-PtNFs and -SH in TBA I. Next, the HPtNCs were prepared and acted not only as nano-carries for thrombin secondary aptamer (TBA II) loading but also as efficient catalyst towards uric acid (UA) for signal amplification. With target thrombin (TB) being present, the sandwiched structure can be formed between the TBA I and HPtNCs labeled TBA II to achieve the enhanced signal. Under optimized conditions, the proposed aptasensor showed a linear range of 0.5 pM to 10 nM with a correlation coefficient of R  = 0.998 and a detection limit of 0.16 pM, which exhibited a wide linear range and a low detection limit.