An electrochemical aptasensor based on MOF-derived bimetallic carbon nanocomposites Au@Cu-C for ultrasensitive detection of Homocysteine on portable potentiostat

Homocysteine (Hcy), a metabolic intermediate of methionine, is a biomarker for neurological, cardiovascular and cerebrovascular diseases. Timely measurement of Hcy acts as a significant role in disease prevention and diagnosis. Given the fast response of the electrochemical sensing method, herein, a sensitive electrochemical aptasensor was proposed for the detection of Hcy. The aptasensor was constructed by utilizing the MOF-derived bimetallic carbon nanocomposites (Au@Cu-C) plus multi-walled carbon nanotubes (MWCNTs) as electrode modification materials and methylene blue (MB) as the signal marker. The Au@Cu-C was synthesized through hydrothermal methods, calcination and simple galvanic replacement reactions. The prepared Au@Cu-C enhance the electrical signal due to the synergistic effect of bimetallic alloy, while the specific morphology facilitated the immobilization of the aptamer. MB, served as the signal marker, can reflect the current changes of the aptasensor caused by the conformational change of aptamer before and after binding Hcy. As a result, the constructed electrochemical aptasensor exhibited a high sensitivity of 0.415 μA·μM−1, a low detection limit of 0.017 μM and an excellent recovery rate in the detection of human serum samples. Besides, the detection was performed on the portable potentiostat which demonstrated the potential application of the aptasensor in medical diagnosis and on-site analysis.