Electrochemical DNA aptamer platform based on CuAlO2/rGO-TEPA@AuPt nanocomposites for dopamine detection

Dopamine (DA) is a neurotransmitter that plays an important role in the central nervous system and has a significant impact on an individual's attention, mood, and cognition. Therefore, real-time monitoring of DA levels could play a key role in the management and treatment of many psychiatric diseases. Herein, we report the development of a sensitive and selective electrochemical aptamer immunosensor for detection of DA. DNA aptamers are used as model protein biomarkers to avoid the effects of interfering substances and to analyze the performance of immunosensors. Copper aluminate (CuAlO2)/reduced graphene oxide-tetraethy lenepentamine (rGO-TEPA) and gold-platinum bimetallic nanoparticles (AuPtNPs) were utilized as modifiers for the sensor fabrication. Notably, rGO-TEPA in the composite was able to induce excess oxygen to CuAlO2, resulting in a strong promotion between CuAlO2 and rGO-TEPA, significantly improving the electron transfer on the immunosensor surface. The bimetallic AuPtNPs would provid more attachment sites for the aptamers, and further improved the sensitivity of the biosensor. Under optimized experimental conditions, the constructed immunosensor was capable of real-time monitoring capabilities within a concentration range of 0.05 nM–10 μM, with a detection limit of 0.017 nM at S/N = 3, highlighting its potential for health management and clinical diagnosis applications.