Bubble-based electrochemical chip integrated with cobalt-nickel bimetallic hybrid for enhanced detection of dopamine

Transition metal-based miniaturized electrochemical platforms for dopamine (DA) detection are highly desirable for screening neurological diseases due to their portability, fast response, and low cost. However, mass transfer in these miniaturized platforms remains a challenge for electrochemical sensing performance. Herein, we report a bubble-based chip integrated with a cobalt-nickel hybrid-modified screen-printed electrode for enhanced detection of DA. A simple piezoelectric transducer was employed to produce bulk acoustic waves (BAWs) to actuate the oscillation of air bubbles captured within the chip. The generated strong microstreaming facilitated the diffusion of the analyte to the electrode surface, enhancing the response signal. With the optimized actuating frequency and voltage, the bubble-based electrochemical platform exhibits two linear detection ranges for DA (1-10 μM, and 10-70 μM), with sensitivities approximately 2 times and 2.6 times larger than those without BAW in the lower and higher linear detection ranges, respectively. The detection limit is calculated to be 0.06 μM (S/N = 3) under BAW, which is significantly lower than that achieved without BAW assistance (0.16 μM, S/N = 3). The feasibility of using this chip for DA determination in real serum samples has also been validated. This miniaturized device shows great promise in point-of-care testing (POCT) fields.