On-chip electrochemical detection of bio/chemical molecule by nanostructures fabricated in a microfluidic channel

We developed the versatile microfluidic device for on-chip electrochemical analysis in a single integrated platform. Gold nanostructures were fabricated at defined positions within microchannels by electrochemical deposition, and used as electrocatalytic materials for glucose detection and suitable sensing surfaces for ultratrace arsenic(III) detection. The continuous streaming solution in microfluidic devices allowed for enhanced mass transport to the electrodes and elimination of fouling effects, resulting in increased currents and high sensitivities. As a result, the current response showed a strong linear dependence (R² = 0.995) in the glucose concentration range of 0.1-9 mM with an excellent sensitivity of 1.10 ± 0.07 mA cm^-2 mM^-1. Furthermore, in ultratrace arsenic(III) analysis, the calibration plot corresponding to peak current shows good linearity (R ² = 0.998) up to the concentration of 30 ppb and remarkable sensitivity of 4.49 ± 1.01 μA cm^-2 ppb^-1 in a short accumulation time of 60 s. We believe that the proposed device is a promising approach for various microfluidic applications with the extensibility of functional nanostructures and possibility of biomolecule self-assembly.