Stable hemoglobin-based biosensor based on coordination-assisted microfluidic technology for hydrogen peroxide determination

Enhancing the stability and sensitivity of electrochemical biosensors is highly significant for their practical application. Herein, inspired by the formation of mussel foot protein, we proposed a strategy to construct a hemoglobin-based biosensor for hydrogen peroxide detection using a hydrophobic ionic liquid (HIL) coordination assisted microfluidic technology. The active layer HIL@Hb was achieved by mixing BBimPF₆ (HIL) and Hb via a microfluidic channel, in which HIL helps to maintain the conformational dynamic mobility of hemoglobin (Hb), while the coordination process in a microfluidic reactor prevents aggregation of Hb. Further, the electrode surface was modified with ultra-thin MXene-Ti₃C₂ nanosheets to ensure the effective adhesion of active layer and collection of sensing signals, thus improving the sensitivity of the sensor by synergistic catalysis. Experimental results demonstrate that our designed sensor has good repeatability and stability, which can retain 93% of the initial current response after 30 uses and about 90.11% of its primary current response to H₂O₂ after 30 days. And it has a good linear response range of 1.996–27.232 μM, detection limit reaching 1.996 nM (signal-to-noise ratio, S/N = 3), sensitivity of 52.08 μA·μM⁻¹·cm⁻². Overall, this research offers a facile and effective strategy for constructing a stable biosensor to effectively detect hydrogen peroxide.