We present a novel electrochemical microfluidic device for the sensitive and selective detection of hydrogen peroxide (H2O2) through a VO2 nanostructure enzyme mimic. The low-cost ($0.50) microfluidic chip was fabricated using a simple and rapid prototyping technique via three syringe needles. Each needle played the role of an electrode (working, reference, and counter), and was connected by micro-hoses to a construction of the electrochemical microfluidic chip. The colloidal VO2 nanoflakes with peroxidase-like activity could be easily transferred on to the electrodes by a syringe, for development of a novel electrochemical platform to enable the detection of H2O2. The unique microfluidic electrochemical sensor delivered a wide linear dynamic range from 0.5 to 300 mM, with a limit of detection of 0.14 mM. The facile, rapid, sensitive, and selective as-fabricated H2O2 sensors were proven to be appropriate for the real-time monitoring of H2O2 released from PC12 cells. The integration of a microfluidic sensor with an enzyme mimic nanostructure is essentially a promising strategy for the low-cost and accurate monitoring of physiological processes.
