Integrated Glass Microfluidics with Electrochemical Nanogap Electrodes

We present a framework for the fabrication of chip-based electrochemical nanogap sensors integrated with microfluidics. Instead of polydimethylsiloxane (PDMS), SU-8 aided adhesive bonding of silicon and glass wafers is used to implement parallel flow control. The fabrication process permits wafer-scale production with high throughput and reproducibility. Additionally, the monolithic structures allow simple electrical and fluidic connections, alleviating the need for specialized equipment. We demonstrate the utility of these flow-incorporated nanogap sensors by performing redox cycling measurements under laminar flow conditions.</p

Electrochemical nanofluidic assays in the absence of reference electrode

Implementing a reliable reference electrode in miniaturized electrochemical sensors is challenging. Here, we present an alternative approach, based on redox cycling within a nanogap sensor consisting of two parallel electrodes, in which the reference electrode is omitted altogether. We show that on disconnection of the reference electrode, the solution potential floats to a certain value, which is explored theoretically and experimentally in order to quantitatively predict the potential. The obtained results are in good agreement with the theoretically reconstituted results

Redox cycling without reference electrodes

The reference electrode is a key component in electrochemical measurements, yet it remains a challenge to implement a reliable reference electrode in miniaturized electrochemical sensors. Here we explore experimentally and theoretically an alternative approach based on redox cycling which eliminates the reference electrode altogether. We show that shifts in the solution potential caused by the lack of reference can be understood quantitatively, and determine the requirements for accurate measurements in miniaturized systems in the absence of a reference electrode