Alignment-less microchannel integration onto a stacked carbon electrode set for highly sensitive electrochemical sensor applications

Herein, we present simple integration of the microchannel and stacked carbon electrode set enabling high electrochemical current signal amplification due to redox cycling effect. The stacked electrode set consists of a substrate-bound carbon electrode and a suspended carbon nanomesh electrode (width = ~300 nm, thickness = ~600 nm) with a narrow electrode gap (~4 μm) achieved using a polymerization-stop layer. A planar PDMS plate ceiling and the side walls of the carbon posts that support the carbon nanomesh enclose the electrode set and thus the sensor-integrated microchannel is completed by simple PDMS bonding process without any complex alignment process. The stacked electrode set embedded in the microchannel showed ~1,300 times amplified current signal in chronoamperometry.