Preparation of metal nanoband microelectrode on poly(dimethylsiloxane) for chip-based amperometric detection

We proposed herein a novel approach for fabricating nanoband microelectrodes for electrochemical detection on an electrophoresis microchip. The metal films were first obtained via region-selective electroless deposition of gold or copper films on PDMS substrates by selective region plasma oxidation through shadow masking. Both metal films show uniform surfaces with the thickness at the level of 100 nm. By casting another PDMS layer on the metal films, the cross section of the sandwich structures can be used as nanoband microelectrodes, which can be renewed just by cutting. These nanoband microelectrodes are successfully used as electrochemical detectors in microchip electrophoresis for the detection of amino acids, proteins and neurotransmitter molecules. Moreover, integrating an Au-Cu double-metal detector with a double-channel electrophoresis system, we can easily distinguish electroactive amino acids from that of non-electroactive amino acids.