Use of Recordable Compact Discs to Fabricate Electrodes for Microchip-based Analysis Systems

This work demonstrates that recordable compact discs (CDs) that contain gold as a reflective layer can be used as an electrode substrate for microchip-based analysis systems. A fabrication procedure that enables the reproducible patterning of multiple electrodes has been developed. It is shown that the microelectrodes can be integrated within a PDMS-based fluidic network and used for amperometric detection of electroactive analytes at both single and dual microelectrodes. A detailed comparison is made between the CD-based patterned electrodes and electrodes made by the traditional method of sputtering gold and titanium adhesion layers onto a glass substrate. It is also shown that mercury can be electrodeposited onto a CD-based microelectrode and the amalgam electrode used to selectively detect thiols. Finally, it is demonstrated that a decoupler for microchip-based electrophoresis can be made by electrodepositing palladium onto a gold electrode and a separate downstream gold working electrode can be used for amperometric detection. These CD-based patterned electrodes are attractive alternatives for situations where device cost is of a concern or sputtering facilities are unavailable.