Ultramicroelectrode array interdigitated

J. Min and A.J. Baeumner, Characterization and optimization of interdigitated ultramicroelectrode arrays as electrochemical biosensor transducers. Electroanalysis 16, 724—729 (2004). 

As it was mentioned earlier, a much larger range of micro/nanofabrication tools are utilized in the design and fabrication of micro/nanotransducers than applied in the fabrication of microfluidic systems. Standard photolithography as described above is only one of the many techniques used. Three examples will be described here the fabrication of freestanding transducers, UV-photolithography with lift-off technique for preparation of interdigitated ultramicroelectrode arrays (IDUAs), and more traditional techniques for microtransducer preparations. 

Fig. 6.7. Photolithography and hft-off process used for the fabrication of gold interdigitated ultramicroelectrode arrays on silicon or glass substrates.

Zhu, M. Jiang, Z. Jing, W. Fabrication of polypyrrole-glucose oxidase biosensor based on multilayered interdigitated ultramicroelectrode array with containing trenches. Sens. Actuators B Chem. 2005, 2, 382-389. 

SECM involves the measurement of the current through an ultramicroelectrode (UME) (an electrode with a radius, a, of the order of a few nm to 25 (zm) when it is held or moved in a solution in the vicinity of a substrate. Substrates, which can be solid surfaces of different types (e.g., glass, metal, polymer, biological material) or liquids (e.g., mercury, immiscible oil), perturb the electrochemical response of the tip, and this perturbation provides information about the nature and properties of the substrate. The development of SECM depended on previous work on the use of ultramicroelectrodes in electrochemistry and the application of piezoelectric elements to position a tip, as in scanning tunneling microscopy (STM). Certain aspects of SECM behavior also have analogies in electrochemical thin-layer cells and arrays of interdigitated electrodes. 

Third Generation. The receptor is bound to an electronic device that transduces and amplifies the signal (e.g., the gate of a field-effect transistor, an array of amperometric ultramicroelectrodes, or interdigitated microelectrodes), utilizing the techniques of microelectronics and micromechanics. 

---