Miniaturized Electroanalytical Sensor Systems in Micromachined Structures

Research into low volume electroanalytical sensors is becoming increasingly relevant, as scientists and engineers seek to explore the analytical benefits of miniaturization. This is particularly noticeable in the fields of biotechnology and drug discovery, where in the future, decrease in size holds a number of potential benefits, including for example, increased throughput. In this article, two methods for the fabrication of such microstructures are described, both involving the integration of metal microelectrodes on glass substrates, using different polymeric systems to fabricate (or "micromachine") the surrounding titre chamber. In this context, photopolymerizable polyimide and SU-8 were used to form chambers with volumes as small as 190 pL (with dimensions in the range 100–160 µm and depths between 20 and 25 µm). Such structures were characterized using model redox compounds including ferrocene monocarboxylic acid and hydrogen peroxide, and finally were applied to the quantitative detection of glucose, using glucose oxidase.