An array of capacitive sensors based on a commercial fingerprint detectors

Capacitance transduction is one of the many possibilities to translate a chemical binding event into an electric signal. However, only few examples of capacitive sensors have been presented because of the complex measurement set-up. Microfabrication offered recently the possibility to develop capacitive sensors but the technology is not available to all the researchers that necessitate to quickly test the sensing materials. Recently, as witnessed with optical sensors, low-cost fingerprint detectors have been released on the market and are currently widely available. Such detectors offer a flat surface endowed with thousands of capacitors that can be functionalized with chemical sensing layers to become chemical sensors. In this paper a demonstration of the possibilities of this technology is shown considering as sensing layer a number of metalloporphyrins, a material yet studied for chemical sensors development. Results show that a good detection of carbon monoxide, ethanol and triethylamine is achieved. The large number of sensors allows also to exploite a number of paradigms learnt from the physiology of olfaction.