Rapid and fast screening of diseases in large communities have the purpose of improving the community health, but nowadays, they are generally limited by the slowness of the classical diagnosis machines. Traditional laboratory instrumentations, indeed, can be very accurate but they are usually characterized also by long time of processing. Therefore, health care and the control of the spreading out of epidemics could take advantage from the development of low cost systems that are easily transportable, easy to use and with fast response. Electrochemical biosensors are a good candidate to support the job of the classical diagnosis on large scale. In this paper, a silicon nanowires nanostructured electrode functionalized with Avidin is presented. The electrode has been tested by electrochemical impedance spectroscopy to reveal Biotin. The results show that the biosensor is able to detect the Biotin bonded on itself and that the electrode, in the future, can be integrated in a portable system for fast screening.