Silicon Nanowire based field effect transistors (FETs) have shown to be capable of both label-free and receptor mediated detection of biochemical species. The attaching of molecules at the surface leads to a gating effect and therefore a change in source-drain current. The use of DNA or peptide aptamers as receptors against biological targets, i.e. viruses or pathogens allows for cheap and reproducible production of artificial antibodies that are more stable than natural ones.