Having in mind the idea of creating a bio/nanosensor, we have pursued a MD research on gold functionalized surfaces with self-assembled monolayers (SAM’s) corresponding to neutral, anionic and cationic alkane thiols in contact with water. Our research has been focussed on the properties of the interfaces between water and appropriate model systems, such as monolayer of 1−hexanethiol 11−mercaptoundecanoic acid (HXT), (MUA) and monolayer monolayer of of 11−amino-1-undecanethiol (AUT). The structure of water in the interfaces and the orientation of monolayer molecules have been investigated in detail. In order to couple the biological system (e.g. a protein) with the electronic devices, one would typically use electrodes or wires to supply or measure the current. Many redox proteins can readily respond to the changes in electric current, but there is still a problem of biocompatibility, i.e. attachment and interaction of the biological system with the metal. This problem may be solved by using various passivating layers, like SAM’s of alkanethiolates.