Vapor-phase deposition-based self-assembled monolayer for an electrochemical sensing platform

Vapor-phase deposition was investigated to prepare electrochemically stable self-assembled monolayers (SAMs) since the promising coating technology can improve the surface functionality for electrochemical biosensors. In our experiments, mercaptopropionic acid (MPA)–Au SAMs in vapor-phase deposition were compared with those in the liquid-phase process, and their electrochemical properties were interrogated by measuring cyclic voltammetry and impedance spectroscopy. As a result, Au–MPA SAMs prepared in a vapor-phase process exhibited much higher electrochemical stability than those in a liquid-phase process. Furthermore, parameters in the vapor–phase deposition process were optimized for reproducible impedance signals, and the as-prepared Au–MPA SAMs under the conditions were adopted for detecting target IgE. It would pave the way for the development of a highly reproducible electrochemical bio-sensing platform.