Reconstitution of a protein monolayer on thiolates functionalized gaas surface

International audienceIn the aim to realize an efficient resonant biosensor, gallium arsenide (GaAs) presents many advantages. In addition to its properties of transduction, GaAs is a crystal for which microfabrication processes were developed, conferring the possibility to miniaturize the device and integrate electronic circuit. Moreover, the biofunctionalization could be realized on the crystalline surface without layer deposition, constituting a real advantage to perform reusable sensor. The functionalization of GaAs surface was engaged in order to immobilize a protein monolayer on this substrate. Functionalization was done using a mixed self assembled monolayer of thiolate molecules. Characterizations at micro and nanoscale were performed to control the surface state, the establishment of thiolates self-assembled monolayer, the surface atomic composition and the topography of the GaAs substrate at the different steps of the process. Protein immobilization on thiolates modified GaAs was revealed through a detailed AFM study and in situ MALDI-TOF MS and MS/MS modified surface interrogations