Surface area enhancement by mesoporous silica deposition on microcantilever sensors for small molecule detection

We demonstrate here an easy and controlled technique to enhance the surface active area via highly porous inorganic nanostructure growth on the surface of a microcantilever. A dip-coating approach was used to deposit a continuous mesoporous silica thin film with an accessible pore size of around 8 nm. Both dynamic and static characterizations were performed showing a sensitivity enhancement to relative humidity up to two orders of magnitude with respect to bare cantilevers. The combination of the two analyses gave the possibility to link the adsorption kinetics to the direct quantification of the adsorbed layer mass. These results obtained with water molecules as test analyte pave the way to the use of these composite systems as improved mass and chemical detectors of other small target molecules.