Preparation of self-supporting mesostructured silica thin film membranes as gateable interconnects for microfluidics

A methodology for the preparation of self-standing 100–200 nm thick mesoporous silica membrane interconnects is reported. Interconnects may become an important component in future microfluidic device technology since it allows extension of microfluidic architectures into the third dimension. The silica film was mechanically supported by a perforated silicon nitride microsieve and covered a hexagonal array of 500 nm-sized holes. The potential applicability of these films as gateable interconnects for controlled dosing of ions was demonstrated. The permeability of ionic species can be controlled by the ionic strength.