Design of microcantilever sensors using SLM based holographic lithography

Abstract

A holographic multiphoton fabrication technique is applied to the development of a microcantilever based analyte sensor. Holograms generated using a spatial light modulator (SLM) initiate the fabrication of sub-micron three-dimensional structures. Chemically functional microstructures are patterned onto the surface of commercially available piezoelectric microcantilevers using this holographic lithography technique. Controlling the form and location of the added structure enables the resonant frequency of the cantilever to be regulated with a higher accuracy than is currently available using bulk lithography techniques and without the inclusion of additional electronic feedback control components. A potential analyte sensor is then developed by patterning on an array of multiple piezoelectric microcantilevers, which are initially identical within manufacturing tolerances. The resonant frequency, was adjusted such that cantilevers, which were initially separated by 2.82 kHz, are tuned to be within 0.13 kHz of each other. Connecting the piezoelectric microcantilevers in series enables the response of each sensor element to be measured simultaneously using a single frequency based data acquisition system and allowing rapid data collection.