Functionalization of Cantilever Array Sensors Using Ink Jet Deposition

Abstract

Micromechanical cantilever arrays can be used as versatile chemical sensors when coated with a layer that absorbs specific molecules leading to changes of surface stress, mass or temperature [1-4]. After their microfabrication processes, reproducible coating procedures are essential to functionalize the cantilevers individually. Here we introduce the use of ink jet to deposit analyte solutions onto cantilevers for functionalization (Figure 1). The method is fast, reliable and versatile. After evaporation of an Au layer, self-assembled mono-layers of alkanethiols or thiol-linked single-stranded DNA can be formed locally within fractions of a second by spotting droplets of solutions onto selected cantilevers. By selective etch diagnostics, we show down to a microscopic level that the quality of the monolayers is similar to those achieved by microcontact printing [5]. We also spotted thin polymer layers from dilute solutions onto cantilevers. The quality of the coatings and the performance were compared with cantilever sensors coated by previous methods.