Arrays of nanoelectromechanical biosensors functionalized by microcontact printing.

The biofunctionalization of nanoelectromechanical systems (NEMS) is critical for the development of new classes of biosensors displaying improved performance and higher levels of integration. In this paper we propose a modified microcontact process (µCP) in order to biofunctionalize arrays of NEMS with a probe molecule on the active sensing areas together with an anti-fouling layer on the passive areas in a single, self-aligned step. We demonstrate the adequate functionalization/anti-fouling of arrays of freestanding nanocantilevers as dense as 10(5) nanostructures cm(-2) by using both fluorescence microscopy and dynamic measurements of the structures' resonant frequency. The proper bioactivity of an antibody deposited onto the cantilevers and the blocking property of a bovine serum albumin layer are both assessed by incubating specific and non-specific tagged secondary antibodies followed by fluorescence imaging. Furthermore, measurement of the resonant frequency of the nanocantilevers before and after functionalization and biological recognition demonstrate that using µCP for device functionalization does not damage the nanostructures and preserves the mechanical sensing capability of our NEMS.

Fabrication and characterization of microlens arrays using a cantilever-based spotter.

We present a quantitative study on the fabrication of microlenses using a low-cost polymer dispending technique. Our method is based on the use of a silicon micro-cantilever robotized spotter system. We first give a detailed description of the technique. In a second part, the fabricated microlenses are fully characterized by means of SEM (Scanning Electron Microscope), AFM (Atomic Force Microscopy) non contact optical profilometry and Mach-Zehnder interferometry. Diameters in the range [25-130mum] are obtained with an average surface roughness of 2.02nm. Curvature radii, focal lengths as well as aberrations are also measured for the first time: the fabricated microlenses present focal lengths in the range [55-181mum] and exhibit high optical quality only limited by diffraction behaviour with RMS aberration lower than lambda/14.