This work describes a laser based technique to adjust curvatures of silicon microcantilevers used for chemical and biological detection. In batch fabricated silicon cantilever arrays used for parallel sensing, it is often desirable that all cantilevers have nearly identical curvatures or flatness. We demonstrate that using the laser technique, it is possible to adjust curvatures by an amount as...

We measure the mechanical thermal noise of soft silicon atomic force microscope cantilevers. Using an interferometric setup, we obtain a resolution down to 10(-14) m Hz(-1/2) on a wide spectral range (3-10(5) Hz). The low frequency behavior depends dramatically on the presence of a reflective coating: almost flat spectra for uncoated cantilevers versus a 1/f like trend for coated ones. The addi...

We have calculated the thermal noise of a v-shaped AFM cantilever (Microlever, Type E, Thermomicroscopes) by means of a finite element analysis. The modal shapes of the first 10 eigenmodes are displayed as well as the numerical constants, which are needed for the calibration using the thermal noise method. In the first eigenmode, values for the thermomechanical noise of the z-displacement at 22...

We report on mechanical dissipation measurements carried out on thin (∼100 nm), single-crystal silicon cantilevers with varying chemical surface termination. We find that the 1-2 nm-thick native oxide layer of silicon contributes about 85% to the friction of the mechanical resonance. We show that the mechanical friction is proportional to the thickness of the oxide layer and that it crucially d...

Here we demonstrate that an astigmatic detection system (ADS), constructed with a modified digital-versatile-disk (DVD) optical head, can achieve real-time measurement of a linear displacement and two-dimensional (2D) tilt angles with a high sensitivity. An atomic force microscope (AFM), using our detection system to sense the deflection of microfabricated cantilevers, can resolve single atomic...

Micro- and nanocantilevers are increasingly employed as mass sensors. Most studies consider the first flexural mode and adsorbed masses that are either discretely attached or homogeneously distributed along the entire length of the cantilever. We derive general expressions that allow for the determination of the total attached mass with any mass distribution along the cantilever length and all ...

Ferrule-top cantilevers are a new generation of all-optical miniaturized devices for utilization in liquids, harsh environments, and small volumes [G. Gruca et al., Meas. Sci. Technol. 21, 094033 (2010)]. They are obtained by carving the end of a ferruled fiber in the form of a mechanical beam. Light coupled from the opposite side of the fiber allows detection of cantilever deflections. In this...

A fast, label-free, and multiplexed method based on piezoresistive cantilevers is reported for the detection of specific protein conformations at the nanoscale level. The ligand-binding domain of the human oestrogen receptor (ERalpha-LBD) is used as the experimental model system, and ERalpha-LBD with or without oestradiol (E2) is detected using the conformation-specific peptides alpha/betaI (Se...

Adhesive cells including fibroblasts produce contractile forces to the underlying substrate for their locomotion. Such forces are not only high enough to deform compliant membranes such as silicone but also bend rigid micro-cantilevers. The cell-induced bending of silicon micro-cantilevers was determined using laser deflection during trypsin treatment. The observed cantilever relaxation corresp...

We present a technology for the fabrication of cantilever arrays aimed to develop an integrated biosensor microsystem. The fabrication process is based on spin coating of the photosensitive polymer and near-ultraviolet exposure. Arrays of up to 33 microcantilevers are fabricated in the novel polymer material SU-8. The low Young's modulus of the polymer, 40 times lower than that of silicon, enab...