A DVD-ROM based high-throughput cantilever sensing platform

This thesis has been written as a partial fulfillment of the requirements for obtaining the PhD degree at DTU Nanotech. The project has been carried out at the Technical University of Denmark (DTU) at the department of Micro- and Nanotechnology, in the three-years period between November 2008 and October 2011.

The project was part of the Xsense research network, funded by the Strategic Danish Research Council, and supervised by Prof. Anja Boisen. The goal of the Xsense project is to design and fabricate a compact and cheap device for explosive sensing in air and liquid. Four different technologies (Cantilevers, Calorimetric, Colorimetric and Raman) were to be integrated into a single portable platform.

My PhD project has been focusing on the cantilever technology part. Furthermore, I have been addressing the issue of designing and fabricating the overall sensing platform, which is going to integrate the four different sensors. The platform was developed specifically for cantilever sensor applications Preliminary tests on Raman-based device integration has been carried out.

The inclusion of the other two sensing techniques is currently under development. This thesis reports on the demonstration of a high-throughput label-free sensor platform utilizing cantilever based sensors. These sensors have often been acclaimed to facilitate highly parallelized operation. Unfortunately, so far no concept has been presented which offers large data sets as well as easy liquid sample handling.

We use optics and mechanics from a DVD player to handle liquid samples and to read-out cantilever deflection and resonant frequency. In a few minutes, several liquid samples can be analyzed in parallel, measuring over several hundreds of individual cantilevers. Three generations of systems have been developed and tested during the three years.

These devices have been used for sensing of proteins, antibodies and explosives. Different rotating platforms, specifically designed for gas and liquid measurements, have also been designed, fabricated and tested. The resulting platform represents a completely novel and powerful tool for analyzing biochemical reactions through cantilever sensors, where the reliability of the measurements is ensured by statistical analysis and by parallel characterization of cantilevers.