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CPM Seminar
Marco Baller IBM Zurich Increasing efforts have been put into the development of cantilever-based sensors for the detection of physical phenomena and chemical and biological reaction. Biological and chemical processes are transduced into nanomechanical motion using a microfabricated silicon cantilever array, allowing quantitative and qualitative detection in gaseous and liquid environment. The motion is tracked by optical beam-deflection using a time multiplexed scheme. Analytes tested in gaseous environment comprise chemical solvents, a homologous series of primary alcohols, soft drinks, alcoholic beverages and natural flavors. Using pattern recognition and neural networks facilitates the application of the device as an artificial nose. The reversible chemical reaction of alkyl amines with self-assembled monolayers has been examined using cantilevers arrays and performing differential surface stress measurements. In liquid environment hybridization of short single-stranded thiol-functionalized DNA oligomers anchored to the gold surface of the cantilever array and the respective complementary strands from a buffer solution has been found to produce bending of the cantilever due to both electrostatic and steric effects. A second cantilever of the array functionalized with a sequence differing from the first by a single base was used as a reference. This enables the cantilever array as an differential instrument for molecular recognition of DNA oligomers with single base resolution. The general applicability of the method to biochemical processes was furthermore demonstrated by monitoring molecular recognition between proteins.
Thursday, November 2nd 2000, 15:30 |