Micro-fabricated silicon cantilevers arrays offer a novel label-free approach where ligand-receptor binding interactions occurring on the sensor generate nanomechanical signals like bending or a change in mass that is optically detected in-situ. We report the detection of multiple unlabelled biomolecules simultaneously down to picomolar concentrations within minutes. Differential measurements including reference cantilevers on an array of eight sensors enables sequence-specific detection of unlabelled DNA. It is suitable for meeting the ultimate challenge: label-free detection of specific RNA gene fragments within a complete genome will be shown (gene fishing).
Ligand-receptor binding interactions, such as antigen recognition will be presented. Antibody activated cantilevers with oriented scFv (single chain fragments) which bind to the indicator proteins show a significant improved sensitivity which is comparable with SPR (Surface Plasmon Resonance).
Patterning of micro- and nanoparticles onto microcantilevers will be demonstrated by means of acoustic streaming. Oscillation of the cantilever generates steady vortex flows, which drag nanobeads towards the nodes and microbeads to the antinodes. Applications range from patterning of bioactive particles on sensor surfaces to self-assembly of nanostructures.
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Purdue University, West Lafayette, IN