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Electrowetting on dielectric digital microfluidic platform with nanostructured biosensor interface for enhanced two-dimensional surface plasmon resonance imaging detection

Posted on:2010-10-15Degree:Ph.DType:Thesis
University:McGill University (Canada)Candidate:Malic, LidijaFull Text:PDF
GTID:2448390002986974Subject:Engineering
Abstract/Summary:
The sensitive and specific detection of biomolecular interactions is at the heart of many routine analyses in fundamental research, medical diagnosis and environmental monitoring. In contrast to laborious and costly multiwell plate assays, recent years have witnessed a significant progress in miniaturized and integrated biosensors, such as surface plasmon resonance (SPR), tailored to these applications. While the design of various SPR biosensors has been described in literature, a robust, multichannel, low-cost and highly sensitive solution has not yet been presented. Specifically, an integrated system that can allow surface functionalization in array format, low-volume multichannel fluidic interfacing, and increased sensitivity is sought.;EWOD device is employed for the dynamic immobilization of bioreceptors on SPRi biosensor surface in an array fashion from sub-muL volume solutions. Programmable EWOD electric interface allows the application of an electric field at the biosensor surface for active control of the immobilized probe density and orientation, enhancing SPRi detection. Two-dimensional SPRi detection is achieved by coupling the EWOD device to SPRi instrumentation. Parallel manipulation of individual droplets allows more efficient exploitation of the biosensor surface by separating different samples for simultaneous and selective SPRi detection. Periodic gold structures (nanoposts, nanogratings and nanogrooves) residing on a surface of glass and plastic substrates are investigated to improve the SPRi sensitivity. The corresponding electromagnetic field enhancements lead to up to a five-fold increase in SPRi response and provide an order of magnitude improvement in the limit of detection. This optimized nanostructure design is integrated with the EWOD platform to increase the capability and enhance SPRi detection. The integrated platform is successfully employed for parallel detection of ii multiple DNA hybridization reactions in 90 nL droplets. More than a two-fold SPRi signal amplification is achieved within 15 min, while the detection time could be further reduced to 2 min for a simple "yes" or "no" answers for the presence of the target DNA in a sample. The proposed system holds a great potential for ultra-low volume, sensitive and rapid detection of biomolecules, such as DNA and proteins, for clinical diagnosis and other bioanalysis applications.;This thesis describes a novel electro-wetting-on-dielectric (EWOD) digital microfluidic device with integrated nanostructured biosensor interface that addresses the aforementioned issues for enhanced surface plasmon resonance imaging (SPRi) detection. We have taken the opportunity of the most recent advances in microfabrication, nanotechnology and SPR technique to develop this integrated platform.
Keywords/Search Tags:Detection, Surface plasmon resonance, Platform, Biosensor, SPR, Integrated, EWOD, Spri
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