February 2009 Highlight: Electrokinetic Sample Focusing and Surface Plasmon Resonance Imaging System for Measuring Biomolecular Interactions

An integrated microfluidics and iSPR platform, where ligand immobilization and subsequent sample solutions are precisely positioned with an electrokinetic focusing technique was recently developed and demonstrated in our lab. This approach does not require complicated microfluidic channel arrangements or pressure driven transport, which requires external pumps and valves. Electrokinetic sample focusing is a valve-less electroosmotically driven technique used for controlling the sample stream in a microfluidic chip. The microfluidic chip arrangement (figure 1) uses the center inlet for sample introduction and upper and lower inlets for guiding. Electrical voltages V_u and V_l control the y-direction position of the sample. Voltage V_c is used to transport the sample in the x-direction. The electrokinetic focusing chip consists of two layers, a bottom glass layer with 24 gold islands, and a poly(dimethylsiloxane) (PDMS) top layer consisting of the microchannels, inlets, outlet and interaction chamber.

An important advantage of this new approach, compared to conventional systems, is the ability to direct a single analyte to a specific ligand location in the microarray, which can facilitate analysis parallelization. As a demonstration, kinetics and affinity have been extracted from measured binding responses of human IgG and goat antihuman IgG using a simple 1:1 model and compared to responses measured with conventional pressure driven analyte transport. The measured results indicate similar binding kinetics and affinity between the electrokinetic and pressure-driven sample manipulation methods and no cross contamination to adjacent measurement locations has been observed.

Figure1: (a) Microfabricated chip (b) iSPR gold imaging array with location (row, column) (c) iSPR chip interface module.

A detailed description can be found in the full paper published in Analytical Chemistry: http://dx.doi.org/10.1021/ac802668z

For more information please contact Ganeshram Krishnamoorthy: g.krishnamoorthy@tnw.utwente.nl

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Home News & Highlights People Vacancies Research Education & Assignments Publications Intranet Internal Links External links Movies Sitemap Search	weblink \| News archive \| Archive Highlights \| Promotie film Ana Valero February 2009 Highlight: Electrokinetic Sample Focusing and Surface Plasmon Resonance Imaging System for Measuring Biomolecular Interactions An integrated microfluidics and iSPR platform, where ligand immobilization and subsequent sample solutions are precisely positioned with an electrokinetic focusing technique was recently developed and demonstrated in our lab. This approach does not require complicated microfluidic channel arrangements or pressure driven transport, which requires external pumps and valves. Electrokinetic sample focusing is a valve-less electroosmotically driven technique used for controlling the sample stream in a microfluidic chip. The microfluidic chip arrangement (figure 1) uses the center inlet for sample introduction and upper and lower inlets for guiding. Electrical voltages V_u and V_l control the y-direction position of the sample. Voltage V_c is used to transport the sample in the x-direction. The electrokinetic focusing chip consists of two layers, a bottom glass layer with 24 gold islands, and a poly(dimethylsiloxane) (PDMS) top layer consisting of the microchannels, inlets, outlet and interaction chamber. An important advantage of this new approach, compared to conventional systems, is the ability to direct a single analyte to a specific ligand location in the microarray, which can facilitate analysis parallelization. As a demonstration, kinetics and affinity have been extracted from measured binding responses of human IgG and goat antihuman IgG using a simple 1:1 model and compared to responses measured with conventional pressure driven analyte transport. The measured results indicate similar binding kinetics and affinity between the electrokinetic and pressure-driven sample manipulation methods and no cross contamination to adjacent measurement locations has been observed. Figure1: (a) Microfabricated chip (b) iSPR gold imaging array with location (row, column) (c) iSPR chip interface module. A detailed description can be found in the full paper published in Analytical Chemistry: http://dx.doi.org/10.1021/ac802668z For more information please contact Ganeshram Krishnamoorthy: g.krishnamoorthy@tnw.utwente.nl