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Parallel Detection (parallel + detection)

Distribution by Scientific Domains
Life Sciences40%

Selected Abstracts

Fast immobilization of probe beads by dielectrophoresis-controlled adhesion in a versatile microfluidic platform for affinity assay

ELECTROPHORESIS, Issue 19 2005
Janko Auerswald Dr.
Abstract The use of probe beads for lab-on-chip affinity assays is very interesting from a practical point of view. It is easier to handle and trap beads than molecules in microfluidic systems. We present a method for the immobilization of probe beads at defined areas on a chip using dielectrophoresis (DEP)-controlled adhesion. The method is fast, i.e., it takes between 10 and 120,s , depending on the protocol , to functionalize a chip surface at defined areas. The method is versatile, i.e., it works for beads with different types of probe molecule coatings. The immobilization is irreversible, i.e., the retained beads are able to withstand high flow velocities in a flow-through device even after the DEP voltage is turned off, thus allowing the use of conventional high-conductivity analyte buffers in the following assay procedure. We demonstrate the on-chip immobilization of fluorescent beads coated with biotin, protein,A, and goat,antimouse immunoglobulin G (IgG). The number of immobilized beads at an electrode array can be determined from their fluorescence signal. Further, we use this method to demonstrate the detection of streptavidin and mouse IgG. Finally, we demonstrate the feasibility of the parallel detection of different analyte molecules on the same chip. [source]

Development and experimental validation of a nifH oligonucleotide microarray to study diazotrophic communities in a glacier forefield

ENVIRONMENTAL MICROBIOLOGY, Issue 8 2009
Laurence Duc
Summary Functional microarrays are powerful tools that allow the parallel detection of multiple strains at the species level and therefore to rapidly obtain information on microbial communities in the environment. However, the design of suitable probes is prone to uncertainties, as it is based so far on in silico predictions including weighted mismatch number and Gibbs free-energy values. This study describes the experimental selection of probes targeting subsequences of the nifH gene to study the community structure of diazotrophic populations present in Damma glacier (Swiss Central Alps) forefield soils. Using the Geniom® One in situ synthesis technology (Febit, Germany), 2727 in silico designed candidate probes were tested. A total of 946 specific probes were selected and validated. This probe set covered a large diversity of the NifH phylotypes (35 out of the 45) found in the forefield. Hybridization predictors were tested statistically. Gibbs free-energy value for probe-target binding gave the best prediction for hybridization efficiency, while the weighted mismatch number was not significantly associated to probe specificity. In this study, we demonstrate that extensive experimental tests of probe-hybridization behaviour against sequences present in the studied environment remain a prerequisite for meaningful probe selection. [source]

Concept of a spectrometer for resonant inelastic X-ray scattering with parallel detection in incoming and outgoing photon energies

JOURNAL OF SYNCHROTRON RADIATION, Issue 1 2010
V. N. Strocov
A spectrometer for resonant inelastic X-ray scattering (RIXS) is proposed where imaging and dispersion actions in two orthogonal planes are combined to deliver a full two-dimensional map of RIXS intensity in one shot with parallel detection at incoming hvin and outgoing hvout photon energies. Preliminary ray-tracing simulations with a typical undulator beamline demonstrate a resolving power well above 11000 with both hvin and hvout near 930,eV, with a vast potential for improvement. Combining this instrument , nicknamed hv2 spectrometer , with an X-ray free-electron laser source simplifies its technical implementation and enables efficient time-resolved RIXS experiments. [source]

Integrated fluorescence sensor based on ring-shaped organic photodiodes

PHYSICA STATUS SOLIDI - RAPID RESEARCH LETTERS, Issue 7 2010
Bernhard Lamprecht
Abstract We demonstrate a novel sensor type, which is based on the monolithic integration of luminescent optical sensor spots together with ring-shaped thin-film organic photodiodes on one substrate. The organic photodiodes serve as integrated fluorescence detectors, simplifying the detection system by minimizing the number of required optical components. The proposed concept enables filter-less discrimination between excitation light and generated fluorescence light. The functionality of the concept is demonstrated by an integrated oxygen sensor, exhibiting excellent performance. The sensor spots are excited by an assembled organic light emitting diode. The integrated optical sensor platform is suitable for the parallel detection of multiple parameters. Sensor schemes for the analytical parameters carbon dioxide, temperature and ammonia, are proposed. (© 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]