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| 3. |
- Kroger, S, et al.
(författare)
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Imprinted polymer based sensor system for herbicides using differential-pulse voltammetry on screen printed electrodes
- 1999
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Ingår i: Analytical Chemistry. - : ACS American Chemical Society. - 0003-2700 .- 1520-6882. ; 71:17, s. 3698-3702
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Tidskriftsartikel (refereegranskat)abstract
- A sensor system for the herbicide 2,4-dichlorophenoxyacetic acid has been developed based on specific recognition of the analyte by a molecularly imprinted polymer and electrochemical detection using disposable screen-printed electrodes. The method involves a competitive binding step with a nonrelated electrochemically active probe. For batch binding assays, imprinted polymer particles are incubated in suspension with the analyte and the probe, followed by centrifugation and quantification of the unbound probe in die supernatant. Two different compounds, namely 2,4-dichlorophenol and homogentisic acid, were tested as potential electroactive probes. Both compounds could be conveniently detected by differential-pulse voltammetry on screen-printed, solvent-resistant three-electrode systems having carbon working electrodes. Whereas 2,4-dichlorophenol showed very high nonspecific binding to the polymer, homogentisic acid bound specifically to the imprinted sites and thus allowed calibration curves for the analyte in the micromolar range to be recorded. An integrated sensor was developed by coating the imprinted polymer particles directly onto the working electrode. Following incubation of the modified electrode in a solution containing the analyte and the probe, the bound fraction of the probe is quantified. This system provides a cheap, disposable sensor for rapid determination of environmentally relevant and other analytes.
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| 4. |
- Nilsson, K, et al.
(författare)
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A General Method for the Immobilization of Cells with Preserved Viability
- 1983
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Ingår i: Applied Microbiology and Biotechnology. ; 17, s. 319-326
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Tidskriftsartikel (refereegranskat)abstract
- Microbial, algal, plant and animal cells have been immobilized, with preserved viability, by entrapment in various matrices according to a new bead polymerization technique. The cell polymer/monomer mixture is kept suspended in a hydrophobic phase such as soy, paraffin, or silicon oil, tri-n-butylphosphate, or dibutyphtalate, which is compatible with the cells. The various monomers or polymers tested include agarose, agar, carrageenan, alginate, fibrin, and polyacrylamide. Furthermore, by adjustment of the stirring speed of the suspension, beads of desired diameter can easily be obtained. The entrapped cells are fully viable and biosynthetically active.
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| 5. |
- Nilsson, S, et al.
(författare)
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Real-time Fluorescence Imaging of Capillary Electrophoresis
- 1995
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Ingår i: Journal of Capillary Electrophoresis. - 1079-5383. ; 2:1, s. 46-52
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Tidskriftsartikel (refereegranskat)abstract
- An arrangement for real-time fluorescence imaging of capillary electrophoretic separations is described. A decoated capillary was excited along a substantial part of its length by a dye laser pumped with an XeCl excimer laser tuned to match the fluorophors in the sample. Light emitted from the migrating, fluorescent molecules was detected by an image-intensified, thermoelectrically cooled charge-coupled device camera. The camera signals were processed by a computer and displayed as moving peaks on a screen in real-time, thus allowing the progress of the separation to be monitored continuously. Basic characteristics of the imaging arrangement such as sensitivity (signal-to-noise ratio) and resolution were checked with fluorescein samples. The imaging principle was also illustrated with a separation of a mixture of DNA fragments on a commercially available capillary designated for DNA separations. The benefits of real-time imaging for separation processes, in particular for capillary electrophoresis, are discussed.
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| 6. |
- Sode, K, et al.
(författare)
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Continuous Production of Somatomedin C with Immobilized Transformed Yeast Cells
- 1988
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Ingår i: Applied Microbiology and Biotechnology. - 0175-7598 .- 1432-0614. ; 28:3, s. 215-221
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Tidskriftsartikel (refereegranskat)abstract
- Yeast cells producing the growth hormonesomatomedin C (SMC) were constructedand applied in the immobilized form continuouslyfor a period of over 10 days in a flowthroughbioreactor. The construction of theMF~I-SMC fusion vector p336/l is given as wellas the results of the influence of various nutrientseffecting hormone production. Immobilization ofthe transformed yeast cells is described and theirapplication in a continuous bioreactor system.This study demonstrates the feasibility of a longtermand high-level hormone production by immobilizedtransformed yeast. The SMC productivitiesof free cells in batch and immobilized cellsunder continuous conditions were 0.2--0.3 and0.5--0.6 mg per g wet cells and day, respectively.
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| 7. |
- Surugiu, Ioana, et al.
(författare)
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Chemiluminescence imaging ELISA using an imprinted polymer as the recognition element instead of an antibody
- 2001
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Ingår i: Analytical Chemistry. - : American Chemical Society (ACS). - 0003-2700 .- 1520-6882. ; 73:3, s. 487-491
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Tidskriftsartikel (refereegranskat)abstract
- An imaging assay analogous to competitive enzyme immunoassays has been developed using a molecularly imprinted polymer instead of an antibody. The antigen 2,4-dichlorophenoxyacetic acid (2,4-D) was labeled with tobacco peroxidase, and the chemiluminescence reaction of luminol was used for detection. Microtiter plates (96 or 384 wells) were coated with polymer microspheres imprinted with 2,4-D, which were fixed in place by using poly(vinyl alcohol) as glue. In a competitive mode, the analyte-peroxidase conjugate was incubated with the free analyte in the microtiter plate, after which the bound fraction of the conjugate was quantified. After addition of the chemiluminescent substrates, light emission was measured in a high-throughput imaging format with a CCD camera. Calibration curves corresponding to analyte concentrations ranging from 0.01 to 100 μg/mL were obtained.
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| 10. |
- Andersson, L I, et al.
(författare)
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Immunoassays using molecularly imprinted polymers
- 1995
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Ingår i: Immunoanalysis of agrochemicals. - : American Chemical Society (ACS). - 0841231494 ; , s. 89-97
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)
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