Team:UCL London/Applications

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=== Applications ===
=== Applications ===
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There are many potential applications of biosensors of different types. The main specifications of a biosensor approach is to be valuable in terms of: research and commercial applications are the identification of a target molecule, availability of a suitable biological recognition element, and the potential for disposable portable detection systems to be preferred to sensitive laboratory-based techniques in some situations.
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The “Traffic-Light Stress Sensor” is intended to be used as biological, complementary tool to mechanical sensor during cell cultivation and bioprocessing. It is created to be sensitive to particular stresses within the ''E.coli'' cell such as misfolding of proteins and low Oxygen levels.
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Our Biosensor was created to be sensitive to particular stresses in the cell such as mis-folded protein and reduction in Oxygen levels. Biosensors such as “The Stress lighter” can be modified to detect various other parameters. Unlike other biosensors, when the cell/organism is stressed the biosensor detects this and switches on the genes for a florescent protein to be transcribed and seen visually. This enables the area in a bioreactor for example where the cells are stressed, to be visually seen as soon as the florescent protein is translated.
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The primary purpose for the application today is that it mainly should be used during process optimisation. The reason for this limitation is transcription and translation of fluorescent proteins is likely to have a negative metabolic impact on product titres during large scale commercial cell cultures.
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Many companies in industry have to spend enormous amount of money to detect and monitor parameters during downstream processing. Fermentation, Centrifugation, Homogenisation and other downstream processing stages increase the risk of the biological product becoming stressed. The usage of “The Stress Lighter”, will detect certain parameters which correlates to the stressed cells.
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There are also environmental applications of a biosensor; e.g. the detection of pesticides and river water contaminants. Eutrophication is a huge problem in our ecosystem. Eutrophication is defined as the increase in the concentration of chemical nutrients in the environment. Depending on the degree of eutrophication, subsequent negative environmental effects such as anoxia and severe reductions in water quality, fish, and other animal populations may occur. “The Traffic Lighter” can be used as a measuring device to monitor the amount of florescence generated by the presence of nutrients such as Nitrate in water bodies.
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Cell mediated detection of when pharmaceuticals proteins (produced in ‘’E.coli’’) are starting to fold improperly and aggregate could lead to much better understanding and design of bioprocesses and expression systems. Microorganisms like the enterobacterium Escherichia coli are great factories for recombinant expression of proteins. Another response encountered in recombinant systems is the accumulation of mis-folded protein in the cytoplasm. The aggregation of proteins in bacterial cells may have resulted from numerous factors such as:
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At UCL we are working on the advancement of “The Stress Lighter”. A Future application of the stress lighter is that it may be used for remote sensing of airborne bacteria e.g. in counter-bioterrorist activities. Furthermore, biosensors can effectively be used to monitor the glucose levels in diabetic patients. Currently researchers all over the world are working to modify the sensitivity of the in vivo glucose sensors to be more analogous to the in vitro sensors.
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Some examples of how “The Stress Lighter” can be applied are listed below:
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*accumulation of high concentrations of folding intermediates
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• Glucose monitoring in diabetic patients
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• Determining levels of toxic substances before and after bioremediation
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*inefficient processing by molecular chaperones
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• Detection and determining of organophosphate
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• Determination of drug residues in food, such as antibiotics and growth promoters, particularly meat and honey.
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• Drug discovery and evaluation of biological activity of new compounds.
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• Detection of toxic metabolites such as mycotoxins
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More information can be found at the following links.
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*changes in Temperature
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http://www.biosensor.se/applications
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http://www.springerlink.com/content/
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Sufficient amount of oxygen transfer is a key parameter for maintaining high growth rate of ‘’E.coli’’. Additionally, during lower oxygen concentrations the ‘’E.coli’’ bacterium is re-adapting its metabolism to a state where it produces an increasing amount of acetate. Higher concentrations of acetate then become inhibitory for the cells. In large fermenters the oxygen level is measured via a DOT-meter. The data measurement device is fed-back, via a computer, to the motor of the impeller to increase agitation. Hence, the concentration of dissolved oxygen can be kept constant in response to the bacteria growing and consuming more oxygen. The DOT range, within which the process is being maintained, is often based on empirical experiments and experiences of what has worked on in the past.
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A biosensor that could signal rapidly from within the cells and give information about how they are adapting their metabolism to the present oxygen level; could shed light over obscure parameters in process design.
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Moreover, within a larger fermenter are there also many so called “dead spots”. These spots are pockets where mixing is reduced. Usually, for the cells trapped in a dead spot, its effect will most rapidly be felt in the form of anoxia. Thus detecting low oxygen levels on an individual cellular level would enable determination of whether the dead spots are present in a reactor and this could possibly also facilitate the localization of dead spots.
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Latest revision as of 03:17, 22 October 2009

Applications

The “Traffic-Light Stress Sensor” is intended to be used as biological, complementary tool to mechanical sensor during cell cultivation and bioprocessing. It is created to be sensitive to particular stresses within the E.coli cell such as misfolding of proteins and low Oxygen levels. The primary purpose for the application today is that it mainly should be used during process optimisation. The reason for this limitation is transcription and translation of fluorescent proteins is likely to have a negative metabolic impact on product titres during large scale commercial cell cultures.

Cell mediated detection of when pharmaceuticals proteins (produced in ‘’E.coli’’) are starting to fold improperly and aggregate could lead to much better understanding and design of bioprocesses and expression systems. Microorganisms like the enterobacterium Escherichia coli are great factories for recombinant expression of proteins. Another response encountered in recombinant systems is the accumulation of mis-folded protein in the cytoplasm. The aggregation of proteins in bacterial cells may have resulted from numerous factors such as:

  • accumulation of high concentrations of folding intermediates
  • inefficient processing by molecular chaperones
  • changes in Temperature

Sufficient amount of oxygen transfer is a key parameter for maintaining high growth rate of ‘’E.coli’’. Additionally, during lower oxygen concentrations the ‘’E.coli’’ bacterium is re-adapting its metabolism to a state where it produces an increasing amount of acetate. Higher concentrations of acetate then become inhibitory for the cells. In large fermenters the oxygen level is measured via a DOT-meter. The data measurement device is fed-back, via a computer, to the motor of the impeller to increase agitation. Hence, the concentration of dissolved oxygen can be kept constant in response to the bacteria growing and consuming more oxygen. The DOT range, within which the process is being maintained, is often based on empirical experiments and experiences of what has worked on in the past. A biosensor that could signal rapidly from within the cells and give information about how they are adapting their metabolism to the present oxygen level; could shed light over obscure parameters in process design.

Moreover, within a larger fermenter are there also many so called “dead spots”. These spots are pockets where mixing is reduced. Usually, for the cells trapped in a dead spot, its effect will most rapidly be felt in the form of anoxia. Thus detecting low oxygen levels on an individual cellular level would enable determination of whether the dead spots are present in a reactor and this could possibly also facilitate the localization of dead spots.



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