Imperial/Infector Detector/Specification

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    <li><a href="https://2007.igem.org/Imperial/Infector_Detector/Introduction" title=""><span>Introduction</span></a></li>
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    <li><a class="current" href="https://2007.igem.org/Imperial/Infector_Detector/Specification" title=""><span>Specifications</span></a></li>
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    <li><a href="https://2007.igem.org/Imperial/Infector_Detector/Design" title=""><span>Design</span></a></li>
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    <li><a href="https://2007.igem.org/Imperial/Infector_Detector/Modelling" title=""><span>Modelling</span></a></li>
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    <li><a href="https://2007.igem.org/Imperial/Infector_Detector/Implementation" title=""><span>Implementation</span></a></li>
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    <li><a href="https://2007.igem.org/Imperial/Infector_Detector/Testing" title=""><span>Testing</span></a></li>
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    <li><a href="https://2007.igem.org/Imperial/Infector_Detector/F2620 Comparison" title=""><span>F2620</span></a></li>
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    <li><a href="https://2007.igem.org/Imperial/Infector_Detector/Conclusion" title=""><span>Conclusion</span></a></li>
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= Infector Detector: Specifications =
= Infector Detector: Specifications =
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== Specifications Table ==
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The system must be able to detect the presence of biofilms on urinary catheters by detection of AHL, at a minimum concentration of 5nM, and report with a visual signal within 3 hours. It must work within a temperature range of 20&deg;-30&deg;C, be portable and easy to use, have a shelf life of at least seven days, and must not be harmful or infectious.
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|<center>System must give a visual signal if bacteria is present</center>
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|style="background:#ffffcc"|Response Time
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|<center>System needs to have a response time under 3 hour</center>
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|style="background:#ffffcc"|Operating Conditions
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|style="background:#ffffcc"|Health & Safety
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|<center>System Must not be living replicating bacteria, and in any way harmful or infectious.</center>
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|<center>System Must not be living replicating bacteria</center>
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== Project Plan ==
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== Specifications in detail ==
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The formation of biofilms in bacteria is a common phenomenon and is present in many opportunistic pathogens. The biofilm is composed of a series of polysaccharides and proteins, which binds together to form a large complex, adhering the bacteria together. The presence of biofilms act as a defensive barrier against the immune system, and also external anti-microbial agents. In order to coordinate the formation of a biofilm, the concentration of bacteria must be relatively large. To do this, many bacteria uses some form of quorum sensing to orchestrate the formation of a biofilm^1^.
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[[Image:IC07 spec sysresponse.png|thumb|400px|left|'''Desired response''' of Infector Detector. Note that the response is not necessarily linear.]]
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* '''<span style="color:#000077 ; font-size:120%;">Input:</span> AHL 5-50nM'''
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It is known that, in Pseudomonas ''aeruginosa'' biofilms, the concentration of AHL is at least 5nM. <sup>[[#References|1-2]]</sup> Therefore, if the system can successfully report the presence of this concentration, it should be able to detect such biofilms.
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* '''<span style="color:#000077 ; font-size:120%;">Output:</span> Visible fluorescent protein'''
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In order for the system to be used by a nurse, without needing any special equipment, the output signal must be visible.
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* '''<span style="color:#000077 ; font-size:120%;">Response Time:</span> < 3 hours'''
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Given that biofilms grow and spread in a period of hours and days, the response time of the system must be as short as possible. The threshold of three hours is achievable in the time constraints of protein expression systems, yet it is short enough in comparison to the growth properties of biofilms. <sup>[[#References|3-6]]</sup>
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* '''<span style="color:#000077 ; font-size:120%;">Operating conditions:</span> Temperatures from 20&deg; to 30&deg;C'''
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The system will be applied to urinary catheters ''in-situ'', and therefore should function at the ambient temperature of hospitals - 20&deg; to 30&deg;C.
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* '''<span style="color:#000077 ; font-size:120%;">Health & safety:</span> Non-living, non-infectious'''
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Because the system will be applied to urinary catheters ''in-situ'', it is likely that contact with the skin of the patient will occur. It is essential that it does not cause any harm or infection to the patient. Furthermore, any living organism is susceptible to mutations that may affect its intended function, or may proliferate in the environment of the catheter and urethra.
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* '''<span style="color:#000077 ; font-size:120%;">Packaging and shelf-life:</span> 7 days'''
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The system should be easily applied by a nurse caring for a patient with a urinary catheter. Hence, it should be packaged as a cream or a spray. In order to extend its usefulness and convenience, the system should also have a shelf-life of at least 7 days in a common hospital storage facility (shelves, cupboards, refrigerators, or freezers).
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Many forms of quorum sensing components are used be bacteria. Some systems including the Lux (Las) system, encoded by the ''lux'' operon used in ''Escherichia'' bacteria. The lux system produces acyl-homoserine lactones (AHL), which is freely diffusible. Also the ''fsr'' system found in ''Enteroccous'' encodes for a signaling peptide, which is detected by a two component signaling system. Both systems are found to be active during biofilm formation, suggesting that quorum sensing is essential in biofilm formation.
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<center>  [https://2007.igem.org/Imperial/Infector_Detector/Introduction << Introduction] | Specifications | [https://2007.igem.org/Imperial/Infector_Detector/Design Design >>]
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For our project, we have decided to target the Lux system, since it is a better understood. Our device will detect the specific signaling molecule 3-oxohexanoyl-homoserine lactone (3OC<sub>6</sub>HSL). This molecule can be detected by the counterpart LuxR.
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== References ==
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For future research, it is possible to attempt to use detectors in other quorum sensing systems, such as those found in ''Enteroccocus''. Alternatively, other pathogen-secreted materials can be used to detect biofilms. Examples will include &alpha;-toxins found in ''Staphylococcus''.
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# Charlton, TS, et al. A novel and sensitive method for the quantification of N-3-oxoacyl homoserine lactones using gas chromatography–mass spectrometry: application to a model bacterial biofilm. Environmental Microbiology 2 (5), 530–541. October 2000.
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# Stickler DJ, Morris NS, McLean RJ, and Fuqua C. Biofilms on indwelling urethral catheters produce quorum-sensing signal molecules in situ and in vitro. Appl Environ Microbiol 1998 Sep; 64(9) 3486-90.
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# Morris NS, Stickler DJ, and McLean RJ. The development of bacterial biofilms on indwelling urethral catheters. World J Urol 1999 Dec; 17(6) 345-50.
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# Drinka PJ. Complications of chronic indwelling urinary catheters. J Am Med Dir Assoc 2006 Jul; 7(6) 388-92. doi:10.1016/j.jamda.2006.01.020 pmid:16843240.
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# Stickler, DJ, et al. A Sensor To Detect the Early Stages in the Development of Crystalline Proteus mirabilis Biofilm on Indwelling Bladder Catheters. Journal of Clinical Microbiology, April 2006, p. 1540-1542, Vol. 44, No. 4.
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# [http://inls.ucsd.edu/~volfson/biofilm/ Growth and ordering of biofilms in controlled environments] available online on 22.10.2007

Latest revision as of 02:34, 27 October 2007



Infector Detector: Specifications

The system must be able to detect the presence of biofilms on urinary catheters by detection of AHL, at a minimum concentration of 5nM, and report with a visual signal within 3 hours. It must work within a temperature range of 20°-30°C, be portable and easy to use, have a shelf life of at least seven days, and must not be harmful or infectious.


Desired response of Infector Detector. Note that the response is not necessarily linear.
  • Input: AHL 5-50nM

It is known that, in Pseudomonas aeruginosa biofilms, the concentration of AHL is at least 5nM. 1-2 Therefore, if the system can successfully report the presence of this concentration, it should be able to detect such biofilms.

  • Output: Visible fluorescent protein

In order for the system to be used by a nurse, without needing any special equipment, the output signal must be visible.

  • Response Time: < 3 hours

Given that biofilms grow and spread in a period of hours and days, the response time of the system must be as short as possible. The threshold of three hours is achievable in the time constraints of protein expression systems, yet it is short enough in comparison to the growth properties of biofilms. 3-6

  • Operating conditions: Temperatures from 20° to 30°C

The system will be applied to urinary catheters in-situ, and therefore should function at the ambient temperature of hospitals - 20° to 30°C.

  • Health & safety: Non-living, non-infectious

Because the system will be applied to urinary catheters in-situ, it is likely that contact with the skin of the patient will occur. It is essential that it does not cause any harm or infection to the patient. Furthermore, any living organism is susceptible to mutations that may affect its intended function, or may proliferate in the environment of the catheter and urethra.

  • Packaging and shelf-life: 7 days

The system should be easily applied by a nurse caring for a patient with a urinary catheter. Hence, it should be packaged as a cream or a spray. In order to extend its usefulness and convenience, the system should also have a shelf-life of at least 7 days in a common hospital storage facility (shelves, cupboards, refrigerators, or freezers).


<< Introduction | Specifications | Design >>

References

  1. Charlton, TS, et al. A novel and sensitive method for the quantification of N-3-oxoacyl homoserine lactones using gas chromatography–mass spectrometry: application to a model bacterial biofilm. Environmental Microbiology 2 (5), 530–541. October 2000.
  2. Stickler DJ, Morris NS, McLean RJ, and Fuqua C. Biofilms on indwelling urethral catheters produce quorum-sensing signal molecules in situ and in vitro. Appl Environ Microbiol 1998 Sep; 64(9) 3486-90.
  3. Morris NS, Stickler DJ, and McLean RJ. The development of bacterial biofilms on indwelling urethral catheters. World J Urol 1999 Dec; 17(6) 345-50.
  4. Drinka PJ. Complications of chronic indwelling urinary catheters. J Am Med Dir Assoc 2006 Jul; 7(6) 388-92. doi:10.1016/j.jamda.2006.01.020 pmid:16843240.
  5. Stickler, DJ, et al. A Sensor To Detect the Early Stages in the Development of Crystalline Proteus mirabilis Biofilm on Indwelling Bladder Catheters. Journal of Clinical Microbiology, April 2006, p. 1540-1542, Vol. 44, No. 4.
  6. [http://inls.ucsd.edu/~volfson/biofilm/ Growth and ordering of biofilms in controlled environments] available online on 22.10.2007
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