Team:TU-Delft/BandAid
From 2013.igem.org
![](https://static.igem.org/mediawiki/2013/e/e4/Frog_transparent.png)
Band Aid
The Band Aid Modeling is related to the final application of our project. Specifically, we are going to use a band aid in which E.coli will be added. By locating the band aid on the wound, the S.aureus should be detected and killed(Figure 1).
![](https://static.igem.org/mediawiki/2013/8/85/Band-aid-schematic.jpg)
As, it is already known, S.aureus is a pathogenic bacterium that utilises quorum sensing (QS), a cell-to-cell signalling mechanism, to enhance its ability to cause disease[1]. The communication is succeeded through small peptides known as AIPs. We engineered the receiver part of S.aureus to E.coli in order to be able for the last to detect AIPs produced by S.aureus.
The main purpose in the band aid modeling is to answer questions like these mentioned underneath:
- Is it possible the AIPs to pass through the membrane in order to be feasible for the E.coli to detect MRSA?
- If the MRSA is detected, is the amount of the produced peptide enough to kill it ?
- What is the maximum diameter of the pores in the membrane so as only the AIPs and the peptides to pass through?
- How many pores are necessary in order to be possible for the peptide to be released?
Differential Equations
Our model consists of two Populations:- Sender: The S.aureus Population
- Receiver: The E.coli Population
For our model we made the aforementioned assumptions:
- The S.aureus population grows exponentially according to the equation:
- The E.coli population is constant.
- Membrane assumed in 47mm diameter and 0.1μm pore size.
- Flux equals to pore size * number of holes * Diffusion.
- No hydrophobic/hydrophilic interactions of the membrane are taken into account.
The differential equations related to each population are represented below.
Sender: S.aureus Population
![](https://static.igem.org/mediawiki/2013/7/7a/Sender.png)
Figure 2:Sender
![](https://static.igem.org/mediawiki/2013/4/4c/SenderEquations.png)
Receiver: E.coli Population
![](https://static.igem.org/mediawiki/2013/b/bc/Receiver.png)
![](https://static.igem.org/mediawiki/2013/7/70/ReceiverEquations.png)
Parameters
Parameter | Description | Reference |
Mi | mRna concentration in Population i | [1][2] |
Ai | agrA concentration in Population i | [1][2] |
Si | agrD concentration in Population i | [1][2] |
ai | AIP concentration in Population i | [1][2] |
Ri | agrC concentration in Population i | [1][2] |
Pi | Proportion of cells that are upregulated in S.aureus population | [1][2] |
s | Ratio of basal to QS transcription | [1][2] |
u | mRNA transcription rate | [1][2] |
l | protein degradation | [1][2] |
l | f | [1][2] |
g1 | unbinding AIP from AgrC | [1][2] |
ks | AgrD loss through AIP production | [1][2] |
ka | AIP production | [1][2] |
la | AIP degradation | [1][2] |
h | receptor loss through AIP binding | [1][2] |
gij | AIP from Population i unbinding from Population j | [1][2] |
bij | AIP binding from Population i to Population j | [1][2] |
ba | Ratio of cognate AIP binding in Population 2 to Population 1 | [1][2] |
r | growth rate | [1][2] |
K | capacity | [1][2] |
D | diffusion coefficient of the membrane | [1][2] |
A | Area of the membrane | [1][2] |
pore size | membrane pore size | [1][2] |