IGEM:IMPERIAL/2009/M2/Assays/2.3

The encapsulation of colanic acid coated E.coli with sodium acetate has never been attempted. Theoretically, the highly negativly charged colanic acid coat should act as a nucleation site for Na+ ions in the sodium aceteate solution, but it would be wise to prove this in the lab as quickly as possible.

Since we can induce colanic acid production chemically, Assay 2.3 will provide a quick answer as to whether we need to investigate alternative secondary encapsulation technologies.

Remember in the design of the pill that the US sodium RDA is less than 2,400 mg. This means that only a small outer-layer should be added. Perhaps consider calcium acetate.

Wet Lab Protocol:

1) Dissolve Sodium Acetate Trihydrate in water (10g/ml) to produce a super saturated solution.

2) Pippete a supersaturated solution into a 96 well plate.

3) Spin colanic acid producing cells down and resuspend in a very small quantitiy of LB.

3) Pippette varying volumes of cell suspension into each of the 96 wells and look for crystalisaion.

4) Once the crystals have set (5 mins), turn the 96 well plate up side down and 'bang out' the pills.

5) Expose the pills to simulated gastric conditions for two hours and observe the rate at which it dissolves.