Notebook

The aim of the interlab this year is to assess the relationship between fluorescence and Abs600 when samples were measured all around the world.

Discussion

This year, we finished our interlab study in July. However, the first version of the protocol provided from iGEM HQ did not suggest a clear λex and λem then. We tracked back to the resource of the Fluorescein Sodium Salt in the Measurement Kit, and found that the λex is 460nm and the λem is 515nm in the Sigma-Aldrich’s website. Therefore, we adopted these values in our interlab study.
The value of Fluorescence deviated much from the standard curve in high Fluorescein Concentration. It is hypothesized that the Fluorescence will be distorted because of self-absorption effect.
It was found that the ratio decreased over time for all samples, except for Test Device 1. Taking the high Fluorescein/Abs600 radio of Test Device 1 into account, there was little variation in readings when using different settings on the plate reader. Given that iGEM HQ has kept the protocol consistent, it is hypothesized that the Fluorescence was high enough to ignore the self-absorption of Fluorescein.
As shown in the results, the growth of the E. coli in the six test devices and both controls were not consistent during the 6-hour period. It is implied that the variation of the Fluorescein could be interfered by the count of E. coli not by the ability to produce Fluorescein.

Team:Mingdao/Notebook