Interlab study: towards absolute units for GFP fluorescence measurements
Aims
One of the big challenges in synthetic biology community is the lack of standards for certain measurements. This year, the interlab study focuses on the challenge of not having a standard unit of measurement for fluorescence.
Measurements of fluorescence are usually not comparable between them because they are reported in different units depending on the way the data is analised.
Usually, the scientific community works around this problem by doing relative expression comparisons. Nonetheless, being unable to easily compare measurements makes it much harder to analyse results, difficult to share information and difficult to interpret data in general.
The objective of this year’s study is, therefore, to calibrate each of the team’s results, and use them to convert a relative unit of fluorescence into an absolute unit.
Methods
We performed the protocol for the 96-wells plate reader provided by iGEM.
First, we measured 4 replicates of the standard LUDOX at OD(600nm). These measurements are needed to be able to to obtain a conversion factor to convert our future data into standard measurements.+
Then, we performed serial dilutions of FITC on PBS, measured their fluorescence at 460nm excitation and 515nm emission, and repeated these measurements in order to create a series os standard curves.
After these initial measurements were performed, we transformed the provided test devices on E. coli DH5alfa. We grew the transformants on LB, at 37ºC and 222rpm, and took samples at 0, 1, 2, 3, 4, 5, and 6 hours. We measured both the OD and the FI of each sample and displayed all our data in the given xls file.