Introduction

Reliable results are crucial in science in general, thus also in synthetic biology. As so, it is important to establish robust protocols which lead to similar outcomes independent from the lab they are generated in. Therefore, iGEM’s Measurement Committee has been developing a robust procedure for measuring green fluorescent protein (GFP), an intensively used marker in synthetic biology.
To make our contribution we decided to take part in this year’s 4^th International InterLab Measurement Study organized by iGEM. The aim of the study is to test whether it is possible to obtain reproducible results for fluorescence measurements carried out all around the world in different labs, with different instruments, by different people using the exact same afore mentioned protocol.
For this year’s study 6 different GFP-expression plasmids, containing divergently strong constitutive promoters, as well as a positive and a negative control were investigated. Therefore, an OD₆₀₀ reference point and a fluorescein fluorescence standard curve were generated, before the constructs were transformed into E. coli DH5α and expression levels were determined by OD₆₀₀ and fluorescence measurement in a plate reader in 2 hour intervals for a total of 6 hours.
For further information visit the Interlab website.

Results

OD₆₀₀ reference point

Figure 1: Measurements for the OD₆₀₀ reference point-a Conversion factor to transform absorbance data into a standard OD₆₀₀ measurement.

Fluorescein standard curve