Every biolab is a little different and so are the results. To monitor these differences, the InterLab study was created. Every participating iGEM team performs the same experiments, with all biases and random errors introduced by differences in working habits and lab equipment. In the end, all the results are compared. In the next year, adjustments are made to the protocols provided to participating teams, to consecutively eliminate differences. By measuring in absolute units with similar devices, InterLab tries to overcome the issues of data being processed in different ways by different work groups. To participate in the InterLab Study, all you need is a plate reader which can measure absorbance and fluorescence, and competent E.coli DH5α cells.


For calibration, we measured absorbance at 600 nm (OD600) of the LUDOX solution provided by iGEM and compared it to water, and computed an OD600 reference point. Silica beads, also provided by iGEM, were used to generate a particle standard curve. We set up a serial dilution of the silica beads solution as described in the protocol and measured the absorbance of these, as well as H2O at 600 nm. A fluorescence standard curve using fluorescein, also provided in the kit, was created. Fluorescence of the serial dilution of fluorescein and PBS was measured by extinction at 485 nm and emission at 520 nm as recommended in the protocol.

For the actual cell measurements, the following Parts were used:



Negative control


Positive control


Test Device 1


Test Device 2


Test Device 3


Test Device 4


Test Device 5


Test Device 6


Negative control



Transformation and measurement was carried out according to InterLab protocol. Molecules of Equivalent Fluorescein (MEFL) per particle was computed from plate reader measurements using InterLab result spreadsheet (Fig. 1).

Fig 1: Molecules of Equivalent Fluorescein (MEFL) per particle.