The InterLab Study requires a plate reader and a spectrophotometer, which is difficult for our team to perform in our lab, so we collaborate with the teams from Beijing National Day School and Peking University. Instructed and helped by the leader of Peking University’s team, our two teams perform the InterLab Study together and generate data for following experiments.


We use LUDOX-S40 as a reference point to convert Absorbance data (Abs600) into standard optical density (OD600).
Protocols we carried out to measure the absorbance 600 nm of all samples:

  1. Add 1000μl LUDOX into cuvettes.
  2. With a standard 1cm spectrophotometer, measure the Abs600 reading of LUDOX.
  3. Rinse the cuvettes and dry it naturally on a paper towel.
  4. Add 1000μl distilled water into the same cuvettes.
  5. With a standard 1cm spectrophotometer, measure the Abs600 reading of distilled water.
  6. Import the data into the Excel sheet.

These are the data we obtained from the protocols. Correction factor is obtained by the calculation.

Fluorescein fluorescence standard curve

We use a dilution series of fluorescein to generate the standard curve.

  1. Serial dilution is carried out: concentrations of fluorescein from 50μM to 0μM with 50% difference are obtained. (The last sample is left empty, therefore 0μM)
  2. Use a plate reader to obtain the fluorescence of the fluorescein.
  3. Import the data into Excel sheet and generate a standard curve.