Team:NTHU Taiwan/InterLab
Interlab
InterLab Study
In the InterLab study of this year, our team followed InterLab_2017_Plate_Reader_Protocol to conduct the experiment. The work can be separated into two parts:(1) Calibration (2) Cell Measurement.
(1) Calibration
a. OD 600 Reference point
Materials:
1ml LUDOX
dd water
96 well plates, clear with a flat bottom
Use LUDOX-S40 as a single point reference to obtain a ratiometric conversion factor to transform the absorbance data into a standard OD 600 measurement.
We will get the data for OD 600 of the H 2 O and LUDOX. The corrected Abs 600 is calculated by subtracting the H 2 O reading. To convert measured Abs 600 to OD 600 is to let Reference OD 600 divided by Abs 600.
b. Protocol fluorescein fluorescence standard curve
Materials:
Fluorescein
10ml 1xPBS
96 well plates, clear with a flat bottom
Prepare a dilution series of fluorescein in 4 replicates and measure the fluorescence in a 96 well plate in the plate reader. Generate a standard curve of fluorescence for fluorescein concentration and use this to correct the cell-based readings to an equivalent fluorescein concentration. We must (1) Prepare the fluorescein stock solution (2) Prepare the serial dilutions of fluorescein. [*See pdf. for detail]
Get “OD 600 reference point” & “Fluorescein standard curve” sheet. [*See the Excel Sheet in pdf. presented below]
(2) Cell Measurement
Materials:
Competent cells (Escherichia coli strain DH5α)
LB (Luria Bertani) media
Chloramphenicol (working stock 25 ug/mL)
50 ml Falcon tube
Incubator at 37°C
1.5 ml Eppendorf tubes
Ice bucket with ice
Pipettes
Devices (from InterLab Measurement Kit):
Positive control
Negative control
Test Device 1: J23101+I13504
Test Device 2: J23106+I13504
Test Device 3: J23117+I13504
Test Device 4: J23101.BCD2.E0040.B0015
Test Device 5: J23106.BCD2.E0040.B0015
Test Device 6: J23117.BCD2.E0040.B0015
Day 1: Transform Escherichia coli DH5α with the Devices
Day 2: Pick 2 colonies from each of plate and grow the cells overnight
Day 3: Cell growth, sampling, and assay [*See pdf. for detail]
Layout for Abs600 and Fluorescence measurement (one plate for each time point: 0, 2, 4, and 6 hours). Get “Raw Plate Reader Measurements” & “Fluorescence Measurement” sheet. [See the Excel Sheet in pdf. presented below]
The experiment went quite smoothly; however, some of the “Summary Statistics” in the Fluorescence Measurement sheet cannot be calculated due to the negative value we got from blanks in Fluorescence – Background. We think that it might be the mistake (ex. wrong concentration, mistakes in the volume or different gain number…) when we’re measuring the reference point, causing the background larger than the sample OD value.
