Cadets2Vets had a Skype call with Dallas McDonald from the Lab Pats team.
The results obtained from the Lab Pats Interlab study were different from Cadets2Vets. At the 6 hour time point, the plasmids with highest to lowest GFP fluorescence were:
- LB + Chloramphenicol
- Negative Control
- Device 6
- Positive Control
- Device 1
- Device 4
- Device 5
- Device 3
- Device 2
After sharing these results, Cadets2Vets were curious why the results were so different. The Lab Pats team speculated that the difference may have been due to pipetting errors or differences in the instruments. Te Lab Pats used a SpectraMax M5, which uses monochromators to excite the GFP instead of filters, which is what Cadets2Vets had in their FilterMax F5 instrument. Cadets2Vets went back to their transformation plates and tried to assess whether the bacterial colonies sill expressed GFP and if the intensity was similar to the pattern gain from the plate reader.
Cadets2Vets’ one-month old transformation plates were still fluorescent, and we used a hand-held blacklight to qualitatively observe the colonies. The order of highest to lowest fluorescence using this method was:
- Positive Control
- Device 2
- Device 4 = Device 1
- Device 6 = Device 3
- Negative Control.
Device 5 was omitted due to the few colonies present were on the edge of the plate and difficult to see clearly.
The sensitivity of using a blacklight was much lower than using a plate reader, and so it was hard to see the differences between some of the plates. However, it appears that the pattern of fluorescence we observed in the plate reader is consistent with the bacteria in the plates. Washington also shared the results of their Interlab study. Summarizing their data in the same way we looked at ours and Lab Pats, the ranking of high to low GFP for Washington was:
- Device 2
- Positive control = Device 4
- Device 5 = Device 1
- Negative control = Device 3 = Device 6 = LB + Chloramphenicol