Has anyone had issues transferring plasmid DNA using an Echo 525?
We can confirm that there is no gDNA, or very little by fragment analysis and sequencing.
The DNA is eluted with DNAse/RNAse free water and prepped with a Qiagen turbo kit.
It appears that on day 1 the DNA transfers fine but after storing overnight at 4 C, there are issues transferring. (The plates are brought up to room temp before attempting transfers.)
We tried transferring gDNA with the 555 and 525 and never had any luck. There seems to be some chain entanglement that is a function of DNA concentration and strand length. The guidance we got was that the upper limit was 10ng/ul for 10kb DNA.
This was a few years back, and I know they’re continuing to work on it - so I don’t know the current status.
This has been a challenge for us too with our 555, we haven’t been able to definitively show that there isn’t some contaminating gDNA in our samples but there isn’t enough to be visible on a gel. The connection to storing overnight is interesting and not something we had noticed though
I previously had issues transferring ~3-5kb constructs with the 525, lots of back and forth with Beckman about how the plasmid DNA was too concentrated (~60ng/uL) and that the stringy nature of DNA was an issue and that it wouldn’t work with those concentrations. Eventually had the field service team come out and they diagnosed the anti-static bar was malfunctioning. After fixing, it worked just fine, they just gave us the run-around.
Bring it up to room temperature and make sure to not spin it too hard (otherwise the meniscus sits at an angle) is the best advice I can give. Quite strange to see different behaviour after storing it cold overnight - did you do a side by side comparison with the same samples stored at room temp?