Recently we had the Attune NxT cytometer in the lab for a demo. The Attune can have up to 14 parameters (plus forward and side scatter) from up to four lasers. The demo model had blue, yellow, red and violet lasers. Optical filters can easily be swapped. You'd expect all that from any new flow cytometer but the Attune does have a unique feature - acoustic focusing.
As any Flow pros reading this will know, most other flow cytometers use hydrodynamic focusing to produce a very narrow core of sample, pushing the cells past the lasers in an orderly line. The problem with this is that if you have a large volume of sample to get through the cytometer it can take a very long time. Turning up the flow rate will speed things along but means that that narrow sample core gets a lot wider. This gives the cells a bit of room to move around so they won’t all pass through the laser interrogation points in a uniform way with the result that the data collected will have broader CVs.
The Attune’s acoustic focusing is designed to get around this problem. It uses sound waves which act like ripples in the stream, pushing all of the cells into the center, even when a large volume is being run. On it’s fastest setting the Attune can analyse 1000ul per minute, with a maximum event rate of 35,000 events per second.
Other benefits of the Attune are that it’s pretty small (just as well given how little bench space there is left in our LIF Lab at the moment), and all fluidics are on board. It’s a syringe driven system so it doesn’t get through huge volumes of sheath fluid and it should be possible to get absolute counts from it too, although this function wasn’t available with the version of the software we had.
The rest of the software seems quite user friendly especially if you’re used to recent versions of Mircrosoft Windows and Office, but with that in mind, it would have been really nice to have a touchscreen. The big buttons on the monitor look like you should be able to tap on them (something I did automatically several times).
The other issue was with carry over between samples. After running a particularly concentrated batch of beads it took a deep clean to get rid of them, the standard "rinse" function wasn't enough. So this could be an issue for those with sticky cells.
Overall the Attune NxT seems pretty good and would be especially suited to those who want to run large volume samples in order to find rare events or just to avoid the inevitable cell loss that comes with processing and spinning down a sample.
Time was limited for the demo and we didn't get to do as much as we would have liked on it. But we did have a bit of a play and the speed is certainly impressive with very dilute samples. A sample that ran at a rather tedious 24 evts/sec on the lowest flow rate zipped along at 800 evts/sec on the 1000ul/ml setting. As promised the CV remains pretty good even at the highest flow rate.
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| PI stained DNA samples run at the lowest and highest speeds. |
The automated compensation is also very easy and speedy, although I did have very good controls (of course). The software was a little buggy in places, on a few occasions nothing showed up on the Scatter plot although the evts/sec indicator showed the sample was running and it can be slow to clear/refresh the plots which is a nuisance when trying to set up the voltages. Hopefully these issues will be fixed in the newer version of the software.
The other issue was with carry over between samples. After running a particularly concentrated batch of beads it took a deep clean to get rid of them, the standard "rinse" function wasn't enough. So this could be an issue for those with sticky cells. Overall the Attune NxT seems pretty good and would be especially suited to those who want to run large volume samples in order to find rare events or just to avoid the inevitable cell loss that comes with processing and spinning down a sample.
Kirsty
