Tuesday, September 23, 2008
eBiosciences (www.ebioscience.com) launched a new set of fluorochrome options for their antibody line. They're calling these fluorochromes, eFluor(TM), and they'll be directly coupled to select antibodies immediately. If you're familiar with the Qdot technology currently offered by Invitrogen (www.invitrogen.com), then you're already familiar with eFluor; A nanocrystal core of Cadmium, Zinc, and Selenium with a biologically active coating to allow antibodies/proteins to stick to it. Even though this is simply a repackaging of an already established technology, it will be a great addition to flow cytometry and imaging cytometry. The ability to combine eBioscience's great line of antibodies with the Qdot technology will make using these things more of a reality. Invitrogen has had a pretty limited stock of directly conjugated antibodies, and hopefully eBioscience can expedite this process. The main advantage of these fluors is the ability to use multiple nanocrystals together using a single 405nm or 355nm laser without a ton of compensation. The emission spectra of these nanocrystals are so tight that it allows you to pack them close together without overlap. Also, by putting some of your antibodies in the UV or Violet channels, it frees up your visible laser channels for other, sometimes more important antibodies. To find out more about eFluor, as well as look at what's available so far, click on over to http://www.ebioscience.com/ebioscience/efluornanocrystals.asp for more information.
Thursday, September 11, 2008
FINALLY!!! This has been on my list of FlowJo improvements for a long time. One of the features I like best on the DiVa 6 software is the ability to bend quadrant lines to account for the spread that is revealed after you compensate. The positive fraction is always a bit higher than the negative fraction. Therefore, it only makes sense that the line you draw to differentiate between single positives and double positives should have a positive slope to it. The slope of the line will depend on the amount of spillover and the spread that ensues. It was nice being able to easily match that slope with a set of quadrants in DiVa, but that wouldn't translate into FlowJo, so you were forced to create individual polygons for each of the populations. And, when you attempted to do this, it was nearly impossible to get all the gates to line up without any whitespace inbetween (more about that in a minute). But now, FlowJo has introduced in the Mac version 8.8 (go figure, the Windows version falls behind again) 'Spider Gates'. Just option-click the center point of the quads and move to bend the quad lines. Wonderful! My only complaint in actually using this is that after you convert your standard quad gates into a spider gate, you can no longer simply grab the center point and move all 4 quads at the same time. You need to do a select all gates function (cmd+a) and then grab the center. A small price to pay, I think, but hey guys, if you're listening, that'd be nice. The second new gating function is what they call molded gates. This gets back to the point of not being able to get all my polygons to match up exactly with no whitespace and no overlap. Now, if you select a bunch of gates (shift-click them, or cmd+a to select all of them) you can hit cmd+opt+m to 'Mold' the gates together. The couple of tries I've made thus far have worked really well. The gates must be 'nearby' meaning that you'll have to spend some time (albeit, much less) to get the gates close, but then, voila! it just works. If you have any questions/problems, send me an email, or submit your bugs directly to folks at FlowJo.