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I have been using the system you describe for a couple of years. One issue is the multichannel pipettes. Most often I have problem filling the the two tips in the middle when using the small-volume pipettor. When it comes to size I also use 100 microliters in the mother liquor-reservoir against 1.5 + 1.5 microliter in the drop-well. I haven't noticed great problems when scaling up conditions, but I have observed that even when I got well shaped crystals in screen conditions these grow worse in hanging drops. Eventually they use to grow well after some condition-refinement. I believe this also could be done to slight differences between the screen solutions and those I make myself . As other people I use 96-well plates only for screening and agree that fishing out crystals can become an arduous task sometimes. I also agree that crystals use to stick to surfaces in the drop-well, but this hasn't always to be an inconvenience, in some cases this might even be due to nucleation on the plate surface. Best regards. Carlos Cabrera > *** For details on how to be removed from this list visit the *** > *** CCP4 home page http://www.ccp4.ac.uk *** > > > This is a non-CCP4 related question, but one that perhaps other CCP4 > users might be concerned with as well. > > We've just switched to 96-well plates to set up our crystallization > screens, using 8-channel pipettes to array out the mother liquor and > set up the drops. We can go down to about 1.5 ul protein/1.5 ul mother > liquor drops with accuracy, and currently use 100 ul of mother > liquor/well. This gives only ~33 times the volume of mother liquor to > drop volume per well when initially set up. This ratio seems small > compared to 24-well plates where it's easy to ensure a much larger > excess of mother liquor. > > Although a 33 fold excess seems like it should be enough for sufficient > vapour diffusion to occur, does anyone who has experience with 96 well > plates say otherwise?? > > Thanks in advance, > > Brian > > ------------------------------------------------------- > Brian L. Mark, MSc, PhD > Department of Microbiology > Room 418, Buller Building > University of Manitoba > Winnipeg, Manitoba > CANADA R3T 2N2 > > Phone (204) 480-1430 > Fax (204) 474-7603 > >
