Suzanne, I think that Danny's sugestion of using an ultraviolet laser might be the way to go. It is not uncommon to have a probe station (for testing electronic devices) with an UV laser. You should contact your nearest microfabrication group to locate such an instrument. It might be possible to further enhance the selectivity of the laser cutting by introducing a flourescent tag on the zona pellucida which absorbs in the apropriate wavelength region. -Mike >>> danny@dbanks.demon.co.uk 3/14/2004 8:48:10 PM >>> Suzanne, David Beebe at UIUC (http://mrel.beckman.uiuc.edu/mems/people.html) is a good person to talk to. He has done a lot of collaborative work in thi sort of area, and is very innovative. Southampton University developed some micromachined blades back in the 1990's, for corneal surgery I believe. Graham Ensell (http://www-icprocessing.ee.surrey.ac.uk/3,6southampton.htm) was my contact there, who showed me the initial research. I have no idea what happened to it, but he should remember it. Alternatively, you may consider using a UV laser, which cuts without generating heat. Although I have no idea if this would be useful in your situation, and suspect it could damage the DNA/RNA unless used very carefully (UV lasers are commonly used in corrective eye surgery). I have found Exitech to be useful in the past (http://www.exitech.co.uk/). Sorry this short, but hope it helps. Danny. (PS/ suffering from a sticky 's' key; apologies if this has caused more than the uual number of typos). At 12:22 14/03/2004 +0100, you wrote: >------------------- > > Hello everyone: > > > > I am only vaguely familiar with MEMS technology, but I have a >question > > about a possible application. I am a veterinary embryologist and I >am > > trying to do "surgery" on embryos that are 100 to 150 microns in > > diameter (they are about 3 days post fertilization and have > > approximately 8 cells). These embryos consist of a clump of very > > fragile cells surrounded by a very small fluid-filled space > > approximately 1 to 5 microns wide, and then enclosed in a soft but >tough > > shell approximately 10 microns thick. I need to remove the clump of > > cells in the middle from their "shell" (the zona pellucida) without > > ripping them apart or bursting them. This can be accomplished using >an > > enzyme to dissolve the shell, but the enzyme does some damage to the > > inner cells. I have also tried using a laser fitted onto the >objective > > lens of a microscope to cut the shell, but the cells are so close to >the > > shell (touching in places) that I can't avoid overexposure to heat >from > > the laser. I can rip a hole in the shell by holding the embryo with > > suction on one side applied to a fine glass pipette, while piercing >the > > other side with a glass needle; however, when I try to remove the >embryo > > by suctioning it out with a glass pipette, the cells get pulled >apart or > > ruptured. I have come to the conclusion that I must cut the >embryo's > > shell with a blade (but can't find one small enough) or make a large > > hole, almost the diameter of the entire embryo, with a sharp >"biopsy" > > device while holding the embryo with my suction device (I have tried > > unsuccessfully to produce a biopsy tool using a glass pipette and a > > grinding wheel). I have a set of micromanipulators that allow me to > > move two tools visualized through an inverted microscope. The >problem > > is that I don't have the tools I need. I am limited to working with > > glass rods or tubing and can pull it, cut it, and do some fairly >crude > > filing with a grinding wheel. The embryo must remain in a liquid >medium > > during this procedure and is generally placed in a drop of this >medium > > in a dish filled with silicone oil. Is there any way that MEMS > > technology could be used to solve my problem? > > Thank you very much for your time. > > Suzanne Walmsley > > > > -- Danny Banks danny@dbanks.demon.co.uk http://www.dbanks.demon.co.uk/ _______________________________________________ MEMS-talk@memsnet.org mailing list: to unsubscribe or change your list options, visit http://mail.mems-exchange.org/mailman/listinfo/mems-talk Hosted by the MEMS Exchange, providers of MEMS processing services. Visit us at http://www.memsnet.org/