6/14/96

I have recently started working with "living" samples and need suggestions on what to use to seal my cover slips to the microscope slide. I have been using acrylic nail polish, but it has been suggested that the acetone might be getting into the samples and changing the biochemistry. I am trying to visualize enzyme action on strands of dna in a fluorescence microscope.

Any suggestions or references would be appreciated.

Neal Nicklaus
email nnicklaus@seq.sarnoff.com

Well, your physics background will smile but an old stand by for this sort of thing is "valap", which is a mixture of equal weights of vasoline, lanolin and paraffin. (I am *not* making this up). You put the ingredients together in a beaker and then heat gently. They melt and you mix well. The stuff will cool and solidify and be good for years. When you want to seal a slide, you heat it up again gently and apply a filet to the coverslip, just like nail polish. It won't make super permanent slides, but it will give you a day or two of life under the scope. Hope this helps,

Tobias Baskin
baskin@biosci.mbp.missouri.edu

To seal living samples, VALAP (equal mixture of vaseline, lanolin, and parafin works well. It melts at low temperature, so it will not heat the slide and sample when applied. It forms a watertight seal. You can make the slide permanent later by perfusing in glutaraldehyde by capillary action (poke small hole at either end of seal and use filter paper at one end to draw fluid through the sample) and then sealing coverglass with nail polish over the valap.

This has worked well for us in live cell experiments.

Jay Jerome
jjerome@bgsm.edu

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