Hello everyone! Here’s another common question we receive at Precisionary Instruments:
How do I hold down slices in my recording/imaging chamber?
Although we sell Compresstomes and other tissue slicer equipment, we have a whole team of scientists and engineers to help our customers with these types of issues. The vast majority of our customers are researchers.
Here is the quick answer:
Harp: Use a stainless steel “harp” to hold down acute spinal cord slices for electrophysiology and imaging experiments. We have had customers recommend the following place to order harps in all sorts of shapes and sizes:
Poly-lysine coverslips: Not many people know about this research “trick” for helping slices stay immobile during experiments. Take some miniature round coverslips, such as these:
Microscope Cover Glasses: Circles - Microscopes, Slides and…
Packed for easy dispensing; clean and ready-to-use.
…Soak the coverslips overnight in 10% ethanol (this helps clean the surfaces so that tissue will adhere better later on). Then spread out coverslips on a paper towel or large petri dish. Pipette poly-lysine solution onto each coverslip. Make sure that the surface tension holds on each coverslip, such that the solution doesn’t “break” and spill everywhere. The poly-lysine solution we use is:
…Incubate the coverslips for a few hours, until the poly-lysine solution has evaporated. There will be a thin layer of poly-lysine left on each coverslip surface. when you put a spinal cord tissue slice on it, use a kimwipe and soak up the extra solution so that the tissue touches the top surface of the coverslip.
You can now place your slice-on-coverslip into your recording chamber and do your experiments! The HUGE advantage of this poly-lysine coverslip method is that there is no damage to the surface of the tissue slice from a harp. The entire surface is smooth and free for patch-clamping. In addition, the coverslip will also hold the tissue and make it immobile for experiments like calcium imaging.
We hope that this helps! Please let us know if you have any questions!