Pipette Puller

Our lab has an older (but still great!) Sutter pipette puller (P-87, I believe), which turns 1 glass capillary tube into two pipettes by pulling the capillary tube to each side while a filament heats the center. WARNING- Never ever touch the filament! They are extremely sensitive but can last yeas if they aren't touched. They aren't expensive or difficult to replace, though doing so will make everyone have to re-make their pipette pulling programs.

The thing we most often use the puller for is pulling injection pipettes, which are pretty easy to make. If you want to make glass electrodes for electrophysiology you are probably going to want to read the manual, and you'll end up making a multi-step program that will be sensitive to the whims of the weather. Instructions for injection pipettes are below:

To pull an injection pipette:

First, try putting a glass capillary tube in the machine, loading program 0 (or program 1, if 0 doesn't work), and pushing 'pull'. It will probably work just fine and you're done. Be careful putting the tube into the machine so that you don't hit the filament, ask someone if you've never done this before.

NOTE: After pulling an injection pipette the tip will either be entirely sealed, or too small to inject anything. Thus you must always cut the tip of an injection pipette with scissors or forceps before using it. If you are unsure how much to cut off, pull a bunch of pipettes and cut the tips and look at them under a microscope, ideally with a size reference slide so you can see how many microns your tip is. I believe you want about 30-100 microns for a typical injection pipette, but it's better to error on the side of being too big at first because small tips are much more likely to clog during surgery.

Troubleshooting:

If the 0 program (or 1) doesn't pull a decent pipette, you may need to remake the program. To do this you will do a ramp test and then change the heat setting accordingly (the basic starting point is the ramp # + 5). A ramp test indicates the heat value necessary to melt the glass. Read the manual and talk to people, it's not that hard. You can also play with the velocity and the pull and air puff but that's all a little too nuanced for just injection pipettes.

If the machine doesn't seem to be pulling right, for instance it's erratic, or just not working at all, you probably need to replace the filament. It's not hard, but a new filament will have a breaking-in period where you'll need to probably adjust the program somewhat regularly until it stabilizes.

The only other regular maintenance that these machines need is to replace the dessicant every couple years (or just bake it dry). And that's probably not at all necessary for just injection pipettes.