Syringes for Viral Injections?

Anyone have any preferences on injectors for viral injections into the spinal cord and brain? I used the popular WPI UMP4 micropump this summer. It worked, but it requires one to fill a Hamilton syringe and glass pipette with mineral oil all the way through in order to maintain pressure throughout the whole setup.

I’ve seen some papers using a pressure injection system, namely the Femtojet (Eppendorf). This looks attractive because it doesn’t require the filling of oil or other liquid. But I don’t see it used as much. Anyone have any experience?

A new minimally-invasive method for microinjection into the mouse spinal dorsal horn - PubMed (femtojet)

@cedric.peirs @RPSeal @SamineniV @liz

We use the WPI UMP3 in our lab, which I’m assuming is just an older version of the UMP4, with a Hamilton syringe. Instead of using the glass pipette + Hamilton syringe combo, we simply use a small-volume (2.5ul) Hamilton syringe with a removable 28 or 33 gauge needle (also from Hamilton). I’m not sure the removable needle would work in the spinal cord, since 33 ga might still be too large, and you may want the precise tip shape that you would be able to achieve by pulling your own glass pipettes. But for brain injections we routinely use the removable needle with injection volumes of 100-1000nl.

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Thanks @liz. Yes for the brain, I’d just use one of those removable needles that come with the Hamilton syringe. But I think they are too big for the cord. I see brain people use those all the time and they don’t mess with the glass pipettes.

I wanted to follow up on this. I did a demo of the Femtojet a while back. I thought it was going to work really nicely since you can control the pressure and you don’t need to put any oil or anything to backload. It was actually still very hard to control the flow rate and also to get consistently get the same needle size, which greatly affects the parameters. So my conclusion is, stick with the WPI or similar mechanical pump.

Sorry to resurrect such an old thread, but we recently started using the WPI Nanofil system in our lab with excellent results. To me it’s the best of both worlds because you can get a very fine needle (up to 36g although the maximum we tried was 35g) that is similar in size to the glass micropipette, but you don’t have to backfill with mineral oil. It’s also compatible with our existing UMP3 injector, which is convenient.
Members of our lab have used this setup to do intraspinal injections in ~P21 mice, for which our typical Hamilton needles are too large.

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That’s fantastic Liz! Wow. Thanks for sharing. I’m going to have to look into this. I hate backfilling those glass pipettes.

@SamineniV

Circling back on this. I found Hamilton has made some neuroscience-specific syringes for low volume, high precision injections. I’d really like to avoid ever having to use a glass pipet.

https://www.hamiltoncompany.com/laboratory-products/syringes/syringe-applications/life-science-syringes/neuros-syringes#why-neuros

I use them for years for CNS targeting and they are fantastic, never used for PNS purposes. When we did bladder injections we used nanofil syringes and they got the job done.

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Nice! Thanks @SamineniV . Glad to hear they work well for you. I’m going to try it out for small volume injects in the periphery.

Hi Liz,

I am just starting to use the WPI Nanofil - UMP3T system in the lab, and I wonder how do you fill up the Nanofil syringe (10uL). I always have an air bubble at the very top corresponding to the air in the empty needle during filling. Is it a problem for you?
Thanks!

@Chloe Did you ever figure this out? @liz any tips?

We would essentially take up the liquid then eject it back into the tube a couple times until there are no visible air bubbles left in the syringe. However, I should update that we eventually gave up on the Hamilton/Nanofil approach and now use a glass pipette for intraspinal injections. The person who does these injections say that it’s much better this way. You do have to backfill with mineral oil, though.

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