[3dem] CP3 versus EM-GP for SPA

Wim Hagen hagen at embl.de
Tue Sep 19 12:28:06 PDT 2017

Hi Laura,

We use Leica, Vitrobot Mark 2 and Mark 4. I can confirm Mike's experience:
Leica is flexible but not very reproducible from session to session, things need to be set and checked each time one uses it. We also have problems with the humidifier.

The Vitrobot Mark 2 humidifier died and unfortunately I can't find the original €25  terrarium humidifier model anymore on the Interwebs... (the official FEI quote was several hundreds €).

The Vitrobot Mark 4 behaves fine and people seem to like it for its reproducibility.

Other than the backside blotting I can't name one thing that makes the Leica favorite for certain things here, but I see people experiment on the Leica more, the we-used-to-be-crystallographers crew just want grids and mainly use the Vitrobot.

My personal views:

Very flexible to play with the simplest to the craziest ideas, not so good session-to-session reproducibility, warm-up takes too long for multi-user facilities, no gas hookup, cheap tweezers and a tweezer alignment tool so you can replace tweezers yourself.
I really like its design and features... if they would work well.

Vitrobot Mark 4:
Reproducible, only double side blotting, no gas hookups (they ditched that after the Mark 3), VERY expensive tweezers (for the reproducibility reason).
Once adjusted properly it does one job but it does it well.

One other thing:
Ethane volume on Leica is smaller and our German safety officer says it then does not have to be in a fume-hood, the Vitrobot however can't be outside the fume-hood, could be a German thing, and I could ask our workshop to make a Vitrobot ethane cup with smaller ethane volume.
Just saying this because I think freezing outside the fume-hood is much cleaner, but the true veterans here however also freeze very clean in the (da) hood.

No experience with Gatan but I would love to get my hands on one because I like its features. 
What's the main reason you debate/consider changing?


Wim Hagen
EMBL Heidelberg

> On Sep 19, 2017, at 20:07, Mike Strauss <mikestrauss13 at crystal.harvard.edu> wrote:
> Hi Laura,
> we have a Leica system for plunging. Most of our projects are SPA, and the results are fine.  It takes some getting used to, and the results seem to be considerably less consistent than the Vitrobot. Once you get to know your system, and learn to adjust the various positions and offsets, it behaves well enough.
> One thing I would warn you of is the long bake-out time on the Leica plunger.  The cryogen area is inside the system, and cannot be accessed by the user in any practical way, so if you want to have multiple users in the day, they need to be right after one another, or well-separated.  Our system has also had troubles with the humidifier unit, where the (distilled) water level has to be perfect, otherwise it will not work properly.  But this too is a matter of getting to know your system.
> I have very little practical experience with the CP3, so I can't comment.
> Regards,
> mike
>> On Mon, Sep 11, 2017 at 5:10 PM, Laura Kim <kimyaunhee at gmail.com> wrote:
>> Hi 3DEM,
>> We are replacing our Gatan CP3, which is quite old and on its way out. We are debating between the purchase of a replacement Gatan CP3 or a Leica EM-GP for our cryo-EM facility, where the majority of projects are single particle. We like that the EM-GP has temperature control and does not require gas hookups, but have heard that most labs using the EM-GP are doing filament-type projects and not SPA. Can any labs using the EM-GP for SPA comment on this? Do people have a preference for one over the other for SPA? Please let me know, thanks.
>> Laura
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