[3dem] Questions on GP2 Filter Paper

[James Streetley]

Hi Jason,

I second Melissa’s suggestion of the SubAngstrom punch for filter paper. The trimmer from Leica themselves is a one-piece cutter that pushes into a cutting mat. In our hands the blade dulled quickly and it was hard to keep the filter paper centered. The SubAngstrom one is in two pieces – the cutter itself and a deep base that holds the filter paper and the cutter pushes through. I strongly prefer it to the Leica cutter. I should also mention that Moritz Wachsmuth-Melm posted up a 3d printable bed for the Leica cutter which might help: https://urldefense.com/v3/__https://www.printables.com/model/397550-bed-for-leica-filter-paper-puncher__;!!Mih3wA!ABxwYn1LDX51dVjPOhcJqawuWnnVteUpYU0OrWW7Wx7-gXET6EWxwwsXsZqCwlYjeGcCHRnWPIvQNzSyHFIfGatq7dfuky1HOss$ .

As Melissa says, in both cases you have to start with a 55mm circle of filter paper though – they only punch the inner hole.

Also, the Leica manual specifically cautions that only Whatman 1 filter paper should be used for the sensor based blotting. We keep both 597 and 1 filter papers for our Leica in manual mode and use just the 1 for sensor-based.

Hope that helps,
James

Dr James Streetley

SCMI Facility Manager
Scottish Centre for Macromolecular Imaging
Sir Michael Stoker Building
464 Bearsden Road
Glasgow
G61 1QH
United Kingdom

+44 141 330 2161 (office)
+44 141 330 7495 (microscope suite)
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From: 3dem <3dem-bounces at ncmir.ucsd.edu> on behalf of Chambers, Melissa G via 3dem <3dem at ncmir.ucsd.edu>
Date: Friday, 11 April 2025 at 15:42
To: Jason NG (CPOS) <jasonng.cpos at hku.hk>, 3dem at ncmir.ucsd.edu <3dem at ncmir.ucsd.edu>
Subject: Re: [3dem] Questions on GP2 Filter Paper
SubAngstrom sells a punch for the center hole but you still need to use 55mm filter paper.
https://urldefense.com/v3/__https://subangstrom.com/hole-punch-for-the-leica-em-gp/__;!!Mih3wA!ABxwYn1LDX51dVjPOhcJqawuWnnVteUpYU0OrWW7Wx7-gXET6EWxwwsXsZqCwlYjeGcCHRnWPIvQNzSyHFIfGatq7dfuWHldvHU$ <https://urldefense.com/v3/__https://subangstrom.com/hole-punch-for-the-leica-em-gp/__;!!Mih3wA!GVhwJtGV3xqiEQ29GyhXEvihxcHFTLYtDzf5-Tl6vMe-Gyz5jaxrvpIvpOnRvoRVn20W7y1MSXS6BgzmYu6rp-k83FMb2LyFy6_S$>

-----
Melissa G. Chambers

Director, CSB Cryo-EM Facility

Center for Structural Biology
Vanderbilt University
The Engineering & Science Building
Office: Rm 554
Facility: Rm 003A
2414 Highland Ave
Nashville TN 37212

https://urldefense.com/v3/__http://www.vanderbilt.edu/csb/facilities/cryo-electron-microscopy__;!!Mih3wA!ABxwYn1LDX51dVjPOhcJqawuWnnVteUpYU0OrWW7Wx7-gXET6EWxwwsXsZqCwlYjeGcCHRnWPIvQNzSyHFIfGatq7dfulq9L3Ng$ <https://urldefense.com/v3/__http://www.vanderbilt.edu/csb/facilities/cryo-electron-microscopy__;!!Mih3wA!GVhwJtGV3xqiEQ29GyhXEvihxcHFTLYtDzf5-Tl6vMe-Gyz5jaxrvpIvpOnRvoRVn20W7y1MSXS6BgzmYu6rp-k83FMb2Pyi2cAd$>


From: 3dem <3dem-bounces at ncmir.ucsd.edu> on behalf of Jason NG (CPOS) via 3dem <3dem at ncmir.ucsd.edu>
Date: Friday, April 11, 2025 at 4:27 AM
To: 3dem at ncmir.ucsd.edu <3dem at ncmir.ucsd.edu>
Subject: [3dem] Questions on GP2 Filter Paper
Dear CryoEM community,

I am writing to inquire about the choice of filter paper for GP2.

We previously used Leica’s filter paper (Whatman No.1) for GP2 and recently changed to Ted Pella’s GP2 filter paper (47000-200, Whatman No.595). It has been discovered that the additional move calibration is not functioning properly, and the cause could be the transparency difference between Whatman No.1 and No.595. The system shows "liquid contact" in green color even when the filter paper is at the home position during the setting of the additional move. It would be great if you could provide feedback on the following questions:
1.            What GP2 filter paper are you using?
2.            If you are using Ted Pella’s filter paper, have you experienced the same issue as us? Does this affect the quality of your sample freezing?
3.            Do you have any suggestions for a GP2 filter paper trimmer so that we can cut filter paper by ourselves?

Thank you.

Best Regards,
Jason NG
Senior Technical Assistant
LKS Cryo-EM Laboratory
Centre for PanorOmic Sciences
LLG03, Laboratory Block
21 Sassoon Road, Pokfulam, Hong Kong
P: +852 3910-3528
E: jasonng.cpos at hku.hk
W: https://urldefense.com/v3/__https://cpos.hku.hk__;!!Mih3wA!ABxwYn1LDX51dVjPOhcJqawuWnnVteUpYU0OrWW7Wx7-gXET6EWxwwsXsZqCwlYjeGcCHRnWPIvQNzSyHFIfGatq7dfu7b1hrdo$ <https://urldefense.com/v3/__https://cpos.hku.hk__;!!Mih3wA!H6Em6Op8kPHcHDRf21mTkF4NE8JGNjUaTV79NWCzihpbu4FXVenkOjRZ5zEVU9PuL8_GQ9Q3vz9IgXJNj-bXSv17jQ$>

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