<div dir="ltr"><div>Hi Jason,</div><div>In addition to using the SubAngstrom punch to make your own #1 (or #4, etc) blotting papers, I strongly recommend using a plastic disk behind the paper. This eliminates the reproducibility issues caused by paper wrinkling in the humid chamber. I use this <a href="https://urldefense.com/v3/__https://www.amazon.com/Nt-Cutter-Ic-1500P-Circular-1-8/dp/B001OYA8C6__;!!Mih3wA!ACuAvx0BJrIgt0VWSbaRC5YKvdSU63W5H_Jn1dd3MU_ALiitN2Og5Ou4HjadWYm6vUi11hU9cJ7Qb3H6G4Q$">circle cutter</a> to cut Aclar sheets and then punch them like filter papers, but you can also buy pre-cut <a href="https://urldefense.com/v3/__https://subangstrom.com/leica-anticontamination-membrane/__;!!Mih3wA!ACuAvx0BJrIgt0VWSbaRC5YKvdSU63W5H_Jn1dd3MU_ALiitN2Og5Ou4HjadWYm6vUi11hU9cJ7QVjPr9KU$">Aclar "anti-contamination" disks from SubAngstrom</a> (they are infinitely reusable with periodic cleaning). I have also tried Teflon but Aclar is stiffer and transparent. The blotting position will have to be adjusted slightly to account for the thickness of the plastic and alternate filter papers.</div><div><br></div><div>Best,</div><div>-da</div></div><br><br><div class="gmail_quote gmail_quote_container"><div dir="ltr" class="gmail_attr">On Fri, Apr 11, 2025 at 2:27 AM Jason NG (CPOS) via 3dem <<a href="mailto:3dem@ncmir.ucsd.edu">3dem@ncmir.ucsd.edu</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><div class="msg2494018512284057939">
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<p class="MsoNormal"><span style="font-size:11pt">Dear CryoEM community,<u></u><u></u></span></p>
<p class="MsoNormal"><span style="font-size:11pt"><u></u> <u></u></span></p>
<p class="MsoNormal"><span style="font-size:11pt">I am writing to inquire about the choice of filter paper for GP2.<u></u><u></u></span></p>
<p class="MsoNormal"><span style="font-size:11pt"><u></u> <u></u></span></p>
<p class="MsoNormal"><span style="font-size:11pt">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:<u></u><u></u></span></p>
<p class="MsoNormal"><span style="font-size:11pt">1. What GP2 filter paper are you using?<u></u><u></u></span></p>
<p class="MsoNormal"><span style="font-size:11pt">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?<u></u><u></u></span></p>
<p class="MsoNormal"><span style="font-size:11pt">3. Do you have any suggestions for a GP2 filter paper trimmer so that we can cut filter paper by ourselves?<u></u><u></u></span></p>
<p class="MsoNormal"><span style="font-size:11pt"><u></u> <u></u></span></p>
<p class="MsoNormal"><span style="font-size:11pt">Thank you.<u></u><u></u></span></p>
<p class="MsoNormal"><span style="font-size:11pt"><u></u> <u></u></span></p>
<p class="MsoNormal"><span style="font-size:11pt">Best Regards,<u></u><u></u></span></p>
<p class="MsoNormal"><span style="font-size:11pt">Jason NG<u></u><u></u></span></p>
<p class="MsoNormal"><span style="font-size:11pt">Senior Technical Assistant<u></u><u></u></span></p>
<p class="MsoNormal"><span style="font-size:11pt">LKS Cryo-EM Laboratory<u></u><u></u></span></p>
<p class="MsoNormal"><span style="font-size:11pt">Centre for PanorOmic Sciences<u></u><u></u></span></p>
<p class="MsoNormal"><span style="font-size:11pt">LLG03, Laboratory Block<u></u><u></u></span></p>
<p class="MsoNormal"><span style="font-size:11pt">21 Sassoon Road, Pokfulam, Hong Kong<u></u><u></u></span></p>
<p class="MsoNormal"><span style="font-size:11pt">P: +852 3910-3528<u></u><u></u></span></p>
<p class="MsoNormal"><span style="font-size:11pt">E: <a href="mailto:jasonng.cpos@hku.hk" target="_blank">jasonng.cpos@hku.hk</a><u></u><u></u></span></p>
<p class="MsoNormal"><span style="font-size:11pt">W: <a href="https://urldefense.com/v3/__https://cpos.hku.hk__;!!Mih3wA!H6Em6Op8kPHcHDRf21mTkF4NE8JGNjUaTV79NWCzihpbu4FXVenkOjRZ5zEVU9PuL8_GQ9Q3vz9IgXJNj-bXSv17jQ$" target="_blank">https://cpos.hku.hk</a><u></u><u></u></span></p>
<p class="MsoNormal"><u></u> <u></u></p>
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