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Dear Matthijn and Kim,</div>
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Thank you both for your thoughtful responses and for sharing your valuable experiences.</div>
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Matthijn, I appreciate your clarification on the physics of cryo-TEM conditions. I apologize for not doing enough research before raising my initial question. As I understand now, under standard cryo-EM doses (such as 20–60 e⁻/Ų for single particle analysis
or 100–120 e⁻/Ų for tomography), the risk is extremely low. However, I am curious about what might happen at much higher doses—on the order of thousands of e⁻/Ų. Would such extreme irradiation potentially change the situation? From my current understanding,
cryo-TEM operates far below both the triple point pressure and temperature of water, placing the sample firmly in the solid or vapor region of the phase diagram, where aerosol formation is not possible. Thus, the question is whether there might be any potential
risks associated with the vapor that is formed under these conditions.</div>
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Additionally, I am interested in situations where the sample might inadvertently warm up in the TEM, for example, due to insufficient liquid nitrogen or a vacuum pump failure. Would there be any recommended follow-up procedures in such scenarios?</div>
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Kim, thank you for sharing your insights on the practical aspects of equipment disposal. It is certainly an important concern, and we will communicate with our local TFS engineer regarding this. Fortunately, our vacuum pumps have been quite stable over the
past half year, and no replacement has been required so far.</div>
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Thank you both again for your guidance and support.</div>
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Best regards,<br>
Jason</div>
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<div id="divRplyFwdMsg" dir="ltr"><font face="Calibri, sans-serif" style="font-size:11pt" color="#000000"><b>From:</b> Gibson, Kimberley <kimberley.gibson@yale.edu><br>
<b>Sent:</b> Thursday, June 12, 2025 21:04<br>
<b>To:</b> Jason NG (CPOS) <jasonng.cpos@hku.hk>; Matthijn VOS <matthijn.vos@pasteur.fr><br>
<b>Cc:</b> 3dem@ncmir.ucsd.edu <3dem@ncmir.ucsd.edu><br>
<b>Subject:</b> Re: [3dem] Seeking Advice on BSL-2 CryoEM Laboratory Setup and Safety Protocols</font>
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Hi Jason, </div>
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Typically, at BSL-2, all equipment can be operated under normal conditions - i.e. in the open on a lab bench (Vitrobot or Leica GPS) with special considerations for the evacuation of N2 gas or Ethane and Ethane/Propane mixtures. </div>
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Issues regarding BSL-2 have only arisen during disposal of equipment. TFS was not allowed to ship an old Ion Getter Pump overseas (from the US back to Eindhoven, NL) if the microscope operated in a BLS-2 lab. The IGP had to be disposed of locally and typically
sprayed down with Ethanol prior to disposal. I have also sprayed an old Peltier device removed from a Vitrobot and sent it for electronic waste disposal. </div>
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Best, </div>
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Kim</div>
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<div id="x_divRplyFwdMsg" dir="ltr"><font face="Calibri, sans-serif" color="#000000" style="font-size:11pt"><b>From:</b> 3dem <3dem-bounces@ncmir.ucsd.edu> on behalf of Matthijn VOS via 3dem <3dem@ncmir.ucsd.edu><br>
<b>Sent:</b> Thursday, June 12, 2025 06:32<br>
<b>To:</b> Jason NG <jasonng.cpos@hku.hk><br>
<b>Cc:</b> 3dem@ncmir.ucsd.edu <3dem@ncmir.ucsd.edu><br>
<b>Subject:</b> Re: [3dem] Seeking Advice on BSL-2 CryoEM Laboratory Setup and Safety Protocols</font>
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<div dir="ltr">Dear Jason,</div>
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<div dir="ltr">could you explain the physics hiw sn electron beam can create aerosols on a solid sample ar -196 degrees in ultra high vacuum (orders of magnitude under the tripple point of water)</div>
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<div dir="ltr">I don’t see how this is possible.</div>
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<div dir="ltr">cheers</div>
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<div dir="ltr">Matthijn </div>
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<blockquote type="cite">On Jun 12, 2025, at 11:01, Jason NG (CPOS) via 3dem <3dem@ncmir.ucsd.edu> wrote:<br>
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<p class="x_x_MsoNormal"><span style="font-size:11.0pt">Dear CryoEM Community,</span></p>
<p class="x_x_MsoNormal"><span style="font-size:11.0pt"> </span></p>
<p class="x_x_MsoNormal"><span style="font-size:11.0pt">We are currently evaluating the risks of becoming BSL-2 CryoEM laboratory and would greatly appreciate your guidance on several safety and setup considerations.</span></p>
<p class="x_x_MsoNormal"><span style="font-size:11.0pt"> </span></p>
<p class="x_x_MsoNormal"><span style="font-size:11.0pt">Specifically, we are interested in understanding:</span></p>
<ul type="disc" style="margin-top:0cm">
<li class="x_x_MsoNormal" style=""><span style="font-size:11.0pt">Given that the electron beam can potentially generate aerosols or cause warming within TEMs, what disinfection protocols or measures have you found effective for maintaining biosafety?</span></li><li class="x_x_MsoNormal" style=""><span style="font-size:11.0pt">Is implementing negative room pressure necessary in a CryoEM lab at BSL-2?</span></li><li class="x_x_MsoNormal" style=""><span style="font-size:11.0pt">For sample preparation instruments such as the TFS Vitrobot and Leica GP2, is it recommended to place them inside a biosafety cabinet? How about large instruments like the Leica ICE—are there
specific safety measures we should consider?</span></li></ul>
<p class="x_x_MsoNormal"><span style="font-size:11.0pt"> </span></p>
<p class="x_x_MsoNormal"><span style="font-size:11.0pt">Your insights and experiences would be extremely helpful as we evaluate the best practices for creating a safe and effective CryoEM environment. Thank you very much for your time and guidance.</span></p>
<p class="x_x_MsoNormal"><span style="font-size:11.0pt"> </span></p>
<p class="x_x_MsoNormal" style="background:white"><span style="font-size:10.0pt; font-family:"Arial",sans-serif; color:#1F497D">Best Regards,</span></p>
<p class="x_x_MsoNormal" style="background:white"><span style="font-size:10.0pt; font-family:"Arial",sans-serif; color:#1F497D">Jason NG</span></p>
<p class="x_x_MsoNormal" style="background:white"><span style="font-size:10.0pt; font-family:"Arial",sans-serif; color:#548DD4">Senior Technical Assistant</span></p>
<p class="x_x_MsoNormal" style="background:white"><span style="font-size:10.0pt; font-family:"Arial",sans-serif; color:#548DD4">LKS Cryo-EM Laboratory</span><span style="font-size:11.0pt; font-family:"Calibri",sans-serif; color:#212121"></span></p>
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<p class="x_x_MsoNormal" style="background:white"><span style="font-size:10.0pt; font-family:"Arial",sans-serif; color:#1F4E79">Centre for PanorOmic Sciences</span><span style="color:#212121"></span></p>
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