Last Revised: June 29, 2022

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Sonication or Homogenization of Recombinant Bacteria in Enclosed Spaces

There are instances on campus where recombinant bacteria are sonicated or homogenized in enclosed spaces, such as cold rooms, without appropriate containment. Most research with recombinant bacteria is subject to the NIH Guidelines For Research Involving Recombinant Or Synthetic Nucleic Acid Molecules (NIH guidelines).

Even for work performed at biosafety containment level 1 (BSL-1), it is the responsibility of the Principal Investigator (PI) “to prevent the release of viable organisms containing recombinant or synthetic nucleic acid molecules to the environment”, recombinant nucleic acid (or plasmids) contained therein, or their potentially hazardous fragments. It is the responsibility of the PI “Section IV-B-7-e-(3). [to] Correct work errors and conditions that may result in the release of recombinant or synthetic nucleic acid molecule materials.” This requirement includes ensuring that personnel are not exposed to recombinant material.

Using an open sonicator or homogenizer in a cold room, other enclosed space, or open lab does not ensure containment due to the potential for significant aerosol generation during use and is contrary to the requirement in the NIH Guidelines that “All procedures are performed carefully to minimize the creation of aerosols”, regardless of biosafety containment level (BSL-1 or BSL-2). Given the nature of cold rooms, this issue is compounded by lack of exhaust and recirculating air and can inadvertently expose the operator or others that use the space.

To comply with the NIH Guidelines, sonication or homogenization of recombinant bacteria must be moved to a Biosafety Cabinet, or similar containment device, or by utilization of an appropriate local exhaust system. If the product does not need to be sterile, sonication or homogenization could be performed in a chemical fume hood.

Please contact a biosafety officer ( if you have any questions. We are happy to work with you to find solutions to keep your material contained.

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