The illustration of DNA aerosols in a lab.

How to Prevent DNA Aerosol Contamination?

“DNA aerosols are unknown, undetectable contamination in any genetic lab and are produced during working with DNA samples. Here is an article on how to prevent DNA aerosol contamination.” 


Snippet:

  • DNA is so tiny that it can’t be seen under a compound microscope. 
  • Plasmid DNA is cytoplasmic DNA present in prokaryotes. 
  • DNA is usually present in the nucleus of a cell and is thus known as nucleic acid. 
  • DNA itself is a common contaminant of any genetic experiment. 

Two days back, while discussing some SOPs with one of my friends I came to know that they have some serious issues with their experiment and can’t understand why it occurs. Although, he is an experienced geneticist. 

After all our efforts, we can know that it might occur by aerosols of DNA. They are silent predators and the last ones we can blame. So the final conclusion is they need to do an assessment or any cleaning that vanishes any type of external DNA source. And we have a unique, easy and simple solution that I will tell you at the end of the article. 

From this, I came to know that it’s a serious issue, occurred many times, with me also, in the past. So why not tell the novice scientists about this silent, unknown and kind of “blackhole” predator of our genetic experiments– DNA aerosols. 

“We know it is there but we can’t see it, we know their consequences but we can’t find it, its existence is still a question.”

Such a problem is underrated mostly, but can’t be avoided when we are dealing with things like infection testing, gene therapy or genetic testing. So What exactly DNA aerosol is? How does it produce and how to prevent them? Let’s find out. 

Read more: How to set up a DNA extraction lab: A comprehensive guide (chemicals, instruments and other utilities).

What is DNA aerosol?

“A liquid droplet carrying any free submicroscopic practice is known as aerosol”- as per the Wikipedia explanation. Such droplets are generated during experimenting and remain in the surrounding or nearby atmosphere all the time.  

So DNA aerosols are the solution, or liquid droplets carrying fragments of unknown DNA. Notedly, it’s important to know that such droplets are so tiny that they can float in the atmosphere. 

The atomized DNA fragment generated by some unhealthy lab practices is also a kind of DNA aerosol. 

DNA aerosols are the source of unwanted exogenous DNA that can affect the reaction, negatively. Any exogenous sources of DNA cause false positive reactions and do amplification other than the target or even in the absence of the target. 

It actually causes more serious problems than you think. Take a look at what it can cause. 

  • It can cause false results. 
  • It can contaminate GMOs or cell lines. 
  • It can compromise the quality of seeds during culture. 
  • It can fail or produce unwanted results in gene transfer experiments. 
  • It fails gene therapy experiments. 
  • It produces unwanted outcomes in any genetic experiments. 

And as I already explained, it’s hard to understand, identify and resolve. So it’s better to take care of things beforehand. To understand the present topic better let’s find out the root cause, why and how DNA aerosols are produced. 

Why and how are DNA aerosols produced? 

DNA is a tiny biomolecule that even can’t be seen under the microscope. Also, RNA is very fragile and can be fragmented easily. These two properties make it more prone to become aerosol. There are a couple of reasons why it occurs. 

  • Rigorous pipetting. 
  • Blank pipetting
  • Leaving pipette tips, Eppendorf tubes and hand gloves in LAF. 
  • Pressurizing DNA solution unwantedly.   
  • Repetitive work with microorganisms and plasmids. 
  • Frequent experimentation at one place/LAF/safety cabinet. 

Rigorous pipetting like mixing a sample generates a huge amount of DNA aerosols. The airflow of the biosafety cabinet easily spreads in the surrounding atmosphere. Having a habit to press the pipette constantly without any reason also generates aerosols. 

Leaving the used utilities in the working hood or safety cabinet is yet another common reason for the occurrence of DNA aerosols. Besides, the lack of proper cleaning activities, managing utilities and roughly experimenting produce a huge amount of DNA aerosols. 

How to prevent DNA aerosol contamination? 

Prepare an excellent working SOP for extraction, PCR and any other genetic experiment and always try to follow it, even with a high workload. 

Make a habit to clear the working area and utilities with alcohol prior to use. Use only autoclaved utilities. 

  • Do pipetting smoothly. Avoid back pipetting. 
  • Avoid blank pipetting. 
  • Discard used things in the discard only and place them separately outside the laminar or working hood. 
  • Use a HEPA filter-equipped safety cabinet. 
  • Follow common lab practices like– wear a mask, cap, lab coat and hand gloves. 
  • Avoid using used tips and tubes. 
  • Prepare solutions, chemicals and stocks separately from the extraction setup.  
  • Perform experiments in the safety cabinet. 
  • Make a proper SOP and system to discard DNA or nucleic acid waste like leftover DNA, old DNA samples, PCR tubes, etc. 
  • Follow international standards for genetic lab setup and working with nucleic acids. 

These are the safety options, we can follow but what if we already have DNA aerosols present in our lab? What to do? I have a better solution, which is tried and tested. Spray water.

Yes, you heard it right. Spray water twice a day. DNA will dissolve and/or settle under the pressure of water droplets. 

Note that fumigation will not work here.

Wrapping up: 

DNA aerosols are classified into bioaerosols which is a serious problem for any molecular laboratory. However, as we said, one simple hack can help in this situation. Scientists also use DNA aerosol techniques for DNA transfer and gene therapy experiments as a technique to transfer DNA. 

So if you are running an extraction or PCR lab and do care about the DNA aerosol contamination, you never know when it starts producing false positive results. I hope you like this article, please share it and bookmark this page. 

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