Oragene is well known for a number of characteristics - ease of use, non-invasive collection, high quality and quantity DNA and, of course, long term storage at ambient temperature. It's often difficult for researchers and clinicians to believe that storage at ambient temperature is possible for DNA samples. We are frequently asked about this specification of our product. However, studies using Oragene prove that customers can rely on the ability to store Oragene/saliva samples at ambient temperatures when collecting samples in remote locations, via the mail, or for event-based recruitment. The figure to the right shows an agarose gel electrophoresis of DNA extracted from Oragene/saliva samples stored at room temperature for years.
The preservation and storage of DNA samples is an important consideration for molecular epidemiology, clinical trials, and population studies. To ensure your success, we have created the following best practices for the long term storage of unpurified saliva samples collected with the Oragene self-collection Kit. We will also highlight the rationale for these recommendations.
Storage at room temperature
DNA from saliva is stable in the Oragene collection tube for years. This stability is achieved as a result of the kit's proprietary reagents that inactivate enzymes in saliva and minimize chemical hydrolysis of DNA. These reagents also prevent the growth of bacteria in the sample.
Oragene/saliva samples may also be stored at temperatures below -20°C. Samples may undergo at least three freeze-thaw cycles with no evidence of DNA degradation. Although the Oragene collection tube is designed to ensure a tight seal, frozen storage may further reduce evaporation of the liquid medium during long term storage.
Aliquots in microcentrifuge tubes
The Oragene collection tube is designed for user friendly saliva collection from donors. However, in the lab, storage in more compact tubes may be preferable. To reduce storage space, an Oragene/saliva sample which has been heated at 50°C for a minimum of 1 hour may be split into 4 aliquots of 1 mL each and stored in 1.5 mL screw-top microcentrifuge tubes. It is advisable to use tubes with O-rings to ensure a tight seal and minimize long term loss from evaporation.
We hope these best practices will help you optimize the long term storage of all your unpurified Oragene samples. If you like this article, watch for an upcoming blog post on the best practices for long term storage of purified DNA from Oragene samples. If you want to be notified of our blog posts, be sure to subscribe to The Genetic Link.