Technology ID

Novel UNEX Buffer and Disk for Safe Storage and Transport at Ambient Temperatures of Clinical Specimens for Molecular Testing of Pathogens

Lead Inventor
Narayanan, Jothikumar (CDC)
Hill, Vincent (CDC)
Vinje, Jan (CDC)
Cromeans, Theresa (CDC)
Research Materials
Occupational Safety and Health
Consumer Products
Therapeutic Areas
Infectious Disease
Development Stages
Lead IC
The development of genomic approaches and nucleic acid based techniques has led to a large number of biological samples, including DNA, RNA, cells, tissues, and environmental samples that require storage. Typically, microbial DNA and RNA samples are stored long-term in laboratory freezers at temperatures ranging from -20°C to -196°C, the lower ranges utilizing liquid nitrogen. This often requires the use of several freezer boxes that can take up space and become difficult to sort through. Additionally, freezer equipment and cold chain transport measures needed for specimen stability are costly and difficult to maintain over time.

CDC developed the universal nucleic acid extraction (UNEX) buffer and disk for stable storage and transport of microbial samples at ambient (room) temperatures, bypassing the need for expensive cold chain (dry-ice) transit. Microbial RNA and DNA in water samples were stable for more than 2 years and 6 months (951 days) in UNEX lysis buffer stored at 4o C. The UNEX buffer inactivates bacteria (e.g., Salmonella serovar Typhimurium, and E. coli) and viruses (e.g., measles, adenovirus, poliovirus and three different strains of Middle East Respiratory Syndrome (MERS) Coronavirus, hepatitis A virus) tested thus far. In addition, a simple heat-elution step enables successful post specimen recovery of microbial RNA and DNA for up to 3 months from UNEX buffer treated cellulose- disks (UNEX disks). CDC’s invention inactivates pathogens and stores total nucleic acid (DNA and RNA) versus current commercial cards that primarily target either DNA or RNA storage only. This technology has great potential as nucleic acid transport and storage media for microbial specimens prior to molecular testing. This can help meet a critical need for safe and inexpensive shipping of nucleic acids from microbial specimens potentially containing pathogens, especially in resource-limited settings.
Commercial Applications
  • Stable method for the storage and transport of microbial specimens at ambient temperatures for downstream molecular testing
  • Applicability in developed countries, rural areas, and developing countries with limited resources lacking laboratory facilities and lacking cold chain transit capabilities
  • Use for shipping of specimens containing other bacteria, viruses including those of high consequence (i.e., flaviviruses), and parasites
  • Monitoring and public health surveillance
  • Research purposes
  • Quality control/quality assurance (e.g., proficiency panels)
Competitive Advantages
  • Liquid and solid phase storage of nucleic acids
  • Storage of nucleic acids at room temperature
  • UNEX disk can be used for inactivation of bacteria and viruses
  • Loading samples on UNEX disks is easy to perform without advanced training and ideal for shipping of samples from resource-limited environments to reference laboratories
  • Frees up costly freezer space in the short-term and saves expense of cold chain transit for microbial specimens
  • Extraction of nucleic acid from UNEX cards can be automated and does not require silica columns or centrifuge
Licensing Contact:
Mitzelfelt, Jeremiah