An efficient method for long-term room temperature storage of RNA

Abstract

RNA is a tool used in many fields, from molecular and cellular biology to medicine and nanotechnology. For most of these uses, the integrity of RNA is required and must be maintained during storage. Even though freezing is currently the storage method of choice, the increasing number of samples to be stored and the costly use of a cold chain have highlighted the need for room temperature preservation methods. Here, we report a new room temperature technology that consists in drying RNA samples in the presence of a stabilizer in stainless steel minicapsules. These air-and water-tight capsules isolate RNA from the atmosphere and maintain an anhydrous and anoxic environment. Through the evaluation of RNA integrity over time at room temperature or 90 1C, we identified atmospheric humidity as a major deleterious factor. The degradation rate dependence in temperature fitted an Arrhenius model, with an activation energy of 28.5 kcal/mol and an extrapolated room temperature degradation rate of 3.2 10 À13 /nt/s (95% confidence interval: 2.3-4.2/nt/s). In these conditions, it is expected that an RNA molecule will be subjected to 0.7-1.3 cut every 1000 nucleotides per century. In addition, we showed that stored RNA is compatible for further analyses, such as reverse transcription-quantitative PCR. No significant change in the C q values was observed over a simulated period of several decades. At last, our data are consistent with a sequence-independent degradation rate of RNA in the solid state.

Evaluation of DNA/RNAshells for Room Temperature Nucleic Acids Storage

“…16 We have demonstrated that the quality of DNA/RNA samples was as good as the original samples after transportation to BGI-Shenzhen at RT for about 1 week. We also show that the DNA and RNA quality was still high after storage simulating about 14 years and 7 years at RT, respectively.…”

“…Storage in RNAshells and storage in RNase free water without protection (NP, non-protected) at 60°C are equivalent to approximately 0 day, 14 days, 100 days, 3 years, and 7 years storage at room temperature. 16 Real-time degradation study (storage at room temperature) DNAshells and RNAshells were stored at room temperature (20*25°C) after being transported to BGI. The quality of the DNA and RNA were analyzed after 6 months and 1 year (DNA for 14 months) preservation.…”

“…16,17 Here we conducted accelerated aging (60°C) and real-time degradation studies to evaluate the long-term preservation quality of DNAshell and RNAshell, including the DNA and RNA yield, purity, and integrity. We showed that DNAshell and RNAshell allow for DNA and RNA long-term preservation at room temperature, and the quality is suitable for common downstream analyses.…”

Long-term Stability of Total RNA in RNAstable® as Evaluated by Expression Microarray

“…This is equivalent to 22 months of RT storage based on extrapolation from the Arrhenius equation. [8][9][10] In Bioanalyzer electropherograms, the 45°C unprotected RNA was severely degraded, with only a broad peak of smaller RNA fragments seen and showing an average RIN of 2.3 -0.0 (Fig. 2B).…”

“…Dried samples were then stored inside a sealed moisturebarrier bag including a desiccant pack at RT or at 45°C to model accelerated aging. [8][9][10] Aliquots of reference control samples (3.4 mg) were stored at -80°C. After 4.5 months, the -80°C samples were shipped on dry ice for overnight delivery, and the RNAstable and unprotected samples were placed into foil sealed bags with desiccant packets and shipped via ground delivery.…”