Instituto Murciano de Investigación Biosanitaria (IMIB)
A sustainable alternative to deep-freezing for DNA preservation.
DNA is a naturally stable molecule that is well suited to long-term storage. However, inadequate storage makes it susceptible to degradation processes that can compromise its quality—especially when it comes to meeting the demands of new and more sensitive molecular biology techniques.
As a result, despite its supposed stability, DNA is still routinely stored in ultra-low temperature freezers, occupying between 10% and 20% of available storage capacity in biobanks and laboratories.
Objective
To assess the technical feasibility of 300K Solutions technology for the dry stabilization of DNA extracted from buffy coat samples of different ages, and to evaluate the impact of repeated freeze-drying cycles and room temperature storage on the integrity of DNA.
Materials and Methods
Samples used for the study
30 DNA samples
Procedure
DNA was extracted from buffy coat samples of different ages. Immediately after extraction, aliquots were either freeze-dried or frozen. The freeze-dried samples were stored at room temperature, while the frozen samples were kept under standard freezing conditions.
In parallel, 10 of the DNA samples (representative of the different storage times) were selected and subjected to two additional lyophilization processes to assess their quality and integrity.
Freeze-dried samples were evaluated alongside frozen samples using established quality criteria to assess the integrity of both storage methods. The same quality parameters were then applied to analyze the impact of multiple freeze-drying cycles on sample quality.
Quality Assurance
Ratio A260/280
DNA Concentration
DNA Integrity Number
Absorbance assays by spectrophotometry and automated electrophoresis were performed to compare the quality and integrity of the frozen and lyophilized DNA samples.
Results
Independently of the sample age (fresh, 4, 7, 9 and 10 years), frozen DNA aliquots stored for 1 month showed lower DIN values when compared with both basal integrity measurements (T0) and DIN values from freeze-dried DNA aliquots stored for 1 month at RT (left).
More importantly, when we compared the effect of consecutive freeze-drying processes on DNA integrity in a representative selection of theses samples (fresh, 4, 7 and 10 years), no remarkable differences in the DIN values were observed when compared with basal measurements (right).
Conclusion
The 300K DNA Stabilization Solution has proven to be a reliable and robust tool that preserves DNA integrity without deterioration—even after multiple freeze-drying cycles. It offers labs and biorepositories a sustainable, efficient, and freezer-free alternative for long-term DNA preservation.
