DNA Preservation in Biological Specimens Using Metal Chelators

INV-20074

 

The growing importance of DNA-based research has created an increasing demand for methods that can preserve high-quality DNA in biological samples. A number of available preservation techniques can delay the degradation of DNA in tissue samples, but many are not easily adapted to the wide range of conditions commonly encountered by researchers working in the field. For example, cryopreservation is considered to be among the best techniques for preserving DNA in tissue, but mechanical freezers and freezing agents such as dry ice and liquid nitrogen are expensive, bulky, hazardous and often subject to transportation and shipping restrictions. Similarly, ethanol (EtOH) is one of the most commonly used preservatives, but is flammable, toxic and considered a controlled substance in many jurisdictions and may work best at cold temperatures. EtOH is also frequently subject to legal and travel restrictions. While a variety of commercial products are available for DNA preservation, these formulations are typically expensive. 

In 1991, Seutin et al introduced a liquid preservative solution that has become widely known as DMSO-salt or DESS. DESS is a formulation widely used to preserve DNA in biological tissue samples. Although it contains three ingredients, dimethyl sulfoxide (DMSO), ethylenediaminetetraacetic acid (EDTA) and sodium chloride (NaCl), it is frequently referred to as a DMSO-based preservative. The effectiveness of DESS has been confirmed for a variety of taxa and tissues. However, the contributions of each component of DESS to DNA preservation have not been evaluated.

 

This invention determines the active ingredient(s) of DES by assessing the relative effectiveness of eight preservatives, including 95% EtOH and seven formulations based on DES, at recovering high molecular weight (HMW) DNA from the tissue of three aquatic species across 5-time points. The seven formulations include DES, each of its three ingredients individually, and all pairwise combinations of its ingredients. After three months of preservation, HMW DNA was recovered from all solutions containing EDTA + NaCl for all three species. Additionally, tissues treated with either DMSO alone, NaCl alone, or DMSO + NaCl consistently failed to preserve HMW DNA, irrespective of taxa. This indicates that neither DMSO nor NaCl is likely the active ingredients. Instead, it concludes that EDTA is the active ingredient but that NaCl may enhance the activity of EDTA in some instances. These results suggest that researchers can remove DMSO from DMSO-salt and still reliably recover HMW DNA while reducing both financial costs and exposure to hazardous chemicals.

 

- Can be transported without restriction

- Is effective at room temperature, avoiding cost and reliability issues associated with cryopreservation 

- Requires no special handling or safety precautions

- Is more effective than the most common alternative

 

DNA preservation for: 

- Basic research 

- Applied research museum preparation 

- Forensic preparations in law enforcement 

- Forensic preparations in food regulation

 

- License

- Partnering

- Research collaboration