Compositions and methods for biological sample storage

Abstract

Compositions and methods are disclosed for substantially dry storage at ambient or elevated temperatures of biological samples such as nucleic acids, proteins and cells in a form from which the samples can be substantially recovered, using a dissolvable or dissociable dry storage matrix comprising a borate composition and a stabilizer as disclosed, such as any of a number of zwitterionic stabilizers.

Description

CROSS-REFERENCE[0001]This application is a divisional of U.S. application Ser. No. 12 / 778,100, filed on May 11, 2010, which claims priority to U.S. Provisional Application No. 61 / 177,161, filed on May 11, 2009, each of which is incorporated by reference in its entirety.TECHNICAL FIELD[0002]The present invention relates generally to improved compositions and methods for biological sample protection, storage, and retrieval. The invention also relates to the use, storage, retrieval and analysis of such biological materials and samples.BACKGROUND OF THE INVENTION[0003]Research in the life sciences field is based upon the analysis of biological materials and samples, such as DNA, RNA, blood, urine, feces, buccal swabs or samples, bacteria, archaebacteria, viruses, phage, plants, algae, yeast, microorganisms, PCR products, cloned DNA, proteins, enzymes, peptides, prions, eukaryotes (e.g. protoctisca, fungi, plantae and animalia), prokaryotes, cells and tissues, germ cells (e.g. sperm and ...

AI Technical Summary

Benefits of technology

The patent text describes a matrix that can protect DNA fragments from degradation during storage in a dry state at room temperature for at least two weeks. The matrix includes a borate composition and a stabilizer, which are present in a specific ratio to each other. The borate composition can be selected from a variety of compounds, such as boric acid and dihydrogen borate. The stabilizer can be selected from a group of compounds, such as pentaerythritol and glycerol phosphate. The matrix prevents degradation of the DNA fragments even at high temperatures.

Problems solved by technology

However, adequate low temperatures often cannot conveniently be maintained for extended time periods such as those required for transportation within or between countries or continents, particularly where an energy source for the refrigeration device is lacking.

Both storage systems are associated with disadvantages.

Storage under low temperature requires costly equipment such as cold rooms, freezers, and / or electric generator back-up systems; such equipment can be unreliable in cases of unexpected power outage or may be difficult to use in areas without a ready source of electricity or having unreliable electric systems.

The storage of nucleic acids on cellulose fibers also results in a substantial loss of material during the rehydration process, since the nucleic acid stays trapped by, and hence associated with, the cellulose fibers instead of being quantitatively recoverable.

Nucleic acid dry storage on cellulose also requires the separation of the cellulose from the biological material, since the cellulose fibers otherwise contaminate the biological samples.

The separation of the nucleic acids from cellulose filters requires additional handling, including steps of pipetting, transferring of the samples into new tubes or containers, and centrifugation, all of which can result in reduced recovery yields and increased opportunity for the introduction of unwanted contaminants or exposure to conditions that promote sample degradation, and which are also cost- and labor-intensive.

The consequent loss of protein activity that may be needed for biological assays typically requires the readjustment of the protein concentration in order to obtain comparable assay results, or costly rejection of compromised protein reagents in favor of procuring new lots.

The common practice of having multiple users of enzyme reagents stored in a laboratory, especially by different users at different times and employing non-standardized handling procedures, further reduces the reliability of experimental data generated with such reagents.

As a result, the half-life of proteins is reduced and expensive reagents have to be replaced frequently, amounting to enormous financial costs to the user.

For the supplier of the proteins, high costs are required to maintain an undisrupted frozen supply chain starting with initial cold room work-ups, for shipment, frozen storage of the sample, and frozen transport of the protein from production to the site of use.

For example, delays during shipment can result in inactivation of proteins, which then have to be replaced at great cost to the supplier; receipt of inactive product can also result in dissatisfied customers.

Drying of proteins and nucleic acids has yet to be universally adopted by the research scientific, biomedical, biotechnology and other industrial business communities because of the lack of standard established and reliable processes, difficulties with recoveries of functional properties and with quantitative recoveries of biological sample material, variable buffer and solvent compatibilities and tolerances, and other difficulties arising from the demands of handling nucleic acids and proteins.

The same problems apply to the handling, storage, and use of other biological materials, such as viruses, phage, bacteria, cells and multicellular organisms.

Dissacharides such as trehalose or lactitol, for example, have been described as additives for dry storage of protein-containing samples (e.g., U.S. Pat. No. 4,891,319; U.S. Pat. No. 5,834,254; U.S. Pat. No. 6,896,894; U.S. Pat. No. 5,876,992; U.S. Pat. No. 5,240,843; WO 90 / 05182; WO 91 / 14773) but usefulness of such compounds in the described contexts has been compromised by their serving as energy sources for undesirable microbial contaminants, by their limited stabilizing effects when used as described, by their lack of general applicability across a wide array of biological samples, and by other factors.

Typically samples that may be tested at later times are stored frozen in freezers at −20° C. to −80° C. However with the rapid expansion of demand and capability for analyzing samples by techniques such as polymerase chain reaction (PCR), nucleic acid sequencing, single nucleotide polymorphism (SNP) analyses and other biochemical and / or molecular biology techniques, the available space for storing these samples is rapidly diminishing.

Hence, and as the energy pricing rates rise concomitantly, the long term sustainability of this approach is being questioned.

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