Biopreservation and Biobanking

Millions of biological samples are currently kept at low tempertures in cryobanks/biorepositories for long-term storage. The quality of the biospecimen when thawed, however, is not only determined by processing of the biospecimen but the storage conditions as well. The overall objective of this article is to describe the scientific basis for selecting a storage temperature for a biospecimen based on current scientific understanding. To that end, this article reviews some physical basics of the temperature, nucleation, and ice crystal growth present in biological samples stored at low temperatures (−20°C to −196°C), and our current understanding of the role of temperature on the activity of degradative molecules present in biospecimens. The scientific literature relevant to the stability of specific biomarkers in human fluid, cell, and tissue biospecimens is also summarized for the range of temperatures between −20°C to −196°C. These studies demonstrate the importance of storage temperature on the stability of critical biomarkers for fluid, cell, and tissue biospecimens.

A new procedure for room-temperature storage of DNA was evaluated whereby DNA samples from human tissue, bacteria, and plants were stored under an anoxic and anhydrous atmosphere in small glass vials fitted in stainless-steel, laser-sealed capsules (DNAshells^®). Samples were stored in DNAshells^® at room temperature for various periods of time to assess any degradation and compare it to frozen control samples and those stored in GenTegra™ tubes. The study included analysis of the effect of accelerated aging by using a high temperature (76°C) at 50% relative humidity. No detectable DNA degradation was seen in samples stored in DNAshells^® at room temperature for 18 months. Polymerase chain reaction experiments, pulsed field gel electrophoresis, and amplified fragment length polymorphism analyses also demonstrated that the protective properties of DNAshells^® are not affected by storage under extreme conditions (76°C, 50% humidity) for 30 hours, guaranteeing 100 years without DNA sample degradation. However, after 30 hours of storage at 76°C, it was necessary to include adjustments to the process in order to avoid DNA loss. Successful protection of DNA was obtained for 1 week and even 1 month of storage at high temperature by adding trehalose, which provides a protective matrix. This study demonstrates the many advantages of using DNAshells^® for room-temperature storage, particularly in terms of long-term stability, safety, transport, and applications for molecular biology research.

Human tissue biobanks are at the epicenter of clinical research, responsible for providing both clinical samples and annotated data. There is a need for large numbers of samples to provide statistical power to research studies, especially since treatment and diagnosis are becoming ever more personalized. A single biobank cannot provide sufficient numbers of samples to capture the full spectrum of any disease. Currently there is no infrastructure in the United Kingdom (UK) to integrate biobanks. Therefore the National Cancer Research Institute (NCRI) Confederation of Cancer Biobanks (CCB) Working Group 3 looked to establish a data standard to enable biobanks to communicate about the samples they hold and so facilitate the formation of an integrated national network of biobanks. The Working Group examined the existing data standards available to biobanks, such as the MIABIS standard, and compared these to the aims of the working group. The CCB-developed data standard has brought many improvements: (1) Where existing data standards have been developed, these have been incorporated, ensuring compatibility with other initiatives; (2) the standard was written with the expectation that it will be extended for specific disease areas, such as the Breast Cancer Campaign Tissue Bank (BCCTB) and the Strategic Tissue Repository Alliances Through Unified Methods (STRATUM) project; and (3) biobanks will be able to communicate about specific samples, as well as aggregated statistics.

The development of this data standard will allow all biobanks to integrate and share information about the samples they hold, facilitating the possibility of a national portal for researchers to find suitable samples for research. In addition, the data standard will allow other clinical services, such as disease registries, to communicate with biobanks in a standardized format allowing for greater cross-discipline data sharing.

Effective tracking of biospecimens within a biobank requires that each biospecimen has a unique identifier (ID). This ID can be found on the sample container as well as in the biospecimen management system. In the latter, the biospecimen ID is the key to annotation data such as location, quality, and sample processing. Guidelines such as the Best Practices from the International Society of Biological and Environmental Repositories only state that a unique identifier should be issued for each sample. However, to our knowledge, all guidelines lack a specific description of how to actually generate such an ID and how this can be supported by an IT system. Here, we provide a guide for biobankers on how to generate a biospecimen ID for your biobank. We also provide an example of how to apply this guide using a longitudinal multi-center research project (and its biobank). Starting with a description of the biobank's purpose and workflows through to collecting requirements from stakeholders and relevant documents (i.e., guidelines or data protection concepts), and existing IT-systems, we describe in detail how a concept to develop an ID system can be developed from this information. The concept contains two parts: one is the generation of the biospecimen ID according to the requirements of stakeholders, existing documentation such as guidelines or data protection concepts, and existing IT-infrastructures, and the second is the implementation of the biospecimen IDs and related functionalities covering the handling of individual biospecimens within an existing biospecimen management system. From describing the concept, the article moves on to how the new concept supports both existing or planned biobank workflows. Finally, the implementation and validation step is outlined to the reader and practical hints are provided for each step.

The impact of shipping temperatures and preservation media used during transport of either peripheral blood mononuclear cells (PBMCs) or Jurkat cells was assessed, in view of implementing of a proficiency testing scheme on mononuclear cell viability. Samples were analyzed before and after shipment at different temperatures (ambient temperature, dry ice, and liquid nitrogen) and in different preservation media (serum with cryoprotectant, commercial cryopreservation solution, and room temperature transport medium). Sample quality was assessed by viability assays (Trypan Blue dye exclusion, flow cytometry, Cell Analysis System cell counting (CASY)), and by ELISpot functional assay. The liquid nitrogen storage and shipment were found to be the most stable conditions to preserve cell viability and functionality. However, we show that alternative high quality shipment conditions for viable cells are dry ice shipment and commercial cryopreservation solution. These were also cost-efficient shipment conditions, satisfying the requirements of a proficiency testing scheme for viable mononuclear cells. Room temperature transport medium dramatically and adversely affected the integrity of mononuclear cells.

Biorepository processing includes nucleic acid extractions in batch mode from a large number of blood samples from many different donors. Handling such a large number of biospecimens presents the challenge of ensuring that samples are not switched or mislabeled during processing. One approach for confirming donor identity from DNA samples is the use of multiplexed fluorescent PCR for detecting Short Tandem Repeat (STR) allelic-size polymorphisms for a set of common autosomal loci. While donor identity of DNA extracted directly from blood collected in standard tubes containing anticoagulants can be easily verified by generating STR profiles, RNA from blood collected in PAXgene Blood RNA tubes (PAXgene RNA tubes) is depleted of DNA and is not amenable to STR fingerprinting for donor identity verification. We investigated the feasibility of isolating DNA directly from blood collected in PAXgene RNA tubes for use as template for STR DNA fingerprinting for blood donor identity verification. We determined that DNA extraction can be performed manually with the QIAamp DNA Blood Minikit or on the QIAxtractor instrument with minimal pre-processing protocol additions, and that DNA isolated from blood collected in PAXgene RNA tubes is of sufficient quantity and quality for successful STR fingerprint analysis. Adaptation of quality assurance methods such as the PAXgene RNA tube DNA extraction/STR fingerprinting assay described here is a good practice that ensures that biobanking collections provide scientists with high quality, donor-verified biomaterial.