A tissue bank, often called a biobank, is an organized repository that collects, processes, stores, and distributes human biological materials and associated data for use in medical research and clinical applications. These facilities operate with stringent protocols to maintain the integrity and quality of the samples, safeguarding them for years or even decades. The fundamental role of a tissue bank is to serve as a bridge between clinical findings and laboratory investigations. By centralizing and managing these materials, tissue banks ensure that scientists and clinicians have reliable access to the diverse biological specimens necessary to study health and disease.
What Biological Materials Are Stored
Tissue banks house human biological materials, ranging from solid tissues to various biofluids. Solid tissues include samples collected during surgery, such as tumor tissue alongside adjacent healthy tissue, which allows for direct comparison in cancer research. Other common solid tissues banked for clinical use are bone, skin, heart valves, and cornea, which are used for transplantation and reconstructive procedures.
Biofluids form a large category of stored samples, including whole blood, plasma, serum, urine, and saliva. These fluids are often processed to separate components, such as isolating peripheral blood mononuclear cells (PBMCs) or extracting plasma for biomarker analysis. Stored samples also include derivatives such as purified DNA, RNA, and proteins, which are essential for genetic and molecular studies. Specialized banks may also store stem cells or established cell lines.
A critical component accompanying every physical sample is the associated clinical data, which is meticulously collected and often de-identified to protect patient privacy. This data includes medical history, treatment response, lifestyle information, and genetic details, making the physical sample more valuable for research purposes.
Research and Clinical Applications
Tissue banks serve as a resource for scientific discovery and patient care. In research, these repositories provide materials for studying disease progression, allowing scientists to track molecular changes over time by analyzing samples collected at different stages of illness. This access is fundamental for identifying new biomarkers and discovering drug targets.
The materials are valuable in personalized medicine, enabling researchers to understand why a specific drug works for some patients but not others based on their unique genetic and molecular profiles. Tissue samples are used to test new drugs and treatment methods in clinical trials, assessing efficacy and safety. Researchers also use these samples to develop and validate new diagnostic tests and screening tools.
In clinical settings, tissue banks supply allografts—tissues transplanted from one person to another—for various surgeries. These materials include skin grafts for burn victims, bone grafts for orthopedic procedures, and heart valves for cardiac surgery. By having readily available, tested, and preserved tissues, banks ensure that these materials are safe and available immediately when needed for transplantation.
Processing and Preservation Techniques
The journey of a biological sample into a tissue bank begins with rigorous processing to ensure its long-term viability. Upon arrival, samples undergo quality control checks to assess their integrity before being processed. Processing often involves dividing the original sample into smaller portions known as aliquots. Proper aliquoting minimizes the degradation that occurs with repeated thawing and refreezing, preserving the sample for multiple future uses.
The primary method for long-term storage is cryopreservation, which involves freezing samples at ultra-low temperatures, typically at or below -80°C or in liquid nitrogen vapor at -196°C. This extreme cold halts nearly all biological activity and chemical degradation, maintaining the structural and molecular integrity of the cells and tissues for many years. Cryoprotectants, such as dimethyl sulfoxide (DMSO), are often added before freezing to prevent damage from ice crystal formation.
Another widely used technique, particularly for solid tissues intended for histological study, is formalin-fixed paraffin embedding (FFPE). The tissue is first immersed in a fixative, commonly 10% neutral buffered formalin, which chemically preserves the tissue structure by cross-linking proteins. After fixation, the sample is dehydrated and embedded in a block of paraffin wax, which provides a solid matrix for thin slicing and allows for indefinite storage at room temperature.
Donor Consent and Governance
The operation of a tissue bank is governed by an ethical and regulatory framework that prioritizes the rights and privacy of the donor. A fundamental requirement is informed consent, where the donor or their next-of-kin must explicitly agree to the donation and the intended use of the biological material. Consent can be specific, limiting the sample use to a particular study, or broad, allowing the material to be used for any future research that meets ethical approval.
Protecting patient privacy is accomplished through anonymization or de-identification, which separates the biological sample from personal identifying information. The data linked to the sample is stripped of direct identifiers, ensuring that researchers cannot trace the material back to the individual donor. This process provides a balance between maximizing the scientific utility of the sample and safeguarding the donor’s confidentiality.
Regulatory oversight is maintained by bodies such as Institutional Review Boards (IRBs) or government agencies, which approve protocols and ensure compliance with ethical and legal standards. These oversight mechanisms ensure that the tissue bank adheres to strict quality control, safety standards, and ethical practices in all aspects of procurement, processing, storage, and distribution. The regulatory environment is continually evolving to address complex issues like the potential for commercial use and the disclosure of research findings to donors.