Superior Pathology

Human Tissue and Biological Samples for Use in Research: 3 Common Types & Their Purposes

Human biological samples are a staple of scientific research. Whether collected from living or diseased human patients, these specimens are vital for various areas of health care. In routine clinical care, tissue and biological samples are used for diagnosis, prognosis, and monitoring of various diseases. On the other hand, in a research context, these specimens are crucial for creating new treatments, understanding human biology, and advancing medical knowledge.

Have you ever wondered what types of specimens are used in research and medical care? This article addresses 3 common types of human and biological samples used in various scientific fields. You’ll learn about the common types of tissue samples, how these specimens are collected, what type of tissue is best for DNA extraction, and more. If you’d like to learn more about the fascinating world of tissue samples in research, keep reading!

The Most Common Types of Tissue Samples and Their Uses

3 Common Types of Human Tissue and Biological Samples Used in Research

1. Epithelial, Connective, Muscle, and Nervous Tissue Samples

There are numerous types of tissue in the human body. Human tissue samples are often organized into four categories:

  • Epithelial Tissue: Epithelial tissue is found in your organs and internal and external body surfaces and is the most prominent tissue in glands. The lining of your intestines and respiratory tract, sweat glands, and the outer layer of your skin (epidermis) are a few types of epithelial tissue in your body. 
  • Connective Tissue: Structures that support and protect other tissues or organs in the human body. Connective tissue often stores fat, aids in transporting nutrients between tissues and organs, and helps restore damaged tissue. Connective tissues include bone, cartilage, lymphatic, and fat tissue. 
  • Muscle Tissue: Muscle tissue comprises cells that shorten and contract to move different body parts. Muscle tissue is often arranged in layers and surrounded by connective tissue. The 3 types of muscle tissue are skeletal, cardiac, and smooth. 
  • Nervous Tissue: The main tissue component of the nervous system. Nervous tissue comprises neurons and neurological cells that control and coordinate countless body activities. This tissue type is prevalent in the brain, spinal cord, and nerves.

The body’s various anatomical regions usually include multiple of the types of tissue samples mentioned above. For example, the lungs are lined with epithelial tissue, supported by connective tissue, regulated by nervous tissue, and contract and relax with smooth muscle tissue. Whether you’re collecting tissue from the brain or cervix, multiple types of tissue samples are most likely present in the anatomical site. Once collected, properly preserving the human tissue samples is essential. Standard preservation techniques include fixing specimens in formalin and embedding in wax, known as Formalin-Fixed Paraffin-Embedded (FFPE) tissue, or rapid freezing in liquid nitrogen, referred to as fresh frozen tissue. Preservation helps maintain the tissue’s cellular structures and molecular makeup, crucial for accurate research results.

How Are Tissue Samples Used in Research?

Human tissue samples are invaluable sources of information for researchers, aiding in advancing scientific research and improving our understanding of health and disease. Here are a few areas of study that use human tissue samples:

  • Biomarker Discovery: Tissue samples help researchers identify biomarkers, which are molecules that point out a specific disease or physiological state. Biomarkers aid in early disease detection, diagnosis, and monitoring. Immunohistochemistry (IHC) is a common technique used in biomarker analysis, determining the location of a particular protein in the tissue or call sample. FFPE tissue blocks collected from individuals carrying various diseases are usually the preferred tissue type used in biomarker research.
  • Disease Research: Biospecimens assist researchers in understanding how diseases affect the body at a cellular level. For instance, FFPE malignant tissue samples are analyzed for better insight into tumor growth, metastasis, and microenvironment. 
  • Drug Development and Testing: Various pharmaceuticals are tested on different types of tissue samples to assess their safety and viability before progressing to clinical trials. Drug testing also includes testing for pharmaceuticals’ potential side effects or toxicity. Drug development can involve numerous FFPE, fresh frozen, or fresh specimens collected from differing anatomical regions. 
  • Neuroscience Study: Normal, malignant, and disease-state brain tissue samples are critical in understanding neurological diseases such as Parkinson’s, Alzheimer’s, and multiple sclerosis. 

Numerous additional research fields use human tissue samples, including developmental biology, immunological studies, genetic analysis, regenerative medicine, and more. There’s no doubt that human tissue samples are paramount to our understanding of the human body and its intricacies.

2. Biofluids

Biofluids is the shortened term for biological fluids. Biofluids are collected from the human body in primarily 3 ways: excretion (e.g., sweat), secretion (e.g., breast milk), or extraction (e.g., blood). Here’s a list of the common forms of biofluids used for research purposes:

  • Blood
  • Urine
  • Sweat
  • Cerebrospinal fluid
  • Bile
  • Breast Milk
  • Plasma
  • Saliva
  • Stool
  • Swabs (nasal, oral, and vaginal fluids)

How Are Biofluids Used in Research?

Biofluids are primarily used to identify, diagnose, and monitor illnesses. However, that’s not all they offer to scientific research; biofluid specimens also make it possible to detect harmful substances in the body, discover the amount of specific proteins or hormones present, and estimate the concentration of drugs. Additionally, these fluids are necessary for biomarker studies, helping scientists and medical professionals track the biological components associated with certain diseases.

In 2020, biofluids proved especially important when COVID-19 instigated a worldwide lockdown. People were diagnosed with COVID-19 using a simple nasal swab during this period. Researchers had to obtain sufficient swab samples from patients with suspected COVID-19 (asymptomatic and symptomatic) and subjects without exposure to COVID-19. Without biofluids, researchers and medical professionals wouldn’t have been able to diagnose or study COVID-19.

3. Cells

Cell samples are groups of cells that can be obtained from biofluids, biopsies, or tissue samples. Below is a list of cell sample types used in scientific research:

  • Myoblasts
  • Buffy Coat
  • Bone Marrow
  • Mononuclear Cells
  • Fibroblasts
  • Epithelial Cells
  • RBCs

How Are Cell Samples Used in Research?

Countless researchers use cell samples for scientific analysis. Here are 2 of the common scientific areas to which cell samples contribute significantly:

  • Drug Development: Before new drugs are released, testing their safety and efficacy using cell samples is essential. Researchers utilize human cells, separated from blood or tissue samples, to assess how drugs could react to cells, their toxicity, and their possible healing effects. This testing is crucial for scientists to perform before advancing to animal models and human clinical trials.
  • Cell Biology Research: Basic cell biology research is integral to understanding a cell or tissue type’s inner workings. While some scientists may use immortalized cell lines, this field of study often requires researchers to obtain primary human cells from patients that carry the disease or indication of interest.

Human cells contribute to cancer research, regenerative medicine, and genetic and molecular biology studies. The main advantage of human cells is that they allow scientists to simplify a disease and focus on a small number of variables. Human cell samples help us better understand basic physiology and dive deeper into numerous diseases affecting countless subjects.

3 FAQs Regarding Tissue and Biological Samples for Use in Research

Here are 3 popular questions we hear regarding specimens that are used in medical research:

1. What’s the best tissue for a DNA sample?

Tissue collected from the brain, heart, or kidney is best for DNA samples.

According to the National Library of Medicine, “Our study suggested that quality and quantity of DNA extracted from tissues of putrefied unidentifiable human corpse was best seen in brain followed by heart and kidney preserved at -80℃ and 4℃. Muscles were found to be least useful for DNA extraction.”

2. How are human tissue and biological samples collected?

Biobanks, hospitals, and laboratories collect tissue and biological samples from voluntary donors. Patients can donate the leftover tissue samples, blood, and other specimens to these professional institutions following lab tests, surgeries, or other medical appointments. Medical facilities like biobanks prepare, store, and keep track of these samples, providing them for international research purposes. Researchers can then order specific types of tissue and biological samples from these facilities, aiding them in learning more about human health and the overall quality of life.

3. Which preservation method is the best for tissue samples?

FFPE is often the gold standard for tissue preservation. Researchers have relied on FFPE tissue samples for decades, knowing this form of conservation and storage holds together the specimens’ original structures and molecular makeups. Since FFPE tissue samples can be stored for up to a decade, scientists rely on this form of preservation for long-lasting studies and research purposes.

Order Quality Tissue and Biological Samples for Your Research Purposes

Do you need specific tissue and biological samples for use in your unique research purposes? At Superior BioDiagnostics, we have thousands of tissue samples ready to satisfy your scientific needs. Our biobank is stocked with normal, malignant, and disease-state FFPE tissue from various anatomical sites such as the brain, lungs, skin, and more. Don’t wait to receive the highest-quality tissue samples for your analysis. Contact Superior BioDiagnostics’ team to order your FFPE tissue samples today!