In short
A reference list of manufacturing, testing and regulatory terms used across the Science Library, each linked to the page that covers it in depth.
Terms A–Z
- 2D culture
- Growing cells as a single layer on a flat surface such as a tissue-culture flask. More on this →
- 3D culture
- Growing cells in three dimensions: on microcarriers, as spheroids or along hollow fibers, usually inside a bioreactor. More on this →
- 21 CFR Part 1271
- The FDA regulation covering human cells, tissues, and cellular and tissue-based products (HCT/Ps), including establishment registration, donor eligibility and current good tissue practice.
- Bioreactor
- A closed vessel that grows cells while monitoring and controlling temperature, pH, dissolved oxygen and feeding. More on this →
- Certificate of Analysis (COA)
- A document reporting the test results for a specific lot. Dual-lab COA verification means results come from two independent laboratories. More on this →
- cGTP
- Current good tissue practice: the requirements in 21 CFR Part 1271 for how HCT/Ps are recovered, processed, stored, labeled and distributed. More on this →
- Cold chain
- Documented temperature control from manufacturing through shipping and receipt.
- Conditioned media
- Culture media collected after cells have grown in it; the starting material for EV and secretome processing. More on this →
- Cryopreservation
- Storing cells at very low temperatures, typically in liquid nitrogen vapor, to preserve them until use.
- Cumulative population doublings (CPD)
- The total number of times a cell population has doubled across all passages. More on this →
- Donor eligibility
- Screening and testing of a tissue donor under 21 CFR Part 1271, Subpart C, including medical and social history and communicable-disease testing. More on this →
- Endotoxin
- Molecules from bacterial cell walls that are tested for, and limited, in lot release. More on this →
- Extracellular vesicle (EV)
- A membrane-enclosed particle released by cells that cannot replicate on its own. The general term recommended by MISEV2023. More on this →
- Exosome
- An EV subtype formed in the cell's endosomal system; also the common commercial name for EV products. More on this →
- FDA-registered facility
- A manufacturing establishment registered with the FDA. Registration is not FDA approval of any product.
- HCT/P
- Human cells, tissues, and cellular and tissue-based products, as defined in 21 CFR Part 1271.
- hUCT-MSC
- Human umbilical cord tissue-derived mesenchymal stromal cells. More on this →
- Identity markers
- Surface proteins used to confirm cell type. For MSCs, the ISCT criteria call for CD73, CD90 and CD105 positive and hematopoietic markers negative. More on this →
- ISCT criteria
- The International Society for Cellular Therapy's minimal criteria for defining MSCs: plastic adherence, a defined marker profile and tri-lineage differentiation in vitro. More on this →
- Lot
- A batch of product made under the same conditions and tracked under one identifier, with its own test results. More on this →
- Mesenchymal stromal cell (MSC)
- A plastic-adherent cell population meeting the ISCT criteria, isolated from tissues such as bone marrow, adipose tissue and umbilical cord tissue. More on this →
- Microcarrier
- A small bead that cells attach to and grow on in suspension, multiplying the growth surface inside a bioreactor. More on this →
- MISEV2023
- The International Society for Extracellular Vesicles' guidance on EV nomenclature and characterization. More on this →
- Mycoplasma
- A small bacterium that can contaminate cell cultures; testing is part of lot release. More on this →
- Nanoparticle tracking analysis (NTA)
- A method that tracks the motion of individual particles in a laser beam to measure their size and count them per milliliter. More on this →
- Passage
- One transfer of cells from a full vessel into new vessels. More on this →
- Population doubling (PD)
- One doubling of cell number. PD = log₂(cells harvested ÷ cells seeded). More on this →
- Post-thaw viability
- The percentage of cells alive after thawing, measured on the lot.
- Replicative senescence
- The gradual slowing and eventual stopping of cell division as cells are expanded. More on this →
- Secretome
- Everything cells release into culture media, including EVs and soluble proteins. More on this →
- Sterility testing
- Testing a lot for bacterial and fungal contamination before release. More on this →
- Wharton's jelly
- The gel-like connective tissue of the umbilical cord, a source of MSCs. More on this →
Frequently asked questions
Who writes these definitions?
The Stem Nova Network team, drawing on the sources in the references below. Definitions describe manufacturing, testing and regulatory terms, not product effects.
Can I suggest a term?
Yes. Send it through our contact page and we will consider it for the next update.
References
- Dominici M, Le Blanc K, Mueller I, et al. Cytotherapy. 2006;8(4):315-317. doi:10.1080/14653240600855905. Cited for: ISCT minimal criteria for defining MSCs.
- Welsh JA, Goberdhan DCI, O'Driscoll L, et al. J Extracell Vesicles. 2024;13(2):e12404 (MISEV2023). doi:10.1002/jev2.12404. Cited for: EV nomenclature and characterization guidance.
- U.S. Code of Federal Regulations, Title 21, Part 1271: Human Cells, Tissues, and Cellular and Tissue-Based Products. eCFR. Cited for: cGTP and donor eligibility requirements.
Citations support manufacturing, characterization and sourcing facts only. They are not claims about any Stem Nova product's effect in the body.