Quick definitions for the most commonly misunderstood terms in cell culture, DMPK transporter assays and bioprocessing — written for researchers, DMPK scientists and procurement teams.
Cell Culture & Serum
| Term | One-line definition | Full guide |
|---|---|---|
| FBS (Fetal Bovine Serum) | The most widely used cell culture supplement — blood serum collected from bovine fetuses, providing growth factors, albumin and nutrients to support cell growth. | Read → |
| Heat Inactivated FBS | FBS heated to 56°C for 30 minutes to destroy complement proteins — used in embryo culture, PBMC assays and virus neutralisation. | Read → |
| Low Endotoxin FBS | FBS tested to <1 EU/mL endotoxin — required for drug screening, AAV production and cytokine assays where LPS would confound results. | Read → |
| Human Platelet Lysate (hPL) | A xeno-free, human-derived FBS alternative produced by freeze-thaw lysis of platelets — releasing concentrated PDGF, EGF, TGF-β and IGF-1 for MSC and primary cell culture. | Read → |
| Off-the-Clot (OTC) Serum | Human serum produced by natural clotting — platelets fully activate and release growth factors, giving higher PDGF and EGF than standard plasma-derived serum. | Read → |
Serum-Free & Albumin
| Term | One-line definition | Full guide |
|---|---|---|
| Xeno-Free Cell Culture | Cell culture containing no components from a species other than the one being cultured — for human cells, no bovine or murine materials; human-derived supplements (hPL, rHSA) are acceptable. | Read → |
| rHSA (Recombinant Human Serum Albumin) | Human serum albumin produced recombinantly in rice or yeast — animal-free, xeno-free, GMP-compatible carrier protein for serum-free cell culture and AAV production media. | Read → |
| Recombinant Human Transferrin (OsrhTF) | Animal-free iron delivery protein for serum-free medium — replaces the transferrin function of FBS; essential to prevent iron starvation during serum-free adaptation. | Read → |
DMPK & Drug Transporters
| Term | One-line definition | Full guide |
|---|---|---|
| BSEP (Bile Salt Export Pump) | The primary hepatocyte canalicular transporter for bile salt secretion — BSEP inhibition causes intracellular bile salt accumulation and is the leading mechanism of cholestatic drug-induced liver injury (DILI). | Read → |
| P-glycoprotein (P-gp / MDR1 / ABCB1) | An ABC efflux transporter expressed at the intestinal epithelium, blood-brain barrier and liver — limits oral bioavailability and CNS penetration; mandatory DDI testing for all NMEs under FDA, EMA and ICH M12. | Read → |
| Vesicular Transport Assay | An in vitro method using inside-out membrane vesicles to measure ABC transporter substrate accumulation and inhibitor IC50 — the only viable method for BSEP, MRP2, MRP3, MRP4 where no cell monolayer model exists. | Read → |
| DILI (Drug-Induced Liver Injury) | Hepatotoxicity caused by a drug or supplement — the leading cause of post-marketing drug withdrawal. BSEP inhibition is the primary mechanism of cholestatic DILI. | Read → |
Related Guides
- Serum-Free Cell Culture Adaptation — Complete Protocol
- Why Your FBS Isn't the Problem — and What to Replace It With
- Human Platelet Lysate (hPL) — Complete Guide
- Vesicular Transport vs. Cell-Based vs. ATPase Assay
- FDA & EMA Mandatory Drug Transporters for IND
- Inside-Out Membrane Vesicles Explained
Can't find a term? Contact us — we add new definitions regularly based on questions from researchers and DMPK scientists.
