Lecture 18 Flashcards
Q: What are the size ranges for particles in biomaterials?
A: Micron: 1–1000 μm; Submicron: 0.1–1 μm; Nanoparticles: 1–100 nm.
Q: Why are particles useful in drug delivery?
A: They can be suspended in fluid, functionalized, and targeted for specific delivery.
Q: Name 3 current uses of micro/nanoparticles.
A: Biomedical imaging, drug delivery, biosensors, cosmetics, food science.
Q: Give an example of a metallic, ceramic, and polymeric biomaterial.
A: Iron oxide (metallic), silica (ceramic), PLGA (polymeric).
Q: What are the three main particle morphologies?
A: Solid core, core shell, fibers
Q: What’s the difference between a microsphere and microcapsule?
A: Microsphere: drug is dissolved in matrix; Microcapsule: drug is enclosed separately.
Q: What is the most common fabrication method for particles?
A: Emulsification-solvent evaporation.
Q: When is single emulsion used?
A: For hydrophobic or lipophilic drugs.
Q: When is double emulsion used?
A: For hydrophilic drugs or biomolecules (w/o/w method).
Q: What are other methods of particle fabrication?
A: Spray drying, phase separation, self-assembly, precursor decomposition.
Q: What does dynamic light scattering (DLS) measure?
A: Precise particle size
Q: What does zeta (ζ) potential indicate?
A: Surface charge; affects uptake by cells. Anionic particles are more easily internalized.
Q: Why do particles often accumulate in the liver?
A: The liver filters particles from circulation—this is a delivery challenge.
Q: What is PEGylation and its benefit?
A: Coating particles with PEG to reduce immune clearance and improve circulation.
Q: Name three delivery barriers for particles.
A: Phagocytosis/degradation, vascular crossing, interstitial delivery.
Q: How can particles be targeted to specific cells?
A: Via surface ligands that bind to cell receptors (e.g., receptor-mediated endocytosis).
Q: Why is receptor-mediated endocytosis useful in drug delivery?
A: It allows selective uptake into cells, but drugs must escape endosomes to reach cytosol.
Q: How does lipid membrane fusion help drug delivery?
A: Lipid-coated particles can bypass endosomes by fusing directly with the cell membrane.
