BME 410 Lecture Notes - Lecture 14: Lactic Acid, Crystallinity, Copolymer
20 Apr 2016
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Document Summary
Biological: natural origin: ceramics, metals, polymers, composites, collagen, elastin, chitin. Natural biomaterials enzymatic degradation (cid:2) (cid:2: mmp= matrix metalloproteinase (enzyme, mesenchymal cells: can differentiate into osteoblasts, chondrocytes, myocytes, and adipocytes. Modified synthetic biomaterials enzymatic degradation: need enzymatically cleavable site. Human body is 72% water (lungs the most, bones the least) H20 added to monomers to break them apart. Chemical structure: susceptible to hydrolysis biodegradable. Ester bond (needs heat: resistant to hydrolysis not biodegradable. Crystallinity and hydrophobicity: amorphous allows water to penetrate; crystalline does not allow water, hydrophilic: small angle, allows water, hydrophobic: large angle, doesn"t allow water, water: polar covalent, bent, methane: nonpolar covalent, tetrahedral. Aliphatic: carbon chains linked together, straight or branched but not in a benzene ring (aromatic) Aromatic: benzene ring: methane, propane, cyclohexane, ethanol, benzene, ethylbenzene, naphthalene. First biodegradable polymer used in medicine: sutures in 1969. Pga/pla co-polymers: amorphous, hydrophilic, tunable, crystalline, long backbone more hydrophobic.
