02392nas a2200289   4500008004100000022001400041245009200055210006900147260001500216300001000231490000700241520154100248653001101789653001601800653003901816653001401855653003201869653001601901653002401917653001801941100002001959700001901979700001801998700001302016700001502029856005802044       1997                        eng d  a0009-308400aFormation of high-axial-ratio-microstructures from natural and synthetic sphingolipids.0 aFormation of highaxialratiomicrostructures from natural and synt  c1997 Aug 8  a21-360 v883 a<p>Amphiphiles that form high-axial-ratio-microstructures (HARMs) are being considered as novel materials for controlled release of drugs and other biologically functional molecules. HARMs consisting of tubules, ribbons, solid rods and helices are formed from sphingolipids by addition of water to a solution of amphiphile in DMF. Single molecular species of galactocerebroside (GalCer) containing long unsaturated fatty acid chains or natural GalCer containing mixed-length, non-hydroxy fatty acids (NFA-GalCer) or alpha-hydroxy fatty acids (HFA-GalCer) form cylindrical structures. In contrast, single molecular species of GalCer containing long saturated fatty acids form ribbons and helices. GalCer HARMs are typically under 100 nm in diameter and have lengths of several microns. The importance of the amide of GalCer for HARM formation was evaluated using psychosine, which forms solid fibers, whereas sphingosine and an analog of GalCer in which the amide is reduced to a secondary amine form amorphous aggregates. Single molecular species of ceramide containing long unsaturated fatty acid chains form cylindrical structures, whereas those with long saturated fatty acids form ribbons and helices. Short chain saturated ceramide also forms cylindrical structures. GalCer analogs with N-acetyl-glycine in place of the galactose form fibers whereas those with N-acetyl-proline yield amorphous material. The N-acetyl-proline-containing amphiphile can de doped into pure GalCer or NFA-GalCer without perturbing tubule formation.</p>10aAmides10aAmino Acids10aCalorimetry, Differential Scanning10aCeramides10aDelayed-Action Preparations10aFatty Acids10aGalactosylceramides10aSphingolipids1 aGoldstein, A, S1 aLukyanov, A, N1 aCarlson, P, A1 aYager, P1 aGelb, M, H  uhttp://www.microfluidicsciences.com/drupal/?q=node/32