Highly stable vesicles composed of a new chain-terminus acetylenic photopolymeric phospholipid.
Stability, ease of production, and storage convenience were addressed for polymerized vesicles composed of 1,2-bis(trideca-12-ynoyl)-sn-glycero-3-phosphocholine. The following vesicle properties were investigated before and after polymerization: size, shape, lamellarity, dispersity, degree of polymerization, membrane fluidity, and structural stability. A fairly monodisperse, unilamellar sub-micron vesicle suspension undergoes nearly complete polymerization of the chain-terminus acetylenic to polyacetylenic conversion as monitored by Fourier transform infrared spectroscopy. (1)H nuclear magnetic resonance spectroscopy and thin layer chromatography provide additional evidence for extensive lipid polymerization. Using differential scanning calorimetry, a gel/liquid transition was not observed for either polymerized or non-polymerized vesicles within the temperature range of 5-65 degrees C. These polymerized vesicles remained structurally stable and suspended for months at room temperature. However, vesicle size did decrease with increasing degree of polymerization. Polymerized vesicles remained spherical but decreased in size by 15% when subjected to 52 wt.% aqueous ethanol and did not change significantly in size and dispersity after a freeze-dry/resuspend cycle.
Stanish
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Naval Research Laboratory, Center for Bio/Molecular Science and Engineering, Code 6930, Naval Research Laboratory Overlook Avenue 4555, Washington, DC 20375, USA.
Singh
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D000480:Alkynes; D005231:Fatty Acids, Unsaturated / Q000737:chemistry*; D008081:Liposomes / Q000737:chemistry*; D008560:Membrane Fluidity; D019906:Nuclear Magnetic Resonance, Biomolecular; D010713:Phosphatidylcholines / Q000737:chemistry; D010743:Phospholipids / Q000737:chemistry*; D010777:Photochemistry; D011108:Polymers / Q000737:chemistry*
D000480:Alkynes; D005231:Fatty Acids, Unsaturated; D008081:Liposomes; D010713:Phosphatidylcholines; D010743:Phospholipids; D011108:Polymers; C031203:2-hexadecynoic acid