Structural characterization of polymeric liposomes

M. CRISTINA TAIRA, EVANDRO L. DUARTE, C. FACUNDO TEMPRANA, JULIETA GASPARRI, M. TERESA LAMY AND SILVIA DEL V. ALONSO.

Montevideo

Congreso; Internacional conferences of Biological Physics (ICBP 2007). 5th Southern Cone Biophysics Congress. 34th Annual meeting of the Argentinean Biophysical Society. Del 27 al 31 de agosto de 2007.; 2007

IUPAP and IUPAB

  The diacetylenic phosphatidylcholine 1,2-bis(10,12-tricosadiynoyl)sn-glycero-3-phosphocholine (DC8,9PC) can form intermolecular cross-linking through the diacetylenic group to produce a highly conjugated polymer within the hydrocarbon region of the bilayer. Addition of the saturated short chain lipid 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC) help the polymerization process of DC8,9PC (Alonso-Romanowski et al. 2003 Chem Phys Lipids 122: 191-203). The present work focuses on the possible relationship between structural properties of polymerized liposomes with mixture composition and polymerization cycles. The polymerization efficiency was found to be dependent on the number of UV polymerization cycles, and the DC8,9PC and DMPC molar ratio. Both DSC and ESR spectra indicate the presence of domains rich in DMPC and non-polymerized DC8,9PC. However, those domains are not constituted just by one of the lipids, as their structural properties are different from those for pure DMPC or DC8,9PC, as shown by DSC and ESR. The knowledge of liposome structures is certainly fundamental for the design of new and better lipid formulations. The diacetylenic phosphatidylcholine 1,2-bis(10,12-tricosadiynoyl)sn-glycero-3-phosphocholine (DC8,9PC) can form intermolecular cross-linking through the diacetylenic group to produce a highly conjugated polymer within the hydrocarbon region of the bilayer. Addition of the saturated short chain lipid 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC) help the polymerization process of DC8,9PC (Alonso-Romanowski et al. 2003 Chem Phys Lipids 122: 191-203). The present work focuses on the possible relationship between structural properties of polymerized liposomes with mixture composition and polymerization cycles. The polymerization efficiency was found to be dependent on the number of UV polymerization cycles, and the DC8,9PC and DMPC molar ratio. Both DSC and ESR spectra indicate the presence of domains rich in DMPC and non-polymerized DC8,9PC. However, those domains are not constituted just by one of the lipids, as their structural properties are different from those for pure DMPC or DC8,9PC, as shown by DSC and ESR. The knowledge of liposome structures is certainly fundamental for the design of new and better lipid formulations.