Sato, Takaaki and Sakai, Hiromi and Sou, Keitaro and Buchner, Richard and Tsuchida, Eishun (2007) Poly(ethylene glycol)-conjugated phospholipids in aqueous micellar solutions: Hydration, static structure, and interparticle interactions. JOURNAL OF PHYSICAL CHEMISTRY B, 111 (6). pp. 1393-1401. ISSN 1520-6106,
Full text not available from this repository. (Request a copy)Abstract
By means of dielectric relaxation spectroscopy (DRS) and small-angle X-ray scattering (SAXS), we have investigated hydration behavior, solvent dynamics, and static structures of aqueous solutions of poly(ethylene glycol)-conjugated distearoyl phosphatidylethanolamine (DSPE-PEG) (molecular weight of PEG: M-PEG = 2000, 5000, and 12 000 Da). A quantitative analysis of the bulk-water relaxation amplitude revealed the effective hydration number of a DSPE-PEG molecule per ethylene oxide monomer unit to be similar to 5.0-5.5, virtually independent of M-PEG. The overall hydration number of a DSPE-PEG molecule is ca. 20% higher than that of the corresponding normal PEG (without DSPE). This is attributed to both hydration of a charged head group of phosphoric acid in DSPE and a packing effect of PEG chains into micellar structures. The pair-distance distribution functions, p(r), extracted from the GIFT analysis of SAXS intensities show that the DSPE-PEGs form spherical-like micelles in water having the maximum diameter of similar to 16, 22, and 31 nm, respectively, for M-PEG = 2000, 5000, and 12 000 Da and nearly identical aggregation numbers of 72 (+/- 10%). The DSPE-PEG micelles behave as charged colloids whose interparticle interaction potential can be approximated by the screened Coulomb potential model. The extracted pair correlation function g(r) demonstrates that both electrostatic repulsion induced by the charged head group and excluded volume effects of the fully hydrated PEG layer contribute to repulsive interactions among the PEG-lipid micelles. This should be a key factor for the function of PEG lipids as a stabilizer of liposomes.
| Item Type: | Article |
|---|---|
| Uncontrolled Keywords: | SMALL-ANGLE SCATTERING; INDIRECT FOURIER TRANSFORMATION; DIELECTRIC-RELAXATION; PHASE-BEHAVIOR; COOPERATIVE DYNAMICS; SURFACE MODIFICATION; HEMOGLOBIN-VESICLES; CELL SUBSTITUTE; LIPOSOMES; MIXTURES; |
| Subjects: | 500 Science > 540 Chemistry & allied sciences |
| Divisions: | Chemistry and Pharmacy > Institut für Physikalische und Theoretische Chemie > Chair of Chemistry VI - Physical Chemistry (Solution Chemistry) > PD Dr. Richard Buchner |
| Depositing User: | Dr. Gernot Deinzer |
| Date Deposited: | 22 Dec 2020 10:14 |
| Last Modified: | 22 Dec 2020 10:14 |
| URI: | https://pred.uni-regensburg.de/id/eprint/33182 |
Actions (login required)
 |
View Item |
