抄録
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 12000 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 ∼5.0-5.5, virtually independent of MPEG. 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 ∼16, 22, and 31 nm, respectively, for MPEG = 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.
| 元の言語 | English |
|---|---|
| ページ（範囲） | 1393-1401 |
| ページ数 | 9 |
| ジャーナル | Journal of Physical Chemistry B |
| 巻 | 111 |
| 発行部数 | 6 |
| DOI | |
| 出版物ステータス | Published - 2007 2 15 |
Fingerprint
ASJC Scopus subject areas
- Physical and Theoretical Chemistry
これを引用
Poly(ethylene glycol)-conjugated phospholipids in aqueous micellar solutions : hydration, static structure, and interparticle interactions. / Sato, Takaaki; Sakai, Hiromi; Sou, Keitaro; Buchner, Richard; Tsuchida, Eishun.
：: Journal of Physical Chemistry B, 巻 111, 番号 6, 15.02.2007, p. 1393-1401.研究成果: Article
}
TY - JOUR
T1 - Poly(ethylene glycol)-conjugated phospholipids in aqueous micellar solutions
T2 - hydration, static structure, and interparticle interactions
AU - Sato, Takaaki
AU - Sakai, Hiromi
AU - Sou, Keitaro
AU - Buchner, Richard
AU - Tsuchida, Eishun
PY - 2007/2/15
Y1 - 2007/2/15
N2 - 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 12000 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 ∼5.0-5.5, virtually independent of MPEG. 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 ∼16, 22, and 31 nm, respectively, for MPEG = 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.
AB - 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 12000 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 ∼5.0-5.5, virtually independent of MPEG. 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 ∼16, 22, and 31 nm, respectively, for MPEG = 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.
UR - http://www.scopus.com/inward/record.url?scp=33847405727&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=33847405727&partnerID=8YFLogxK
U2 - 10.1021/jp067011k
DO - 10.1021/jp067011k
M3 - Article
C2 - 17286354
AN - SCOPUS:33847405727
VL - 111
SP - 1393
EP - 1401
JO - Journal of Physical Chemistry B Materials
JF - Journal of Physical Chemistry B Materials
SN - 1520-6106
IS - 6
ER -