Composition dependence of the micellar architecture made from poly(ethylene glycol)-block-poly(partially benzyl-esterified aspartic acid).
Poly(ethylene glycol)-block-poly(partially benzyl-esterified aspartic acid), denoted by PEG-P(Asp(Bzl)), is one of the most examined blockcopolymers for drug carriers. However, little is known about fundamental physical properties. Nine samples of PEG-P(Asp(Bzl)) with different benzylation fractions (F(Bzl)) and aspartic chain lengths (DP(Asp)) were synthesized, and the aggregation number (N(agg)), core radius (R(C)), and other structural parameters were determined with combination of light scattering and synchrotron X-ray small-angle scattering. The major factor to determine N(agg) and R(C) was found to be F(Bzl), i.e., the hydrophobic nature of the core, even though F(Bzl) was changed in the relatively small composition range from 66 to 89 mol %. When we compared the data for the same F(Bzl), the scaling theory was consistent with the core chain length dependence of both core and micelle sizes. The overcrowding nature of the tethered PEG chains on the micelles was increased about 1.3-2.9 times with increasing N(agg) compared with the unperturbed state in solutions.
Department of Chemistry and Biochemistry, The University of Kitakyushu, 1-1 Hibikino, Wakamatsu-ku, Kitakyushu, Fukuoka 808-0135, Japan.
Yusuke
Y
Sanada
Isamu
I
Akiba
Satoshi
S
Hashida
Kazuo
K
Sakurai
Kouichi
K
Shiraishi
Masayuki
M
Yokoyama
Naoto
N
Yagi
Yuya
Y
Shinohara
Yoshiyuki
Y
Amemiya
D001224:Aspartic Acid / Q000737:chemistry*; D001704:Biopolymers / Q000737:chemistry*; D004337:Drug Carriers / Q000737:chemistry; D008823:Micelles; D015394:Molecular Structure; D011092:Polyethylene Glycols / Q000737:chemistry*
D001704:Biopolymers; D004337:Drug Carriers; D008823:Micelles; C416210:poly(ethylene oxide)-block-poly(beta-benzyl aspartate); D001224:Aspartic Acid; D011092:Polyethylene Glycols