Aggregation Number of Cholesterol Moieties in Hydrophobic Microdomains Formed by Self-Association of a Cholesterol-Bearing Polyelectrolyte in Water

Binding of Bile Salts to an Amphiphilic Polysulfonate Modified with Cholesterol Moieties

“…Values of M n , M w , and M w =M n for these polymers estimated by GPC are listed in Table I. As reported in our earlier paper, 12 the cholesterol-bearing amphiphilic polyelectrolyte, p(AMPS/ Chol), forms a multipolymer aggregate consisting of a number of hydrophobic microdomains in one polymer aggregate. The mean aggregation number of the cholesteryl groups forming one hydrophobic microdomain was estimated to be ca.…”

“…This type of multipolymer aggregate can be envisaged as an intermolecularly bridged flower micelle. 12 SC is known to form a micelle in water. 24 To obtain information about the micellization of SC, we measured 1 H NMR spin-spin relaxation times (T 2 ) at varying concentrations of SC ([SC]) in the presence and absence of p(AMPS/Chol).…”

“…27 Therefore, it can be concluded that T 2 for SC in the monomer and micellar states are more or less 160 and 120 ms, respectively. In the presence of p(AMPS/Chol) (C 12 The R 90 values are proportionally related to the molecular mass for multipolymer aggregates. As [SC] is increased, R 90 for p(AMPS/Chol) decreases remarkably, indicating that the bridged flower micelle is disrupted by the addition of SC.…”

“…The cholesteryl moiety (5 mol %) bearing random copolymer (p(AMPS/Chol) in Figure 1) and sodium 2-(acrylamido)-2-methylpropanesulfoante homopolymer (p(AMPS) in Figure 1) employed in this study are the same polymers as those used in our previous work. 12 Water was purified with a Millipore Milli-Q system. Other reagents were used as received.…”

“…8,9 Previously, we reported that random copolymers of sodium 2-(acrylamido)-2-methylpropanesulfonate (AMPS) and cholesterol bearing methacrylate with low contents of cholesterol bearing monomer units ( 10 mol %) showed a strong tendency for interpolymer association in water even at very low polymer concentrations (C p ). [10][11][12] The cholesterol-bearing amphiphilic random copolymers form a ''closed'' type 13 multi-polymer flower micelle consisting of a number of hydrophobic microdomains (i.e., cores) in one polymer micelle. The mean aggregation number of the cholesteryl groups in one hydrophobic microdomain is very small.…”