Cholesteryl group

Another trend observed during the past decade was the coating of liposomes with mucoadhesive polymers. Liposomes are coated with chitosan, long-ehain polyvinyl alcohol, and polyacrylates bearing a cholesteryl group [90]. Chitosan-eoated liposomes showed superior adhesion properties to rat intestine in vitro than the other polymer-eoated liposomes. In vivo, chitosan-coated liposomes containing insulin substantially reduced blood glueose levels after oral administration in rats, whieh were sustained up to 12 hr after administration [90]. 

It is noteworthy that although WAXS data indicate that DDOA and CAB exhibit comparable types of molecular organization in their bulk solid states 93. their gel fibers are very different. Junction zones of DDOA gels are dry and crystalline, while those of CAB and CAQ are swollen lyotropic microdomains whose organization is clearly different from that of the solid 114]. ALS and AZOC gelators confirm that the cholesteryl group is an important element in... 

Because the micellar interior is far from being rigid, a solubilized substrate is relatively mobile. Like micelle formation, solubilization is a dynamic equilibrium process. Representative recent examples are the solubilization of benzene, naphthalene, anthracene, and pyrene in aqueous solution by the addition of 1-dodecanesulfonic acid [391], the solubilization of fullerene Ceo in aqueous solutions of the non-ionic surfactant Triton X-100 [392], and the solubilization of a cholesteryl-group bearing pullulane (a hydrophobized polysaccharide) [393]. 

There have been very few families of dendrimers built up around a pure siloxane core. One such dendrimer consisted of a dendritic methylsesquioxane matrix (Nq = 3, Mb = 2, Fig. 21) to which six terminal cholesteryl groups were attached via undecylene spacers [178]. This G1 compound exhibited a very broad temperature SmA phase (G -1.5 SmA 120 I). The molecules arrange in a single layer smectic phase with complete overlap of the cholesteryl meso-gens separated by siloxane layers. 

Similarly, the functionalization of the GO, G1 and G2 PPI dendrimers with cholesteryl groups through carbamate linkage appeared to be the right strategy to induce mesomorphism in these systems [206]. They all exhibit a glass transition between 63 and 78 °C, and after a rich thermal history, all melt into birefringent fluids at ca. 149-162 °C, identified as a SmA phase. GO then clears at 170 °C, whereas both G1 and G2 clear at 210 °C. 

In order to test the coordination ability of compound 12, the phenoxarsinine and phenothiarsinines with a bioactive cholesteryl group, viz. 13, were prepared by reacting 10-chloro-10//-phenothiarsinine 10 and 10-chloro-10//-phenox-arsinine 1 with compound 12. The latter is an anionic phosphorothioate ligand that incorporates a bioactive cholesteryl group, and was obtained from the phenyl phosphoramidate 11 (Scheme 6) <2000HAC6>. 

An acid chloride functionalized liquid crystalline material was tried to bond to the silanol group in silica. The direct reaction does not seem to be successful also, a spacer with a substituted dichlorodimethyl silane is not successful. The reaction scheme is shown in Figure 16.8. However, a separation performance is observed rather by deposition than by bonding of the liquid crystals. The liquid crystalline materials used in this study was based on cholesteric moieties. It is suspected that the reaction failed because of the large size of the cholesteryl group. In another study, dimeth-ylchlorosilane was added to the allyl group of 4-methoxyphenyl-4-allyloxy benzoate. This intermediate could be bonded to silica. Several other routes to fix liquid crystalline moieties on silica have been reviewed. ... 

Coating of emulsion particles with cholesterol-bearing polysaccharides, such as pullulan, amylopectin, and mannan, led to a reduction of the divalent metal ion-induced aggregation of Che emulsion droplets. The cholesteryl group behaves as a hydrophobic anchor in the surface lipid layer resulting in a lower fluidity of the. surface of the emulsion droplets (24). 

Figure 7 Sacrificial spacer method, as exemplified by the imprinting of cholesterol (a) cholesteryl (4-vinyl)phenyl carbonate 8 is used as the template monomer to form a covalently imprinted polymer (b) in the polymerization step, the carbonyl group of the carbonate ester holds the functional monomer and template oxygen atoms apart by two bond distances (c) hydrolysis results in loss of the template and loss of the spacer as CO2 (d) rebinding can now occur with the cholesterol ligand occupying essentially the same space as the template cholesteryl group (adapted from Ref. 10).

FIGURE 42 Imidazolium salts with terminally attached mesogenic groups and with [Eu(tta)4] counter ions. Only the compound with two cholesteryl groups (structure at the bottom) shows liquid-crystalline properties Cr 121 (SmA 101) 1 (Goossens et ah, 2008). 

Meng, F. Lian, J. Zhang, B. Sun, Y., Chiral Side-Chain Liquid-Crystalline Polysiloxanes Bearing Fluorinated Mesogens and Cholesteryl Groups. Eur. Polym. J. 2008, 44, 504-513. 

Tamaoki and coworkers reported some chiral azobenzenes and diphenylbutadiene-based LC dimers 13-15 exhibiting light-induced phase transition behavior starting from smectic phases [26, 51-55]. For example, dimers 15, which were synthesized by connecting a cholesteryl group with 1,4-diphenylbutadiene unit, were found to experience isothermal phase transition from SmA to N and further to the isotropic state upon UV light irradiation at 366 nm [26]. 

Mallia, V. A. Tamaoki, N. Design of chiral dimesogens containing cholesteryl groups formation of new molecular organizations and their application to molecular photonics. Chem. Soc. Rev. 2004,33,76. 

Regular surface-rehef calcium carbonate structures were prepared by a cooperated directing agent of soluble poly(acryhc acid) (PAA, Mw = 2000) and a substrate of cholesterol-bearing pullulans (Fig. 15) [231]. At low temperature, adapted PAA concentration, and with cholesteryl groups, a high quality periodic calcite structure can be formed by a self-organization process in the reaction-diffusion system with competition between precipitation and ion diffusion. 

Fujioka-kobayashi, M., Ota, M.S., Shimoda, A., Nakahama, K., Akiyoshi, K., Miyamoto, Y, Iseki, S., 2012. Cholesteryl group and acryloyl group-bearing pullulan nanogel to dehver BMP2 and FGF18 for bone tissue engineering. Biomaterials 33, 7613-7620. 

Vincent N, Genin C, Malvoisin E. Identification of a conserved domain of the HIV-1 transmembrane protein gp41 which interacts with cholesteryl groups. Biochim Biophys Acta. 2002 1567(1-2) 157-164. 

In Reference 113, an aptamer-modified MEKC method consisting of nonionic micelles (surfactant is Tween 20) and a hydrophobic cholesteryl group-tagged aptamer (Choi Apt), which partitioned into the uncharged micellar phase, was used. When a 50-p,m-i.d., PVA-coated, bubble-cell capillary (total/effective lengths 64.5/56 cm) was filled with a 20-mM phosphate buffer with pH 7.0 with 5-mM KCl and 5-mM MgCU, ADP (adenosine diphosphate), and ATP (adenosine triphosphate) were baseline separated AMP (adenosine monophosphate) could be partially separated. The T veen 20 concentration was 35 mM. 

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