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Biodegradable amphiphilic copolymers were successfully synthesized by the conjugation of various densities of hydrophobic biocompatible cholesterol (Chol) moieties onto poly(2-hydroxyethyl aspartamide) and poly(N-isopropylaminoethyl-co-2-hydroxyethyl aspartamide). These were obtained from polysuccinimde, the thermal polycondensation product of L-as...
Contexts in source publication
Context 1
... amphiphilic polyaspartamide derivatives with alcohol and N-isopropylamine pendant groups con- taining Chol moieties (PHEA-Chol and PNIEA- Chol) were successfully synthesized, and their struc- tures and characteristics were confirmed by 1 H- NMR spectroscopy. As shown in Figure 1, the C and D peaks were characterized as the two methylene groups of the EA pendant group in PHEA. In Figure 2, peaks C, D, E, and F were assigned to the NIPEDA pendant group, and peaks G and H were related to the two methylene protons of EA. ...
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... we discussed pre- viously, the presence of the N-isopropylamine group in PNIEA caused an increase in Chol conjugation, but on the other hand, it seemed to accelerate the hydrolysis process in aqueous media; this led to a reduction in the particle size over a short time. Changes in the particle size distribution of the PNIEA-Chol series as function of time are shown in Figure 10. The particle size of this system decreased to several 10s of nanometers over a few days, and finally, the particles could not be detected by DLS because of their low intensity. ...
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... particle size of this system decreased to several 10s of nanometers over a few days, and finally, the particles could not be detected by DLS because of their low intensity. Additionally, the decreasing Chol content was confirmed by 1 H-NMR, and these results are shown in Figure 11. The faster degradation phenomenon in the PNIEA-Chol system may have been due to the presence of neighboring secondary amine groups on the polymer, which could catalyze the hydrolytic cleavage of the carbonate link- age between the polymer and cholesteryl moiety. ...
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... addition to the hydrophilic property of PNIEA, which increased the solubility of the PNIEA-Chol system in water, the presence of amine groups in this system resulted in a pH-dependant particle size distribution, as shown in Figure 12. All the copoly- mers were totally dissolved in water (1 wt % con- centration), and the initial pH values were recorded; the micelle size was measured by DLS. ...
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Citations
The synthesis of a series of PEG and polyaspartamide-based block copolymers containing azide and alkyne function groups and its micelle formation in aqueous solution were described. The self-assembly behavior of these amphiphilic copolymers in aqueous media to form nano-sized micelle and the core-crosslinking reaction to convert them to stable nanoparticle were investigated. The particle size distributions were measured by dynamic light scattering (DLS). The resulting nanogel, prepared by click reaction within the mixed micelle core has been shown to exhibit stability upon dilution and also in the presence of SDS, a small molecule surfactant, suggesting the potential use as carrier for current drug delivery system.
The production of poly-[(N-2-hydroxyethyl)-aspartamide](PHEA)based materials is hampered by the unsatisfactory synthesis and low reactivity in terms of post-modification. Herein, we report the controlled synthesis of PHEA-based polymers, unraveled the hydrogen bonding in PHEA, developed effective approaches to enhance the reactivity of PHEA by improving the temperature, and further demonstrated the desired aqueous solubility as well as the lyophilization stability of PHEA-based amphiphiles. This study will provide insights into the design of useful and functionalized polypeptide-based biomaterials.
Water-soluble neutral and charged copolymers of cholesterol methacrylate with 2-deoxy2-methacrylamido-D-glucose and methyl sulfate salt of N,N,N-trimethyl(aminoethyl methacrylate) and ?-cyclodextrin-containing polymers of different compositions were synthesized. The interactions of the ?dark? and luminescence-labeled copolymers with models of lowmolecular-weight hydrophobic compounds (cholesterol and acridine orange) and of highmolecular-weight biologically active compounds containing hydrophobic fragments with bovine serum albumin were studied by the method of polarized luminescence. Cholesteroland ?-cyclodextrin-containing polymers actively bind these compounds by inclusion them into hydrophobic domains or due to the formation of host?guest complexes. The variation of the polymer structure makes it possible to control the degree of binding. The synthesized polymers are promising carriers of hydrophobic substances and can further serve as a basis for manufacturing systems for control of the level of hydrophobic substances in aqueous solutions and biological liquids.
Cholesterol is a ubiquitous molecule in biological systems, and in particular plays various important roles in mammalian cellular processes. The presence of cholesterol is integral to the structure and behavior of biological membranes, and profoundly influences membrane involvement in cellular mechanisms. This review focuses on the incorporation of cholesterol into synthetic nanomaterials and assemblies, focusing on LC phase behavior, morphology/self-organization and hydrophobic interactions, all important factors in the design of nanomedicines. We highlight cholesteryl conjugates, liposomes and polymeric micelles, focusing on self-assembly capabilities, drug encapsulation and intracellular delivery. An area of considerable interest identified in this review is the use of cholesteryl-functional vectors to deliver drugs or nucleic acids. Such applications depend on the ability of the nanoparticle carrier to associate with both the cellular and endosomal membrane.
Cholesterol is a molecule with many tasks in nature but also a long history in science. This feature article highlights the contribution of this small compound to bionanotechnology. We discuss relevant chemical aspects in this context followed by an overview of its self-assembly capabilities both as a free molecule and when conjugated to a polymer. Further, cholesterol in the context of liposomes is reviewed and its impact ranging from biosensing to drug delivery is outlined. Cholesterol is and will be an indispensable player in bionanotechnology, contributing to the progress of this potent field of research.
