Micelles polymeric

Block copolymers spontaneously assemble into nanoscaled polymeric micelles. Self-assembling block copolymer micelles have long been explored 

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Figure C2.3.11 Key surfactant stmctures (not to scale) in emulsion polymerization micelles containing monomer and oligomer, growing polymer particle stabilized by surfactant and an emulsion droplet of monomer (reservoir) also coated with surfactant. Adapted from figure 4-1 in [67],...

Mortensen K 1998 Structural properties of self-assembled polymeric micelles Curr. Opin. Colloid Interface Sol. 3 12-19... 

Soap. A critical ingredient for emulsion polymerization is the soap (qv), which performs a number of key roles, including production of oil (monomer) in water emulsion, provision of the loci for polymerization (micelle), stabilization of the latex particle, and impartation of characteristics to the finished polymer. 

A large variety of drug delivery systems are described in the literature, such as liposomes (Torchilin, 2006), micro and nanoparticles (Kumar, 2000), polymeric micelles (Torchilin, 2006), nanocrystals (Muller et al., 2011), among others. Microparticles are usually classified as microcapsules or microspheres (Figure 8). Microspheres are matrix spherical microparticles where the drug may be located on the surface or dissolved into the matrix. Microcapsules are characterized as spherical particles more than Ipm containing a core substance (aqueous or lipid), normally lipid, and are used to deliver poor soluble molecules... 

Oheme and co-workers investigated335 in an aqueous micellar system the asymmetric hydrogenation of a-amino acid precursors using optically active rhodium-phosphine complexes. Surfactants of different types significantly enhance both activity and enantioselectivity provided that the concentration of the surfactants is above the critical micelle concentration. The application of amphiphilized polymers and polymerized micelles as surfactants facilitates the phase separation after the reaction. Table 2 shows selected hydrogenation results with and without amphiphiles and with amphiphilized polymers for the reaction in Scheme 61.335... 

Arimura H, Ohya Y, Ouchi T (2005) Formation of core-shell type biodegradable polymeric micelles from amphiphilic poly(aspartic acid)-Wock-polylactide diblock copolymer. Biomacromolecules 6 720-725... 

Fig. 9 Preparation of PIC-coated polymeric micelles and their atomic force microscope (AFM) images. Reprinted from [201] with permission...

Nishiyama N, Okazaki S, Cabral H, Miyamoto M, Kato Y, Sugiyama Y, Nishio K, Matsumura Y, Kataoka K (2003) Novel cisplatin-incorporated polymeric micelles can eradicate solid tumors in mice. Cancer Res 63 8977-8983... 

Bae Y, Kataoka K (2009) Intelligent polymeric micelles from functional poly(ethylene glycol)-poly(amino acid) block copolymers. Adv Dmg Deliv Rev 61 768-784... 

Fig. 30 Types of nanocarriers for drug delivery, (a) Polymeric nanoparticles polymeric nanoparticles in which drugs are conjugated to or encapsulated in polymers, (b) Polymeric micelles amphiphilic block copolymers that form nanosized core-shell structures in aqueous solution. The hydrophobic core region serves as a reservoir for hydrophobic drugs, whereas hydrophilic shell region stabilizes the hydrophobic core and renders the polymer water-soluble.

In dilute aqueous solutions, copolymers having hydrophobic and hydrophilic parts may form polymeric micelles, i.e. stable particles with a core-shell structure. The association of the hydrophobic parts of the block copoly-... 

The copolymer-based systems possessing the core-shell structure in solutions are known and studied rather well (see, e.g., [14-16]). These copolymers in aqueous media tend to form polymeric micelles, which are often considered as promising drug delivery nano-vehicles [ 17,18], i.e., these macromolecular systems are not only of scientific, but also of considerable applied significance. Among such systems there are interesting examples, whose properties are very similar to the properties that should be inherent in the protein-like copolymers. All of these macromolecules possess the primary structure of... 

Synthetic polyisoprene, 9 559 Synthetic polymer architectures, 26 786 Synthetic polymeric micelles, 20 482 Synthetic polymers... 

Toshima, N., Takahashi, T., and Hirai, H., Polymerized micelle-protected platinum clusters-preparation and application to catalyst for visible light-induced hydrogen generation, J. Macromol. Sci. -Chem., A25, 669,1988. 

Birrenbach G, Speiser PP (1976) Polymerized micelles and their use as adjuvants in immunology. J Pharm Sci 65 1763-1766. 

Cytotoxicity of Polymeric Micelles Modulated by Temperature Changes References... 

Thermoresponsive Polymeric Micelles for Double Targeted Drug Delivery... 

We have shown that polymeric micelles constmcted of block copolymers of poly(ethylene oxide) (PEG) and poly(L-asparate) containing the anticancer dmg (adriamycin, ADR) selectively accumulate at solid tumor sites by a passive targeting mechanism. This is likely due to the hydrophilicity of the outer PEG chains and micellar size (<100 nm) that allow selective tissue interactions [17,18]. Polymeric micelle size ranges are tailored during polymer synthesis steps. Carefully selection of block polymer chemistry and block lengths can produce micelles that inhibit nonselective scavenging by the reticuloendothelial system (RES) and can be utilized as targetable dmg... 

Scheme 2 Thermoresponsive polymeric micelle structures and fimctions.

Polymeric micelles with selected chemistries and molecular architecture of block copolymers, such as PIPAAm-CigHgs, PIPAAm-PSt, PIPAAm-PBMA, and PIPAAm-PLA micelles, showed the same LCST and the same thermoreponsive phase transition kinetics as those for PIPAAm irrespective of the hydrophobic segment incorporation. This confirms two points (a) that hydroxyl groups or amino goups of PIPAAm termini completely react with the hydrophobic segment end groups and (b) that the block copolymers form core-shell micellar structures with hydrophobic iimer cores completely isolated from the aqueous phase. 

ON-OFF SWITCHABLE DRUG RELEASE FROM THERMORESPONSIVE POLYMERIC MICELLES... 

CYTOTOXICITY OF POLYMERIC MICELLES MODULATED BY TEMPERATURE CHANGES... 

Shown in Figure 6 is in vitro cytotoxic activity of PIPAAm-PBMA micelles loaded with ADR or micelles without ADR at 29°C (below the LCST) and at 37°C (above the LCST) compared with that of free ADR. In vitro cytotoxic activity was measured using bovine aorta endothelial cells. Bovine aortic endothelial cells were obtained as previously reported using dispase for cell dissociation from freshly harvested bovine aorta [13]. The cells plated at a density of 3 x cells/well, were exposed with free ADR or micelles loaded with ADR at below and above the LCST for 5 days. In order to assay cytotoxicity of the free ADR or micelles loaded with ADR, culture medium was replaced with 10% FBS-supplemented phenol red-free DMEM containing 10% alamar Blue, a dye that is subject to reduction by cytochrome c activity and changes the color from blue to red [38]. After 4-hour incubation, reduction of the dye was estimated by absorbance at 560 and 600 nm. PIPAAm-PBMA polymeric micelles loaded with ADR showed higher cytotoxic activity than that of free ADR at 37°C (above the LCST)... 

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