Micelle Preparation

Gaucher G, Dufresne MH, Sant VP et al (2005) Block copolymer micelles preparation, characterization and application in drug delivery. J Control Release 109 169-188... 

Addition of a selective solvent to molecularly dissolved chains has been used by many research teams to prepare block copolymer micelles. The initial nonselective solvent can be further eliminated by evaporation or can be gradually replaced by the selective solvent via a dialysis process. The stepwise dialysis initially introduced by Tuzar and Kratochvil is now widely used for micelle preparation [6], especially for the formation of aqueous micelles [32],... 

The micellar structure depicted in Fig. 2 is of course only valid for simple AB diblock copolymers. The situation can be much more complex for micelles prepared from block copolymers with complex architectures, as will be discussed later. 

SANS has been recently used to study problems related to micelle preparation and kinetics, as reported by Bates and coworkers who have used time-resolved SANS to study molecular exchange and micelle equilibration for PEO-PB diblocks in water [71]. The authors have shown that the micellar structures initially formed upon dissolution were completely locked in up to 8 d after preparation. Fluorometry and DLS have also been used to monitor micelle equilibration [72],... 

Using N-terminus modified polylysine, we developed a synthesis for an amphiphilic polychelator, A,a-(DTPA-polylysyl)glutaryl phosphatidyl ethanolamine (DTPA-PL-NGPE). This polychelator was incorporated into the liposomal membrane and micelle core during liposome or micelle preparation. This system sharply increased the number of chelated Gd atoms attached to a single lipid anchor. This increased the number of bound reporter metal atoms per vesicle and decreased the dosage of an administered... 

CdS AND CdTe NANOPARTICLES MADE IN REVERSE MICELLES PREPARATION MODES AND OPTICAL PROPERTIES... 

A higher level of size and morphology control in the incipient semiconductors has been accomplished in reversed micelles prepared from cadmium AOT [614] and from mixtures of cadmium AOT and sodium AOT [615] or, alternatively, by arresting particle growth by surface derivatization [592, 621, 622]. Indeed, surface derivatization of semiconductor clusters was first reported for particles in reversed micelles [621] the reversed micelles act to confine precursor ions and to control the growth of the semiconductor particles. Conditions are typically arranged so that, initially, there is no more than one metal ion (say Cd2+) per water pool. Addition of a heptane solution of bis(trimethylsilyl) selenium resulted in the formation of size-quantized metal selenide particles (say CdSe) in the reversed micelles. This solution could be evaporated to dryness and the resultant particles could be reconstituted in a hydrocarbon solvent Alternatively, addition of metal (say Cd2+) ions to the reversed-micelle-entrapped metal selenide particles, followed by the addition of alkyl(trimethylsilyl)selenium, RMSiMe3, led to the formation of alkyl-capped... 

Intestinal absorption studies of Mn-MP were undertaken in an effort to assess the viability of the metalloporphyrin as an oral hepatobiliary agent [101, 102]. Mixed micelles of Mn-MP complexed with monoolein and taurocholate were administered to rats, resulting in liver image enhancement 68% above baseline levels six hours after administration [101]. In pigs, the mixed micelle preparation showed variable enhancement over 24 hours. Observation that Mn-MP interacts with oleic acid vesicles [103] led to investigations of the effect of oleic acid on the absorption rate of Mn-MP from the small bowel into the circulatory system [102,104]. The increase in absorption of the complex was mediated by a decrease in the relaxivity of the metalloporphyrin resulting from the interaction with the lipid vesicles. 

Harada, A. and Kataoka, K. (1999b) Novel polyion complex micelles entrapping enzyme molecules in the core. 2. Characterization of the micelles prepared at nonstoichiometric mixing ratios. Langmuir, 15, 4208 1212. 

Gaucher, G., et al. (2005), Block copolymer micelles Preparation, characterization and apphcation in drug delivery, J. Controlled Release, 109(1-3), 169-188. 

Micelle preparation starts from the design of the block copolymer precursors. Even if two blocks of the copolymer have to be incompatible in order to guide the self-assembly, their solubility in the dispersion solvent can vary between two extreme cases (1) the two blocks can have a different solubility such that the use of a selective solvent will trigger the micelle formation and (2) the two blocks can have the same solubility, the solvent being non-selective. In this case, micelles will be produced by the in situ formation of multiple cross-linking points. 

We have systematically examined the micellar size of the different polyesters completely neutralized with the amines listed in Table II. The size of the micelles prepared by the laboratory technique is constant, within experimental errors, for a given... 

Table IV. Micellar Characteristics of Carboxy Terminated Polyesters Micelles Prepared by an Industrial Procedure...

Evidence for this process has been obtained in systems of charged micelles prepared from linolenic acid (48) and by chemiluminescence in very early stages of lipid oxidation in oils and a variety of foods (49). 

Fig. 15 Panel for the micelle with targeting moiety, a Chemical structure of lactosy-lated PEG-PAMA and its micelle formation with pDNA. b Effect of transfection time on gene expression. HepG2 cells were transfected with acetal- or lactose-micelles prepared at N/P = 6.25 in the medium (DMEM -t 5% FBS) containing 100 xM HCQ. Transfection with LipofectAMlNE was done in the same medium without HCQ ( SEM, n = 4). c Inhibitory effect of asialofetuin (ASF) on gene transfer to HepG2 cells co-incubated with the micelles with or without ligand moiety. The transfection time was fixed to 6 h. ( SEM, = 4) (Fig. 15c Reprinted with permission from [135])...

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