Encapsulation macromolecules

Bryant, S. J., Davis-Arehart, K. A., Luo, N., Shoemaker, R. K., Arthur, J. A. Anseth, K. S. (2004) Synthesis and characterization of photopolymerized multifunctional hydrogels water-soluble poly(vinyl alcohol) and chondroitin sulfate macromers for chondroc5te encapsulation. Macromolecules, 37, 6726-6733. 

Above we described the possibilities how to introduce the macromolecules into the hollow capsules by regulation of shell permeability. Pores in the polyelectrolyte shell can be opened and closed by variation of pH, salt and/or solvent exchange. The main drawback if this approach is low encapsulation efficiency for macromolecules. Indeed, one could capture in the hollow capsules only the macromolecules, which are floating in the capsule interior when pores are closed. In following we propose another approach to encapsulate macromolecules and nanoparticles which could provide rather high encapsulation efficiency. This approach consists in combination of layer-by-layer approach and controlled precipitation of polymers on surface of colloidal particles. 

Straubinger, R. M., N. Duzgunes and D. Papahadjopoulos, 1985, pH-sensitive liposomes mediate cytoplasmic delivery of encapsulated macromolecules. FEES Lett 179 148-154. 

R 127 T. Dziembowska, P.E. Hansen and Z. Rozwadowski, Studies Based on Deuterium Isotope Effect on C Chemical Shifts , p.l R 128 P.E. Flynn, Multidimensional Multinuclear Solution NMR Studies of Encapsulated Macromolecules , p. 31... 

The volume of the inner aqueous phase is a significant factor in evaluating the entrapping ability of aqueous compounds a vesicle system with a large internal volume can encapsulate macromolecules more efficiently than systems with smaller internal volumes. The work reported here investigates the protein-trapping capability and efficiency of three different types of vesicles formed by soybean phosphatidylcholine. 

Chemically, GA is a complex mixture of macromolecules of different size and composition (mainly carbohydrates and proteins). Today, the properties and features of GA have been widely explored and developed and it is being used in a wide range of industrial sectors such as textiles, ceramics, lithography, cosmetics and pharmaceuticals, encapsulation, food, etc. Regarding food industry, it is used as a stabilizer, a thickener and/or an emulsifier agent (e.g., soft drink syrup, gummy candies and creams) (Verbeken et al., 2003). 

It appears that none of these process techniques is dominant, at least with the lactide/glycolide materials. Researchers have considerable choices available in regard to fabrication of microspheres from these polymers. The most commonly used procedures employ relatively mild conditions of pH and temperature and are usually quite compatible with the bioactive agents to be entrapped, including proteins and other macromolecules. Only in the case of live virus and living cell encapsulation have serious deactivation problems been encountered and those problems were due to solvents used in the process. 

Shew, R. L., and Deamer, D. W. (1985). A novel method for encapsulation of macromolecules in liposomes, Biochim. Biophys. 

This manuscript describes the dendritic macromolecules for optical and optoelectronic apph-cations, particularly stimulated emission, laser emission, and nonlinear optics. Dendrimers have been designed and synthesized for these applications based on simple concepts. A coreshell structure, through the encapsulation of active imits by dendritic branches, or a cone-shaped structure, through the step-by-step reactions of active imits, can provide particular benefits for the optical high-gain media and nonlinear optical materials. It also described experimental results that support the methods presented for designing and fabricating functionalized dendrimers for optoelectronic applications, and theoretical results that reveal the intermolecular electronic effect of the dendritic structure. 

Fig. 10.6 Macromolecules can also be encapsulated in liposomes. This is done by drying a mixture of liposomes and macromolecules these form polylayer structures, the macromolecules being embedded in alternating layers. Almost half the macromolecules are incorporated in liposomes on rehydration (Deamer, 1998)...

Initial efforts gave rise to well-characterized dendritic macromolecules, but applications remained limited because of the lack of specific functionalities. An exponential increase of publication volume observed for about 15 years testified the growing interest for dendrimers and has led to versatile and powerful iterative methodologies for systematically and expeditiously accessing complex dendritic structures. The perfect control of tridimensional parameters (size, shape, geometry) and the covalent introduction of functionalities in the core, the branches, or the high number extremities, or by physical encapsulation in the microenvironment created by cavities confer such desired properties as solubility, and hydrophilic/hydrophobic balance. Thus, creativity has allowed these structures to become integrated with nearly all contemporary scientific disciplines. 

The process of combining cyanine and squaraine dyes by encapsulation, or covalent or noncovalent attachment with macrocyclic hosts, macromolecules, and micro- or nano-particles is a promising way to design novel probes and labels with substantially improved properties and for the development of advanced fluorescence-based assays. Nevertheless, the physicochemical properties of these dye-compositions are strongly dependent on the dye structure as well as the nature of the host macrocycle, macromolecule, or particle. Finally, development of new methods to synthesize these tracers can also be considered a challenging task. 

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