Encapsulated protein

The second part, on biological applications of interfacial phenomena, has ten chapters that deal successively with protein encapsulation, membranes, effects of phospholi-... 

Water-in-Oil Microemulsions Protein Encapsulation and Release Douglas G. Hayes... 

Kida T, Inoue K, Akagi T et al (2007) Preparation of novel polysaccharide nanoparticles by the self-assembly of amphiphilic pectins and their protein-encapsulation ability. Chem Lett 36 940-941... 

Akagi T, Shima F, Akashi M (2011) Intracellular degradation and distribution of protein-encapsulated amphiphilic poly(amino acid) nanoparticles. Biomaterials 32 4959 1967... 

W. Jin and J.D. Brenan, Properties and applications of proteins encapsulated within sol-gel derived materials. Anal. Chim. Acta 461, 1—36 (2002). 

Proteins may be stabilized by encapsulation in polyanhydride microspheres. Stability of proteins with respect to water-induced aggregation has been demonstrated to be a function of polymer hydrophobicity for insulin and bovine somatotropin as model proteins (Ron et al., 1993). Encapsulation and enzymatic activity of a variety of other proteins encapsulated in P(SA FAD) was studied by Tabata et al. (1993). 

FIGURE 8.15 Protein encapsulation in a silica matrix via sol-gel processing the process include (a) formation of the sol particles during hydrolysis and initial condensation, (b) addition of the protein into the sol solution, and (c) the growing silica network entraps the protein molecule. (Reprinted from M. Kato et al. Anal. Chem., 74 1915 (2002). With permission. Copyright American Chemical Society 2002.)... 

Kato, M., Samwatari, H., Sakai-Kato, K., and Toyo oka, T. (2004). Silica sol-gel/organic hybrid material for protein encapsulated column of capillary electrochromatography.. Chromatogr. A 1044, 267-270. 

Counterion extraction Due to the relative slowness of back extraction based on the methods above, the back-extraction of proteins encapsulated in AOT reverse micelles was evaluated by adding a counterionic surfactant, either TOMAC or DTAB, to the reverse micelles [33]. This novel backward transfer method gave higher backward extraction yields compared to the conventional method. The back-extraction process with TOMAC was found to be 100 times faster than back-extraction with the conventional method, and as much as three times faster than forward extraction. The 1 1 complexes of AOT and TOMAC in the solvent phase could be efficiently removed using adsorption onto montmorillonite so that the organic solvent could be reused. 

Few works on proteins encapsulation have been presented. A recent study by Young et al. [60] deals with the encapsulation of lysozyme in biodegradable polymer microspheres. A 1-10 pm lysozyme particle suspension in a polymer solution was sprayed into a CO2 vapour phase through a capillary nozzle. The droplets solidified after falling into the liquid phase. By delaying the precipitation in the vapour phase, the larger microparticles obtained were able to encapsulate the suspended lysozyme. The final capsules were in the range of 5 - 70 pm. This work is a nice example of protein encapsulation for microparticle delivery systems. 

It also should offer promise for cell extractions, which, after all, are lipid/protein encapsulated mixtures of polar and nonpolar compounds. It would be interesting to see the effect of DMSO or DMF on the extraction of proteins. My guess is that protein might denature in 50% DMSO and precipitate so they could be filtered off or might renature and refold on lOx dilution in water and stay in solution. This might make an interesting research problem for recovering membrane-bound proteins. 

Volodkin DV, Larionova NI, Sukhorukov GB (2004) Protein encapsulation via porous CaC03 microparticles templating. Biomacromolecules 5 1962-1972... 

Petrov Al, Volodkin DV, Sukhorukov GB (2005) Protein-calcium carbonate co-precipitation. A tool for protein encapsulation. Biotechnol Prog 21 918-925... 

In addition, tween 20 reduced the number of aqueous channels between the internal aqueous droplets as well as those communicating with the external medium. The inventors claimed that these results constitute a step ahead in the improvement of an existing technology in controlling protein encapsulation and delivery from microspheres prepared by the multiple solvent evaporation method [215]. 

Peptide/Protein Encapsulated into Biodegradable Microspheres Case Study... 

PEPTIDE/PROTEIN ENCAPSULATED INTO BIODEGRADABLE MICROSPHERES 419... 

Fu, K., Griebenow, K., Hsieh, L., Klibanov, A. M., and Langer, R. (1999), FTIR characterization of the secondary structure of proteins encapsulated within PLGA microspheres, /. Controlled Release, 58, 357-366. 

Park,T. G., Lu, W., and Crotts, G. (1995), Importance of in vitro experimental conditions on protein release kinetics, stability and polymer degradation in protein encapsulated poly(D,L-lactic acid-co-glycolic acid) microspheres,/. Controlled Release, 33,211-222. 

Schwendeman, S. P. (2002), Recent advances in the stabilization of proteins encapsulated in injectable PLGA delivery systems, Crit. Rev. Therap. Drug Carrier Syst., 19, 73-98. 

---