コアセルベーション、コロイド脱混合現象

Wikipedia preview

出典(authority):フリー百科事典『ウィキペディア（Wikipedia）』「2015/09/03 10:08:21」(JST)

wiki en

Coacervation is a unique type of electrostatically-driven liquid-liquid phase separation, resulting from association of oppositely charged macro-ions. The term "coacervate" is sometimes used to refer to spherical aggregates of colloidal droplets held together by hydrophobic forces.^[1] Coacervate droplets can measure from 1 to 100 micrometres across, while their soluble precursors,^[2]^[3] are typically on the order of less than 200 nm.^[4] The name "coacervate" derives from the Latin coacervare, meaning "to assemble together or cluster".

The process of coacervation was famously proposed by Alexander Oparin and J. B. S. Haldane as crucial in his early theory of abiogenesis (origin of life/ prozikhozhdenic zhiney). This theory proposes that metabolism predated information replication, although the discussion as to whether metabolism or molecules capable of Template replication came first in the origins of life remains open^[5] and for decades the theory of Oparin and Haldane was the leading approach to the origin of life question.

History

These structures were first investigated by the Dutch chemist H.G. Bungenberg de Jong, in 1932.^{[citation needed]} A wide variety of solutions can give rise to them; for example, coacervates form spontaneously when a disordered polypeptide, such as gelatin, reacts with another biologically derived polyelectrolyte, such as gum arabic. They are interesting not only in that they provide a locally segregated environment, but also in that their boundaries allow the selective absorption of simple organic molecules from the surrounding medium. For example, a mix of carbohydrate solution with a protein solution, will favor the spontaneous formation of amoeba-like coacervates which change shape, merge, divide, form "vacuoles", release "vacuole contents", and show other lifelike properties.^[6] In Oparin's view this amounts to an elementary form of metabolism. British scientist Bernal commented that they are "the nearest we can come to cells without introducing any biological – or, at any rate, any living biological – substance." However, the lack of any mechanism by which coacervates can reproduce leaves them far short of being living systems.^[7]

Complex coacervation

Complex coacervation commonly refers to the liquid-liquid phase separation that results when solutions of two oppositely charged macroions are mixed, resulting in the formation of a dense macroion-rich phase, the precursors of which are soluble complexes.^[8]^[9]

References

^ Priftis, D.; Tirrell, M. "Phase behaviour and complex coacervation of aqueous polypeptide solutions". Soft Matter. |accessdate= requires |url= (help)
^ Water, J.J.; Schack, M.M.; Velazquez-Campoy, A.; Maltesen, M.J.; van de Weert, M.; Jorgensen, L. "Complex coacervates of hyaluronic acid and lysozyme: Effect on protein structure and physical stability". European Journal of Pharmaceutics and Biopharmaceutics. |accessdate= requires |url= (help)
^ Definition of coacervate, Memidex dictionary.
^ Schmitt, Christophe; Turgeon, Sylvie L. "Protein/polysaccharide complexes and coacervates in food systems". Advances in Colloid and Interface Science. |accessdate= requires |url= (help)
^ Origins of Life and Evolution of the Biosphere, Volume 40, Numbers 4-5, October 2010 , pp. 347-497(151)
^ Creating Coacervates. Larry Flammer, Indiana State University.
^ Dick, Steven J. (1999). The Biological Universe: The Twentieth Century Extraterrestrial Life Debate and the Limits of Science. Cambridge University Press. p. 340. ISBN 978-0-521-66361-8.
^ Kizilay, E (Sep 14, 2011). "Complexation and coacervation of polyelectrolytes with oppositely charged colloids.". Adv Colloid Interface Sci. 167: 24–37. doi:10.1016/j.cis.2011.06.006. |accessdate= requires |url= (help)
^ Research — Complex Coacervates, Tirrel Research Group.

English Journal

Microencapsulation of sulforaphane from broccoli seed extracts by gelatin/gum arabic and gelatin/pectin complexes.

García-Saldaña JS1, Campas-Baypoli ON2, López-Cervantes J3, Sánchez-Machado DI3, Cantú-Soto EU3, Rodríguez-Ramírez R3.
Food chemistry.Food Chem.2016 Jun 15;201:94-100. doi: 10.1016/j.foodchem.2016.01.087. Epub 2016 Jan 21.
Sulforaphane is a phytochemical that has received attention in recent years due to its chemopreventive properties. However, the uses and applications of this compound are very limited, because is an unstable molecule that is degraded mainly by changes in temperature and pH. In this research, the use
PMID 26868553

Coacervation of β-conglycinin, glycinin and isoflavones induced by propylene glycol alginate in heated soymilk.

Hsiao YH1, Lu CP2, Kuo MI2, Hsieh JF3.
Food chemistry.Food Chem.2016 Jun 1;200:55-61. doi: 10.1016/j.foodchem.2016.01.011. Epub 2016 Jan 6.
This study investigated the propylene glycol alginate (PGA)-induced coacervation of β-conglycinin (7S), glycinin (11S) and isoflavones in heated soymilk. The addition of 0.9% PGA caused 7S, 11S, daidzein and genistein to coacervate following a 1h incubation period. SDS-PAGE showed that the protein
PMID 26830560

Microencapsulation of stearidonic acid soybean oil in Maillard reaction-modified complex coacervates.

Ifeduba EA1, Akoh CC2.
Food chemistry.Food Chem.2016 May 15;199:524-32. doi: 10.1016/j.foodchem.2015.12.011. Epub 2015 Dec 7.
The antioxidant capacity of Maillard reaction (MR)-modified gelatin (GE)-gum arabic (GA) coacervates was optimized to produce microcapsules with superior oxidative stability compared to the unmodified control. MR was used to crosslink GE and GA, with or without maltodextrin (MD), to produce anti-oxi
PMID 26776004

Japanese Journal

シャンプー製剤における毛髪表面の滑り改善技術 (特集髪を中心とした美のトライボロジー)

辻野義雄,上門潤一郎,西垣祥子
トライボロジスト 59(8), 477-483, 2014
NAID 40020186585

Purification and Characterization of Coacervate-Forming Cuticular Proteins from Papilio xuthus Pupae

Yamanaka Masahiro,Ishizaki Yumi,Nakagawa Taro [他]
Zoological science 30(7), 534-542, 2013-07
NAID 40019687033

Coacervation Properties of Hydrophobic Elastin-derived Pentapeptide Analogues

MANIWA Yuka,INOUE Asako,WATANABE Noriko,OGINO Yuki,YAMASAKI Yuko,NOSE Takeru,MAEDA Iori
Peptide science : proceedings of the ... Japanese Peptide Symposium 2012, 391-392, 2013-03-01
NAID 10031161667