Vesicles, self-assembly

H. Noguchi and G. Gompper, Dynamics of vesicle self-assembly and dissolution, J. Chem. Phys. 125, 164908 (2006). 

In the past decades, it has become more and more obvious that students and scientists of chemistry and engineering should have some understanding of surface and colloid chemistry. The textbooks on physical chemistry tend to introduce this subject insufficiently. Modern nanotechnology is another area where the role of surface and chemistry is found of much importance. Medical diagnostics applications are also extensive, where both microscale and surface reactions are determined by different aspects of surface and colloid chemical principles. Drug delivery is much based on lipid vesicles (self-assembly structure) that are stabilized by various surface forces. 

CHE Chen, X., Ding, X., Zheng, Z., and Peng, Y., Thermosensitive polymeric vesicles self-assembled by PNIPAAm-i-PPG-6-PNIPAAm triblock copolymers. Coll. Polym. Sci., 283, 452, 2005. 

A. Jahn, W. Vreeland, M. Gaitan, and L. Locascio, Controlled vesicle self-assembly in microfluidic channels with hydrodynamic focusing, Journal of the American Chemical Society, 126, 2674-2675, 2004. 

Robinson, B.H. Bucak. S. Fontana, A. On the concept of driving force applied to micelle and vesicle self-assembly. Langmuir 2000, 16. 8231-8237, and references therein. Shioi. A. Hatton, T.A. Model for formation and growth of vesicles in mixed anionic/cationic surfactant systems. Langmuir 2002. 18, 7341-7348. 

Vesicles Self-Assembled firm Polypeptide Copolymers. 186... 

Vesicles Self-Assembled from Polypeptide Copolymers... 

In some cases, vesicles can also be obtained simply by dissolving and mixing the required components in aqueous solution, that is, purely by self-assembly. For example, the so-called catanionic vesicles self-assemble when cationic and anionic amphiphiles (each in the form of a micellar solution) are mixed in an equimolar ratio. Also supramolecular amphiphiles (Section 3.3) form vesicles by self-assembly when two (or more) components are mixed in the appropriate molar ratio. 

Vesicle-forming amphiphiles must not be held together by covalent interactions exclusively it is easily conceivable that an amphiphile is formed by noncovalent interaction of two (or more) components. Hence, although the individual components cannot form vesicles, vesicles self-assemble upon mixing of the components in the appropriate molar ratio. In this respect, the first example of... 

Aqueous solutions of didodecyldimethylammonium bromide (DDAB) exhibit an interesting self-assembly phenomenon." Each amphiphilic molecule of DDAB has two hydrophobic tails, so that DDAB molecules spontaneously form inverted micelles in hydrocarbons and nano-size spherical vesicles in dilute aqueous solutions. However, in aqueous solutions, at the DDAB concentration of about lO moldm , the spherical vesicles self-assemble into a multilayer onion-like structure shown in Figure 7.3. It is also notable that at the same DDAB concentration, the interfacial tension between water and a hydrocarbon (octane) almost vanishes, becoming less than 0.1 mNm and suggesting that the formation of the multilayer structure may be accompanied by water-oil interface instability. 

Nevertheless, the authors have reported so far a large range of applications on lipid and membrane systems of sizes comparable to those studied using MARTINI, including spontaneous vesicle self-assembly, monolayer collapse, vesicle to micelle transformation and membrane fusion. The SDK model thus represents a powerful and promising approach to investigate finely tuned chemical properties of large lipid assemblies when cheaper but less accurate CG models turn out to be unsuccessful. 

Zhang K-D, Zhou T-Y, Zhao X, Jiang X-K, Li Z-T (2012) Redox-responsive reverse vesicles self-assembled by pseudo[2]rotaxanes for tunable dye release. Langmuir 28 14839-14844... 

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