Micelles polypeptide-based

The phase behaviour of biomimetic polypeptide-based copolymers in solution was described and discussed with respect to the occurrence of secondary structure effects. Evidently, incorporation of crystallisable polypeptide segments inside the core of an aggregate has impact on the curvature of the corecorona interface and promotes the formation of fibrils or vesicles or other flat superstructures. Spherical micelles are usually not observed. Copolymers with soluble polypeptide segments, on the other hand, seem to behave like conventional block copolymers. A pH-induced change of the conformation of coronal polypeptide chains only affects the size of aggregates but not their shape. The lyotropic phases of polypeptide copolymers indicate the existence of hierarchical superstructures with ordering in the length-scale of microns. 

A distinct characteristic of polypeptide-based micelles, with respect to those based on ordinary flexible polymers, is the intrinsic stiffness of the polypeptide chains, in particular if the chains are able to adopt a secondary structure such as an a-helix. This affects the self-assembly in various ways thus owing to the limited conformational entropy of the chain, the ability to accommodate effective chain packing is reduced. For the same reason, polypeptides are not able to gain significant conformational entropy when molecularly dissolved, which further stabilizes the formed nanostructures. Together with facilitated specific inter-chain interactions, this leads to a rich phase behavior. In particular, because of this rather pronounced stiffness, polypeptides have a natural tendency to self-assemble into vesicular... 

J. Rodriguez-Hernandez, E. Ibarboure, E. Papon, Surface segregation of polypeptide-based block copolymer micelles an approach to engineer nanostructured and stimuli responsive surfaces, European Polymer Journal 47 (2011) 2063-2068. 

It can be concluded that MD is a very powerful tool to refine structures of proteins and polypeptides in solution, based on 2D NMR data. This combination of techniques emerges as an important means to determine the 3 D structure of macromolecules up to a molecular weight of 20,000 in solution or in micelles or membrane fragments. 

Recent progress in novel micellar structures, including micelles containing exotic blocks such as natural or synthetic polypeptides and metal-containing segments, micelles from ABC triblock copolymers, Janus micelles and other noncentrosymmetric micelles, micelles based on interpolyelectrolyte or other noncovalent complexes, and metallosupramolecular micelles, will be discussed in Sect. 7. 

Rodriguez-Hemandez J, Lecommandoux S (2005) Reversible inside-out micellization of pH-responsive and water-soluble vesicles based (m polypeptide dibloek copolymers. J Am... 

The aim of this chapter is to give a brief selective overview of typical biomedical areas where cationic polymers can be employed. The use of cationic polymers in tissue engineering is a high priority topic in this chapter and several aspects on this phenomenon are given related to this is the potential of cationic hydrogels for medical and pharmaceutical applications. The importance of cationic polymers and copolymers as non-viral vectors in gene therapy is described, as well as how micelles and vesicles based on cationic polypeptides can form nanostructures by self-assembly. The potential of cationic polymers for drug delivery applications is also elucidated. 

The use of phenyl esters as terminal groups in polypeptide synthesis has been reconunended. They are stable to many of the usual conditions encountered in peptide coupling reactions and can be removed selectively by treatment with one equivalent of hydrogen peroxide at pH 10.5 in various solvents containing dimethyl sulphide. m-Nitrophenyl esters could also find use in this context being quite acid stable (they survive conditions which are sufficiently acidic to hydrolyse JV -Z groups) but rather base labile (removed by 0.1M-NaOH). p-Nitro-phenyl esters can be hydrolysed specifically in some cases by N-lauroylhistidine in the presence of cationic micelles. ... 

Checot F, Rodiiguez-Hemandez J, Gnanou Y, Lecommandoux S. pH-responsive micelles and vesicles nanocapsules based on polypeptide diblock copolymers. Biomol Eng 2007 24 81-85. 

Rao J, Luo F, Ge Z, Liu H, Liu S (2007) Schizophrenic micellization associated with coil-to-helix transitions based on polypeptide hybrid double hydrophilic rod-coil diblock copolymer. Biomacromolecules 8 3871-3878... 

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