Polypeptide block, copolymers with

Polypeptide-containing polymers can not only gel organic solvents but can also form hydrogels. First examples were polypeptide block copolymers with a hydro-phobic polypeptide block with well-defined secondary structure and a charged polypeptide block in the coil form [61, 62]. The assembly mechanism was found to occur via an association of a-helices perpendicular to the long dimensions of the... 

Lin J, Zhang S, Chen T et al (2007) Micelle formation and drug release behavior of polypeptide graft copolymer and its mixture with polypeptide block copolymer. Int J Pharm 336 49-57... 

Fig. 37. Example of an electron micrograph of copolymers with a polyvinyl block and a polypeptide block. Copolymer polybutadiene-poly(benzyl-L-glutamate) BG.530 containing 33% polypeptide with polydiene chains have been stained with osmium tetroxide...

Block copolymers with a hydrophobic polyvinyl block and a hydrophobic polypeptide block (BG, SG, SC, SL, BCK and SCK copolymers) exhibit well organized meso-phases in dioxane, 1,2-dichloroethane, 2,3-dichloro 1-propene, etc., solutions. These mesophases are observed for solvent concentrations smaller than about 60% and for dry samples obtained by evaporation of the solvent at a slow rate. 

Fig. 38. Example of variation of the geometrical parameters of the lamellar structure of copolymers with a polyvinyl block and a hydrophobic polypeptide block. Copolymer BG.530 in dioxane solution22 ...

Simple geometric considerations suggest that block copolymers with a (hyper-) branched hydrophobic segment of polypeptide grafts or a polypeptide dendron, like the ones described by Chen et al. [45] (PE()i33-b-PFJ233-g-PBLGlu23-269) and Frechet et al. [46] (PFOm, 227-h-[G-3]-PALLys) (Fig. 6),... 

Block copolymers with polypeptide segments were occasionally used to stabilise oil-in-water emulsions or as emulsifiers in heterophase polymerisation processes. 

Fig. 6 Illustration of the undulated lamellar superstructure formed by PS-PZLL diblock copolymers with low (A), moderately (B) and highly polydisperse (C) polypeptide blocks. (Reprinted with permission from [48]. Copyright 2004. American Chemical Society)...

Linear polypeptide block copolymers, block copolymers with pendent sugar or peptide grafts, and modified linear or dendritic homopolymers have been used to produce vesicles based on hydrophobic interactions and packing issues. Usually, the peptides or sugars make the minority hydrophilic part of the copolymers and are thus incorporated in the corona and not in the membrane of the vesicles. For the inverse case, the hydrophobic peptides in the membrane are often too short to adopt a stable secondary structure. 

The lattice model, as put forth by Flory [84, 85], has been proved successful in the treatments of the liquid crystallinity in polymeric systems, despite its artificiality. In our series of work, the lattice model has been extended to the treatment of biopolypeptide systems. The relationship between the polypeptide ordering nature and the LC phase structure is well established. Recently, by taking advantage of the lattice model, we formulated a lattice theory of polypeptide-based diblock copolymer in solution [86]. The polypeptide-based diblock copolymer exhibits lyotropic phases with lamellar, cylindrical, and spherical structures when the copolymer concentration is above a critical value. The tendency of the rodlike block (polypeptide block) to form orientational order plays an important role in the formation of lyotropic phases. This theory is applicable for examining the ordering nature of polypeptide blocks in polypeptide block copolymer solutions. More work on polypeptide ordering and microstructure based on the Flory lattice model is expected. 

Li T, Lin J, Chen T, Zhang S (2006) Polymeric micelles formed by polypeptide graft copolymer and its mixtures with polypeptide block copolymer. Polymer 47 4485-4489... 

SYNTHESIS, STRUCTURAL STUDY AND PRELIMINARY HEMOCOMPATIBILITY TESTS OF AB AND ABA BLOCK COPOLYMERS WITH POLYVINYL AND POLYPEPTIDE BLOCKS... 

The synthesis of AB and ABA block copolymers with a polyvinyl and one or two polypeptide blocks is performed in 3 steps. At first the polyvinyl block is obtained by anionic or radical polymeriza-... 

Schlaad H, Antonietti M (2003) Block copolymers with amino acid sequences molecular chimeras of polypeptides and synthetic polymers. Eur Phys J E 10 17-23... 

PEO-polypeptide block copolymers, another combination potentially interesting for biomedical applications, were also shown to produce stable monolayers with very interesting features relating to the orientation of peptide helices at the interface, additionally influenced by the presence of poly(ethylene glycol), PEG [48]. In particular, PEG seems to adsorb partly at the interface, and thus inhibits the perfect perpendicular arrangement of the polyleucine helices. On the other hand, the helical conformation of peptide segments is unaffected by the monolayer packing state, as shown by CD spectroscopy. 

Schlaad et al. reported in greater detail on the solid-state phase behavior of linear and bottle-brush shaped polystyrene-block-poly(Z-L-lysine) in a wide range of molecular weight, composition, and architectures [76]. According to earlier reports on rod-coil block copolymers with polypeptides, mainly (undulated) lamellar morphologies were observed (see Figure 21). 

Calcium Ion Sensor. Cyclic voltammograms (CV) of ferrocyanide/ferricyanide redox couple with the modified electrode were measured. The peak currents due to the reversible electrode reaction of a Fe(CN) /Fe(CN) system on a bare Pt electrode were almost completely suppressed by the coating witti the polyvinyl-polypeptide block copolymer. This indicates that the electrode was covered with the hydrophobic polymer and was insulated from redox active species. 

Figure 4. FTIR sj ctra of the polymer film from the polyvinyl-polypeptide block copolymer, (a) the intact, (b) that treated with the alkaline (KOH) solution, and (c) the hydrolyzed film treated with Ca " ".

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