Dendritic block copolymers surface

In line with our the previous findings that linear-dendritic block copolymers denx)nstrated an affinity for polysaccharides and sequestered bulky hydrophobic organic compounds, the data of the current investigation show that laccase surface-modified with the amphiphilic copolymer [G2]-PEGSk-[G2] is capable... 

The properties of the hybrid diblock structures can be altered drastically by simply taking advantage of the high terminal functionality of the dendritic block. For example unusual diblock structures useful for the modification of surfaces have been prepared by ATRP of polystyrene (PS) initiated from the benzylic halide focal point of Frechet-type dendrons with terminal isophthalate ester groups [9b], Well-defined copolymers with narrow molecular weight distributions were obtained and excellent agreement was observed between calculated... 

PEO formed a surface while the hydrophobic carbosilane dendritic block was incorporated into the micelle core. Micellar characteristics were determined using fluorescence techniques and dynamic light scattering. Copolymers with a third-generation dendritic block could not be dispersed in water. 

Hydrosilation chemistry is presently having, and will continue to have, an important impact on certain areas of materials chemistry. The rapidity and cleanliness of the reaction, and the stability of the resulting Si-C bonds, have been used to produce dendritic polymers and block copolymers with well-defined structures [21]. The reaction can also be employed to attach molecules to surface Si-H groups, notably the Si-H present on the surfaces of aqueous etched single crystal, or nanoparticular Si [22], or other siliceous substrates, with substantial modification to their physical and chemical properties [23]. 

The combination of standard techniques described above has also been used by other authors19-20 to determine accurately the structure of dendritic systems prepared by the convergent-growth approach. Imperfections may be detected, and reactions can be easily monitored for product purity. Therefore, by following a predetermined synthetic strategy, molecules of discrete size and molecular weight can be prepared. In the following text, the characterization techniques described above, will be extended to determine and confirm the structure of more complex dendritic macromolecules such as surface-functionalized and other block copolymers. 

To bring the nanocontainer to a specific place where it should release its pay-load, targeting is a required approach. Hence, much work has been carried out to attach ligands or antibodies to the hydroxyl end-group of PEG-based assemblies [150,181,243], Biotinylated nondegradable block copolymer assemblies have been shown to attach to surfaces coated with the biotin receptor avidin [146,147, 150,244], Coupling chemistry has been applied to conjugate either an antihuman IgG, or antihuman serum to PEG-carbonate- or PEG-polyester-assembled polymer vesicles [149,245], HIV-derived Tat peptide attached to PEG-PBD polymersomes enhanced the cellular delivery of nanoparticles [246] and increased dendritic cell uptake in vitro [181]. 

The application of water-soluble, unmodified enzymes for practical purposes is often hampered by their protease susceptibility, thermal instability and inactivation by the intermediates, products formed or pH of the medium. One of the main thrusts in our research is the construction of micellar complexes of enzymes and amphiphilic block copolymers that contain linear and perfectly branched (dendritic) segments and their catalytic evaluation in aqueous media. Unique feature of these supermolecules is that the water-soluble biocatalyst, hydrophobic substrates and eventual mediator compounds are confined within the core of a normal micelle. The hydrophobic dendritic fragments have the primary function to serve as enzyme surface anchoring devices for the copolymer molecules while the hydrophilic linear portion of the copolymer will ensure the aqueous solubility and the stability of the entire construction. The complex is schematically presented in Fig. 1. 

Wooley and coworkers utilized click chemistry to prepare block copolymer micelles and shell cross-linked nanoparticles (SCKs) presenting click-reactive functional groups on their surfaces [144,145]. Moreover, they presented the preparation of well-defined core cross-linked polymeric nanoparticles, utilizing multifunctional dendritic cross-linkers that allow for the effective stabilization of supramolecular polymer assemblies and the simultaneous introduction of reactive groups within the core domain [146]. 

To synthesise polymers with unusual properties from existing basic monomers one needs to place the monomer units in ordered arrays rather than at random. Thus polymer architecture control remains an important area of research. Possible structural elements include block, graft and comb copolymers as well as star and dendritic/hyperbranched topographies. Potential for such structures in the surface coatings and adjacent industries include use as... 

Figure L Schematic cross-section of a linear-dendritic enzyme complex. The linear portion of the copolymer (black, wavy lines) extends into the aqueous phase while the monodendritic blocks of the copolymer (black, near the center) are anchored at the surface of the enzyme (grey feature at the center).

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