Hyperbranched Conjugated Polymers

Hyperbranched conjugated polymers (HBPs) are specialty high performance polymers which possess advanced structure and properties as compared to conventional linear conjugated 

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Keywords Polyfether amide) and polyfether amide-imide), polyfarylene ether), benzoxazine polymers, polyfether ether ketone) (PEEK), polytriazole, hyperbranched conjugated polymers, alternating copolymers... 

Figure 1.14 Chemical structure of the hyperbranched conjugated polymers. Reproduced from reference 13 with permission from Elsevier.

The subject of this review is complexes of DNA with synthetic cationic polymers and their application in gene delivery [1 ]. Linear, graft, and comb polymers (flexible, i.e., non-conjugated polymers) are its focus. This review is not meant to be exhaustive but to give representative examples of the various types (chemical structure, architecture, etc.) of synthetic cationic polymers or polyampholytes that can be used to complex DNA. Other interesting synthetic architectures such dendrimers [5-7], dendritic structures/polymers [8, 9], and hyperbranched polymers [10-12] will not be addressed because there are numerous recent valuable reports about their complexes with DNA. Natural or partially synthetic polymers such as polysaccharides (chitosan [13], dextran [14,15], etc.) and peptides [16, 17] for DNA complexation or delivery will not be mentioned. 

The complexation of DNA and polycations is a function of the intrinsic properties of the two components. For instance, from the use of synthetic polycations for complexing DNA also arises the problem of polydispersity of polymers (a polymer sample is usually composed of macromolecular species of differing molar masses) compared with DNA, which is monodisperse. Because the polydispersity of the polycation could be an issue in studies of IPECs, sugar-based polymers (usually polydisperse except if fractionated), conjugated polymers (polydispersity, Mw/Mn > 2), branched PEI derivatives, and hyperbranched polymers are out of the scope of this review, as already mentioned. Only polymers synthesized via controlled or living polymerization methods will be discussed [55-57]. 

Figure 7.5 Synthesis of hyperbranched glyco-conjugated polymer (Poly6a and Poly6b) by ringopening multibranching polymerization of 1,4-anhydroerythiitol (6a) and 1,4-anhydro-L-threitol (6b) using trifluoromethanesulfonic acid (CF3SO3H) or fluorosulfonic acid (FSO3H).

Although the anionic polymerization of 13 tended to form gels, the cationic polymerization proceeded through a proton-transfer reaction mechanism to produce hyperbranched glyco-conjugated polymer Poly 13 mainly consisting of 2,5-anhydro-D-glucitol units. This was the first report of the synthesis of a hyperbranched polymer via a cyclopolymerization mechanism. 

Unimolecular Reversed Micelle Based on Hyperbranched Glyco-Conjugated Polymer Core... 

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