Polyesters, amphiphilic

Keywords Aliphatic polyesters Amphiphilic polymers Polymer micelles Self-assembly Smart materials... 

Gref R, Rodrigues J, Couvreur P (2002) Polysaccharides grafted with polyesters novel amphiphilic copolymers for biomedical applications. Macromolecules 35 9861-9867... 

To design amphiphilic and/or reactive copolymers containing aliphatic polyesters, one of the most promising approaches is copolymerization with functional monomers having protected reactive side-chain groups. Some kinds of monomers having reactive (hydrophilic) side-chain groups have been reported (Fig. 3). Recently, the synthesis of various types of functional polyesters has been reviewed [15-19],... 

Many kinds of nonbiodegradable vinyl-type hydrophilic polymers were also used in combination with aliphatic polyesters to prepare amphiphilic block copolymers. Two typical examples of the vinyl-polymers used are poly(/V-isopropylacrylamide) (PNIPAAm) [149-152] and poly(2-methacryloyloxyethyl phosphorylcholine) (PMPC) [153]. PNIPAAm is well known as a temperature-responsive polymer and has been used in biomedicine to provide smart materials. Temperature-responsive nanoparticles or polymer micelles could be prepared using PNIPAAm-6-PLA block copolymers [149-152]. PMPC is also a well-known biocompatible polymer that suppresses protein adsorption and platelet adhesion, and has been used as the hydrophilic outer shell of polymer micelles consisting of a block copolymer of PMPC -co-PLA [153]. Many other vinyl-type polymers used for PLA-based amphiphilic block copolymers were also introduced in a recent review [16]. 

Research on the second strategy has been reported for several types of PRX materials. Most studies concern pPRXs formation between a-CD and polyesters (Table 1) [278-290]. A pPRX of a-CD/PLLA was firstly demonstrated by Tonelli and coworkers [282], Subsequently, we reported the pPRX formation of a-CDs and PLLA-b-PEG-b-PLLA triblock copolymer [288]. In this report, the formation of an inclusion complex and the stoichiometry of the amphiphilic biodegradable triblock... 

The amphiphilic nature of the polyester/PHEMA networks provides gels able to swell in both organic and aqueous media, which prompted us to study them as controlled drug delivery systems [114]. The most valuable characteristic feature of these amphiphilic networks is their potential to sustain the drug delivery... 

Finally, Lecomte and coworkers reported the synthesis of mikto-arm star-shaped aliphatic polyesters by implementing a strategy based on click chemistry (Fig. 36) [162]. Firstly, the polymerization of sCL was initiated by a diol bearing an alkyne function. The chain-ends were protected from any further undesired reaction by the esterification reaction with acetyl chloride. The alkyne was then reacted with 3-azidopropan-l-ol. The hydroxyl function located at the middle of the chain was then used to initiate the ROP of sCL and y-bromo-s-caprolactone. Finally, pendant bromides were reacted successfully with sodium azide and then with N, N-dimethylprop-2-yn-l-amine to obtain pendant amines. Under acidic conditions, pendant amines were protonated and the polymer turned out to exhibit amphiphilic properties. 

In recent years cationic dendritic structures such as carbosilane-based [215], triazine-based [216], polyester [217] and amphiphilic dendrimers [218] have been investigated for transfection purposes with promising results, thus offering novel alternatives to the exploration of dendrimer-based nucleic acid delivery. 

The latter two successful processes were combined in the solvent-free lipase-catalyzed reaction of 1-O-ethyl glucoside with trimethylene carbonate or -caprolactone to form amphiphilic oligomers and polymers [20]. The products are biodegradable polycarbonates and polyesters that are formed regioselectively by reaction with the primary hydroxyl group of the sugar moiety. 

Nathan [4] prepared poly(monostearoyl glycerol-co-glyceryl monooleate-succinate), (IV), to prepare amphiphilic block polyester microdispersions that were bioabsorbable and biocompatible and useful as drug delivery agents. 

Water-soluble polymers prepared from a hydrophilic polyester have been shown to be highly effective water-soluble polymer-supported catalysts for aqueous biphasic hydrogenations [169]. The necessary amphiphilic polyester 134 with a BINAP ligand in the main polymer chain was prepared according to Eq. 74 using terephthaloyl chloride, dihydroxy-PEG4000) a diaminated BI-... 

For example, PLA oligomers prepared by direct condensation of D,L-lactic acid have an amphiphilic surfactant similar structure, since the polymers are composed of a hydrophobic polyester chain ended with a carboxylic acid group, which can be ionized to form hydrophilic carboxylate polar heads at neutral pFl in water. 

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