PEG-polypeptide hybrid block

Osada, K. and Kataoka, K Drug and Gene Delivery Based on Supramolecular Assembly of PEG-Polypeptide Hybrid Block Copolymers. Vol. 202, pp. 113-154. 

Osada K, Kataoka K (2006) Drug and gene delivery based on supramolecular assembly of PEG-polypeptide hybrid block copolymers. Adv Polym Sci 202 113-153... 

Recently, polypeptide hybrid polymers, particularly poly(ethylene glycol) (PEG)-polypeptide block copolymers, have been attracting significant interest for polymer therapeutics, such as drug and gene dehvery systems [1-5]. 

Poly(ethylene glycol)-polypeptide block copolymers are of particular interest, from both a structural and a functional point of view. In addition to microphase separation and the tendency of the peptide blocks towards aggregation, crystallization of poly(ethylene glycol) (PEG) introduces an additional factor that can influence the structure formation of these hybrid block copolymers. Ma and coworkers (Zhang et ai, 2003) have investigated the solid-state structure and properties of three poly(ethylene glycol)-Z /ocA -poly(L-Alanine) (PEG-Z -PLAla) copolymers that were prepared from a PEG macroinitiator with M = 2 kg/mol. The diblock copolymers contained 39.8, 49.6 and 65.5 mol% alanine. Erom FTIR spectra and differential scanning calorimetry (DSC) measurements, the authors proposed a microphase-separated bulk structure. 

This chapter will introduce polymer systems containing either naturally occurring maaomolecules (polysaccharides, proteins, DNA) or their subunits (bioanalogous molecules, amino acids, short peptides and peptide derivatives, polypeptides, polynucleotides), respectively. The natural building blocks can be connected by covalent bonds or by self-assembly and either can be used alone (see, e.g.. Section 5.4) or in combination with synthetic polymer units (biohybrids). Alternatively the building block itself may be a hybrid of a natural and synthetic molecule (bioconjugate cf. Section 3.5), as, for instance, a PEG-peptide conjugate. 

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