PEGylation and BioPEGylation of Polyhydroxyalkanoates: Synthesis, Characterisation and Applications

Abstract

Chemical conjugations with poly(ethylene glycols) (PEGs) are established procedures to facilitate solubilisation of hydrophobic compounds. Techniques for PEGylation are currently applied to various hydrophobic pharmaceutical agents for drug delivery. More recently PEGylation has been applied to members of a novel family of microbial biopolyesters: the ‘Polyhydroxyalkanoates’ (PHAs). Complementing these chemical techniques, PEG modulation of bioprocessing protocols for the production of PHAs has shown that the strategic addition of certain PEGs not only supports hybrid synthesis, but may provide a technique for control of PHA composition and molecular mass. Furthermore, the addition of PEGs to the microbial cultivation systems can also result in end-capping of the hydrophobic polymer chains; a process termed ‘bioPEGylation’. In this chapter we review the processes of PEGylation and bioPEGylation of PHAs as well as the influence they exert on the physiochemical, material and biological properties of the resulting natural-synthetic hybrid copolymer materials.