Monodisperse engineered PEGs for bio-related applications

The importance of monodisperse poly(ethylene glycols) (PEGs) and their derivatives is rapidly increasing. Focusing on the merits of heterobifunctional PEGs, we developed a chromatography-free procedure for the preparation of monodisperse monotosylated PEGs. This technique enables the preparation of 8- to 16-mers in relatively large quantities, with good yields and purities, and facilitates the investigation of PEG-based functional molecules. For example, we synthesized structured PEGs consisting of monodisperse PEGs and polyols, which had specific two-dimensional shapes. These structured PEGs exhibited unique properties in aqueous environments; the triangular molecule dehydrated at a lower temperature than linear compounds with a similar molecular weight and could thus suppress the aggregation of proteins at high temperatures. We also found that the introduction of an aromatic group into the PEG skeleton lowered the dehydration temperature, which decreased the critical solution temperatures (LCSTs). Recent achievements in the development of engineered poly(ethylene glycol)s (PEGs) will be highlighted in this review.