Poly(2-oxazoline)-derived star-shaped polymers as potential materials for biomedical applications: A review

Poly(2-oxazoline)s (POx) are a unique class of polymers with an enormous potential for the preparation of functional materials. Their synthesis via the cationic ring-opening polymerisation (CROP) of 2-oxazolines enables the design of tailored polymers with reactive sites at their alpha-or to-end (telechelic POx), or in the side chain. Due to their biocompatibility and low-fouling properties, hydrophilic POx have shown promise as novel stealth -polymers for applications in the biomedical area. In this context, the development of defined high molar mass POx to reduce renal clearance and improve blood circulation times beyond linear polymers has drawn attention. In this contribution, different strategies for the design of star-shaped POx will be summarised. The CROP of 2-oxazolines is presented as a manifold tool to obtain cross-linked or branched star-like materials. In addition, strategies which combine CROP with other controlled polymerisation techniques will be discussed. Star-shaped POx are showcased a versatile platform to create high molar mass POx in a controlled manner and tune the properties of the resulting polymers.