Poly(2-oxazoline)s are a versatile class of materials, in particular due to the broad range of side-chain functionalities and the plethora of polymeranalogous reactions these polymers can be subjected to. Notably, numerous 2-oxazoline monomers undergo (pseudo-)living cationic ring-opening polymerizations, yielding (biocompatible) polymers with a narrow distribution of molecular weights that are ideal candidates for biomedical applications. Unlike thiol groups, olefinic functionalities in the monomers’ side-chains do not require protection group chemistry during polymerization, and, hence, the UV-mediated thiol-ene reaction among (co-)poly(2-oxazoline)s with olefinic side-chains and thiols is a straight-forward strategy for the preparation of functional and/or crosslinked poly(2-oxazoline)s.<br/>The versatility of this approach will be detailed in this lecture: Implantable drug-loaded poly(2-oxazoline)-based resins can be loaded with active pharmaceutical ingredients during crosslinking, notably without affecting them as the reaction occurs at room temperature. The swelling degrees can be tuned by the monomer composition during polymerization. Degradation studies of resins with hydrolyzable bonds revealed that these types of gels can be degraded in alkaline media as well as by esterases. Surface functionalization of ground gels by thiol-ene reactions with cysteine-bearing peptides exhibiting the arginine-glycine-aspartic acid (RGD) motif yields microparticles with enhanced recognition of human cancer cells compared to healthy endothelial cells (Figure 1). Diblock copolymers of 2-ethyl-2-oxazoline and 2-dec-9’-enyl-2-oxazoline form worm-like micelles with hydrodynamic radii from 82 to 106 nm in aqueous media. The micelles can be crosslinked by the UV-mediated thiol-ene reaction. Pharmaceutically active agent such as Zidovudine can be covalently attached to the micelles by the the Huisgen 1,3-dipolar cycloaddition.

UV-mediated crosslinking of poly(2-oxazoline)s: Fabrication of polymers for biomedical applications

2019 Spring National Meeting

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