Star‐Shaped Block Copolymers by Copper‐Catalyzed Azide‐Alkyne Cycloaddition for Potential Drug Delivery Applications

Star-shaped poly(ϵ-caprolactone) is synthesized by ring-opening polymerization and subsequently functionalized with alkyne groups. These are utilized for the attachment of linear poly(ethylene glycol) monomethyl ether azide (mPEG-N3) and poly(2-ethyl-2-oxazoline) azide (PEtOx-N3) by copper-catalyzed azide-alkyne cycloaddition (CuAAC). The resulting amphiphilic star-shaped block copolymers are characterized by SEC, MALDI-TOF mass spectrometry, NMR spectroscopy, and DLS. In order to elucidate the potential of both systems as drug carriers their loading capacity is studied with a model system, the hydrophobic dye fat brown RR. Furthermore, erythrocyte aggregation tests provide first indications that the two different star-shaped block copolymers are compatible for potential applications in a biological context.