Efficient catalytic synthesis of dendritic polymers having internal fluorescence labels for bioconjugation

Here we present an efficient synthesis of functional dendritic polymers carrying internal fluorescence labels for bioconjugation. Specifically, dendritic polymers having pyrene as fluorescence label in the core and N-hydroxysuccinimide (NHS) functional groups at the periphery were synthesized by coupling heterobifunctional PEG to hydroxyl functionalized dendritic polyethylene core. The dendritic polyethylene cores containing one pyrene label per polymer molecule were prepared through a one-step transition-metal-catalyzed polymerization using a pyrene-labeled Pd(II)-alpha-diimine chain walking catalyst. A series of pyrene-labeled dendritic scaffolds were obtained with different molecular weights and sizes. NHS active end groups were introduced to the periphery of the dendritic scaffolds through end-group functionalization. Those NHS-functionalized dendritic scaffolds were successfully used to conjugate a model protein, ovalbumin, to yield protein-polymer conjugates carrying multiple copies of protein attached to each scaffold.