Synthesis of Maleimide-End-Functionalized Star Polymers and Multimeric Protein-Polymer Conjugates

Protein-polymer conjugtes exhibit Superior properties 10 Unmodified proteins, generating a high demand for these materials in the fields of medicine, biotechnology, and nanotechnology Multimeric conjugates are predicted to Surpass the activity of monomeric conjugates Herein, we report a straightforward method to synthesize multimeric polymer conjugates Four-armed poly(N-isopropylacrylamade) (pNIPAAm) was synthesized by reversible addition-fragmentation chain transfer (RAFT) polymerization in the presence of a tetrafunctionalized trithiocarbonate chain transfer agent (CTA). The polymer molecular weight, architecture, and polydispersity index (PDI) were verified by gel permeation chromatography (GPC) dynamic light scattering gel permeation chromatography (DLS-GPC), and matrix-assisted laser desorption/ ionization time-of-flight (MALDI-TOF) mass spectrometry. This approach afforded well-defined polymers (PDI's < 1 06) and the ability to target various molecular weights. Malcimide functional groups were introduced at the chain ends by heating the polymers in the presence of a furna-protected azo-intiator. This allowed for site-specific conjugation of V131CT4 lysozyme to the polymers to generate multimeric protein- polymer conjugates MALDI-TOF mass spectrometry, electrospray ionization gas-phase electrophoretic mobility macromolecule analysis (ESI-GEMMA), gel electrophoresis, and liquid chromatogrpahy tandem mass spectrometry (LC-MS/MS) of the trypsin digests demonstrated that multimeric protein-polymer conjugates had formed. This simple strategy provides ready access to star protein-polymer conjugates for application in the fields of drug discovery, drug, and nanotechnology