Protein ROMP: Aqueous Graft-from Ring-Opening Metathesis Polymerization

Area of Science:

• Polymer Chemistry
• Bioconjugation
• Catalysis

Background:

• Ring-opening metathesis polymerization (ROMP) is a powerful tool for polymer synthesis.
• Performing ROMP under aqueous conditions is challenging due to catalyst and reagent solubility.
• Protein modification with synthetic polymers offers unique biomaterial properties.

Purpose of the Study:

• To develop a water-soluble catalyst for surface-initiated ROMP from proteins.
• To synthesize high molecular weight protein/polymer conjugates in aqueous media.
• To investigate the kinetics of graft-from ROMP initiated by a protein macroinitiator.

Main Methods:

• Modification of Grubbs' third-generation catalyst with PEGylated pyridyl groups to create a water-soluble species.
• Immobilization of the modified catalyst onto a protein surface to form a stable macroinitiator.
• Polymerization of water-soluble norbornene monomers using the protein macroinitiator under aqueous buffered conditions.
• Analysis of polymer molecular weight and macroinitiator conversion over time.

Main Results:

• A highly active, water-soluble Grubbs' catalyst was synthesized for aqueous ROMP.
• Stable protein macroinitiators were successfully created for graft-from polymerization.
• High molecular weight protein/polymer conjugates were obtained in aqueous solutions.
• Kinetic studies revealed control over molecular weight evolution and monomer conversion.

Conclusions:

• Surface-initiated ROMP from proteins is feasible under aqueous conditions using a tailored water-soluble catalyst.
• This method provides a versatile route to novel protein-polymer bioconjugates with tunable properties.
• The developed system offers a promising platform for advanced biomaterials and drug delivery applications.