Modular Genetic Code Expansion Platform and PISA Yield Well-Defined Protein-Polymer Assemblies

Area of Science:

• Biomaterials Science
• Polymer Chemistry
• Nanotechnology

Background:

• Developing versatile platforms for creating complex biohybrid nanostructures is crucial for advanced material applications.
• Protein-polymer conjugates offer unique properties by combining biological recognition with tunable synthetic polymer characteristics.

Purpose of the Study:

• To present a modular and facile platform for generating biohybrid protein-polymer nanostructures.
• To demonstrate the use of a genetically encoded initiator for polymerization-induced self-assembly (PISA).

Main Methods:

• Utilized a mutant superfolder green fluorescent protein (sfGFP) as the stabilizing A block in an aqueous PISA system.
• Genetically encoded an atom-transfer radical polymerization (ATRP) initiation site onto sfGFP.
• Grafted hydroxypropyl methacrylate (HPMA) as the solvophobic B block.
• Characterized nanostructure formation using dynamic light scattering (DLS), gel permeation chromatography (GPC), and transmission electron microscopy (TEM).

Main Results:

• Successfully generated uniform micellar morphologies of biohybrid protein-polymer nanostructures.
• Demonstrated control over nanoparticle size (15-48 nm) by varying the HPMA block length.
• sfGFP provided effective solvophilic stabilization, acting as an ideal PISA initiator.

Conclusions:

• The developed platform offers a straightforward and modular approach to creating protein-polymer nanostructures.
• This biohybrid system has significant potential for generating complex nanostructures for diverse protein-polymer systems.
• The genetically encoded sfGFP initiator facilitates controlled self-assembly into tunable nanoparticles.