Dextran-block-poly(benzyl glutamate) block copolymers via aqueous polymerization-induced self-assembly

Area of Science:

• Biomaterials Science
• Polymer Chemistry
• Nanotechnology

Background:

• Polysaccharide-polypeptide conjugates offer potential for low-toxicity, biodegradable nanostructures.
• Synthesis of such nanostructures is challenging due to solubility, purification, and characterization difficulties.
• Previous methods involved complex polymer-polymer coupling and post-polymerization modifications.

Purpose of the Study:

• To synthesize dextran-block-poly(benzyl glutamate) block copolymers in water.
• To investigate nanostructure formation using polymerization-induced self-assembly (PISA).
• To elucidate the role of dextran's self-interactions on nanostructure morphology.

Main Methods:

• Synthesis of dextran-block-poly(benzyl glutamate) via PISA in aqueous solution.
• Morphological characterization using transmission electron microscopy (TEM).
• Computational analysis using coarse-grained molecular dynamics simulations.

Main Results:

• TEM revealed globular, non-spherical nanostructures, unlike those formed with poly(ethylene glycol) (PEG).
• Molecular dynamics simulations showed stronger dextran-dextran interactions and less dense water packing around dextran compared to PEG.
• These dextran self-interactions led to unexpected nanostructure formation.

Conclusions:

• Dextran's intrinsic self-interactions influence nanostructure morphology in block copolymers.
• These interactions result in unique nanostructures compared to systems using other hydrophilic blocks like PEG.
• The findings suggest new strategies for designing novel polysaccharide-polypeptide nanostructures.