Encapsidated atom-transfer radical polymerization in Qβ virus-like nanoparticles.

Area of Science:

• Biotechnology
• Nanotechnology
• Materials Science

Background:

• Virus-like particles (VLPs) are versatile macromolecular structures with significant potential in biomedicine and biomaterials.
• The Qβ VLP, a 30 nm-diameter structure, offers a robust scaffold for internal functionalization.

Purpose of the Study:

• To functionalize the interior of Qβ VLPs with polymers using a multi-step approach.
• To investigate the properties and cellular uptake of the resulting polymer-containing nanostructures.
• To assess the potential of these modified VLPs for delivering small interfering RNA (siRNA).

Main Methods:

• A three-step process involving RNA removal, initiator molecule attachment to unnatural amino acids, and atom-transfer radical polymerization.
• Polymerization of tertiary amine-bearing methacrylate monomers within the VLP interior.
• Characterization of polymer confinement, particle size, charge, and cellular uptake.

Main Results:

• Successful functionalization of Qβ VLPs with polymers, leading to moderate size expansion.
• Evidence of polymer confinement within the protein shell, indicated by limited avidin accessibility to biotin-derivatized polymers.
• The polymer-containing particles exhibited positive charges, enabling efficient mammalian cell entry and siRNA delivery.

Conclusions:

• The functionalization strategy effectively modified Qβ VLPs, creating positively charged nanostructures.
• These novel nanostructures demonstrate efficient cellular uptake and hold promise for targeted RNA delivery applications.
• The study highlights the potential of engineered VLPs as platforms for advanced biomedical interventions.