Caging Cationic Polymer Brush-Coated Plasmonic Nanostructures for Traceable Selective Antimicrobial Activities.

Area of Science:

• Biomaterials Science
• Polymer Chemistry
• Nanotechnology

Background:

• Cationic polymers show promise for antimicrobial applications but face challenges due to toxicity from non-specific interactions.
• Developing targeted antimicrobial strategies with reduced host toxicity is crucial for clinical translation.

Purpose of the Study:

• To design and evaluate a "caging" strategy for cationic polymer brushes on gold nanorods (AuNRs) to achieve enzyme-triggered antimicrobial activity and reduce toxicity.
• To utilize a lipase-degradable block copolymer for controlled release of antimicrobial agents.

Main Methods:

• Coating gold nanorods (AuNRs) with cationic polymer brushes.
• Developing a block copolymer comprising a stealth block (poly(ethylene glycol)) and an anionic, lipase-degradable block (poly(ε-caprolactone-co-methacrylic acid)).
• Caging the cationic polymer brushes on AuNRs with the block copolymer to create neutrally charged surfaces.

Main Results:

• The "caged" AuNRs exhibited neutral surface charge, reducing non-specific binding and toxicity to mammalian cells.
• Activation by bacterial lipase released the cationic polymer brushes, resulting in potent bactericidal effects against target pathogens.
• Non-target bacteria lacking lipase and mammalian cells showed minimal interaction and toxicity.

Conclusions:

• The "caging" strategy effectively shields cationic antimicrobial polymers until activated by specific bacterial enzymes.
• This approach offers a promising method for the safe and targeted delivery of antimicrobial agents, mitigating toxicity concerns.
• Multifunctional AuNRs serve as scaffolds, photothermal agents, and imaging probes, enhancing the therapeutic potential.