Bacterial biofilm destruction by size/surface charge-adaptive micelles

Area of Science:

• Biomaterials Science
• Antimicrobial Drug Delivery
• Bacterial Biofilm Research

Background:

• Bacterial biofilms are a primary cause of multidrug resistance, posing significant challenges in treatment.
• Biofilm matrices impede antimicrobial agent diffusion, limiting therapeutic efficacy.
• Developing strategies to overcome biofilm barriers is crucial for combating persistent infections.

Purpose of the Study:

• To design and evaluate novel poly(aspartamide)-derived micelles for enhanced biofilm penetration and eradication.
• To create micelles that adapt their size and surface charge in response to the acidic biofilm microenvironment.
• To achieve spatiotemporal release of biofilm-disrupting and antibacterial agents.

Main Methods:

• Self-assembly of cationic copolymers with azithromycin-conjugated and pH-sensitive components.
• Loading of cis-aconityl-d-tyrosine (CA-Tyr) via electrostatic interactions.
• In vitro testing on Pseudomonas aeruginosa biofilms in microwells and in vivo evaluation using catheter-implanted rats.

Main Results:

• Micelles exhibited a size decrease from 107 nm to 54 nm and a zeta potential shift from -11.7 mV to +26.4 mV in acidic conditions, facilitating biofilm penetration.
• Acid-labile release of d-tyrosine disintegrated the biofilm matrix.
• Lipase-triggered release of azithromycin effectively eradicated bacteria within the biofilms.

Conclusions:

• Size and surface charge-adaptive micelles demonstrate effective infiltration into dense biofilm matrices.
• The spatiotemporal release mechanism ensures targeted delivery of biofilm dispersion and antibacterial agents.
• This approach offers a promising strategy for comprehensive treatment of biofilm-related infections.