Exploiting Bacterial Metabolism for Targeted Antimicrobial Release from Smart Nanocarriers

Area of Science:

• Biomaterials Science
• Microbiology
• Drug Delivery Systems

Background:

• Acidogenic and aciduric bacteria contribute to pathological acidification in diseases like dental caries and infections.
• Current antimicrobial strategies lack specificity, leading to off-target effects and resistance.
• Targeting microbial metabolic byproducts offers a novel approach for selective antimicrobial therapy.

Purpose of the Study:

• To develop a pH-responsive nanoparticle system for targeted antimicrobial drug delivery.
• To create a system that selectively releases antimicrobials in acidic microenvironments generated by bacteria.
• To demonstrate the efficacy of this system in eradicating acid-producing bacteria in an oral microbiome model.

Main Methods:

• Fabrication of mesoporous silica nanoparticles with pH-responsive gatekeepers.
• Loading nanoparticles with a broad-spectrum antimicrobial agent.
• Testing nanoparticle performance in a human oral microbiome model.
• Utilizing single-cell-scale fluorescence imaging to monitor pH and bacterial viability.
• Employing proton NMR and contact angle measurements to elucidate the gating mechanism.

Main Results:

• Nanoparticles remained sealed at physiological pH but rapidly released payload under acidic conditions.
• Selective eradication of acid-producing bacteria was observed in the oral microbiome model.
• Metabolic acidification by bacteria directly triggered the antimicrobial release and bacterial killing.
• Mechanistic studies confirmed the gating mechanism relies on synergistic molecular interactions and hydrophilicity-hydrophobicity transitions.

Conclusions:

• The developed nanoparticle platform enables on-site antimicrobial strategies triggered by metabolic acidification.
• This approach effectively targets microbes with undesirable metabolic features, enhancing therapeutic control.
• The findings pave the way for more precise and controlled infection therapies, minimizing collateral damage to beneficial microbes.