Infection microenvironment-responsive composites based on a Ag(I) complex for targeted antimicrobial treatment.

Area of Science:

• Materials Science
• Nanotechnology
• Biomedical Engineering

Background:

• Silver ions (Ag+) exhibit broad-spectrum antimicrobial activity but suffer from uncontrolled release.
• Existing antimicrobial strategies often require additional carriers, leading to potential side effects in infection microenvironments.

Purpose of the Study:

• To develop infection microenvironment-responsive composites for on-demand Ag+ release and enhanced antimicrobial efficiency.
• To create a smart drug delivery system that minimizes side effects associated with constant Ag+ exposure.

Main Methods:

• Designed a silver complex (1) with high Ag+ content, coated with hyaluronic acid (HA) or Fe(III)-tannic acid (Fe(III)-TA).
• Investigated stimuli-responsive coating decomposition triggered by hyaluronidase (HAase) and acidity (pH 5.5).
• Characterized the silver complex using single-crystal X-ray diffraction and evaluated antimicrobial activity via minimum inhibition concentrations (MICs) and inhibition zones.

Main Results:

• Composites 1@HA and 1@Fe(III)-TA showed significantly suppressed Ag+ release (14.99% and 3.31%) under non-infection conditions.
• In simulated infection microenvironments, Ag+ release increased to 59.26% (1@HA) and 23.92% (1@Fe(III)-TA).
• 1@Fe(III)-TA demonstrated enhanced acid-triggered performance against P. aeruginosa and carbapenem-resistant E. coli.

Conclusions:

• Developed stimuli-responsive composites for controlled Ag+ delivery, addressing the limitations of always-on silver release.
• The smart design effectively utilizes infection-specific cues for on-demand antimicrobial action, reducing degradation side effects.
• This strategy offers a promising approach for targeted antimicrobial treatment of bacterial infections.