Antimicrobial Activity of Microgels with an Immobilized Copper(II) Complex Linked to Cross-Linking and Composition

Area of Science:

• Materials Science
• Microbiology
• Chemistry

Background:

• Increasing global bacterial resistance to antibiotics necessitates novel antimicrobial strategies.
• The peptidoglycan layer of Gram-positive bacteria is a key target for antimicrobial agents.
• Microgels demonstrate potential for hydrolyzing glycosidic bonds, similar to peptidoglycan components.

Purpose of the Study:

• To investigate the antimicrobial properties of polyacrylate microgels embedded with copper(II) complexes.
• To establish a structure-activity relationship for these novel antimicrobial agents.
• To evaluate their efficacy against Staphylococcus aureus.

Main Methods:

• Synthesis and characterization of polyacrylate microgels with varying cross-linking percentages and embedded copper(II) complexes.
• Antimicrobial susceptibility testing against Staphylococcus aureus, comparing microgels with commercial agents.
• Determination of minimum inhibitory concentration (MIC) and assessment of microgel stability using zeta potential measurements.

Main Results:

• Polyacrylate microgels with embedded copper(II) complexes exhibit significant antimicrobial activity against Staphylococcus aureus.
• A specific microgel formulation (60 mol % cross-linking, ^Cu₂^LP_60%) demonstrated potent bactericidal effects at 1 μg/mL, outperforming vancomycin.
• The minimum inhibitory concentration for ^Cu₂^LP_60% was as low as 0.64 μg/mL, indicating high efficacy.
• Microgels showed excellent stability in aqueous solutions, confirmed by negative zeta potentials.

Conclusions:

• Polyacrylate microgels containing copper(II) complexes are effective antimicrobial agents against Staphylococcus aureus.
• The microgel matrix composition, particularly the embedded metal complex, is crucial for antimicrobial activity.
• These microgels represent a promising new class of antimicrobial agents to combat antibiotic resistance.