Iodine-loaded metal organic framework as growth-triggered antimicrobial agent

Area of Science:

• Materials Science
• Chemistry
• Microbiology

Background:

• Zeolitic imidazolate framework-8 (ZIF-8) is an accessible metal-organic framework.
• Metal-organic frameworks offer tunable properties for various applications.

Purpose of the Study:

• To develop a pH-responsive bactericide using ZIF-8 loaded with iodine (ZIF-8@I).
• To investigate the antimicrobial activity of ZIF-8@I against Gram-negative and Gram-positive bacteria at different pH levels.

Main Methods:

• Facile preparation of ZIF-8 by mixing zinc nitrate and 2-methylimidazole solutions.
• Loading ZIF-8 with iodine from an n-heptane solution.
• Testing the antimicrobial efficacy of ZIF-8@I against Escherichia coli, Staphylococcus epidermidis, and Staphylococcus aureus at varying pH conditions.

Main Results:

• ZIF-8 readily loaded with approximately 0.9g of iodine per gram.
• ZIF-8@I demonstrated potent bactericidal activity against tested bacteria at pH 6.0 within 3 minutes.
• No significant antimicrobial activity was observed at pH above 7.0.
• Antimicrobial activity was attributed to iodine release from ZIF-8@I disintegration at acidic pH.
• ZIF-8@I coated surfaces and agar plates showed triggered antimicrobial effects in response to acidic pH or bacterial growth.

Conclusions:

• ZIF-8@I functions as an effective pH-responsive bactericide.
• The material's efficacy is dependent on the release of iodine triggered by acidic environments.
• This highlights the potential of ZIF-8@I for targeted antimicrobial applications.