Photosensitizable ZIF-8 BioMOF for Stimuli-Responsive Antimicrobial Phototherapy

Area of Science:

• Nanotechnology
• Materials Science
• Biomedical Engineering

Background:

• Rising antimicrobial resistance necessitates novel therapeutic strategies.
• Antimicrobial photodynamic therapy (aPDT) offers a promising alternative by utilizing photosensitizers, light, and oxygen to generate reactive oxygen species (ROS).
• Photosensitizer limitations like photobleaching and aggregation hinder clinical application, driving research into carrier systems.

Purpose of the Study:

• To address heterogeneous particle size distribution in metal-organic frameworks (MOFs) for photosensitizer delivery.
• To synthesize and characterize Rose Bengal (RB) and porphyrin loaded ZIF-8 nanoparticles (NPs).
• To evaluate the efficacy of RB@ZIF-8 NPs in generating ROS and combating multidrug-resistant bacteria.

Main Methods:

• Room-temperature synthesis of ZIF-8 NPs with controlled particle size (150 ± 50 nm).
• Single-step loading of Rose Bengal (RB) and porphyrin photosensitizers into ZIF-8.
• In vitro assessment of ROS generation upon green LED irradiation.
• Evaluation of pH-responsive behavior and antimicrobial activity against Escherichia coli.

Main Results:

• RB@ZIF-8 demonstrated superior singlet oxygen generation compared to porphyrin@ZIF-8 at low concentrations.
• The RB@ZIF-8 complex exhibited pH-responsive properties relevant for biological conditions.
• RB@ZIF-8 showed a more favorable IC50 value against Escherichia coli than bare photosensitizers or ZIF-8 alone.

Conclusions:

• ZIF-8 serves as an effective biocompatible carrier for photosensitizers, overcoming limitations of free dyes.
• The developed RB@ZIF-8 exhibits enhanced antimicrobial photodynamic efficacy against resistant bacteria.
• This BioMOF strategy holds significant potential for treating multidrug-resistant bacterial infections.