Logo: to the web site of Uppsala University

Antimicrobial infection has emerged as one of the principal health problems in the world that requires urgent effective prevention. In order to deal with this reality, antibacterial photodynamic therapy using photosensitizers such as IR820 is one of the most encouraging and innovative methodologies to combat bacteria-caused infections. However, their activity is limited due to low photostability, short circulation, and lack of targeted bio-distribution. Herein, we have developed a user-friendly and universal approach to overcome such limitations of cyanine dye IR820 by encapsulating it with zeolitic imidazolate framework-8 (ZIF-8) keeping its activity intact. The synthesized ZIF8-IR820 nano-MOFs are characterized using electron microscopic and optical spectroscopic techniques. Moreover, the formation of hybrids is confirmed from the charge transfer process obtained from time resolved fluorescence transient and first principles DFT based analysis. The ultrafast charge transfer dynamic enhances the red-light sensitive reactive oxygen species (ROS) production capability which is further catalyzed in acidic pH and DFT based calculation validates the experimental results. The enhanced ROS production of ZIF8-IR820 nano-MOFs makes it superior in NIR induced antibacterial activity. Overall, the study demonstrates a detailed physical understanding of photosensitizer encapsulated nano-MOF system which shows efficient NIR light induced photo-dose dependent antibacterial activity that can be beneficial for potential bacterial remediation.