Encapsulation of colloidal semiconductor quantum dots into metal-organic frameworks for enhanced antibacterial activity through interfacial electron transfer

Quantum dots (QDs) recently have aroused great interest in the field of photocatalytic bacteriostasis. However, rapid charge recombination, poor stability, and easy aggregation result in unsatisfactory catalytic performance, which hinders their further application. Herein, colloidal semiconductor QDs (GSH capped Zn-Ag-In-S QDs) were successfully encapsulated into metal-organic frameworks (ZIF-8) by a simple coordination-assisted self-assembly method. The results showed that MOFs and ZAIS QDs nanocomposite (QDs@ZIF-8) exhibited excellent antibacterial performance against E. coli and S. aureus under visible light irradiation. The enhanced photocatalysis disinfection can be assigned to the efficient interfacial electron transfer between ZIF-8 and ZAIS QDs, which leads to the generation of more reactive oxygen species (ROS). Furthermore, it was found that the antibacterial mechanism of QDs@ZIF-8 was realized by destroying the bacterial cell membrane, degrading the intracellular biomolecules such as DNA and protein, and oxidizing GSH. The ROS quenching experiment confirmed that singlet oxygen (O-1(2)), superoxide anions (center dot O-2(-)), and photogenerated electrons (e(-)) played a major role in the bacteriostatic process. In summary, this work provides a new strategy for the rational design of photocatalytic disinfection materials based on MOFs and semiconductor quantum dots.

Automated summary

This study successfully encapsulated colloidal semiconductor QDs in metal-organic framework ZIF-8, demonstrating excellent photocatalytic antibacterial performance possibly achieved through efficient interfacial electron transfer generating more reactive oxygen species.