Gold Nanoclusters-Decorated Zeolitic Imidazolate Frameworks with Reactive Oxygen Species Generation for Photoenhanced Antibacterial Study.

The serious threat of antibiotic-resistant bacterial infections has brought an urgent need for the development of new antibacterial nanomaterials. We encapsulate glutathione (GSH)-protected gold nanoclusters (AuNCs) in zeolitic imidazolate frameworks-8 (ZIF-8) and present their potential in antibacterial capabilities. Under white light irradiation, AuNCs-embedded ZIF-8 nanocomposites show assembly-enhanced emission and reactive oxygen species (ROS) generation. AuNCs@ZIF-8 exhibit almost complete inactivation of bacterial growth within 60 min of light irradiation. Scanning electron microscopic results show that AuNCs@ZIF-8 nanocomposites are captured by bacterial cells, and the leakage of alkaline phosphatase and nucleotides from bacteria demonstrate that the photoinduced ROS can easily destroy the bacterial surface and totally kill the bacteria. Herein, our antibacterial nanocomposites have photoenhanced bactericidal capability and show promising applications for sterilization.

Au Nanoflowers for Catalyzing and In Situ Surface-Enhanced Raman Spectroscopy Monitoring of the Dimerization of p-Aminothiophenol.

In this work, we demonstrated a facile approach for fabrication of Au nanoflowers (Au NFs) using an amino-containing organosilane, 3-aminopropyltriethoxysilane (APTES), as a shape-directing agent. In this approach, the morphology of the Au particles evolved from sphere-like to flower-like with increasing the concentration of APTES, accompanied by a red shift in the localized surface plasmon resonance peak from 520 to 685 nm. It was identified that the addition of APTES is profitable to direct the preferential growth of the (111) plane of face-centered cubic gold and promote the formation of anisotropic Au NFs. The as-prepared Au NFs, with APTES on their surface, presented effective catalytic and surface-enhanced Raman scattering (SERS) performances, as evidenced by their applications in catalyzing the dimerization of p-aminothiophenol and monitoring the reaction process via in situ SERS analysis.

ICG@ZIF-8/PDA/Ag composites as chemo-photothermal antibacterial agents for efficient sterilization and enhanced wound disinfection.

Bacterial infection has increasingly affected people's lives, therefore it is significant to explore novel antibacterial agents and strategies for efficient disinfection. Herein, we designed ZIF-8 based composites ICG@ZIF-8/PDA/Ag, which encapsulate photothermal agent indocyanine green (ICG) and grow polydopamine (PDA) on their surface for in situ reduction to generate Ag nanoparticles. With 20 min of 808 nm laser irradiation at 1.5 W cm-2, 100 µg mL-1 ICG@ZIF-8/PDA/Ag exhibited 100% bactericidal effects toward E. coli and S. aureus bacteria resulting from both hyperthermia of ICG and PDA and chemical toxicity of the released Ag and Zn ions. When the bacterial incubation period was extended to 12 h, the minimum bactericidal concentration (MBC) of ICG@ZIF-8/PDA/Ag was reduced to 6.25 µg mL-1, and this extremely low MBC was due to the long-term chemo-photothermal combinational effect induced by NIR irradiation. Additionally, the composites successfully promote the healing of S. aureus infected wounds on mice. This work constructed photo-responsive antibacterial composites that realize chemo-photothermal synergistic therapy.

Ag functionalized SnS2 with enhanced photothermal activity for safe and efficient wound disinfection.

Severe bacterial infections have brought an urgent threat to our daily life, and photothermal therapy (PTT) has acted as an effective method to kill bacteria. Herein we decorated Ag on the surface of SnS2 (Ag@SnS2), which has outstanding photothermal conversion capability and good biocompatibility. The decoration of Ag on SnS2 improved the absorption of near-infrared (NIR) light in comparison to SnS2, resulting in a temperature increase of 50 °C after 5 min of NIR light irradiation (1.9 W cm-2) and a photothermal conversion efficiency of 31.3%. Ag@SnS2 exhibits almost 100% growth inhibition of E. coli and S. aureus bacteria due to hyperthermia, with a concentration larger than 0.5 mg mL-1 and 5 min of NIR irradiation. Meanwhile, SEM images of treated bacterial cells showed the attachment of Ag@SnS2 on the cell surface and obvious cellular membrane destruction. Ag@SnS2 can also accelerate in vivo wound healing through PTT-induced bacterial disinfection. Therefore, Ag@SnS2 exhibits great potential for photothermal antibacterial application and wound disinfection.