Bioactive NIR-II gold clusters for three-dimensional imaging and acute inflammation inhibition

Area of Science:

• Nanomaterials Science
• Biomedical Engineering
• Catalysis

Background:

• Near-infrared-II (NIR-II) fluorophores often struggle to achieve both strong fluorescence and high catalytic activity due to electron utilization conflicts.
• This limitation hinders their potential applications in biological imaging and therapy.

Purpose of the Study:

• To develop atomically precise gold clusters with enhanced NIR-II fluorescence and potent enzyme-mimetic activities.
• To investigate the impact of atomic engineering, specifically doping with copper, on the properties of gold clusters.
• To evaluate the potential of these engineered clusters for monitoring and treating cisplatin-induced renal injury.

Main Methods:

• Synthesis of atomically precise gold clusters (Au22) and their modification with single copper atoms (Au21Cu1).
• Characterization of fluorescence properties in the NIR-II window (950-1300 nm).
• Assessment of enzyme-mimetic activities, including antioxidant, catalase-like, and superoxide dismutase-like functions.
• Evaluation of renal clearance and in vivo monitoring of cisplatin-induced renal injury using NIR-II light-sheet microscopy.
• Assessment of therapeutic effects on oxidative stress and inflammation in a cisplatin-treated mouse model.

Main Results:

• Au21Cu1 clusters demonstrated strong NIR-II fluorescence with negligible loss compared to Au22 clusters.
• Doping with single Cu atoms significantly enhanced enzyme-mimetic activities: 18-fold higher antioxidant, 90-fold higher catalase-like, and 3-fold higher superoxide dismutase-like activities.
• Copper doping reduced the bandgap of the clusters, facilitating high catalytic activities.
• The clusters were renal clearable and effectively monitored cisplatin-induced renal injury within a 20-120 minute window.
• In vivo studies showed that the clusters inhibited oxidative stress and inflammation in cisplatin-treated mice, particularly in kidneys and brain.

Conclusions:

• Atomically engineered Au21Cu1 clusters overcome the trade-off between fluorescence and catalytic activity in NIR-II fluorophores.
• These clusters show significant potential as theranostic agents for monitoring and treating kidney injury.
• The findings open new avenues for designing multifunctional nanomaterials for biomedical applications.