Luminescent gold-peptide spheric aggregates: selective and effective cellular targeting

Area of Science:

• Nanotechnology
• Biomedical Engineering
• Materials Science

Background:

• Aggregation-induced emission enhancement (AIEE) is crucial for luminescent materials.
• The regulation mechanism of AIEE in gold nanoclusters (AuNCs) remains unclear.
• Understanding AuNCs AIEE is vital for developing advanced imaging probes.

Purpose of the Study:

• Investigate the Zn2+-induced AIEE process of thiolate-protected AuNCs.
• Explore the pH-dependent aggregation and emission enhancement of AuNCs.
• Develop a strategy for targeted tumor cell imaging using AuNCs.

Main Methods:

• Synthesized AuNCs protected by cysteine, glutathione, and an 8-mer peptide.
• Studied the pH-dependent evolution of AuNCs from single particles to aggregates.
• Utilized photoluminescent enhancement ratio to define "mid-pH" for optimal aggregation.
• Investigated cell uptake mechanisms using RGD-functionalized AuNCs and integrin αvβ3.

Main Results:

• Identified a pH-dependent aggregation process of AuNCs induced by Zn2+.
• Proposed the concept of "mid-pH" (5.7-7.5) for forming spherical AuNCs aggregates with tunable properties.
• Demonstrated successful targeted tumor cell uptake and imaging at physiological pH.
• Elucidated the cell uptake mechanism involving RGD-integrin αvβ3 interaction and clathrin-mediated endocytosis.

Conclusions:

• Developed a method to regulate AuNCs aggregation for enhanced AIEE.
• Created efficient, targeted cellular imaging probes based on AuNCs aggregates.
• Provided insights into the design of novel AIEE-based probes for biomedical applications.