Size-Controlled Synthesis of Modifiable Glycine-Terminated Au Nanoclusters as a Platform for Further...

Area of Science:

• Nanomaterials Science
• Chemical Synthesis
• Biomedical Engineering

Background:

• Gold nanoclusters (Au NCs) offer unique optical and electronic properties.
• Functionalization of Au NCs is crucial for targeted applications.
• Controlling Au NC size and surface chemistry is an ongoing challenge.

Purpose of the Study:

• To develop a simple and improved synthetic method for producing stable, narrow-sized glycine-cystamine (Gly-CSA)-functionalized Au NCs.
• To investigate the size control of Au NCs based on reducing agent concentration.
• To explore the functionalization of Au NCs via Michael addition for potential biomedical applications.

Main Methods:

• Synthesis of Fmoc-Gly-CSA-functionalized Au NCs.
• Size control using varying concentrations of sodium borohydride (NaBH4).
• Characterization using UV-vis spectroscopy, 1H NMR, and TEM.
• Functionalization of amine groups via Michael addition with methyl acrylate.

Main Results:

• A simple synthetic route to stable, narrow-sized Gly-CSA-functionalized Au NCs was established.
• Au NC size was directly controllable by NaBH4 concentration, yielding smaller diameters at higher concentrations.
• Formation of atom-precise Au25(SR)18 NCs was confirmed, with successful ester-termination via Michael addition.
• Functionalization did not alter the size of the Au NCs, confirmed by TEM.

Conclusions:

• The developed method allows for controllable synthesis of Gly-CSA-functionalized Au NCs.
• The functionalized Au NCs exhibit stability and tunable size.
• These Au NCs show promise as scaffolds for diverse biomedical applications due to their facile functionalization and controllable properties.