Observing atomically precise nanocluster aggregates in solution by mass photometry.

Area of Science:

• Nanotechnology
• Materials Science
• Analytical Chemistry

Background:

• Atomically precise nanoclusters (NCs) are building blocks for novel nanomaterials.
• Understanding the assembly and structure of NCs in solution is crucial for their application.
• Characterizing nanoaggregates of NCs presents significant analytical challenges.

Purpose of the Study:

• To perform the first mass photometric characterization of nanoaggregates of atomically precise nanoclusters in solution.
• To investigate the structural evolution of silver-gold alloy NC nanoaggregates with varying solvent compositions.
• To correlate mass photometry data with structural information obtained from cryo-electron microscopy.

Main Methods:

• Utilized mass photometry (MP) with protein calibration for precise mass determination of nanoaggregates.
• Examined nanoaggregates of silver-gold alloy NCs, specifically [Ag_11-Au(DPPB)₅Cl₅O₂]²⁺ (x = 1-5).
• Conducted MP studies across a range of solvent compositions to probe structural changes.

Main Results:

• Successfully determined the masses of differently-sized nanoaggregates formed in solution.
• Observed a correlation between the masses of nanoaggregates and their structures (15-50 nm diameter) identified via cryo-electron microscopy.
• Demonstrated the influence of solvent composition on the structural evolution of the nanoaggregates.

Conclusions:

• Mass photometry is a powerful tool for characterizing nanoaggregates of atomically precise nanoclusters in solution.
• The study provides insights into the assembly and structural dynamics of silver-gold alloy NCs.
• This work lays the foundation for precise control and design of NC-based nanomaterials.