A comparative study of colloidal particles as imaging standards for microscopy.

Area of Science:

• Materials Science
• Nanotechnology
• Surface Science

Background:

• Colloidal particles are established imaging standards for electron microscopy and scanning probe microscopy.
• Accurate size and shape standards are crucial for reliable microscopy measurements.

Purpose of the Study:

• To evaluate gold, polystyrene, and silica colloidal particles as potential standards for microscopy.
• To determine the suitability of these particles for precise shape and size calibration.

Main Methods:

• Analysis using transmission electron microscopy (TEM) and atomic/scanning force microscopy (AFM/SFM).
• Measurement of particle circumference, diameter, and shadow length for shape and height determination.
• Comparison of height data obtained from TEM shadow analysis and AFM/SFM imaging.

Main Results:

• Cleaned silica and polystyrene particles demonstrated near-perfect sphericity.
• Gold particles showed good height agreement between TEM and AFM/SFM but often deviated from spherical shape.
• Metal shadowing in AFM/SFM provided a 'nanoscale metric' for calibration.

Conclusions:

• Silica particles are recommended as the best choice for microscopy standards due to their shape and physical properties.
• Metal shadowing offers a valuable calibration tool for scanning probe microscopy applications.