Zonal rotor centrifugation revisited: new horizons in sorting nanoparticles

Area of Science:

• Materials Science
• Nanotechnology
• Biophysics

Background:

• Density gradient centrifugation is a proven technique for purifying small particles.
• Zonal rotors enable large-scale separations by eliminating the need for centrifuge tubes.
• Previous applications focused on biological separations, from cells to proteins.

Purpose of the Study:

• To demonstrate the application of zonal rotor centrifugation for sorting synthetic nanoparticles.
• To explore the potential of this method beyond biological applications.
• To achieve high-resolution fractionation of complex nanoparticle mixtures like "colloidal molecules".

Main Methods:

• Utilized hollow zonal rotors for density gradient centrifugation.
• Developed methods for loading and unloading the rotor during spinning to enhance accuracy.
• Employed differential centrifugal sedimentation for evaluating separation performance.

Main Results:

• Successfully fractionated mixtures of synthetic nanoparticles, including "colloidal molecules."
• Achieved pure fractions of particle monomers, dimers, trimers, and tetramers.
• Demonstrated high resolution, narrow zone widths, efficient sorting, and good recovery rates.

Conclusions:

• Zonal rotor centrifugation is a scalable and effective method for fractionating synthetic nanoparticle mixtures.
• This technique opens new possibilities for organizing nanoparticles into advanced hierarchical structures.
• The method provides precise control over nanoparticle assembly for materials science applications.