Measuring Concentration of Nanoparticles in Polydisperse Mixtures Using Interferometric Nanoparticle Tracking...

Area of Science:

• Nanotechnology
• Biophysics
• Analytical Chemistry

Background:

• Accurate nanoparticle concentration measurement is crucial for medical and food industries.
• Existing methods struggle with polydisperse samples and overlapping size distributions.
• Interferometric nanoparticle tracking analysis (iNTA) was previously developed for precise nanoparticle size and refractive index determination.

Purpose of the Study:

• To demonstrate iNTA's capability for quantitative concentration measurement of nanoparticle subpopulations.
• To validate iNTA's performance on monodisperse and polydisperse samples.
• To assess iNTA's utility for measuring SARS-CoV-2 concentrations in biological samples.

Main Methods:

• Utilizing iNTA to track nanoparticle trajectories crossing the focal plane.
• Counting trajectory crossings to determine subpopulation concentrations.
• Evaluating the method on samples with known concentrations, including monodisperse and mixed populations.
• Applying the technique to measure SARS-CoV-2 concentrations in infected cell supernatant.

Main Results:

• iNTA successfully quantifies nanoparticle concentrations in polydisperse mixtures without requiring calibration standards.
• The method accurately measures concentrations of individual subpopulations within complex samples.
• Validation studies confirmed the reliability of iNTA across various sample types.
• The study successfully assessed SARS-CoV-2 concentrations in relevant biological samples.

Conclusions:

• iNTA provides a robust and calibration-free method for quantitative nanoparticle concentration analysis.
• This technique overcomes limitations of conventional methods, particularly for polydisperse samples.
• iNTA offers a valuable tool for applications in nanotechnology, diagnostics, and quality control across industries.