Nanoparticle Tracking Analysis

Nanoparticle Tracking Analysis infers hydrodynamic diameter from how rapidly each illuminated particle undergoes Brownian motion. The recorded movement reflects diffusion, and the method applies the relationship between diffusion and particle size to calculate the diameter. Because the estimate comes from particle motion in liquid, the result describes hydrodynamic size rather than simply a geometric dimension.

Tracking scattered light from individual particles helps preserve information that a single bulk measurement could obscure. Particles within the same sample can contribute to different size populations, so individual-particle observations allow Nanoparticle Tracking Analysis to reveal heterogeneity. This is especially relevant when a biological or engineered material contains more than one particle population or changes during development.

Size distribution and concentration answer different questions about a liquid sample. Distribution shows how particle sizes are represented across the measured population, whereas concentration indicates how many particles are present. Considering both measurements helps distinguish a change in population abundance from a change in size composition, supporting interpretation of biological materials and engineered formulations.

A basic measurement starts with a liquid sample and laser illumination. The system records light scattered by individual particles, follows their Brownian motion, and uses the relationship between diffusion and particle size to calculate hydrodynamic diameters and particle concentration. The resulting measurements can then be examined for size distributions, heterogeneity, and changes in particle populations.

In bioengineering, researchers can apply Nanoparticle Tracking Analysis to extracellular vesicles, protein aggregates, liposomes, and other nanoparticle-based systems. The method supplies size and concentration information for comparing biological or engineered materials. Those measurements support characterization, quality control, and formulation development, while also contributing to studies of how such particle populations relate to biological transport.

By comparing samples, researchers can determine whether a material’s particle population remains consistent or shifts. Changes in size distribution may indicate altered population composition, while concentration changes reflect a different abundance of particles. Nanoparticle Tracking Analysis therefore helps identify heterogeneity and evaluate biological or engineered formulations using more than a single representative particle size.