A Nanoparticle Tracking Analysis (NTA) System is an advanced analytical technique used for visualizing and characterizing nanoparticles in liquid suspensions. It provides comprehensive information on the size, size distribution, and concentration of individual nanoparticles, offering a unique particle-by-particle analysis approach. NTA systems operate by illuminating nanoparticles in a liquid sample with a laser light source. A high-sensitivity camera (e.g., CCD or EMCCD) captures the light scattered by individual particles as they undergo Brownian motion. Specialized software then tracks the movement of each particle frame by frame. By analyzing the rate of Brownian motion, the hydrodynamic size of each particle is calculated using the Stokes-Einstein equation. Typical size measurement ranges for NTA are from 10 nanometers (nm) to 1000 nm, with some systems capable of measuring up to 15 micrometers (µm). Particle concentrations can be determined accurately, typically ranging from 10⁶ to 10⁹ particles/mL. The size measurement accuracy can be as precise as ±5 nm. NTA is extensively applied in various fields, particularly in biomedical research for the characterization of biological nanoparticles such as exosomes, microvesicles, extracellular vesicles, and viruses. It is also crucial for drug delivery system development, nanotoxicology studies, and protein aggregation research. Unlike ensemble techniques like Dynamic Light Scattering (DLS), NTA's particle-by-particle analysis provides higher resolution size distributions and is particularly beneficial for polydisperse samples or those containing materials not well characterized by DLS. These systems typically require low sample volumes and minimal sample preparation, contributing to reduced running costs. They are non-destructive, allowing for sample recovery if needed. Many NTA systems offer additional capabilities, such as fluorescent particle analysis for labeled nanoparticles, expanding their utility in biological and labeling studies. The accompanying software provides high-resolution results, visual validation of data, and often allows for the creation of customizable Standard Operating Procedures (SOPs) for routine analysis.