Dynamic light scattering (DLS) analysis

A Zetasizer Nano-ZS dynamic light scattering (DLS) system (Malvern, Montréal, QC, Canada) was used to measure the particle hydrodynamic diameter of the isolated exosomes. Each sample (100 mL) was loaded into an ultraviolet microcuvette (BRAND; Essex, CT, USA) at 4°C. The Brownian motion of a particle was measured by the fluctuations of scattered light intensity at a wavelength of 633 nm and a fixed angle of 173° to indicate the velocity distribution of particle movement in solution. The diameter of the exosomes was measured using the Stokes-Einstein equation to determine the particle's hydrodynamic radius. Each data point from each replicate represents an average of three measurements of 12-18 runs, which was set automatically. The average particle diameter was obtained from the peak of the Gaussian model fit to the particle distribution. The polydispersity index (PdI) was determined to reflect the width of the primary size distribution in solution ²².