Modes used – AFM
An innovative life sciences therapeutic company uses stem cells to produce exosomes. Post purification by ultra centrifugation, they needed to cross verify the size distribution, surface morphology and clustering behaviour. The AFM is an accepted orthogonal method to measure nanoparticle sizes in the biotech sector. The AFM measurement showed a normal distribution centred at 200 nm with a variation from 100 to 300 nm. It also showed significant outliers with sizes >300 nm, indicating potential clustering. Particle diameter in air on a substrate was higher than measured using DLS, but the particle volume showed a match. High resolution images also show that smaller ( ~ 10 nm diameter) fibrous structures are present.