A Novel Capturing Method for Quantification of Extra-Cellular Nanovesicles

Extracellular vesicles (EVs), secreted by cells and found in body fluids play important roles in intercellular communication. Therefore, EVs are receiving increasing attention as potential biomarkers in the diagnosis and prognosis of various diseases. However, the detection and the quantification of EVs are hampered by the nanometer scale of these particles and by the lack of optimized quantification methods. Atomic force microscopy (AFM) is a powerful technology that can detect small particles. Here we report a 3D capture method for sample preparation of AFM which improves the accuracy, sensitivity and reproducibility for EVs' detection, compared to conventional sample preparation methods. By shaking a mica plate in EV solution, all the EVs were captured onto the 2D surface. The majority of the captured particles have a size ranging from 10 to 120 nm, which correlates with size data obtained from transmission electron microscopy studies. This novel sample preparation method has high adaptability potential and can also be applied to other organic and inorganic nanoparticles.