No abstract

Exosomes are cell-secreted nanovesicles present in biological fluids in normal and diseased conditions. Owing to their seminal role in cell-cell communication, emerging evidences suggest that exosomes are fundamental regulators of various diseases. Due to their potential usefulness in disease diagnosis, robust isolation and characterization of exosomes is critical in developing exosome-based assays. In the last few years, different exosome characterization methods, both biophysical and molecular, have been developed to characterize these tiny vesicles. Here, in this review we summarize: first, biophysical techniques based on spectroscopy (e.g., Raman spectroscopy, dynamic light scattering) and other principles, for example, scanning electron microscopy, atomic force microscopy; second, antibody-based molecular techniques including flow cytometry, transmission electron microscopy and third, nanotechnology-dependent exosome characterization methodologies.

Highlights We leverage the idea of ‘Markov blanket’ as a statistical boundary to provide an analysis of partitions in neuronal systems. We show this partition is applicable to multiple scales, from single neurons, brain regions, and brain-wide networks. Based on the canonical micro-circuitry, our treatment has practical applications for effective connectivity. Our proposed partition highlights the limitations of ‘modular’ proposals considering a single level of description.