Engineered multicompartment vesicosomes for selective uptake by living cells.

Small extracellular vesicles (sEVs) have attracted tremendous interest in recent years due to their exceptional properties for therapeutic and diagnostic applications. Although much research was focused on the quantity and content of sEVs, less efforts have been put into discovering the interaction between sEVs and cells. Here we engineered multicompartment particles, termed vesicosomes, by deposition of sEVs derived from MCF7, CHO cells and human plasma onto the surface of polyelectrolyte (PE)-coated silica (SiO2) microparticles. Uptake of the PE-coated SiO2 microparticles by parent cells was significantly enhanced by coating them with sEVs, compared to PE-coated SiO2 microparticles independent of the terminated polyelectrolyte layer. This study highlights the emerging role of sEVs membrane receptors in the sEV-cells interaction and demonstrates the potential application of sEV-like multicompartment particles as therapeutic carriers.

Asymmetric depth-filtration: A versatile and scalable method for high-yield isolation of extracellular vesicles with low contamination.

We developed a novel asymmetric depth filtration (DF) approach to isolate extracellular vesicles (EVs) from biological fluids that outperforms ultracentrifugation and size-exclusion chromatography in purity and yield of isolated EVs. By these metrics, a single-step DF matches or exceeds the performance of multistep protocols with dedicated purification procedures in the isolation of plasma EVs. We demonstrate the selective transit and capture of biological nanoparticles in asymmetric pores by size and elasticity, low surface binding to the filtration medium, and the ability to cleanse EVs held by the filter before their recovery with the reversed flow all contribute to the achieved purity and yield of preparations. We further demonstrate the method's versatility by applying it to isolate EVs from different biofluids (plasma, urine, and cell culture growth medium). The DF workflow is simple, fast, and inexpensive. Only standard laboratory equipment is required for its implementation, making DF suitable for low-resource and point-of-use locations. The method may be used for EV isolation from small biological samples in diagnostic and treatment guidance applications. It can also be scaled up to harvest therapeutic EVs from large volumes of cell culture medium.

Dynamic surface tension probe for measuring the concentration of extracellular vesicles.

The concentration of extracellular vesicles (EVs) is an essential attribute of biofluids and EV preparations. EV concentration in body fluids was correlated with health status. The abundance of EV secreted by cultured cells into growth medium is vital in signaling studies, tissue and disease models, and biomanufacturing of acellular therapeutic secretome. A limited number of physical principles sensitive to EV concertation have been discovered so far. Particle-by-particle counting methods enumerate individual particles scattering light, modulating the Coulter current, or appearing in EM images. The available ensemble techniques in current use rely on the concentration-dependent signal intensity, as in the case of ELISA. In this study, we propose for the first-time the ensemble-based characterization of EV concentration by dynamic surface tension (DST) probe and demonstrate its implementation. We show that DST measurements agree with the widely used NTA measurements of EV concertation. The proposed method is low-cost and requires only basic laboratory equipment for implementation.