Extracellular vesicles (EVs) are nanometer-scale particles that are secreted by cells and mediate intercellular communication by transferring biomolecules between cells. Harnessing this mechanism for therapeutic biomolecule delivery represents a promising frontier for regenerative medicine and other clinical applications. One challenge to realizing this goal is that to date, our understanding of which factors affect EV uptake by recipient cells remains incomplete. In this study, we systematically investigated such delivery questions in the context of breast cancer cells, which are one of the most well-studied cell types with respect to EV delivery and therefore comprise a facile model system for this investigation. By displaying various targeting peptides on the EV surface, we observed that although displaying GE11 on EVs modestly increased uptake by MCF-7 cells, neuropeptide Y (NPY) display had no effect on uptake by the same cells. In contrast, neurotensin (NTS) and urokinase plasminogen activator (uPA) display reduced EV uptake by MDA-MB-231 cells. Interestingly, EV uptake rate did not depend on the source of the EVs; breast cancer cells demonstrated no increase in uptake on administration of breast cancer-derived EVs in comparison to HEK293FT-derived EVs. Moreover, EV uptake was greatly enhanced by delivery in the presence of polybrene and spinoculation, suggesting that maximal EV uptake rates are much greater than those observed under basal conditions in cell culture. By investigating how the cell's environment might provide cues that impact EV uptake, we also observed that culturing cells on soft matrices significantly enhanced EV uptake, compared to culturing on stiff tissue culture polystyrene. Each of these observations provides insights into the factors impacting EV uptake by breast cancer cells, while also providing a basis of comparison for systematically evaluating and perhaps enhancing EV uptake by various cell types.

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Genetically modifying T cells can enable applications ranging from cancer immunotherapy to HIV treatment, yet delivery of T cell-targeted therapeutics remains challenging. Extracellular vesicles (EVs) are nanoscale particles secreted by all cells that naturally encapsulate and transfer proteins and nucleic acids, making them an attractive and clinically-relevant platform for engineering biocompatible delivery vehicles. We report a suite of technologies for genetically engineering cells to produce multifunctional EV vehicles—without employing chemical modifications that complicate biomanufacturing. We display high affinity targeting domains on the EV surface to achieve specific, efficient binding to T cells, identify a protein tag to confer active cargo loading into EVs, and display fusogenic glycoproteins to increase EV uptake and fusion with recipient cells. We demonstrate integration of these technologies by delivering Cas9-sgRNA complexes to edit primary human T cells. These approaches could enable targeting vesicles to a range of cells for the efficient delivery of cargo.

Extracellular vesicles (EVs) are secreted nanoscale particles that transfer biomolecular cargo between cells in multicellular organisms. EVs play a variety of roles in intercellular communication and are being explored as potential vehicles for delivery of therapeutic biomolecules. However, EVs are highly heterogeneous in composition and biogenesis route, and this poses substantial challenges for understanding the role of EVs in biology and for harnessing these mechanisms for therapeutic applications, for which purifying therapeutic EVs from mixed EV populations may be necessary. Currently, technologies for isolating EV subsets are limited by overlapping physical properties among EV subsets. To meet this need, here we report an affinity chromatography-based method for enriching a specific EV subset from a heterogeneous EV starting population. By displaying an affinity tagged protein (tag-protein) on the EV surface, tagged EVs may be specifically isolated using simple affinity chromatography. Moreover, recovered EVs are enriched in the tag-protein relative to the starting population of EVs and relative to EVs purified from cell culture supernatant by standard differential centrifugation. Furthermore, chromatographically enriched EVs confer enhanced delivery of a cargo protein to recipient cells (via enhancing the amount of cargo protein per EV) relative to EVs isolated by centrifugation. Altogether, affinity chromatographic enrichment of EV subsets is a viable and facile strategy for investigating EV biology and for harnessing EVs for therapeutic applications.

The ability of pathogens to develop drug resistance is a global health challenge. Severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) presents an urgent need wherein several variants of concern resist neutralization by monoclonal antibody (mAb) therapies and vaccine‐induced sera. Decoy nanoparticles—cell‐mimicking particles that bind and inhibit virions—are an emerging class of therapeutics that may overcome such drug resistance challenges. To date, quantitative understanding as to how design features impact performance of these therapeutics is lacking. To address this gap, this study presents a systematic, comparative evaluation of various biologically derived nanoscale vesicles, which may be particularly well suited to sustained or repeated administration in the clinic due to low toxicity, and investigates their potential to inhibit multiple classes of model SARS‐CoV‐2 virions. A key finding is that such particles exhibit potent antiviral efficacy across multiple manufacturing methods, vesicle subclasses, and virus‐decoy binding affinities. In addition, these cell‐mimicking vesicles effectively inhibit model SARS‐CoV‐2 variants that evade mAbs and recombinant protein‐based decoy inhibitors. This study provides a foundation of knowledge that may guide the design of decoy nanoparticle inhibitors for SARS‐CoV‐2 and other viral infections.