(19/19) I am also extremely grateful for @santicorreaphd.bsky.social and all my lab-mates and co-authors at the Nanoscale Immunoengineering Lab @Columbia BME for their support, insights, and collaboration, and am excited to continue working on this project and discover the potential of this system.

(18/19) The day we successfully made our first gel showed the power of such a collaboration, and none of this would have been made possible without having @catecipi.bsky.social in our lab to not only establish these protocols but become an influential mentor to me throughout this journey.

(17/19) This project began by asking what it would take to reliably make hydrogels from EVs—made possible through collaboration between our lab’s nanomaterials experience and our University of Padova partners (@catecipi.bsky.social & Elisa Cimetta), who brought expertise in agricultural EVs.

(16/19) By leveraging polymer engineering and yogurt as a scalable EV source we highlight design considerations and new opportunities for regenerative materials enabled by EV-driven biofunctionality.

(15/19) This work establishes a design framework for EV-crosslinked hydrogels that are injectable, supramolecular, and intrinsically bioactive.

(14/19) When injected into immune-competent mice, they promoted spontaneous angiogenesis within 1 week and recruited a distinct immune niche enriched in myeloid cells and regulatory T cells—with no added cues.

(13/19) We were originally motivated to formulate hydrogels with EVs due to their biological signaling potential. Our yogurt EV formulations not only provided a scalable platform for design exploration, they also possessed surprising innate bioactivity in vivo.

(12/19) The platform is not only mechanically tunable, but it also works with vesicles derived from microbial and mammalian cell sources, suggesting these principles will work for EVs coming from a variety of sources!

(11/19) We were also able to tune hydrogel mechanical properties through changing EV concentration and found that EVs not only serve as supramolecular crosslinkers, but in some contexts (like higher concentrations), also act as macromolecular crowders, reinforcing the hydrogel network.

(9/19) When we increased the carbon chain length to C18; however, we did not observe the same trend, and saw that adding EVs actually weakened the material, suggesting that the addition of EVs might have an antagonistic rather than synergistic effect on polymer-polymer interactions.

(9/19) Polymers with longer alkyl chains (C14/C16) performed better: they were stiffer, enabled gel formation with fewer EVs, and showed robust self-healing, allowing for injectability across EV concentrations. This likely stems from stronger, more stable polymer interactions with the EV membrane.

(8/19) In order to optimize the system, we turned to polymer engineering and varied alkyl-chain length, degree of hydrophobic modification, and polymer and EV concentration, revealing how each affects hydrogel formation, stiffness, and self-healing.

(7/19) But with EVs, the C12 modified polymer didn’t behave the same way: we found that 10x more EVs were required to form a gel, even with a higher polymer concentration, and even then, we observed poor self-healing.

(6/19) We mixed EVs with alkyl-modified cellulose polymers to form hydrogels, which enables gelation via supramolecular crosslinking through hydrophobic interactions with the EV membrane. This was inspired by our earlier work on liposomal hydrogels, in which liposomes crosslinked HPMC-C12 polymers.

(5/19) Bovine milk whey is a byproduct of yogurt production, and allowed us to isolate EVs with up to 100x the yield of traditional cell sources.

This scalability allowed us to use this model system to systematically investigate the design parameters governing EV-mediated hydrogel formation.

(4/19) Her experience utilizing agricultural sources for scalable EV isolation prompted her to turn to her Italian expertise and spearhead creation of a protocol to isolate EVs from bovine milk whey in our lab.

(3/19) In our pursuit to find a scalable source of EVs to make formulation of these hydrogels possible, we were lucky to have a visiting PhD student from Italy, co-first author @catecipi.bsky.social, with a background in isolating EVs from parmesan cheese!

(2/19) Harnessing the intercellular communication potential of EVs is a growing area of interest in biomaterials research.

But major scalability and formulation challenges have made it difficult to integrate EVs into engineered systems—especially injectable hydrogels.