Engineering of Extracellular Vesicles for Targeted Delivery of Prodigiosin

The therapeutic potential of prodigiosin as a hydrophobic anticancer agent can be enhanced by various approaches, one of which is the loading of PG into extracellular vesicles. Drug distribution and stability in aqueous media play a crucial role in targeting and accumulation, thereby enabling the attainment of therapeutically effective drug concentrations. Extracellular vesicles are nano-sized, cell-derived vesicles with a lipid bilayer membrane. Extracellular vesicles can be utilized as drug carriers for both water-soluble and non-water-soluble therapeutic agents. We hypothesized that microvesicles could effectively address the current challenges of prodigiosin delivery. Several different techniques have been developed for fabricating extracellular vesicles. These include microvesicles induction by cytochalasin B treatment as well as cell cultivation in serum depleted media. In our study, prodigiosin, like cytochalasin B, demonstrated efficacy in microvesicles formation based on protein quantification and Nanoparticle Tracking Analysis. In addition, Nanoparticle Tracking Analysis showed that vesicles from mesenchymal stem cells are more stable under ultrasound exposure. Microvesicles encapsulating prodigiosin, compared to unmodified naïve ones, demonstrated slightly increased zeta potentials and hydrodynamic diameters, which probably contributed to better stability. We demonstrated that ultrasonic treatment for the loading of prodigiosin does not significantly increase the proportion of prodigiosin-positive microvesicles in comparison with microvesicles induced with prodigiosin; moreover, this method cannot be considered as optimal due to its disadvantages, such as particle aggregation. Prodigiosin-induced and prodigiosin-loaded microvesicles from mesenchymal stem cells were significantly smaller and less polydisperse in size. Overall, prodigiosin encapsulated in extracellular vesicles might be more suitable for medical and clinical applications compared to pure forms of PG due to their cell membrane compatibility.