Representative probiotic extracellular vesicles engineered with modified hyaluronic acid and tea polyphenol for enhancing bioactive stability and targeted cellular delivery.

Curcumin (Cur) and anthocyanin (Ant) are typical plant-derived bioactives with promising biological benefits, but poor stability and bioavailability limit their applications. To address these challenges, we engineered a targeted co-delivery platform by systematically comparing two representative, probiotic-derived extracellular vesicle carriers: outer membrane vesicles (OMVs) from Escherichia coli Nissle 1917 and extracellular vesicles (EVs) from Lactobacillus plantarum. Encapsulation efficiency (EE) of Cur was 41.6% for OMVs and 35.9% for EVs, whereas EE of Ant was 25.4% and 24.6%, respectively. Both vesicle types were further synergistically functionalized with specifically acylated epigallocatechin palmitate (EGCp) and octenyl succinic anhydride-grafted hyaluronic acid (OSA-HA). The incorporation efficiency of EGCp was 27.2% for OMVs and 37.3% for EVs. The self-assembly process yielded composite nanovesicles with a reduced particle size (OMVs: from 165.6 nm to 143.2 nm; EVs: from 156.8 nm to 120.8 nm) and a more negatively charged surface (from -20.8 mV to -37.5 mV for OMVs; from -18.3 mV to -35.3 mV for EVs) compared to their native counterparts, indicating improved colloidal properties. In addition, both engineered nanovesicles effectively protected the encapsulated bioactives, significantly enhancing their stability against simulated gastrointestinal digestion and oxidative stress. For example, the retention of Cur under oxidative conditions increased from 24.2% in unmodified OMVs to 69.1% in the optimized formulation within 2 h. Cellular uptake assays confirmed the OSA-HA coating achieved targeted delivery to inflammatory macrophages, with OSA-HA-modified OMVs exhibiting higher cellular internalization (75.4% at 12 h) than similarly modified EVs (61.8% at 12 h). While both types of functionalized nanovesicles enhanced intracellular antioxidant activity to a similar extent, the OMV-based system demonstrated superior suppression of pro-inflammatory mediators (NO, TNF-α, and IL-6) in mitigating lipopolysaccharide (LPS)-induced cell damage. This comparative study establishes a biocompatible probiotic-based colloidal platform, demonstrating the potential of two selected engineered probiotic vesicles and functionalized polysaccharides for the encapsulation and targeted cellular delivery of sensitive bioactive compounds.