Engineering extracellular vesicles for multi-cargo co-delivery in silicosis and related fibrotic diseases: design strategies and translational prospects.

Silicosis remains therapeutically intractable because its three driver axes-the NLRP3 inflammasome, ROS/Nrf2 oxidative stress, and TGF-β/Smad fibrosis-interlock into a self-reinforcing network whose topological redundancy reroutes signalling around any single-target drug, the structural basis for repeated single-agent failure. Existing nanocarriers cannot meet the resulting demand for multi-cargo delivery: lipid nanoparticles risk triggering NLRP3, polymeric carriers escape endosomes too poorly to deliver nucleic acids, and inorganic particles intensify the ROS-driven fibrotic loop. Engineered exosomes close this gap. Their native architecture matches the silicotic microenvironment and can carry nucleic acids, proteins, and small molecules together at defined ratios across the vesicle population, while surface CD47 can confer immune evasion, donor-encoded integrins can direct cell-selective pulmonary tropism, and membrane fusion can deliver payloads directly into the cytoplasm, - properties we argue must be demonstrated for each engineered construct rather than assumed. Here, we evaluate the complete engineering pipeline - donor-cell selection, GMP-compatible isolation, cargo loading by electroporation and bio-orthogonal surface click chemistry, and stimuli-responsive release whose triggering thresholds have been established in oncological rather than fibrotic settings and require validation in silicosis. Preclinical evidence, graded by a three-tier scheme, is consistent with coordinated multi-axis efficacy spanning NLRP3 suppression, Nrf2 restoration, and TGF-β/Smad blockade, but remains predominantly Grade B and C; we critically appraise manufacturing scalability, co-loading optimization, and endotype-matched dosing as the milestones still separating this platform from clinical deployment.