Engineered exosomes as programmable nanocarriers for targeted theranostic and translational applications

Exosomes are nanoscale extracellular vesicles secreted by cells that possess molecular and pathological characteristics of their cellular origin. Acting as natural carriers, they efficiently transport a diverse cargo of biomolecules, including proteins, nucleic acids, lipids, metabolites, and small molecules facilitating highly specific intercellular communication. Owing to their inherent biocompatibility, target specificity, and cargo versatility, exosomes have emerged as one of the most promising platforms for diagnostic and therapeutic applications. This review comprehensively elaborates on intricate biogenesis and regulatory pathways governing exosome production, examines their structural composition and cargo loading preferences, and highlights emerging strategies to enhance their functional capabilities. We further explore recent breakthroughs at the intersection of exosome biology and nanotechnology, emphasizing their roles in maintaining cellular homeostasis, advancing disease diagnostics, and enabling targeted therapeutic delivery. Finally, we critically address current challenges and limitations in exosome research, offering insights into innovative solutions and future directions for their clinical translation.