The potential of organic nanoparticles and plant-derived adjuvants for vaccine design.

Organic nanoparticles (NPs) are nanoscale entities composed of natural or synthetic carbon-based compounds. In biomedicine, particularly in vaccine development, their properties facilitate antigen loading, stabilization, and delivery, while exerting immunostimulatory effects that enhance immune responses. Compared to inorganic NPs, organic NPs often exhibit higher safety profiles, greater chemical versatility for functionalization, and superior mucoadhesive properties. Over the past three decades, organic NP-based nanovaccines have been increasingly explored, generating preclinical evidence demonstrating ability to induce robust immune responses and confer immunoprotection. Within this context, plant-derived compounds have attracted growing interest due to their chemical diversity and broad spectrum of bioactivities, including immunostimulatory effects, making them promising candidates as vaccine adjuvants. The data presented in this review were derived from review of peer-reviewed literature identified through searches on PubMed, Scopus, and ScienceDirect, covering studies published between 2000 and 2025, with earlier foundational studies included. This review discusses the application of organic NPs in nanovaccine platforms, detailing key properties, advantages, and the promising vaccine prototypes reported in the literature. Special attention is given to the potential of plant-derived compounds as adjuvants, highlighting their role in optimizing organic NP-based nanosystems for vaccine delivery, while providing insights into key design considerations for developing effective vaccines.