Green Formation of Robust Supraparticles for Cargo Protection and Hazards Control in Natural Environments

In parallel with important technological advances, nanoparticles have brought numerous environmental and toxicological challenges due to their high mobility and nonspecific surface activity. The hazards associated with nanoparticles can be significantly reduced while simultaneously keeping their inherent benefits by superstructuring. In this study, a low-temperature and versatile methodology is employed to structure nanoparticles into controlled morphologies from biogenic silica, used as a main building block, together with cellulose nanofibrils, which promote cohesion. The resultant superstructures are evaluated for cargo loading/unloading of a model, green biomolecule (thymol), and for photo-accessibility and mobility in soil. The bio-based superstructures resist extremely high mechanical loading without catastrophic failure, even after severe chemical and heat treatments. Additionally, the process allows pre and in situ loading, and reutilization, achieving remarkable dynamic payloads as high as 90 mg g^-1 . The proposed new and facile methodology is expected to offer a wide range of opportunities for the application of superstructures in sensitive and natural environments.