Nanotoxicity of Porous Silica Nanoparticles: Physicochemical Properties and Mechanistic Cellular Endpoints

This review provides a comprehensive overview of the fundamental aspects of nanoparticles (NPs), emphasizing their physicochemical properties and biological interactions, with particular focus on porous silica nanoparticles (PSNs). The review provides information on the Safe-by-design (SbD) S.A.F.E. (Standardised characterization, Assessment of biocompatibility, Facilitation of toxicity and exposure routes and Evaluation of clinical translation) framework. It discusses critical factors influencing NP toxicity and cellular uptake, including particle size, shape, pore size, surface charge, surface functionalisation, and crystallinity. The review also examines exposure routes of NPs-inhalation, dermal, oral, systemic and mucosal-and their subsequent biological effects. A key section is dedicated to the formation of the protein corona, a critical determinant of NP fate in biological systems, and its influence on circulation time, immune clearance and cellular responses. Particular attention is given to assessing the biological interactions of the PSNs and the mechanisms underlying PSN-induced cytotoxicity and genotoxicity, with a focus on the assays commonly employed to evaluate these effects. The review explores the use of gene expression profiling as a powerful tool to elucidate the molecular mechanisms underlying nanoparticle-induced cellular changes. This review aims to provide an integrated perspective on the SbD considerations and safety implications of nanomaterials. It highlights the need for a deeper understanding of complex biological interactions to establish SbD principles and enable the translation of PSNs into clinical applications. Finally, current regulatory frameworks and guidelines for testing nanomaterials, including PSNs, that support their safe and sustainable development are discussed.