The field of nanotechnology has experienced exponential growth, with the unique properties of nanomaterials (NMs) being employed to enhance a wide range of products across diverse industrial sectors. This study examines the toxicity of metal- and carbon-based NMs, with a particular focus on titanium dioxide (TiO₂), zinc oxide (ZnO), silica (SiO₂), cerium oxide (CeO₂), silver (Ag), and multi-walled carbon nanotubes (MWCNTs). The potential health risks associated with increased human exposure to these NMs and their effect on the respiratory, gastrointestinal, dermal, and immune systems were evaluated using in vitro assays. Physicochemical characterisation of the NMs was carried out, and in vitro assays were performed to assess the cytotoxicity, genotoxicity, reactive oxygen species (ROS) production, apoptosis/necrosis, and inflammation in cell lines representative of the systems evaluated (3T3, Caco-2, HepG2, A549, and THP-1 cell lines). The results obtained show that 3T3 and A549 cells exhibit high cytotoxicity and ROS production after exposure to ZnO NMs. Caco-2 and HepG2 cell lines show cytotoxicity when exposed to ZnO and Ag NMs and oxidative stress induced by SiO₂ and MWCNTs. THP-1 cell line shows increased cytotoxicity and a pro-inflammatory response upon exposure to SiO₂. This study emphasises the importance of conducting comprehensive toxicological assessments of NMs given their physicochemical interactions with biological systems. Therefore, it is of key importance to develop robust and specific methodologies for the assessment of their potential health risks.

The development of effective inhalable drugs remains a key challenge in the treatment of pulmonary diseases, due to the physiological barriers of the respiratory tract and the lack of predictive models that accurately reproduce the human lung environment. In this context, liposomes (LP) have emerged as promising nanocarriers for pulmonary drug delivery due to their high biocompatibility, surfactant-like composition, capacity to encapsulate both hydrophilic and lipophilic drugs, and potential to provide sustained drug release while reducing systemic toxicity. This study evaluates the influence of size and PEGylation on their physicochemical properties, cytotoxicity, interaction with the pulmonary mucus, and cellular internalisation. LP of 100 nm (LP 100), 200 nm (LP 200), and 600 nm (LP 600) were characterised physiochemically and evaluated in pulmonary cell lines (A549 and Calu-3) exposed in liquid–liquid interface (LLI) and air–liquid interface (ALI) by nebulisation. In addition, artificial pulmonary mucus (APM) was employed to analyse LP penetration through the pulmonary mucus barrier. Results indicate that LP 100 exhibits greater colloidal stability, lower cytotoxicity, and sustained migration through the APM over time with respect to larger particles. PEGylation of LP 100 (LP-PEG) further increases their stability and ability to penetrate the APM, although cellular internalisation is reduced due to the steric effect of the PEG coating. These findings highlight the importance of adjusting the size and surface modifications of LPs according to the therapeutic target of the drug, optimising their persistence on the epithelial surface or their cellular uptake.

Superparamagnetic iron oxide nanoparticles (SPIONs) are widely employed as platforms for ligand‐mediated targeting in multimodal imaging and targeted therapeutic applications owing to their intrinsic magnetic properties and versatility for surface and core modification. In addition to magnetic resonance imaging contrast, SPIONs can be labeled with radioisotopes incorporated into the crystalline structure or functionalized with chemically bound dyes or chelating agents, enabling complementary imaging modalities such as fluorescence imaging and positron emission tomography. However, chemical functionalization of nanoparticles with targeting ligands can induce alterations not only in their physicochemical properties but also in their interactions with biological systems. These nano‐biointeractions are critical determinants of biological performance and must be carefully evaluated. In this study, we investigate the impact of ligand functionalization on SPION‐cancer cell interactions to elucidate key parameters relevant to the successful clinical translation of nanomedicine‐based targeted imaging agents.