Nanotoxicology

Nanotoxicology is the scientific study of the toxic effects of nanoscale materials and structures, typically defined as 1 to 100 nanometers in at least one dimension. It investigates how nanoscale properties, such as large surface area, quantum effects, and chemical reactivity, influence interactions with biological systems and environmental health.

Nanoparticles can cross biological barriers more readily than bulk materials, leading to unique toxicokinetics and mechanisms. Reported adverse effects include oxidative stress, inflammation, cytotoxicity, genotoxicity, and unintended modulation of immune and endocrine processes. Outcomes depend on material composition, size, shape, surface chemistry, coating, aggregation state, dissolution rate, dose, exposure route, and organism. Common exposure routes include inhalation, ingestion, dermal contact, and, for medical or consumer products, injection.

Assessment approaches include thorough physico-chemical characterization, in vitro assays, and in vivo models, supported by computational modeling and high-throughput screening. Dosimetry and appropriate dose metrics (mass, surface area, or particle number) are critical for interpreting effects. Toxicokinetics, biodistribution, and environmental fate are also studied to understand long-term risks.

Regulatory and risk assessment frameworks vary by jurisdiction, and nanotoxicology findings inform safety guidelines for consumer products, medicines, cosmetics, and industrial processes. Challenges include material heterogeneity, dynamic transformations in biological media (such as protein corona formation), aggregation, dissolution, and a lack of standardized testing protocols that translate to real-world exposure.

Notable nanomaterials studied include silver nanoparticles, carbon nanotubes, titanium dioxide, silica, and quantum dots; research continues to distinguish material-specific hazards from particle-specific effects. The field supports safety-by-design approaches and responsible development to minimize harm while enabling beneficial applications.