Brain organoids in environmental neurotoxicology: applications, mechanisms, and future perspectives.

The advent of human induced pluripotent stem cell (hiPSC)-derived brain organoids represents a significant advance in environmental neurotoxicology, propelling the discipline toward human-relevant, mechanistic, and predictive in vitro paradigms. This review explores the utility of brain organoids in environmental neurotoxicology, which uniquely address critical limitations of traditional models by recapitulating key aspects of human brain development, including three-dimensional (3D) cytoarchitecture, multilineage cellular heterogeneity, and functional network activity. This review systematically elaborates on their construction principles, unique advantages in neurotoxicological research, and the significant progress made in elucidating mechanisms of toxicity. Notably, brain organoids exhibit enhanced sensitivity in identifying the subtle adverse outcomes of chronic, low-dose exposures to environmental contaminants, often eluding conventional approaches. Their key advantage lies in the greater capacity to deconstruct complex toxicological pathways, enabling precise tracing of adverse outcome pathways (AOPs). Future development requires enhancing model complexity through vascularization, promoting automation and standardization, and integrating artificial intelligence (AI) for data analysis. Concurrently, establishing sustained ethical oversight and standardized frameworks is essential to ultimately advance the field toward more precise and efficient hazard identification and risk characterization.Highlights1. Human brain organoids bridge species gaps for more human-relevant neurotoxicity assessment.2. Brain organoids effectively recapitulate chronic, low-dose and mixture environmental risks.3. Integrating brain organoid data into the AOP frameworks enhances mechanistic understanding.4. Coupling brain organoids with organ-on-a-chip and AI advances next-generation risk assessment.