Environmental pollutant nanoplastics (NPs) cross the blood–brain barrier and induce central nervous system toxicity through multiple pathways, with oxidative stress as the core neurotoxicity initiator. However, the brain penetration depth of NPs and associated oxidative stress distribution have not yet been investigated. Herein, we developed a flexible electrochemical sensor based on platinum nanoparticle-modified carbon nanotube fiber (Pt/CNF) to minimize insertion damage. The sensor exhibits excellent mechanical compliance and high sensitivity for hydrogen peroxide (H₂O₂) detection. Using this sensor for real-time in situ H₂O₂ monitoring in human cortical organoids (COs), we systematically investigated the oxidative stress levels at depths of 100 and 300 µm in COs exposed to polystyrene nanoplastics (PS-NPs) for different durations within 6 days. Our results demonstrate that oxidative stress at the same depth increased with longer exposure time, and showed distinct spatial locality, concentrating primarily in the ~ 100 µm-deep penetration region. This study quantifies the spatiotemporal neurotoxicity of nanoplastics in human brain models and provides a robust technical framework for environmental health risk assessment in other tissues.

The detection and analysis of circulating tumor cells (CTCs) from patients′ blood is important to assess tumor status; however, it remains a challenge. In the present study, we developed a programmable DNA-responsive microchip for the highly efficient capture and nondestructive release of CTCs via nucleic acid hybridization. Transparent and patternable substrates with hierarchical architectures were integrated into the microchip with herringbone grooves, resulting in greatly enhanced cell-surface interaction via herringbone micromixers, more binding sites, and better matched topographical interactions. In combination with a high-affinity aptamer, target cancer cells were specifically and efficiently captured on the chip. Captured cancer cells were gently released from the chip under physiological conditions using toehold-mediated strand displacement, without any destructive factors for cells or substrates. More importantly, aptamer-containing DNA sequences on the surface of the retrieved cancer cells could be further amplified by polymerase chain reaction (PCR), facilitating the detection of cell surface biomarkers and characterization of the CTCs. Furthermore, this system was extensively applied to the capture and release of CTCs from patients′ blood samples, demonstrating a promising high-performance platform for CTC enrichment, release, and characterization.