Mwcnts

The surface modification of the sites was performed using 3,4-Ethylenedioxythiophene (EDOT) (Aladdin, Shanghai, China), polystyrene sulfonate (PSS) (HEROCHEM, Shanghai, China), and short multi-walled carbon nanotubes (MWCNTs) (XFNANO, Nanjing, China). Reference 600 (Gamry Instruments, Warminster, PA, USA) evaluated the MEA site impedance. P-chlorophenylalanine (PCPA) (Sigma–Aldrich, Shanghai, China) and phosphate-buffered saline (PBS) (Sigma–Aldrich, Shanghai, China) were used to induce insomnia in rats. R520IP (RWD Life Science, Shenzhen, China) was used to anesthetize the rats. KeyGEN BioTECH (Nanjing, China) provided cell membrane orange fluorescent dye (DiI). Brain slices were manufactured by leica1950 (Leica Biosystems, Deer Park, IL, USA). The brain slices were imaged by ZEISS Axio Observer (ZEISS, Jena, Germany). The 128-channel neural data recording system (Blackrock Microsystems, Tampa, FL, USA), micropositioner (model 2662, David KOPF instrument, Los Angeles, CA, USA), and a classic stereotaxic instrument for rats (Stoelting, Wood Dale, IL, USA) were used to capture intracranial electrophysiological signals in rats.

Al₂O₃ NPs, TiO₂ NPs, SiO₂ NPs, MWCNTs, BCs, and GOs were purchased from XFNANO Materials Tech Co., Ltd. (Nanjing, China), and graphenes were provided by Strem Chemicals, Inc (Newburyport, MA, USA). FeOx NPs were synthesized using iron (III) chloride hexahydrate (FeCl₃·6H₂O) according to a mechanochemical method with a few modifications (three times KCl addition) [14 (link)]. The urban particulate matter sample (SRM 1648a), obtained from the National Institute of Standards and Technology (NIST), was used as a standard for comparative toxicity evaluation between PM and NPs.
All particles were subjected to the same procedure for characterization. After dispersion in the culture medium by ultrasonication (5 min), number-weighted hydrodynamic diameters and zeta potentials were characterized by dynamic light scattering (DLS, Brookhaven NanoBrook 90Plus PALS, Holtsville, NY, USA) and zeta potential analyzer (Malvern, Zetasizer Nano ZS90, Worcestershire, UK), respectively. The shape, size, and agglomeration status of NP/PM samples were then determined using a field emission scanning electron microscope (FESEM, Hitachi SU8220, Tokyo, Japan).