Superhydrophobic Thermoplastic Polyurethane Foam Fabricated by Phase Separation and Silica Coating for Oil-Water Separation.

Oil spills and the presence of oily wastewater have resulted in substantial ecological damage. Superhydrophobic polymer foam with selectivity and adsorption capacity is a promising candidate for efficient oil-water separation. In this study, a method that combines phase separation and silica coating to produce superhydrophobic thermoplastic polyurethane (TPU) foam is proposed. The TPU foam demonstrates superhydrophobicity with a water contact angle of 155.62°, and exhibits a maximum saturated adsorption capacity of 54.11 g g-1 . Furthermore, the foam can be utilized as a filter for oil-water separation, maintaining its filtration efficiency (41.2 m3  m2  h-1 ) even after ten filtration cycles.

PDMS-Parylene Hybrid, Flexible Micro-ECoG Electrode Array for Spatiotemporal Mapping of Epileptic Electrophysiological Activity from Multicortical Brain Regions.

Epilepsy detection and focus location are urgent issues that need to be solved in epilepsy research. A cortex conformable and fine spatial accuracy electrocorticogram (ECoG) sensor array, especially for real-time detection of multicortical functional regions and delineating epileptic focus remains a challenge. Here, we fabricated a polydimethylsiloxane (PDMS)-parylene hybrid, flexible micro-ECoG electrode array. The multiwalled carbon nanotubes (MWCNTs)/poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) nanocomposite-modified electrode interface significantly improved the sensing performance with low impedance (20.68 ± 6.65 kΩ), stable phase offset, and high sensitivity. The electrophysiological activities of multicortical brain regions (somatosensory cortex, parietal association cortex, and visual cortex) were simultaneously monitored during normal and epileptic statuses. The epileptic ECoG activities spread spatiotemporally from the starting point toward the adjacent cortex. Significant variations of the waveform, power, and frequency band were observed. The ECoG potential (123 ± 23 µV) at normal status was prominently up to 417 ± 87 µV at the spike wave stage. Besides, the power for epileptic activity (11.049 ± 4.513 µW) was 10 times higher than that (1.092 ± 0.369 µW) for normal activity. In addition, the theta frequency band was found to be a characteristic frequency band of epileptic signals. These joint analysis results of multicortical regions indicated that the active micron-scale region on the parietal association cortex was more likely to be the epileptogenic focus. Cortical mapping with high spatial detail provides the accurate delineation of lesions. The flexible micro-ECoG electrode array is a powerful tool for constructing a spatiotemporal map of the cortex. It provides a technical platform for epileptic focus location, biomedical diagnosis, and brain-computer interaction.

PtNPt/MWCNT-PEDOT:PSS-Modified Microelectrode Arrays for the Synchronous Dopamine and Neural Spike Detection in Rat Models of Sleep Deprivation.

In this study, a biosensor assembly based on microelectrode arrays (MEAs) modified with PtNPt/MWCNT-PEDOT:PSS nanocomposites is presented to synchronously detect the dopamine (DA) and electrophysiological activities in rat brains. Different morphological and electrochemical characterizations were conducted to show the excellent mechanical and electrical properties of the as-prepared probes. The developed biosensors realized the sensitive and selective detection of DA with the existence of significant interferences such as uric acid (UA), ascorbic acid (AA), glutamate (Glu), and 3,4-dihydroxyphenylacetic acid (DOPAC). Calibration curve for the DA response was linear with the concentration from 0.05 µM to 79 µM (R = 0.999), with a sensitivity of 30.561 pA/µM and detection limit as low as 50 nM. Finally, the proposed microelectrode was applied to be implanted into the cortex and caudate putamen (CPU) of rats, which was demonstrated to stably measure the synchronous neurochemical and neurophysiological changes caused by 72 h sleep deprivation. The in vivo measuring results showed that the sleep deprivation increased the DA release and neural spike activity in both cortex and CPU. The local field potential (LFP) power in the delta and theta band was significantly increased as well. These changes in brain may reflect the brain's adaptive reaction toward the side effects induced by sleep deprivation and may partially explain the mechanism of forced wakefulness in the presence of accumulated sleep pressure.

SWCNTs/PEDOT:PSS-Modified Microelectrode Arrays for Dual-Mode Detection of Electrophysiological Signals and Dopamine Concentration in the Striatum under Isoflurane Anesthesia.

Accurate detection of the degree of isoflurane anesthesia during a surgery is important to avoid the risk of overdose isoflurane anesthesia timely. To address this challenge, a four-shank implantable microelectrode array (MEA) was fabricated for the synchronous real-time detection of dual-mode signals [electrophysiological signal and dopamine (DA) concentration] in rat striatum. The SWCNTs/PEDOT:PSS nanocomposites were modified onto the MEAs, which significantly improved the electrical and electrochemical performances of the MEAs. The electrical performance of the modified MEAs with a low impedance (16.20 ± 1.68 kΩ) and a small phase delay (-27.76 ± 0.82°) enabled the MEAs to detect spike firing with a high signal-to-noise ratio (> 3). The electrochemical performance of the modified MEAs with a low oxidation potential (160 mV), a low detection limit (10 nM), high sensitivity (217 pA/µM), and a wide linear range (10 nM-72 µM) met the specific requirements for DA detection in vivo. The anesthetic effect of isoflurane was mediated by inhibiting the spike firing of D2_SPNs (spiny projection neurons expressing the D2-type DA receptor) and the broadband oscillation rhythm of the local field potential (LFP). Therefore, the spike firing rate of D2_SPNs and the power of LFP could reflect the degree of isoflurane anesthesia together. During the isoflurane anesthesia-induced death procedure, we found that electrophysiological activities and DA release were strongly inhibited, and changes in the DA concentration provided more details regarding this procedure. The dual-mode recording MEA provided a detection method for the degree of isoflurane anesthesia and a prediction method for fatal overdose isoflurane anesthesia.