Search

Transparent electrode arrays have emerged as promising platforms for neural interfacing by enabling simultaneous electrophysiological recording and optical measurements. Soft and thin devices also have compelling advantages due to their less mechanical mismatch with the brain tissue. Here we demonstrate a bilayer-nanomesh-based transparent microelectrode array (MEA) on ultrathin Polydimethylsiloxane (PDMS) substrate. We have successfully fabricated 32-channel, bilayer-nanomesh microelectrodes on PDMS with total device thickness down to only 10μm. In addition to excellent electrode performance, device reliability, and optical transparency, we have also demonstrated successful hydrophilic surface modification and great sterilization compatibility.

Introduction: Sirt1 is a NAD+ dependent deacetylase that is known as an important metabolic regulator for type 2 diabetes melitus. To determine the role of Sirt1 in ischemic stroke-induced metabolic imbalance, we generated the neuronal specific Sirt1 knock-in (nSirt1 KI) and knock-out (Sirt1 KO) mice and examined its effect and mechanism. Methods: To determine the role of Sirt1 in ischemic stroke-induced impaired metabolic actions including insulin and glucose abnormality, we tested the pharmacological effects of Metformin and Sirtinol as Sirt1 activator and inhibitor. To determine the genetic role of neuronal Sirt1 in the brain, we generated the nSirt1 KI mice and Sirt1 KO. We used the Ischemia/Reperfusion (I/R: 1h middle cerebral artery occlusion (MCAO)/23h reperfusion) injury model to induce the abnormal metabolic changes. Infarction volume was measured by TTC staining and we determined neurological deficit score (NDS) at 23h after 1h MCAO. The level of glucose and insulin were measured by a drop of tail blood using test-strip and ELISA Kit before, during (every 10 minutes interval), and after MCAO. Results: Metformin reduced infarction volume and Sirtinol worsened the infarction volume via Sirt1 signaling pathway. Heterozygous Sirt1 KO (Sirt1 +/-) mice showed decreased relative cerebral blood flow (rCBF) and worsen infarction volume in ischemic areas, whereas nSirt1 KI mice exhibited increased rCBF, improved NDS, regulating abnormal blood glucose and insulin, and reduced infarction volume by 42% compare to that of littermate control in I/R injury model (n=7, p Conclusion: These findings indicate that the important neuroprotective effect of neuronal cells is mediated by Sirt1 overexpression and suggest that upregulation of neuronal Sirt1 may be an important therapeutic target for ischemic stroke via regulating metabolic imbalance.

Introduction: The role of neuronal cell specific ROCK2 in ischemic stroke in vivo has been poorly investigated. We investigated the pharmacological effect of selective ROCK2 inhibition by selective ROCK2 inhibitor, KD025 and the genetic effect using neuronal specific ROCK2 knockout (ROCK2Eno2-/-) mice. Methods: Isoflurane-anesthetized littermate control (LC) and ROCK2Eno2-/- mice (20-22 g) underwent ischemia (2h middle cerebral artery occlusion (MCAO)/reperfusion (22h after 2h MCAO) injury model. An 8.0 nylon monofilament coated with a silicone was introduced into the left internal carotid artery up to the anterior cerebral artery. To assess the mechanism of ROCK2 deficiency in neuronal cells, we seeded hippocampal neuronal (HT22) cells in 6-well plates and transfected ROCK2 siRNA. Phosphorylated glycogen synthase kinase 3 beta (pGSK-3β) and Tau proteins which were involved in neuroprotection were measured by western blotting from brain lysates and neuronal cells. Infarction volume was measured by TTC staining and evaluation of behavioral was assessed by neurological deficit score (NDS) at 22h after MCAO. Results: In WT mice, ROCK2 inhibition by KD025 (100 mg/kg, p.o.) decreased infarct volumes and improved the NDS in ischemic stroke. ROCK activity (p-MYPT1 to MYPT1 ratio) of the brain lysates by KD025 was decreased dose-dependently in ischemic mice brain. In genetic modified mice, infarction volume (64.6 ± 10.4 vs. LC (102.3 ± 12.4), n=5) of ROCK2Eno2-/- mice was significantly decreased by 37% and the NDSs (1.8 ± 0.4 vs. LC (2.8 ± 0.5), n=5) were improved by 36% compared to the LC groups. Both pGSK-3β and Tau in HT22 cells with ROCK2 siRNA transfection and ROCK2Eno2-/- mice brain was significantly decreased compared to each respective controls. Conclusion: These findings indicate that neuronal ROCK2 plays important role in ischemic stroke via GSK-3β and Tau signaling pathways and inhibition of neuronal specific ROCK2 may have therapeutic benefits in ischemic stroke.