BubbleDrive, a low-volume incubation chamber for acute brain slices.

Acute brain slices are a common and useful preparation in experimental neuroscience. A wide range of incubation chambers for brain slices exists but only a few are designed with very low volumes of the bath solution in mind. Such chambers are necessary when high-cost chemicals are to be added to the solution or when small amounts of substances released by the slice are to be collected for analysis. The principal challenge in designing a very low-volume incubation chamber is maintaining good oxygenation and flow without mechanically disturbing or damaging the slices. We designed and validated BubbleDrive, a 3D-printed incubation chamber with a minimum volume of 1.5 mL which can hold up to three coronal mouse slices from one hemisphere. It employs the carbogen gas bubbles to drive the flow circulation in a consistent and reproducible manner, and without disturbing the brain slices. The BubbleDrive design and construction were successfully validated by comparison to a conventional large-volume incubation chamber in several experimental designs involving measurements of extracellular diffusion parameters, the electrophysiology of neuronal and astrocytic networks, and the effectiveness of slice incubation with hyaluronidase enzyme.

Probing Neuropeptide Volume Transmission In Vivo by Simultaneous Near-Infrared Light-Triggered Release and Optical Sensing.

Neuropeptides are abundant signaling molecules in the central nervous system. Yet remarkably little is known about their spatiotemporal spread and biological activity. Here, we developed an integrated optical approach using Plasmonic nAnovesicles and cell-based neurotransmitter fluorescent engineered reporter (CNiFER), or PACE, to probe neuropeptide signaling in the mouse neocortex. Small volumes (fL to pL) of exogenously supplied somatostatin-14 (SST) can be rapidly released under near-infrared light stimulation from nanovesicles implanted in the brain and detected by SST2 CNiFERs with nM sensitivity. Our measurements reveal reduced but synchronized SST transmission within 130 µm, and markedly smaller and delayed transmission at longer distances. These measurements enabled a quantitative estimation of the SST loss rate due to peptide degradation and binding. PACE offers a new tool for determining the spatiotemporal scales of neuropeptide volume transmission and signaling in the brain.

Printed microfluidic sweat sensing platform for cortisol and glucose detection.

Wearable sweat biosensors offer compelling opportunities for improved personal health monitoring and non-invasive measurements of key biomarkers. Inexpensive device fabrication methods are necessary for scalable manufacturing of portable, disposable, and flexible sweat sensors. Furthermore, real-time sweat assessment must be analyzed to validate measurement reliability at various sweating rates. Here, we demonstrate a "smart bandage" microfluidic platform for cortisol detection and continuous glucose monitoring integrated with a synthetic skin. The low-cost, laser-cut microfluidic device is composed of an adhesive-based microchannel and solution-processed electrochemical sensors fabricated from inkjet-printed graphene and silver solutions. An antibody-derived cortisol sensor achieved a limit of detection of 10 pM and included a low-voltage electrowetting valve, validating the microfluidic sensor design under typical physiological conditions. To understand effects of perspiration rate on sensor performance, a synthetic skin was developed using soft lithography to mimic human sweat pores and sweating rates. The enzymatic glucose sensor exhibited a range of 0.2 to 1.0 mM, a limit of detection of 10 µM, and reproducible response curves at flow rates of 2.0 µL min-1 and higher when integrated with the synthetic skin, validating its relevance for human health monitoring. These results demonstrate the potential of using printed microfluidic sweat sensors as a low-cost, real-time, multi-diagnostic device for human health monitoring.

Brain extracellular space of the naked mole-rat expands and maintains normal diffusion under ischemic conditions.

Brain extracellular space (ECS) forms a conduit for diffusion, an essential mode of molecular transport between brain vasculature, neurons and glia. ECS volume is reduced under conditions of hypoxia and ischemia, contributing to impaired extracellular diffusion and consequent neuronal dysfunction and death. We investigated the ECS volume fraction and diffusion permeability of the African naked mole-rat (NM-R; Heterocephalus Glaber), a rodent with a remarkably high tolerance for hypoxia and ischemia. Real-Time Iontophoretic and Integrative Optical Imaging methods were used to evaluate diffusion transport in cortical slices under normoxic and ischemic conditions, and results were compared to values previously collected in rats. NM-R brains under normoxic conditions had a smaller ECS volume fraction than rats, and a correspondingly decreased diffusion permeability for macromolecules. Surprisingly, and in sharp contrast to rats, the NM-R ECS responded to ischemic conditions at the center of thick brain slices by expanding, rather than shrinking, and preserving diffusion permeabilities for small and large molecules. The NM-R thick slices also showed a blunted accumulation of ECS potassium compared to rats. The remarkable dynamic response of the NM-R ECS to ischemia likely demonstrates an adaptation for NM-R to maintain brain function in their extreme nest environment.

Antitumour activity of Annona muricata L. leaf methanol extracts against Ehrlich Ascites Carcinoma and Dalton's Lymphoma Ascites mediated tumours in Swiss albino mice.

The use of plants as a source of sedative or treatment for cancer is reasonably widespread worldwide. Annona muricata Linn exhibits a vast array of medicinal and ethno-pharmaceutical benefits, attributed by different plant parts. The activity of this plant is regarded to the bio-production of secondary metabolites like alkaloids, phenols, flavonoids, and most unique group of compounds, namely, annonaceous acetogenins. Whilst this plant is gaining popularity as an anticancer treating plant, this study was undertaken to verify the plausible anticancer effect of leaf methanol extracts of A. muricata (LEAM). Acute toxicity study was carried to obtain safe dose in mice models using haematological, biochemical, and histological evaluations in Swiss albino mice. In-vitro cytotoxicity towards Dalton's Lymphoma Ascites (DLA) and Ehrlich Ascites Carcinoma (EAC) cell lines were determined by trypan blue exclusion method. In-vivo antitumour activity of LEAM (100, 200, and 500mg/kg b.wt.) was evaluated using DLA induced solid carcinoma and EAC induced ascites carcinoma models and its comparison with standard drug Cisplatin. Acute toxicity studies did not exhibit significant variations in treated mice suggesting diminutive side effects of LEAM. Statistical analysis revealed the IC50 values for DLA and EAC cell lines as 85.56 ± 5.28 and 68.07 ± 7.39 µg/mL, respectively, indicating better cytotoxic activity against EAC than DLA cells. LEAM decreased the tumour burden in dose-dependent manner. In comparison, with different concentrations tested, treatment with LEAM (200 mg/kg b.wt. and 500 mg/kg b.wt.) significantly reduced the solid tumour volume development by 58.11% and 65.70%, respectively. While lifespan was prolonged up to 51.43% in 500 mg/kg b.wt. LEAM treated ascites tumour-induced mice. This study thus indicates that LEAM possesses potent cytotoxic and antineoplastic activity and calls for more methodical safety assessments and other end-points of anti-tumourigenesis. Abbreviations: LEAM: Leaf methanol extract of Annona muricata; DLA: Dalton's Lymphoma Ascites; EAC: Ehrlich Ascites Carcinoma; IC50 : Half maximal inhibitory concentration; CPCSEA: Committee for the Purpose of Control Supervision of Experiments on Animal; IAEC: Institutional Animal Ethics Committee; ARRIVE: Animal Research: Reporting In-vivo Experiments; DMSO: Dimethyl sulphoxide; LD50 : Lethal Dose, 50%; SD: Standard Deviation; Hb: Haemoglobin; RBC: Red blood cells; WBC: White blood cells; HCT: Hematocrit; MCV: Mean cell volume; MCH: Mean cell haemoglobin; MCHC: Mean cell haemoglobin concentration; SALP: Serum alkaline phosphatase; SGPT: Serum glutamic pyruvic transaminase; SGOT: Serum glutamic oxaloacetic transaminase; ATP: Adenosine triphosphate; EGFR: Epidermal Growth Factor Receptor.

In vitro evaluation of Annona muricata L. (Soursop) leaf methanol extracts on inhibition of tumorigenicity and metastasis of breast cancer cells.

PURPOSE: The present study evaluates the in-vitro anti-tumorigenic potential of leaf methanol extracts of Annona muricata (LMAM). MATERIALS AND METHODS: The cytotoxic activity was assessed in MCF-7 cells by MTT assay at various concentrations ranging from 25-250µg/mL. MCF-7 cells were treated with 50 and 100 µg/mL LMAM for 24 h. To detect LMAM-induced apoptosis; Hoescht 33342 staining along with Cell cycle analysis, Annexin-PI probe as well as oxidative stress damage by reactive oxygen species (ROS) measurements were determined using flow cytometric analysis. While caspase-3 expression levels were studied employing the qRT-PCR method. RESULTS: LMAM exhibited significant inhibition of MCF-7 cells with an IC50 value of 85.55 µg/mL. Hoescht staining showed marked morphological features characteristic of apoptosis in LMAM treated cells. Cell cycle analysis confirmed the proven capability of LMAM showing a 30% rise in G1 phase upon treatment with 100 µg/mL LMAM, thus inducing cell cycle arrest at G1 phase and a rise in sub G0-G1 population paralleled with a decrease in S phase. Flow cytometric analysis with Annexin V-FITC-PI staining indicated an increase in the early and late apoptotic population with a 3.38% and 19.47% rise respectively when treated with 100 µg/mL LMAM. Treatment with 100 µg/mL LMAM caused an increase in intracellular ROS with MFI value 3334.08. Upregulation of caspase-3 was observed with a 2.18 and 32.47 fold increase compared to control in MCF-7 cells cultured at 50 µg/mL and 100 µg/mL LMAM respectively suggesting caspase-dependent apoptosis. CONCLUSION: LMAM proved as a potent ethno-chemopreventive agent and a potential lead in cancer treatment attributable to the synergistic interactive properties of phytoconstituents.

Integrity of White Matter is Compromised in Mice with Hyaluronan Deficiency.

Brain white matter is the means of efficient signal propagation in brain and its dysfunction is associated with many neurological disorders. We studied the effect of hyaluronan deficiency on the integrity of myelin in murine corpus callosum. Conditional knockout mice lacking the hyaluronan synthase 2 were compared with control mice. Ultrastructural analysis by electron microscopy revealed a higher proportion of myelin lamellae intruding into axons of knockout mice, along with significantly slimmer axons (excluding myelin sheath thickness), lower g-ratios, and frequent loosening of the myelin wrappings, even though the myelin thickness was similar across the genotypes. Analysis of extracellular diffusion of a small marker molecule tetramethylammonium (74 MW) in brain slices prepared from corpus callosum showed that the extracellular space volume increased significantly in the knockout animals. Despite this vastly enlarged volume, extracellular diffusion rates were significantly reduced, indicating that the compromised myelin wrappings expose more complex geometric structure than the healthy ones. This finding was confirmed in vivo by diffusion-weighted magnetic resonance imaging. Magnetic resonance spectroscopy suggested that water was released from within the myelin sheaths. Our results indicate that hyaluronan is essential for the correct formation of tight myelin wrappings around the axons in white matter.

ECS Dynamism and Its Influence on Neuronal Excitability and Seizures.

Seizure activity is governed by changes in normal neuronal physiology that lead to a state of neuronal hyperexcitability and synchrony. There is a growing body of research and evidence suggesting that alterations in the volume fraction (α) of the brain's extracellular space (ECS) have the ability to prolong or even initiate seizures. These ictogenic effects likely occur due to the ECS volume being critically important in determining both the concentration of neuroactive substances contained within it, such as ions and neurotransmitters, and the effect of electric field-mediated interactions between neurons. Changes in the size of the ECS likely both precede a seizure, assisting in its initiation, and occur during a seizure, assisting in its maintenance. Different cellular ion and water transporters and channels are essential mediators in determining neuronal excitability and synchrony and can do so through alterations in ECS volume and/or through non-ECS volume related mechanisms. This review will parse out the relationships between how the ECS volume changes during normal physiology and seizures, how those changes might alter neuronal physiology to promote seizures, and what ion and water transporters and channels are important in linking ECS volume changes and seizures.

Direct Printing of Graphene Electrodes for High-Performance Organic Inverters.

Scalable fabrication of high-resolution electrodes and interconnects is necessary to enable advanced, high-performance, printed, and flexible electronics. Here, we demonstrate the direct printing of graphene patterns with feature widths from 300 µm to ∼310 nm by liquid-bridge-mediated nanotransfer molding. This solution-based technique enables residue-free printing of graphene patterns on a variety of substrates with surface energies between ∼43 and 73 mN m-1. Using printed graphene source and drain electrodes, high-performance organic field-effect transistors (OFETs) are fabricated with single-crystal rubrene (p-type) and fluorocarbon-substituted dicyanoperylene-3,4:9,10-bis(dicarboximide) (PDIF-CN2) (n-type) semiconductors. Measured mobilities range from 2.1 to 0.2 cm2 V-1 s-1 for rubrene and from 0.6 to 0.1 cm2 V-1 s-1 for PDIF-CN2. Complementary inverter circuits are fabricated from these single-crystal OFETs with gains as high as ∼50. Finally, these high-resolution graphene patterns are compatible with scalable processing, offering compelling opportunities for inexpensive printed electronics with increased performance and integration density.

Photonic Resins: Designing Optical Appearance via Block Copolymer Self-Assembly.

Despite a huge variety of methodologies having been proposed to produce photonic structures by self-assembly, the lack of an effective fabrication approach has hindered their practical uses. These approaches are typically limited by the poor control in both optical and mechanical properties. Here we report photonic thermosetting polymeric resins obtained through brush block copolymer (BBCP) self-assembly. We demonstrate that the control of the interplay between order and disorder in the obtained photonic structure offers a powerful tool box for designing the optical appearance of the polymer resins in terms of reflected wavelength and scattering properties. The obtained materials exhibit excellent mechanical properties with hardness up to 172 MPa and Young's modulus over 2.9 GPa, indicating great potential for practical uses as photonic coatings on a variety of surfaces.

Direct Imprinting of Scalable, High-Performance Woodpile Electrodes for Three-Dimensional Lithium-Ion Nanobatteries.

The trend of device downscaling drives a corresponding need for power source miniaturization. Though numerous microfabrication methods lead to successful creation of submillimeter-scale electrodes, scalable approaches that provide cost-effective nanoscale resolution for energy storage devices such as on-chip batteries remain elusive. Here, we report nanoimprint lithography (NIL) as a direct patterning technique to fabricate high-performance TiO2 nanoelectrode arrays for lithium-ion batteries (LIBs) over relatively large areas. The critical electrode dimension is below 200 nm, which enables the structure to possess favorable rate capability even under discharging current densities as high as 5000 mA g-1. In addition, by sequential imprinting, electrodes with three-dimensional (3D) woodpile architecture were readily made in a "stack-up" manner. The height of architecture can be easily controlled by the number of stacked layers while maintaining nearly constant surface-to-volume ratios. The result is a proportional increase of areal capacity with the number of layers. The structure-processing combination leads to efficient use of the material, and the resultant specific capacity (250.9 mAh g-1) is among the highest reported. This work provides a simple yet effective strategy to fabricate nanobatteries and can be potentially extended to other electroactive materials.

Rapid, Large-Area Synthesis of Hierarchical Nanoporous Silica Hybrid Films on Flexible Substrates.

We report a simple strategy for the creation of large-area nanoporous hybrid films of silica, carbon, and gold on polyethylene terephthalate via photothermal processing. This method enables the selective heating of light-absorbing thin films on low-temperature substrates using sub-millisecond light pulses generated by a xenon flash lamp. The film contains gold nanoparticles as the nanoheaters to convert light energy to heat, a sacrificial block copolymer surfactant to generate mesopores, and cross-linked polyhedral oligomeric silsesquioxane as the silica source to form the skeleton of the porous structure. Hierarchical porous structures are achieved in the films after photothermal treatment, with uniform mesopores (44-48 nm) on the surface and interconnected macropores (>50 nm) underneath resulting from a foaming effect during release of gaseous decomposition products. The loading of gold nanoparticles is up to 43 wt % in the product, with less than 2 wt % organic residue. This rapid and large-area process for the synthetis of porous structures is compatible with roll-to-roll manufacturing for the fabrication of flexible devices.

Identifying Quality Indicators Used by Patients to Choose Secondary Health Care Providers: A Mixed Methods Approach.

BACKGROUND: Patients in health systems across the world can now choose between different health care providers. Patients are increasingly using websites and apps to compare the quality of health care services available in order to make a choice of provider. In keeping with many patient-facing platforms, most services currently providing comparative information on different providers do not take account of end-user requirements or the available evidence base. OBJECTIVE: To investigate what factors were considered most important when choosing nonemergency secondary health care providers in the United Kingdom with the purpose of translating these insights into a ratings platform delivered through a consumer mHealth app. METHODS: A mixed methods approach was used to identify key indicators incorporating a literature review to identify and categorize existing quality indicators, a questionnaire survey to formulate a ranked list of performance indicators, and focus groups to explore rationales behind the rankings. Findings from qualitative and quantitative methodologies were mapped onto each other under the four categories identified by the literature review. RESULTS: Quality indicators were divided into four categories. Hospital access was the least important category. The mean differences between the other three categories hospital statistics, hospital staff, and hospital facilities, were not statistically significant. Staff competence was the most important indicator in the hospital staff category; cleanliness and up-to-date facilities were equally important in hospital facilities; ease of travel to the hospital was found to be most important in hospital access. All quality indicators within the hospital statistics category were equally important. Focus groups elaborated that users find it difficult to judge staff competence despite its importance. CONCLUSIONS: A mixed methods approach is presented, which supported a patient-centered development and evaluation of a hospital ratings mobile app. Where possible, mHealth developers should use systematic research methods in order to more closely meet the needs of the end user and add credibility to their platform.