Visual Quantitative Detection of Circulating Tumor Cells with Single‐Cell Sensitivity Using a Portable Microfluidic Device

Immunocytological technologies, molecular technologies, and functional assays are widely used for detecting circulating tumor cells (CTCs) after enrichment from patients' blood sample. Unfortunately, accessibility to these technologies is limited due to the need for sophisticated instrumentation and skilled operators. Portable microfluidic devices have become attractive tools for expanding the access and efficiency of detection beyond hospitals to sites near the patient. Herein, a volumetric bar chart chip (V‐Chip) is developed as a portable platform for CTC detection. The target CTCs are labeled with aptamer‐conjugated nanoparticles (ACNPs) and analyzed by V‐Chip through quantifying the byproduct (oxygen) of the catalytic reaction between ACNPs and hydrogen peroxide, which results in the movement of an ink bar to a concentration‐dependent distance for visual quantitative readout. Thus, the CTC number is decoded into visually quantifiable information and a linear correlation can be found between the distance moved by the ink and number of cells in the sample. This method is sensitive enough that a single cell can be detected. Furthermore, the clinical capabilities of this system are demonstrated for quantitative CTC detection in the presence of a high leukocyte background. This portable detection method shows great potential for quantification of rare cells with single‐cell sensitivity for various applications.     

Synthesis and characterization of a novel poly (vinyl alcohol)-based zinc oxide (PVA-ZnO) composite proton exchange membrane for DMFC

Electrolyte polymeric membranes were synthesized by impregnating zinc oxide (ZnO) nanoparticles (NPs) in a cross-linked PVA matrix for Direct Methanol Fuel Cell (DMFC) applications. The novel membranes consist of PVA as the support while zinc oxide nanoparticles serve as inorganic ion exchangers. The fabricated composite proton exchange membranes exhibit a wide variety of advantages which include good thermal and chemical stability. The synthesized membranes demonstrate a high percentage of water uptake (85%–105%) and a low percentage of methanol uptake (17%–21%). Other important properties such as transport number (0.88) and ion exchange capacity (0.78 meq.g^?1) were also determined, and they were found comparable to Nafion®117. Ionic conductivity (3.9 mS/cm) of the composite membranes was determined and found comparable to other PVA based composite membranes reported in literature. Characterization of the membranes was carried out using Fourier-Transform Infrared Spectroscopy (FT-IR), X-ray diffraction (XRD), Scanning Electron Microscope (SEM), Energy-dispersive X-ray Spectroscopy (EDX) and Thermogravimetric analysis (TGA). These characterizations revealed the structural interaction between the support and the ion exchanger, crystalline nature, surface morphology, elemental analysis and the thermal stability (upto 280 °C) of the membranes, respectively. The mechanical characterization of the membranes was also carried out on a Universal Testing Machine (UTM), revealing satisfactory mechanical stability. The results demonstrate the possibility of synthesis of a low-cost proton exchange membrane for DMFC applications.     

Performance of PVDF supported silica immobilized phosphotungstic acid membrane (Si-PWA/PVDF) in direct methanol fuel cell

PVDF supported silica-immobilized phosphotungstic acid membrane (Si-PWA/PVDF) was synthesized by impregnation of silica immobilized phosphotungstic acid particles in porous PVDF film. Pore size distribution as well as stability of membrane in oxidative environment was determined using Fenton's reagent test. Stability of membrane against leaching of PWA which provides ion exchanging capacity was also determined and found to be adequate. Properties which affect performance of membrane in DMFC like water uptake, methanol cross-over and proton conductivity were measured. Water uptake of the membrane increased from 30.3% to 37.9% as the temperature was increased from 25 °C to 80 °C. The proton conductivity of the membrane increased from 4.3 mS cm⁻¹ to 20 mS cm⁻¹ with increase in the temperature from 25 °C to 80 °C. Methanol uptake of the Si-PWA/PVDF membrane was low compared to Nafion membrane and changed by very small amount with increase in temperature. Effect of operating parameters on performance of direct methanol fuel cell (DMFC) with the synthesized Si-PWA/PVDF was determined. DMFC performance improved on increasing temperature. As the temperature was increased from 25 °C to 60 °C, open circuit voltage (OCV) increased from 0.685 V at 0.815 V and the peak power density increased from 21.4 mW cm⁻² to 44.0 mW cm⁻². Maximum peak power density was obtained with 1 M methanol concentration and 60% relative humidity. Peak power density decreased with further increase in both methanol concentration and relative humidity.     

Synthesis of silica immobilized phosphotungstic acid (Si-PWA)-poly(vinyl alcohol) (PVA) composite ion-exchange membrane for direct methanol fuel cell

A 80 μm thick composite ion-exchange membrane was synthesized by uniformly dispersing sub-micron to nano sized silica immobilized phosphotungstic acid (Si-PWA) inorganic ion exchanger into cross-linked poly(vinyl alcohol) (PVA) matrix. ATR-IR spectrum confirmed the PVA cross-linking and presence of Si-PWA in membrane. Amorphous behavior of the membrane indicated uniform blending of crystalline Si-PWA particles with cross-linked PVA. Membrane's tensile strength (93 MPa) was much higher than Nafion 117 (34 MPa). Ion exchange capacity of the membrane (0.90 meqg⁻¹) was higher than the values reported for the other PVA based membranes. Na⁺ transport number was 0.92, indicating good ion-selectivity of the membrane. Membrane showed a high water uptake of 35% while its methanol uptake was low (8.4%) and thereby reduced methanol permeability (1.6 × 10⁻⁷ cm² s⁻¹) compared to Nafion-117 was observed, a highly desirable property for DMFC application. Proton conductivity increased from 7.04 mS cm⁻¹ to 10.5 mS cm⁻¹ with increase in temperature from 30 °C to 50 °C. At 35 °C, the single cell DMFC with membrane showed higher OCV (0.8 V) and comparable peak power density to Nafion-117.     

Monoamine Oxidase Inhibitory Activity: Methyl‐ versus Chlorochalcone Derivatives

Numerous studies have shown that chalcones are promising scaffolds for the development of new monoamine oxidase‐B (MAO‐B) inhibitors. As a continuation of our ongoing research into the development of reversible human MAO‐B (hMAO‐B) inhibitors, two series of twenty chalcones containing electron‐donating and electron‐withdrawing substituents were synthesized. All compounds were found to be competitive, selective, and reversible inhibitors of hMAO‐B except (2E)‐1‐(4‐methylphenyl)‐3‐(4‐nitrophenyl)prop‐2‐en‐1‐one ( P7 ) and (2E)‐1‐(4‐chlorophenyl)‐3‐(4‐nitrophenyl)prop‐2‐en‐1‐one ( P17 ), which were found to be selective inhibitors of hMAO‐A. The most potent hMAO‐B inhibitor, (2E)‐1‐(4‐chlorophenyl)‐3‐(4‐ethylphenyl)prop‐2‐en‐1‐one ( P16 ), showed a K_i value of 0.11±0.01 μm . Molecular docking simulations were carried out to identify the hypothetical binding mode for the most potent compounds in the active sites of hMAO‐A and B. The ability of the compounds to cross the blood–brain barrier was assessed by parallel artificial membrane permeability assay (PAMPA). Additionally, the most potent hMAO‐B inhibitor P16 showed no toxicity in cultured hepatic cells at concentrations of 5 and 25 μm .     

Urban drainage in Ireland – embracing sustainable systems

The current approach to stormwater management in Ireland requires that outflows from new developments are restricted to greenfield values that would have occurred prior to development. This typically involved the use of holding tanks constructed within developments to attenuate stormwater from where it was released at a reduced rate via a control structure to a nearby drainage network or watercourse. Improved drainage policies now require that sustainable drainage systems (SuDS) are used to meet this objective. This study presents an evaluation of perceived issues that may impede the adoption of new policies. The findings are based on surveys and focus groups of practitioners involved with the planning and design of drainage systems. Although the study indicates that benefits of SuDS are reasonably well understood, their use, for many reasons, has remained less popular. Concerns with ongoing maintenance and long‐term responsibility of SuDS remain impediments to the embracing of these systems in drainage strategies.