Heterogeneous Morphologies and Hardness of Co-Sputtered Thin Films of Concentrated Cu-Mo-W Alloys.

Heterogeneous microstructures in Cu-Mo-W alloy thin films formed by magnetron co-sputtering immiscible elements with concentrated compositions are characterized using scanning transmission electron microscopy (STEM) and nanoindentation. In this work, we modified the phase separated structure of a Cu-Mo immiscible system by adding W, which impedes surface diffusion during film growth. The heterogeneous microstructures in the Cu-Mo-W ternary system exhibited bicontinuous matrices and agglomerates composed of Mo(W)-rich phase.

Collagen IV assembly is influenced by fluid flow in kidney cell-derived matrices.

Kidney podocytes and endothelial cells assemble a complex and dynamic basement membrane that is essential for kidney filtration. Whilst many components of this specialised matrix are known, the influence of fluid flow on its assembly and organisation remains poorly understood. Using the coculture of podocytes and glomerular endothelial cells in a low-shear stress, high-flow bioreactor, we investigated the effect of laminar fluid flow on the composition and assembly of cell-derived matrix.

Structural alignment of ZnO columns across multiple monolayer MoS layers as compliant substrates.

Understanding the behavior of materials in multi-dimensional architectures composed of atomically thin two-dimensional (2D) materials and three-dimensional (3D) materials has become mandatory for progress in materials preparation various epitaxy techniques, such as van der Waals and remote epitaxy methods. We investigated the growth behavior of ZnO on monolayer MoS as a model system to study the growth of a 3D material on a 2D material, which is beyond the scope of remote and van der Waals epitaxy. The study revealed column-to-column alignment and inversion of crystallinity, which can be explained by combinatorial epitaxy, grain alignment across an atomically sharp interface, and a compliant substrate.

Graphene-Based Transparent Flexible Strain Gauges with Tunable Sensitivity and Strain Range.

Monolayers of graphene oxide, assembled into densely packed sheets at an immiscible hexane/water interface, form transparent conducting films on polydimethylsiloxane membranes after reduction in hydroiodic acid (HI) vapor to reduced graphene oxide (rGO). Prestraining and relaxing the membranes introduces cracks in the rGO film. Subsequent straining opens these cracks and induces piezoresistivity, enabling their application as transparent strain gauges.

Exploring the association between social skills struggles and social communication difficulties and depression in youth with autism spectrum disorder.

Autism spectrum disorder is characterized by social communication difficulties and social skills abilities that are significantly differ from neurotypical populations as well as restricted and repetitive behaviors and interests. Furthermore, many autistic youth experience co-occurring conditions, with one of the most common being depression. This depression is suggested to be, in part, the result of the relative social isolation experienced by autistic youth.

Stability Bounds for Micron Scale Ag Conductor Lines Produced by Electrohydrodynamic Inkjet Printing.

Continuous conducting lines of width 5-20 μm have been printed with a Ag nanoparticle ink using drop-on-demand (DOD) electrohydrodynamic (EHD) inkjet printing on Si and PDMS substrates, with advancing contact angles of 11° and 35°, respectively, and a zero receding contact angle. It is only possible to achieve stable parallel sided lines within a limited range of drop spacings, and this limiting range for stable line printing decreases as the contact angle of the ink on the substrate increases. The upper bound drop spacing for stable line formation is determined by a minimum drop overlap required to prevent contact line retraction, and the lower bound is governed by competing flows for drop spreading onto an unwetted substrate and a return flow driven by a Laplace pressure difference between the newly deposited drops and the fluid some distance from the growing tip.

Compositionally-Driven Formation Mechanism of Hierarchical Morphologies in Co-Deposited Immiscible Alloy Thin Films.

Co-deposited, immiscible alloy systems form hierarchical microstructures under specific deposition conditions that accentuate the difference in constituent element mobility. The mechanism leading to the formation of these unique hierarchical morphologies during the deposition process is difficult to identify, since the characterization of these microstructures is typically carried out post-deposition. We employ phase-field modeling to study the evolution of microstructures during deposition combined with microscopy characterization of experimentally deposited thin films to reveal the origin of the formation mechanism of hierarchical morphologies in co-deposited, immiscible alloy thin films.

Acoustic Poration and Dynamic Healing of Mammalian Cell Membranes during Inkjet Printing.

We have investigated the effect of piezoelectric actuating voltage on cell behavior after drop on demand inkjet printing using mouse 3T3 cells as a model cell line. Cell viability after printing was assessed using a live/dead assay, Alamar Blue as an assay for cell proliferation, and propidium iodide (PI) and Texas Red labeled dextran molecular probes to assess cell membrane integrity. No significant difference was found for the cell death rate compared between an unprinted control population and after printing at 80, 90, and 100 V, respectively.

Stability of Lines with Zero Receding Contact Angle Produced by Inkjet Printing at Small Drop Volume.

We present an experimental study of the maximum and minimum bounding drop spacing for a parallel-sided liquid line produced by inkjet printing with drop volumes of 1.5 and 8.5 pL, on substrates with advancing contact angles of 46 and 54°, and zero receding contact angle.

Fabrication of microvascular constructs using high resolution electrohydrodynamic inkjet printing.

Fabrication of the intricate anatomy of vasculature within engineered tissue remains one of the key challenges facing the field of tissue engineering. We report the use of electrohydrodynamic (EHD) inkjet printing to create hydrogel-based microvascular tissues with hierarchical and branching channels, whose minimum feature size of 30m approaches the physical scale of native capillary blood vessels. The principle relies on the use of complementary thermoreversible gelling properties of Pluronic F127 (PF-127) and gelatin methacryloyl, which served as sacrificial templates and permanent matrices respectively.

Atmospheric Pressure Catalytic Vapor Deposition of Graphene on Liquid Sn and Cu-Sn Alloy Substrates.

The chemical vapor deposition (CVD) of graphene on liquid substrates produces high quality graphene films due to the defect-free and atomically flat surfaces of the liquids. Through the detailed study of graphene growth on liquid Sn using atmospheric pressure CVD (APCVD), the quality of graphene has been found to have a close relationship with hydrogen flow rate that reflects on hydrogen partial pressure inside the reactor (P) and hydrogen solubility of the growth substrates. The role of P was found to be crucial, with a low defect density monolayer graphene being obtained in low P (90.

Nanoindentation of Molecular Crystals: Lessons Learned from Aspirin.

Nanoindentation enables the measurement of mechanical properties from single crystals with dimensions of a few micrometers. This experimental technique, however, has only recently been applied to molecular crystals. Key differences between the application of this technique to molecular crystals and metals and other inorganics are identified.

Fluid/Fiber Interactions and the Conductivity of Inkjet Printed Ag on Textile Substrates.

X-ray tomographic reconstruction reveals that the distribution of Ag after inkjet printing and sintering a nanoparticle conducting ink on a woven polyester textile substrate is strongly controlled by the fiber surface properties and fabric architecture. Capillarity confines the transport of the ink predominantly within the warp or weft yarns of the fabric and there is little transport of ink between the yarns. Changing the fiber surface energy through the Scotchgard treatment leads to an increase in the contact angle, reducing ink transport along the fibers and an increase in conductance.

Aberrant Differentiation of Human Pluripotent Stem Cell-Derived Kidney Precursor Cells inside Mouse Vascularized Bioreactors.

Background: Numerous studies have documented the in vitro differentiation of human pluripotent stem cells (hPSCs) into kidney cells. Fewer studies have followed the fates of such kidney precursor cells (KPCs) inside animals, a more life-like setting. Here, we tested the hypothesis that implanting hPSC-derived KPCs into an in vivo milieu surgically engineered to be highly vascular would enhance their maturation into kidney tissues.

Probing Ink-Powder Interactions during 3D Binder Jet Printing Using Time-Resolved X-ray Imaging.

Capillary-driven ink infiltration through a porous powder bed in three-dimensional (3D) binder jet printing (inkjet printing onto a powder bed) controls the printing resolution and as-printed "green" strength of the resulting object. However, a full understanding of the factors controlling the kinetics of the infiltration remains incomplete. Here, high-resolution synchrotron radiography provides time-resolved imaging of the penetration of an aqueous solution of eythylene glycol through a porous alumina powder bed, used as a model system.

The systemic influence of chronic smoking on skin structure and mechanical function.

One of the major functions of human skin is to provide protection from the environment. Although we cannot entirely avoid, for example, sun exposure, it is likely that exposure to other environmental factors could affect cutaneous function. A number of studies have identified smoking as one such factor that leads to both facial wrinkle formation and a decline in skin function.

Direct 3D printing of graphene using capillary suspensions.

Conventional 3D printing of graphene requires either a complex formulation of the ink with large quantities of polymers or essential post-processing steps such as freeze drying to allow printability. Here we present a graphene capillary suspension (GCS) containing 16.67 wt% graphene nanoparticles in aqueous suspension with 3.

Tiled Monolayer Films of 2D Molybdenum Disulfide Nanoflakes Assembled at Liquid/Liquid Interfaces.

Thin films of MoS bilayer nanoflakes, which are predominantly a single flake thick and with flakes in edge-to-edge contact, have been produced via self-assembled tiling at the planar interface between two immiscible liquids. Films of several square centimeters extent can be produced with a total covered area approaching 90% and over 70% of the film covered by single flakes without overlap. Films produced through liquid/liquid assembly are shown to produce a lower uncovered area fraction and more uniform thickness when compared with films of similar areal coverage produced by the "top-down" techniques of spin coating and spray coating.

Patterned, morphing composites via maskless photo-click lithography.

Morphing materials, also known as smart materials are attracting increasing attention as sensors, actuators and in soft robotic applications. In this work bilayered morphing composites were created by exploiting the thiol-ene photoclick reaction via maskless digital light processing (DLP). This technique allows for gradients and patterns of near infrared (nIR)-triggered materials to be efficiently crosslinked to substrates, with suitable interfacial adhesion to realise complex morphing.

The formation mechanism of hexagonal MoC defects in CVD graphene grown on liquid copper.

Thin MoC hexagonal defects precipitate in CVD graphene when Mo crucibles are engaged to hold the liquid copper substrate, while these defects disappear when W crucibles are present. These defects have been identified as the thin precipitates of MoC. The growth mechanism of the MoC defects is demonstrated through thermodynamic calculations.

Light-Induced Molecular Adsorption of Proteins Using the PRIMO System for Micro-Patterning to Study Cell Responses to Extracellular Matrix Proteins.

Cells sense a variety of extracellular cues, including the composition and geometry of the extracellular matrix, which is synthesized and remodeled by the cells themselves. Here, we present the method of Light-Induced Molecular Adsorption of Proteins (LIMAP) using the PRIMO system as a patterning technique to produce micro-patterned extracellular matrix (ECM) substrates using a single or combination of proteins. The method enables printing of ECM patterns in micron resolution with excellent reproducibility.

Screen-Printing of a Highly Conductive Graphene Ink for Flexible Printed Electronics.

Conductive inks for the future printed electronics should have the following merits: high conductivity, flexibility, low cost, and compatibility with wide range of substrates. However, the state-of-the-art conductive inks based on metal nanoparticles are high in cost and poor in flexibility. Herein, we reported a highly conductive, low cost, and super flexible ink based on graphene nanoplatelets.

Angiogenesis and tissue formation driven by an arteriovenous loop in the mouse.

The rapid vascularisation of biomaterials and artificial tissues is a key determinant for their in vivo viability and ultimately for their integration in a host; therefore promoting angiogenesis and maintaining the newly formed vascular beds has become a major goal of tissue engineering. The arteriovenous loop (AVL) has been an extensively studied platform which integrates microsurgery with cells scaffolds and growth factors to form neotissues. Most AVL studies to date are limited to larger animal models, which are surgically easier to perform, but have inherent limits for the understanding and interrogation of the underlying in vivo mechanisms due the paucity of transgenic models.