Printed dry electrode for neuromuscular electrical stimulation (NMES) for e-textile.

Muscle atrophy is a well-known consequence of immobilization and critical illness, leading to prolonged rehabilitation and increased mortality. In this study, we develop a solution to preserve muscle mass using customized biocompatible neuromuscular electrical stimulation (NMES) device. Commercially available NMES solutions with gel-based electrodes often lead to skin irritation.

Interfacial Engineering of PVDF-TrFE toward Higher Piezoelectric, Ferroelectric, and Dielectric Performance for Sensing and Energy Harvesting Applications.

The electrical properties of pristine fluoropolymers are inferior due to their low polar crystalline phase content and rigid dipoles that tend to retain their fixed moment and orientation. Several strategies, such as electrospinning, electrohydrodynamic pulling, and template-assisted growing, have been proven to enhance the electrical properties of fluoropolymers; however, these techniques are mostly very hard to scale-up and expensive. Here, a facile interfacial engineering approach based on amine-functionalized graphene oxide (AGO) is proposed to manipulate the intermolecular interactions in poly(vinylidenefluoride-trifluoroethylene) (PVDF-TrFE) to induce β-phase formation, enlarge the lamellae dimensions, and align the micro-dipoles.

Inkjet Printing of Electrodes on Electrospun Micro- and Nanofiber Hydrophobic Membranes for Flexible and Smart Textile Applications.

With the increasing demand for smart textile and sensor applications, the interest in printed electronics is rising. In this study, we explore the applicability of electrospun membranes, characterized by high porosity and hydrophobicity, as potential substrates for printed electronics. The two most common inks, silver and carbon, were used in inkjet printing to create a conductive paths on electrospun membranes.

Flexible, Wearable and Fully-printed Smart Patch for pH and Hydration Sensing in Wounds.

Wound healing is a complex and dynamic regeneration process, wherein the physical and chemical parameters are continuously changing. Its management and monitoring can provide immense benefits, especially for bed-ridden patients. This work reports a low-cost, flexible, and fully printed on-skin patch sensor to measure the change in pH and fluid content in a wound.

[Electrical stimulation against loss of muscles and function in a patient admitted with COVID-19].

This is a case report of a hospitalised 62-year-old male patient with COVID-19, who received unilateral neuromuscular electrical stimulation treatment with a customised anti-embolic compression stocking and maintained muscle mass as well as maximum voluntary quadriceps contraction and balance during six days of illness-induced immobilisation. This illustrates, that short durations of neuromuscular electrical stimulation can help maintaining muscle mass and physical function in patients with SARS-CoV-2.

Droplet-Based Techniques for Printing of Functional Inks for Flexible Physical Sensors.

Printed electronics (PE) is an emerging technology that uses functional inks to print electrical components and circuits on variety of substrates. This technology has opened up new possibilities to fabricate flexible, bendable, and form-fitting devices at low-cost and fast speed. There are different printing technologies in use, among which droplet-based techniques are of great interest as they provide the possibility of printing computer-controlled design patterns with high resolution, and greater production flexibility.

PVDF-BaTiO Nanocomposite Inkjet Inks with Enhanced β-Phase Crystallinity for Printed Electronics.

Polyvinylidene difluoride (PVDF) and its copolymers are promising electroactive polymers showing outstanding ferroelectric, piezoelectric, and pyroelectric properties in comparison with other organic materials. They have shown promise for applications in flexible sensors, energy-harvesting transducers, electronic skins, and flexible memories due to their biocompatibility, high chemical stability, bending and stretching abilities. PVDF can crystallize at five different phases of α, β, γ, δ, and ε; however, ferro-, piezo-, and pyroelectric properties of this polymer only originate from polar phases of β and γ.

Electrically Conducting Hydrogels for Health care: Concept, Fabrication Methods, and Applications.

Electrically conducting hydrogels are gaining increasing attention due to their potential application in smart patches, biosensors, functional tissue engineering scaffolds, wound management, and implants. The current review focuses on these novel materials, their synthesis routes, and their composites. Special attention is paid to fabrication routes to produce functional composites with organic and inorganic components.

Aerosol-Jet-Printed Preferentially Aligned Carbon Nanotube Twin-Lines for Printed Electronics.

The alignment of carbon nanotubes (CNTs) is of great importance for the fabrication of high-speed electronic devices such as a transistor as the electron mobilities can be greatly enhanced with aligned CNT architectures. Here, we report, for the first time, a methodology to obtain preferentially aligned CNT traces on a flexible polyimide substrate utilizing the high-resolution aerosol jet printing technique and evaporation-driven self-assembly process. A self-assembled twin-line of CNT ("coffee-ring" effect) is observed in the deposit patterns, and the field-emission scanning electron microscopy (FESEM) images reveal highly self-ordered CNT in the resulting CNT twin-line.

Sessile droplets containing carbon nanotubes: a study of evaporation dynamics and CNT alignment for printed electronics.

Carbon nanotubes (CNTs) are 1-dimensional (1D) and flexible nanomaterials with high electric conductivity and a high aspect ratio. These features make CNTs highly suitable materials for the fabrication of flexible electronics. CNTs can also be made into dispersions which can be used as the feedstock material for droplet-based 3D printing technologies, e.

Wearable Bandage-Based Strain Sensor for Home Healthcare: Combining 3D Aerosol Jet Printing and Laser Sintering.

Flexible and stretchable strain sensors are in great demand for many applications like wearables and home health. This work reports a strain sensor fabricated using aerosol jet printing technology on a commercially available bandage to be used as a low-cost wearable. Laser light is explored to sinter the silver nanoparticle ink on a low-temperature bandage substrate.

A novel 3D bioprinted flexible and biocompatible hydrogel bioelectronic platform.

Bioelectronics platforms are gaining widespread attention as they provide a template to study the interactions between biological species and electronics. Decoding the effect of the electrical signals on the cells and tissues holds the promise for treating the malignant tissue growth, regenerating organs and engineering new-age medical devices. This work is a step forward in this direction, where bio- and electronic materials co-exist on one platform without any need for post processing.

Fabrication of titanium based biphasic scaffold using selective laser melting and collagen immersion.

Tissue engineering approaches have been adopted to address challenges in osteochondral tissue regeneration. Single phase scaffolds, which consist of only one single material throughout the whole structure, have been used extensively in these tissue engineering approaches. However, a single phase scaffold is insufficient in providing all the properties required for regeneration and repair of osteochondral defects.

Perovskite Solar Cells: Beyond Methylammonium Lead Iodide.

Organic-inorganic lead halide based perovskites solar cells are by far the highest efficiency solution-processed solar cells, threatening to challenge thin film and polycrystalline silicon ones. Despite the intense research in this area, concerns surrounding the long-term stability as well as the toxicity of lead in the archetypal perovskite, CH3NH3PbI3, have the potential to derail commercialization. Although the search for Pb-free perovskites have naturally shifted to other transition metal cations and formulations that replace the organic moiety, efficiencies with these substitutions are still substantially lower than those of the Pb-perovskite.

A maskless synthesis of TiO2-nanofiber-based hierarchical structures for solid-state dye-sensitized solar cells with improved performance.

TiO2 hierarchical nanostructures with secondary growth have been successfully synthesized on electrospun nanofibers via surfactant-free hydrothermal route. The effect of hydrothermal reaction time on the secondary nanostructures has been studied. The synthesized nanostructures comprise electrospun nanofibers which are polycrystalline with anatase phase and have single crystalline, rutile TiO2 nanorod-like structures growing on them.

Structure, sodium ion role, and practical issues for β-alumina as a high-k solution-processed gate layer for transparent and low-voltage electronics.

Sodium β-alumina (SBA)-based gate dielectric films have been developed for all solution-processed, transparent and low voltage field-effect transistors (FETs). Its high dielectric constant has been ascribed to sodium (Na+) ions in the crystal structure; however, there are no published experimental results concerning the contribution of Na+ ions to the dielectric behavior, and the degree of crystallinity of the thin films. In addition, as an ionic conductor, β-alumina could give rise to some issues such as leakage current caused by Na diffusion, threshold voltage shift due to interface charge accumulation and longer response time due to slower polarization of the Na+ ions.