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Atopic dermatitis (AD) is one of the most common skin disorders, affecting nearly one-fifth of children and adolescents worldwide, and currently, the only method of monitoring the condition is through an in-person visual examination by a clinician. This method of assessment poses an inherent risk of subjectivity and can be restrictive to patients who do not have access to or cannot visit hospitals. Advances in digital sensing technologies can serve as a foundation for the development of a new generation of e-health devices that provide accurate and empirical evaluation of the condition to patients worldwide. The goal of this review is to study the past, present, and future of AD monitoring. First, current medical practices such as biopsy, tape stripping and blood serum are discussed with their merits and demerits. Then, alternative digital methods of medical evaluation are highlighted with the focus on non-invasive monitoring using biomarkers of AD—TEWL, skin permittivity, elasticity, and pruritus. Finally, possible future technologies are showcased such as radio frequency reflectometry and optical spectroscopy along with a short discussion to provoke research into improving the current techniques and employing the new ones to develop an AD monitoring device, which could eventually facilitate medical diagnosis.

This paper presents a holistic and authoritative review of the role of microwave technologies in enabling a new generation of wearable devices. A human-centric Internet of Things (IoT) covering remote healthcare, distributed sensing, and consumer electronics, calls for high-performance wearable devices integrated into clothing, which require interdisciplinary research efforts to emerge. Microwaves, the “interconnect” of wireless networks, can enable, rather than solely connect, the next generation of autonomous, sustainable, and wearable-friendly electronics. First, enabling technologies including wireless power transmission and RF energy harvesting, backscattering and passive communication, RFID, and electromagnetic sensing are reviewed. We then discuss the key integration platforms, covering smart fabrics and electronic textiles, additive manufacturing, printed electronics, natively-flexible and organic RF semiconductors, and fully-integrated CMOS systems, where opportunities for hybrid integration are highlighted. The emerging research trends, from mmWave 6G, RF sensing and imaging, to healthcare applications including neural implants, drug delivery, and safety upon exposure to microwaves are revisited and discussed, presenting a future roadmap for interdisciplinary research towards sustainable and reliable next-generation wearables.

Ulcers and chronic wounds are a large and expensive problem, costing billions of pounds a year and affecting millions of people. Electrical stimulation has been known to have a positive effect on wound healing since the 1960s and this has been confirmed in numerous studies, reducing the time to heal, and the incidence of adverse events such as infections. However, because each study used different parameters for the treatment, inclusion criteria and metrics for quantifying the success, it is currently hard to combine them statistically and gain a true picture of its efficacy. As such, electrical stimulation has not been universally adopted as a recommended treatment for various types of wound.This paper summarises the biological basis for electrical simulation treatment and reviews the clinical evidence for its effectiveness. Notable is the lack of research focused on the electrodes used to deliver electrostimulation treatment. However, a significant amount of work has been conducted on electrodes for other medical applications in the field of e-textiles. This e-textile work is reviewed with a focus on its potential in electrostimulation and proposals are made for future developments to improve future studies andapplications for wound healing via electrical stimulation.

Textile-based antennas are typically realized using conductive fabrics adhered to thick non-woven fabrics such as felt, which are not suited for additive manufacturing due to their roughness. This paper presents screen printing on thin and breathable polyurethane films as a method for realizing e-textile antennas without altering the feel of the fabric, demonstrated through a microstrip antenna on standard felt fabric. The fabricated proximity-coupled patch maintains at least 100 MHz (4\%) bandwidth from 2.46 to 2.56~GHz regardless of bending and human proximity, 6.6~dBi measured gain, and 69\% radiation efficiency. The robustness of the proposed antenna is demonstrated, for the first time, through the measured radiation properties, showing that the antenna maintains its peak gain and radiation patterns after more than 10,000 bending cycles.

The functionalisation of textiles with electronic capabilities presents diverse applications where the electronics provide health monitoring, diagnostic and treatment platforms to the wearer [1]. However, the integration methods for incorporating such electronics into the textile in the research and commercial domains often compromise the natural characteristics and end-of-use recyclability of the textile [2], and more importantly the susceptibility of the wearer where the integrated electronics remain visible to the environment. This paper introduces a platform technology in the EPSRC funded project - Novel manufacturing methods for functional electronic textiles (FETT) in Figure 1, which combines standard microelectronic circuit fabrication and textile production techniques to hide modular electronics in bespoke pockets within textiles in the form 60 µm thick polyamide filament circuits [3]. The filament circuits are not visible after integration to the wearer or their environment. Unlike other integration methods where the textile is not detachable from the integrated circuits bonded to it mechanically or chemically, these filament circuits are loosely secured within the textile and are easily removable so as to enable end-of-use recycling of the textile and prevent electronic contamination. The key novelty of the project is the patented vacuum forming packaging of its filaments before integration within the textile filed with application number PCT/GB2019/052906. The filaments are conformally encapsulated with a thermoplastic film which enhances durability of the filaments by situating the electronic layer on the neutral axis. Prototypes are shown to be reliable surviving more than 1500 bending cycles around a 90ᵒ bending angle and 50 washing cycles at 60 ᵒC. Example demonstrator applications with this technology include accelerometer and temperature sensing e-textile circuits. Textiles with in-situ processing capability using miniaturised microcontrollers have also been demonstrated with digitally sequenced LED lighting patterns on the fabric.

The weaving of flexible electronic filaments directly into the body of textiles during manufacture represents the state-of-the-art process for integrating electronic functionality into fabrics in a manner that obscures the presence of the electronics from the wearer. The reliability of emerging prototypes under typical stresses from washing and bending is primarily dependent on the durability of the electrical conductors, and their interconnections with the electronic components attached to them on polyimide filaments. To improve the durability of these filaments, this paper uses the classical beam theory to investigate the material characteristics (thickness and elastic modulus) and suitability of different encapsulations such as polyimide, polyurethane, mylar and peek films for limiting the mechanical stress on the electrical conductors.

WEARPLEX is a multidisciplinary research and innovation action with the overall aim to integrate printed electronics with flexible and wearable textile-based biomedical multi-pad electrodes. It aims to answer the growing need for user-friendly electrodes for pervasive measurement of electrophysiological signals and application of electrical stimulation. It focuses on the development of the printable electronics and manufacturing processes for stretchable textile based multi-pad electrodes with integrated logic circuits that enable a significant increase in the number of electrode pads (channels) and facilitate the creation of new products in the sectors of medical electronics and life-style. The advanced printed electronics integrated in WEARPLEX electrodes will allow the individual pads to be connected in arbitrary configurations to the output leads of the electrode. Therefore, the pads will be flexibly organized into several virtual electrodes of arbitrary position, shape and size that can be connected to any standard multi-channel recording and stimulation system. In addition, software methods will be developed for automatic calibration of these virtual electrodes, to detect stimulation/recording hotspots and adjust the virtual electrodes accordingly. Therefore, the WEARPLEX project will lead to a new generation of smart electrodes that will be able to adapt simultaneously to the user (wearable and stretchable garment), recording/stimulation scenario (movement type and target muscles) and recording/stimulation system (number of channels). This is a paradigm shift in designing the recording and stimulation systems, as the switching electronics is shifted from the custom-made stimulator/recording device to the smart electrode, leading to a universal solution compatible with any system. WEARPLEX is funded under the EU Horizon2020 call ICT-02-2018, the work program is over 3 years starting on the 1st of January 2019; this abstract is therefore an opportunity to introduce the project to the community and discuss research directions and early results for the project. The individual components of the project are at TRL2-4 with the goal of improving and combining them to achieve TRL6-7 industrial demonstrators by the end of the project.

Triboelectric nanogenerators (TENG) are one of the most promising candidates for powering wearable and portable devices. Example TENGs have demonstrated flexibility, light weight, biocompatibility, versatility and good performance. Textiles are a potential substrate onto, or into, which wearable technology is increasingly being incorporated but supplying power remains an enduring challenge. TENGs are a potential textile based mechanical energy harvesting power supply and there has been an increasing effort to combine TENGs with fabrics. A significant challenge exists in the integration without losing the performance of the TENG or the original properties (appearance, breathability, washability, and durability) and feel of the textile. Various approaches towards the realisation of textile-based TENGs (T-TENGs) have been demonstrated. Depending on its structure, T-TENGs can be divided into two main types, fabric-based TENG and fibre-based TENG. The fabric-based TENG is composed of conventional and/or modified fabrics, which serve as a substrate and/or a triboelectric material. The fibre-based TENG is fabricated as a single fibre or a collection of interlaced fibres. This paper provides an up to date review of the progress in the research of T-TENGs. The paper covers the basic operating principles, possible operation modes, textile manufacturing methods, material selections, T-TENG fabrication process, surface modification and structural designs. Issues, such as standardised measurement parameters, the challenges and limitations of T-TENG are discussed.

This paper presents a piezoelectric vibration energy harvester fabricated using screen printing. The formulation of a novel tungsten based polymer ink enables the deposition of an inertial mass enabling the entire structure to be fabricated by the printing process. The devices have been designed for use on an aircraft Health and Usage Monitoring System (HUMS). Initial devices produce a peak power of 117?w at 6.9m/s2 and 70Hz with an optimum load of 140kW and an output voltage of 2.9V.

This paper compares two thick-film actuation technologies and assesses their suitability for use within micromachined devices. The materials are a piezoelectric composition, which exhibits a d33 coefficient of the order of 130pC/N, and a magnetostrictive material which possess a magnetostriction of 4.4ppm at a magnetic field of 11.5kA/m. Examples of their application in micromachined devices are also given.

Electronic Textiles (e-textiles) should ideally be handled and cleaned like traditional textiles. Therefore, we can expect e-textiles to be machine washed or hand washed. As e-textiles enhance traditional fabrics with electronic functionality, any embedded microsystem i.e., flexible electronic circuits, will be expected to survive and show functionality after the e-textile has been washed multiple times to ensure the garment is practical. Therefore, the choice of encapsulation material for microsystems in a textile must be hydrophobic and offer minimal expansion when washed and ensure the electronics are undetectable when the textile is handled or cleaned. This paper evaluates five different base/curing agent mixing ratios—5:1, 7:1, 10:1, 15:1, and 20:1—of commercial polydimethylsiloxane (PDMS) as an electronic packaging encapsulation. Contact angle and aqueous permeability experiments were conducted to tailor the PDMS mixture specifically for washable e-textile applications. The experimental results show that 20:1 PDMS is the most suitable as it is sufficiently hydrophobic with minimal swelling in commercial washing machine trials. Following this, a 40.3 µm-thick 20:1 conformal encapsulation of PDMS upon an touch and proximity flexible circuit that can be integrated into textiles via knitting and/or weaving, was examined. Results show the washing spin speed is a crucial factor with washing cycle duration having minimal impact when determining circuit functionality survival. Overall, the e-textiles in this work survived between 10 and 15 washes with microscopic inspection of the circuits revealing failure of the external wires but not the PDMS encapsulation—suggesting its sufficient robustness and durability as a suitable encapsulation material for washable electronic textiles.