Thermoelectric Hydrogel Electronic Skin for Passive Multimodal Physiological Perception.

Electronic skins (e-skins) are being extensively researched for their ability to recognize physiological data and deliver feedback via electrical signals. However, their wide range of applications is frequently restricted by the indispensableness of external power supplies and single sensory function. Here, we report a passive multimodal e-skin for real-time human health assessment based on a thermoelectric hydrogel. The hydrogel network consists of poly(vinyl alcohol)/low acyl gellan gum with [Fe(CN)6]4-/3- as the redox couple. The introduction of glycerol and Li+ furnishes the gel-based e-skin with antidrying and antifreezing properties, a thermopower of 2.04 mV K-1, fast self-healing in less than 10 min, and high conductivity of 2.56 S m-1. As a prospective application, the e-skin can actively perceive multimodal physiological signals without the need for decoupling, including body temperature, pulse rate, and sweat content, in real time by synergistically coupling sensing and transduction. This work offers a scientific basis and designs an approach to develop passive multimodal e-skins and promotes the application of wearable electronics in advanced intelligent medicine.

Electric field and viscous fluid polarity effects on capillary-driven flow dynamics between parallel plates.

-Micropumps have attracted considerable interest in micro-electro-mechanical systems (MEMS), microfluidic devices, and biomedical engineering to transfer fluids through capillaries. However, improving the sluggish capillary-driven flow of highly viscous fluids is critical for commercializing MEMS devices, particularly in underfill applications. This study investigated the behavior of different viscous fluid flows under the influence of capillary and electric potential effects. We observed that upon increasing the electric potential to 500 V, the underfill flow length of viscous fluids increased by 45% compared to their capillary flow length. To explore the dynamics of underfill flow under the influence of an electric potential, the polarity of highly viscous fluids was altered by adding NaCl. The results indicated an increase of 20-41% in the underfill flow length of highly viscous conductive fluids (0.5-4% NaCl additives in glycerol) at 500 V compared to that at 0 V. The underfill viscous fluid flow length improved under the electric potential effect owing to the polarity across the substance and increased permittivity of the fluid. A time-dependent simulation, which included a quasi-electrostatic module, level set module, and laminar two-phase flow, was executed using the COMSOL Multiphysics software to analyze the effect of the external electric field on the capillary-driven flow. The numerical simulation results agreed well with the experimental data, with an average deviation of 4-7% at various time steps for different viscous fluids. Our findings demonstrate the potential of utilizing electric fields to control the capillary-driven flow of highly viscous fluids in underfill applications.

Self-Powered Respiratory Monitoring Strategy Based on Adaptive Dual-Network Thermogalvanic Hydrogels.

As a low-grade sustainable heat source, the breath waste heat exhaled by human bodies is always ignored, although producing a greater temperature than ambient. Converting this heat into electric energy for use as power sources or detecting signals is extremely important in cutting-edge wearable medicine. This heat-to-electricity conversion is possible with thermogalvanic hydrogels. However, challenges remain in their antifreezing and antidrying properties, significantly restricting the durability of thermogalvanic gels in practical applications. Herein, a dual-network poly(vinyl alcohol)/gelatin (PVA/GEL) gel thermogalvanic device with Fe(CN)63-/4- as a redox pair is developed, with an outstanding low-temperature durability and antidrying capacity. These features result from the use of a binary H2O/GL (glycerin) solvent to limit hydrogen bonding between water molecules. The prepared thermogalvanic gel patch is capable of easily converting physiological data into understandable electrical impulses using the temperature difference between the ambient environment and the heat produced by human breathing, realizing a simple self-powered respiratory monitoring strategy for the first time. Even below zero temperature, the gel patch-based mask can operate normally, implying it fits into low-temperature environments. This study sheds fresh light on the development of active wearable medical electronics that are powered by demic low-level heat.

High-Resolution, Transparent, and Flexible Printing of Polydimethylsiloxane via Electrohydrodynamic Jet Printing for Conductive Electronic Device Applications.

In the field of soft electronics, high-resolution and transparent structures based on various flexible materials constructed via various printing techniques are gaining attention. With the support of electrical stress-induced conductive inks, the electrohydrodynamic (EHD) jet printing technique enables us to build high-resolution structures compared with conventional inkjet printing techniques. Here, EHD jet printing was used to fabricate a high-resolution, transparent, and flexible strain sensor using a polydimethylsiloxane (PDMS)/xylene elastomer, where repetitive and controllable high-resolution printed mesh structures were obtained. The parametric effects of voltage, flow rate, nozzle distance from the substrate, and speed were experimentally investigated to achieve a high-resolution (5 µm) printed mesh structure. Plasma treatment was performed to enhance the adhesion between the AgNWs and the elastomer structure. The plasma-treated functional structure exhibited stable and long strain-sensing cycles during stretching and bending. This simple printing technique resulted in high-resolution, transparent, flexible, and stable strain sensing. The gauge factor of the strain sensor was significantly increased, owing to the high resolution and sensitivity of the printed mesh structures, demonstrating that EHD technology can be applied to high-resolution microchannels, 3D printing, and electronic devices.

A Single-Channel Wireless EEG Headset Enabled Neural Activities Analysis for Mental Healthcare Applications.

Electroencephalography (EEG) is a technique of Electrophysiology used in a wide variety of scientific studies and applications. Inadequately, many commercial devices that are available and used worldwide for EEG monitoring are expensive that costs up to thousands of dollars. Over the past few years, because of advancements in technology, different cost-effective EEG recording devices have been made. One such device is a non-invasive single electrode commercial EEG headset called MindWave 002 (MW2), created by NeuroSky Inc that cost less than 100 USD. This work contributes in four distinct ways, first, how mental states such as a focused and relaxed can be identified based on EEG signals recorded by inexpensive MW2 is demonstrated for accurate information extraction. Second, MW2 is considered because apart from cost, the user's comfort level is enhanced due to non-invasive operation, low power consumption, portable small size, and a minimal number of detecting locations of MW2. Third, 2 situations were created to stimulate focus and relaxation states. Prior to analysis, the acquired brain signals were pre-processed to discard artefacts and noise, and band-pass filtering was performed for delta, theta, alpha, beta, and gamma wave extraction. Fourth, analysis of the shapes and nature of extracted waves was performed with power spectral density (PSD), mean amplitude values, and other parameters in LabVIEW. Finally, with comprehensive experiments, the mean values of the focused and relaxed signal EEG signals were found to be 30.23 µV and 15.330 µV respectively. Similarly, average PSD values showed an increase in theta wave value and a decrease in beta wave value related to the focus and relaxed state, respectively. We also analyzed the involuntary and intentional number of blinks recorded by the MW2 device. Our study can be used to check mental health wellness and could provide psychological treatment effects by training the mind to quickly enter a relaxed state and improve the person's ability to focus. In addition, this study can open new avenues for neurofeedback and brain control applications. Supplementary Information: The online version contains supplementary material available at 10.1007/s11277-022-09731-w.

Isolated Female Epispadias with Urinary Incontinence.

Isolated female epispadias without bladder extrophy is a rare variant of female urethral anomaly reported rarely in the literature. For optimal and early management, early clinical diagnosis is important. Female with isolated epispadias usually presents with primary urinary incontinence with abnormal looking external genitalia on examination. We present a case of a 23-year female with urinary incontinence with bifid clitoris and widely separated labia minora on genital examination. Reconstructive surgery of urethra, labia minora and bifid clitoris was performed in one stage. The goals of management in this case were to achieve urinary continence with reasonable time between voids and cosmetically acceptable female genitalia. Key Words:  Epispadias, Bifid clitoris, Urinary incontinence.

A Ferroelectric Ceramic/Polymer Composite-Based Capacitive Electrode Array for In Vivo Recordings.

A new implantable capacitive electrode array for electrocorticography signal recording is developed with ferroelectric ceramic/polymer composite. This ultrathin and electrically safe capacitive electrode array is capable of attaching to the biological tissue conformably. The barium titanate/polyimide (BaTiO3 /PI) nanocomposite with high dielectric constant is successfully synthesized and employed as the ultrathin dielectric layer of the capacitive BaTiO3 /PI electrode array. The performance of the capacitive BaTiO3 /PI electrode array is evaluated by electrical characterization and 3D finite-element modeling. In vivo, neural experiments on the visual cortex of rats show the reliability of the capacitive BaTiO3 /PI electrode array. This work shows the potentials of capacitive BaTiO3 /PI electrode array in the field of brain/computer interfaces.

A new natural gel of Fagonia indica Burm f. extract for the treatment of burn on rats.

Fagonia indica Burm f. (Mushikka or white spine) is a plant distributed in the deserts of Asia and Africa and reported to be medicinal in the scientific literature as well as in the folk medicine. Earlier investigations, the authors isolated a number of bioactive constituents from the plant including flavonoids, sterols and tritepenoids; In addition its flavonoidal content was found remarkably high reaching 3% (calculated as flavonol on dry weight). The present study is an attempt to formulate, characterize and evaluate a natural wound-healing gel preparation containing the crude plant extract. Three formulae (F1-F3) were prepared. The gel properties such as viscosity, swelling ratio, bio-adhesion, in vitro release, stability, microbiological studies, in vivo burn healing test on rats and histopathological features were assessed. The results of the in vitro evaluation and stability studies showed that F3 (0.5% (w/w) of plant extract in 4% (w/w) chitosan) was significantly (p<0.05) the superior compared to other formulations. Besides, from the in vivo burn healing and histological results, F3 enhanced the skin wound re-epithelialization and speed up the healing process compared to the conventional commercial product. Thus, the Fagonia extract loaded chitosan topical gel would be used successfully in burn wound care.

Anti-inflammatory and gastroprotective activities of the aqueous extract of Micromeria fruticosa (L.) Druce ssp Serpyllifolia in mice.

Micromeria fruticosa is used widely in many Mediterranean regions for various inflammatory conditions. The aim of this work was to assess the anti-inflammatory and gastroprotective activities of the aqueous extract of Micromeria fruticosa. The aqueous extract of Micromeria fruticosa was tested orally in mice at doses of 50, 100 and 200 mg/kg in carrageenan-induced paw edema, vascular permeability, myeloperoxidase activity (MPO) and indomethacin-induced gastric ulceration. In the paw edema model, the extract at dose of 200 mg/ kg, exhibited a significant anti-inflammatory effect, while the extract at 100 and 200 mg/kg reduced significantly the vascular permeability and MPO activity in a dose dependant manner. Oral pretreatment of the aqueous extract reduced significantly the development of gastric lesions induced by indomethacin at dose of 200 mg/kg only. Results suggest that the aqueous extract of Micromeria fruticosa has both anti-inflammatory as well as, gastroprotective activities. Thus it could be used as an alternative or supplementary herbal remedy for the treatment of inflammatory diseases especially when combined with strong anti-inflammatory medications that have ulcerogenic side effects such as NSAIDs.