Protocol for preparation of a textile magnetoelastic generator patch.

The magnetoelastic generator (MEG) is a fundamentally new platform technology to convert mechanical motions into electrical signals for sensing, therapeutics, and energy applications. Here, we present a protocol for fabricating and characterizing the MEG for personalized muscle physiotherapy when integrated into a wearable textile patch. We describe the steps for fabricating such a textile MEG, including the magnetomechanical coupling (MC) and magnetic induction (MI) layers, and characterizing their magnetoelastic and electrical properties.

Advances in Machine Learning for Wearable Sensors.

Recent years have witnessed tremendous advances in machine learning techniques for wearable sensors and bioelectronics, which play an essential role in real-time sensing data analysis to provide clinical-grade information for personalized healthcare. To this end, supervised learning and unsupervised learning algorithms have emerged as powerful tools, allowing for the detection of complex patterns and relationships in large, high-dimensional data sets. In this Review, we aim to delineate the latest advancements in machine learning for wearable sensors, focusing on key developments in algorithmic techniques, applications, and the challenges intrinsic to this evolving landscape.

Permanent fluidic magnets for liquid bioelectronics.

Brownian motion allows microscopically dispersed nanoparticles to be stable in ferrofluids, as well as causes magnetization relaxation and prohibits permanent magnetism. Here we decoupled the particle Brownian motion from colloidal stability to achieve a permanent fluidic magnet with high magnetization, flowability and reconfigurability. The key to create such permanent fluidic magnets is to maintain a stable magnetic colloidal fluid by using non-Brownian magnetic particles to self-assemble a three-dimensional oriented and ramified magnetic network structure in the carrier fluid.

A multimodal magnetoelastic artificial skin for underwater haptic sensing.

Future exploitation of marine resources in a sustainable and eco-friendly way requires autonomous underwater robotics with human-like perception. However, the development of such intelligent robots is now impeded by the lack of adequate underwater haptic sensing technology. Inspired by the populational coding strategy of the human tactile system, we harness the giant magnetoelasticity in soft polymer systems as an innovative platform technology to construct a multimodal underwater robotic skin for marine object recognition with intrinsic waterproofness and a simple configuration.

In Situ Grown Silver-Polymer Framework with Coordination Complexes for Functional Artificial Tissues.

Self-sensing actuators are critical to artificial robots with biomimetic proprio-/exteroception properties of biological neuromuscular systems. Existing add-on approaches, which physically blend heterogeneous sensor/actuator components, fall short of yielding satisfactory solutions, considering their suboptimal interfaces, poor adhesion, and electronic/mechanical property mismatches. Here, a single homogeneous material platform is reported by creating a silver-polymer framework (SPF), thus realizing the seamless sensing-actuation unification.

Spherical Magnetoelastic Generator for Multidirectional Vibration Energy Harvesting.

Vibration is a common, usually wasted energy, and an attractive target for sustainable electricity generation. In this work, we introduce a new working mechanism to the vibration energy harvesting community by contributing a spherical magnetoelastic generator (S-MEG), which permits multidirectional vibration and is highly adaptable to many natural oscillation frequencies, exhibiting a resonant frequency of 24 Hz and a relatively wide working bandwidth of 15 Hz in the low-frequency range. It also features a low internal impedance of 70 Ω, which can respectively deliver a maximum short-circuit current density of 7.

Wearable respiratory sensors for COVID-19 monitoring.

Since its outbreak in 2019, COVID-19 becomes a pandemic, severely burdening the public healthcare systems and causing an economic burden. Thus, societies around the world are prioritizing a return to normal. However, fighting the recession could rekindle the pandemic owing to the lightning-fast transmission rate of SARS-CoV-2.

Self-Powered Programming of Fibroblasts into Neurons via a Scalable Magnetoelastic Generator Array.

Developing scalable electrical stimulating platforms for cell and tissue engineering applications is limited by external power source dependency, wetting resistance, microscale size requirements, and suitable flexibility. Here, a versatile and scalable platform is developed to enable tunable electrical stimulation for biological applications by harnessing the giant magnetoelastic effect in soft systems, converting gentle air pressure (100-400 kPa) to yield a current of up to 10.5 mA and a voltage of 9.

Harvesting Hydropower via a Magnetoelastic Generator for Sustainable Water Splitting.

Energy consumption and the resulting climate change are the two major challenges to human sustainability. Hydrogen (H) is a form of environmentally friendly renewable energy with an extremely high energy density of 143 MJ kg. Water splitting is a practical and cost-effective approach to generate H through the decomposition of HO by electrolysis with an external power supply.

Smart Textiles for Healthcare and Sustainability.

At the forefront of the smart textile community, healthcare and sustainability are the two crucial objectives targeted by researchers. The development of such powerful devices has been driven by innovative fabrications of breathable, skin-conformable technologies through the use of functional and programmable materials and device structures. This Perspective focuses on the current smart textiles available in the research field, categorized into personalized healthcare, including diagnostics and therapeutics, and sustainability, including energy harvesting and conservation─personalized thermoregulation.

A Soft Magnetoelastic Generator for Wind-Energy Harvesting.

The current energy crises and imminent danger of global warming severely limit the ability to scale societal development sustainably. As such, there is a pressing need for utilizing renewable, green energy sources, such as wind energy, which is ubiquitously available on Earth. In this work, a fundamentally new wind-energy-harvesting technology is reported, which is based on the giant magnetoelastic effect in a soft composite system, namely, magnetoelastic generators.

Discovering giant magnetoelasticity in soft matter for electronic textiles.

We discovered a giant magnetoelasticity in soft matter with up to 5-fold enhancement of magnetomechanical coupling factors compared to that of rigid metal alloys without an externally applied magnetic field. A wavy chain analytical model based on the magnetic dipole-dipole interaction and demagnetizing field was established, fitting well to the experimental observation. To explore its potentials in electronic textiles, we coupled it with magnetic induction to invent a textile magnetoelastic generator (MEG), a new working mechanism for biomechanical energy conversion, featuring an intrinsic waterproofness, an ultralow internal impedance of approximately 20 Ω, and a high short-circuit current density of 1.

Kirigami-Inspired Pressure Sensors for Wearable Dynamic Cardiovascular Monitoring.

Continuously and accurately monitoring pulse-wave signals is critical to prevent and diagnose cardiovascular diseases. However, existing wearable pulse sensors are vulnerable to motion artifacts due to the lack of proper adhesion and conformal interface with human skin during body movement. Here, a highly sensitive and conformal pressure sensor inspired by the kirigami structure is developed to measure the human pulse wave on different body artery sites under various prestressing pressure conditions and even with body movement.

Giant Magnetoelastic Effect Enabled Stretchable Sensor for Self-Powered Biomonitoring.

Interfacing with the human body, wearable and implantable bioelectronics are a compelling platform technology for healthcare monitoring and medical therapeutics. However, clinical adoption of these devices is largely shadowed by their weakness in humidity resistance, stretchability, durability, and biocompatibility. In this work, we report a self-powered waterproof biomechanical sensor with stretchability up to 440% using the giant magnetoelastic effect in a soft polymer system.

Electronic Textiles for Wearable Point-of-Care Systems.

Traditional public health systems are suffering from limited, delayed, and inefficient medical services, especially when confronted with the pandemic and the aging population. Fusing traditional textiles with diagnostic, therapeutic, and protective medical devices can unlock electronic textiles (e-textiles) as point-of-care platform technologies on the human body, continuously monitoring vital signs and implementing round-the-clock treatment protocols in close proximity to the patient. This review comprehensively summarizes the research advances on e-textiles for wearable point-of-care systems.

Advances in 4D-printed physiological monitoring sensors.

Physiological monitoring sensors have been critical in diagnosing and improving the healthcare industry over the past 30 years, despite various limitations regarding providing differences in signal outputs in response to the changes in the user's body. Four-dimensional (4D) printing has been established in less than a decade; therefore, it currently offers limited resources and knowledge. Still, the technique paves the way for novel platforms in today's ever-growing technologies.

Wearable Ultrahigh Current Power Source Based on Giant Magnetoelastic Effect in Soft Elastomer System.

In this study, we present the observation of the giant magnetoelastic effect that occurs in soft elastomer systems without the need of external magnetic fields and possesses a magnetomechanical coupling factor that is four times larger than that of traditional rigid metal-based ferromagnetic materials. To investigate the fundamental scientific principles at play, we built a linear model by using COMSOL Multiphysics, which was consistent with the experimental observations. Next, by combining the giant magnetoelastic effect with electromagnetic induction, we developed a magnetoelastic generator (MEG) for biomechanical energy conversion.

Soft fibers with magnetoelasticity for wearable electronics.

Magnetoelastic effect characterizes the change of materials' magnetic properties under mechanical deformation, which is conventionally observed in some rigid metals or metal alloys. Here we show magnetoelastic effect can also exist in 1D soft fibers with stronger magnetomechanical coupling than that in traditional rigid counterparts. This effect is explained by a wavy chain model based on the magnetic dipole-dipole interaction and demagnetizing factor.

Triboelectric Nanogenerators for Therapeutic Electrical Stimulation.

Current solutions developed for the purpose of in and on body (IOB) electrical stimulation (ES) lack autonomous qualities necessary for comfortable, practical, and self-dependent use. Consequently, recent focus has been placed on developing self-powered IOB therapeutic devices capable of generating therapeutic ES for human use. With the recent invention of the triboelectric nanogenerator (TENG), harnessing passive human biomechanical energy to develop self-powered systems has allowed for the introduction of novel therapeutic ES solutions.

Advances in triboelectric nanogenerators for biomedical sensing.

Biomedical sensors have been essential in improving healthcare outcomes over the past 30 years, though limited power source access and user wearability restraints have prevented them from taking a constant and active biomedical sensing role in our daily lives. Triboelectric nanogenerators (TENGs) have demonstrated exceptional capabilities and versatility in delivering self-powered and wear-optimized biomedical sensors, and are paving the way for a novel platform technology able to fully integrate into the developing 5G/Internet-of-Things ecosystem. This novel paradigm of TENG-based biomedical sensors aspires to provide ubiquitous and omnipresent real-time biomedical sensing for us all.

Smart Insole for Robust Wearable Biomechanical Energy Harvesting in Harsh Environments.

Footfall contains the highest harvestable biomechanical energy from the human body, which can attain 67 W, showing great potential as a pervasive and sustainable power source for wearable bioelectronics in the era of the Internet of Things. Developing an effective technology for robust and efficient energy harvesting from human walking remains highly desired. Here, we present a waterproof smart insole, based on a triboelectric nanogenerator, for highly efficient and robust human biomechanical energy harvesting.

Microfluidic Point-of-Care Ecarin-Based Clotting and Chromogenic Assays for Monitoring Direct Thrombin Inhibitors.

Direct thrombin inhibitors (DTIs), such as bivalirudin and dabigatran, have maintained steady inpatient and outpatient use as substitutes for heparin and warfarin, respectively, because of their high bioavailability and relatively safe "on-therapy" range. Current clinical methods lack the capacity to directly quantify plasma DTI concentrations across wide ranges. At present, the gold standard is the ecarin clotting time (ECT), where ecarin maximizes thrombin activity and clotting time is evaluated to assess DTIs' anticoagulation capability.