The outstanding properties of graphene have initiated myriads of research and development; yet, its economic impact is hampered by the difficulties encountered in production and practical application. Recently discovered laser-induced graphene is generated by a simple printing process on flexible and lightweight polyimide films. Exploiting the electrical features and mechanical pliability of LIG on polyimide, we developed wearable resistive bending sensors that pave the way for many cost-effective measurement systems. The versatile sensors we describe can be utilized in a wide range of configurations, including measurement of force, deflection, and curvature. The deflection induced by different forces and speeds is effectively sensed through a resistance measurement, exploiting the piezoresistance of the printed graphene electrodes. The LIG sensors possess an outstanding range for strain measurements reaching >10% A double-sided electrode concept was developed by printing the same electrodes on both sides of the film and employing difference measurements. This provided a large bidirectional bending response combined with temperature compensation. Versatility in geometry and a simple fabrication process enable the detection of a wide range of flow speeds, forces, and deflections. The sensor response can be easily tuned by geometrical parameters of the bending sensors and the LIG electrodes. As a wearable device, LIG bending sensors were used for tracking body movements. For underwater operation, PDMS-coated LIG bending sensors were integrated with ultra-low power aquatic tags and utilized in underwater animal speed monitoring applications, and a recording of the surface current velocity on a coral reef in the Red Sea.npj Flexible Electronics (2019) 3:15 ; https://doi.

Flexible and wearable magnetoelectronics add intriguing new functionalities to our natural perception. Of particular interest regarding these artificial skins are wireless sensing and touchless interactions. Biocompatibility and imperceptibility are the most significant features of wearable devices attached to our bodies. In this work, a biocompatible magnetic skin is introduced. It offers extreme flexibility, stretchability (>300%), and lightweight while maintaining a remanent magnetization up to 360 mT. The magnetic skin is comfortable to wear, can be realized in any desired shape or color, and adds tunable permanent magnetic properties to the surface it is applied to. It provides remote control functions and combined with magnetic sensors; it implements a complete wearable magnetic system. For example, eye tracking is realized by attaching the magnetic skin to the eyelid. The advantage that it does not require any wiring makes it an extremely viable solution for soft robotics and human-machine interactions. Wearing the magnetic skin on a finger or integrated

Graphene has shown considerable potential for sensing magnetic fields based on the Hall Effect, due to its high carrier mobility, low sheet carrier density, and low-temperature dependence. However, the cost of graphene in comparison to conventional materials has meant that its uptake in electronic manufacturing has been slow. To lower technological barriers and bring more widespread adoption of graphene Hall sensors, we are using a one-step laser scribing process that does not rely on multiple steps, toxic chemicals, and subsequent treatments. Laser-scribed graphene Hall sensors offer a linear response to magnetic fields with a normalized sensitivity of ~1.12 V/AT. They also exhibit a low constant noise voltage floor of ~ 50 nV/$$\sqrt {{\mathrm{Hz}}}$$ Hz for a bias current of 100 µA at room temperature, which is comparable with state-of-the-art low-noise Hall sensors. The sensors combine a high bendability, come with high robustness and operating temperatures up to 400 °C. They enable device ideas in various areas, for instance, soft robotics. As an example, we combined a laser-scribed graphene sensor with a deformable elastomer and flexible magnet to realize low-cost, compliant, and customizable tactile sensors.

Flexible and wearable magnetoelectronics add intriguing new functionalities to our natural perception. Of particular interest regarding these artificial skins are wireless sensing and touchless interactions. Biocompatibility and imperceptibility are the most significant features of wearable devices attached to our bodies. In this work, a biocompatible magnetic skin is introduced. It offers extreme flexibility, stretchability (>300%), and lightweight while maintaining a remanent magnetization up to 360 mT. The magnetic skin is comfortable to wear, can be realized in any desired shape or color, and adds tunable permanent magnetic properties to the surface it is applied to. It provides remote control functions and combined with magnetic sensors; it implements a complete wearable magnetic system. For example, eye tracking is realized by attaching the magnetic skin to the eyelid. The advantage that it does not require any wiring makes it an extremely viable solution for soft robotics and human-machine interactions. Wearing the magnetic skin on a finger or integrated

In article number 2100346, Jürgen Kosel and coworkers develop a facile magnetic tracking system for subcutaneous medical devices, consisting of a lightweight, flexible permanent magnet at the tip and a sensing unit to scan the dermal surface. It enables locating and tracking in a handheld format without the use of x-ray imaging and contrast dyes.

The largest disadvantage of modern day minimally invasive surgery is the required use of X‐ray or fluoroscopic imaging for locating or tracking medical catheters and tubes. The implications are increased costs and effort, limited availability for instance in less developed countries, and the cumulative exposure to contrast dyes and ionizing radiation are detrimental to health, especially in young patients and neonates with increased sensitivity. In order to reduce the use of X‐ray imaging and provide a wider accessibility, a facile magnetic system is proposed for subcutaneous medical device localization. It consists of a lightweight and flexible, biocompatible, and permanent magnet at the tip of the subcutaneous device and a sensing device to scan the dermal surface and locate the magnetic tip. The mechanical and magnetic properties of the magnetic tip are tailored to fit the requirements of the delicate catheter application. Evaluation of the tracking system using a 5 Fr magnetic tip resulted in a depth‐dependent position and orientation error of 0.75 mm and 3.7°. Additionally, a maximum placement depth error of 0.96 mm is achieved. Evaluation of the system in vivo revealed its practicality and accuracy as well as the influence of potential user errors.

The use of subcutaneous devices has greatly advanced the field of medicine and surgery. However, localizing these devices internally requires imaging techniques such as X‐ray or ultrasound. A novel magnetic tracking system for subcutaneous medical devices is presented, providing the capability for precise device localization in an extremely compact and portable pocket‐size format. It is entirely benign, avoids X‐rays, and can be used to immediately confirm the proper instrument placement. It is implemented on umbilical catheters and endotracheal tubes and is characterized by bench‐test, cadaveric, and in vivo studies. The systems consist of a magnetic tip fixed to the distal end of the subcutaneous device, as well as a Magnetic Sensing‐Array Device that utilizes a matrix of magnetic field sensors to localize the magnetic tip. The bench‐tests show a high localization accuracy for a distance up to 4 cm. The accuracy is slightly reduced during cadaveric and in vivo tests, due to factors impacting the application, such as the dermal surface topography. Regardless, the magnetic subcutaneous medical device tracking system is shown to be robust in performance and functionality in real‐world clinical applications, and with its intuitive approach and portability, it has the potential to make real‐time subcutaneous device tracking widely accessible.

No abstract