scholarly journals Ultrasoft, Adhesive and Millimeter Scale Epidermis Electronic Sensor for Real-Time Enduringly Monitoring Skin Strain

Sensors ◽  
2019 ◽  
Vol 19 (11) ◽  
pp. 2442
Author(s):  
Jianpeng Zhang ◽  
Yuhang Li ◽  
Yufeng Xing
Keyword(s):  
Wound Healing ◽  
Real Time ◽  
Human Skin ◽  
Large Strain ◽  
Strain Range ◽  
Gauge Factor ◽  
Human Hand ◽  
Adhesive Properties ◽  
Two Stage ◽  
Analytical Results

Epidermal electronic sensors (EESs) possess great advantages in the real-time and enduring monitoring of human vital information compared to the traditional medical device for intimately making contact with human skin. Skin strain is a significant and effective routine to monitor motion, heart rate, wrist pulse, and skin growth in wound healing. In this paper, a novel skin sensor combined with a ternary conductive nanocomposite (Carbon black (CB)/Decamethylcyclopentasiloxane (D5)/Silbione) and a two-stage serpentine connector is designed and fabricated to monitor skin strain. The ultrasoft (~2 kPa) and adhesive properties of the ternary conductive nanocomposite ensure the capacity of the EES to intimately couple with human skin in order to improve accuracy with a relative error of 3.39% at strain 50% as well as a large strain range (0~50%) and gauge factor (GF ~2.5). The millimeter scale EES (~5 mm × 1 mm × 100 μm), based on the micro-nano fabrication technique, consisted of a two-stage serpentine connector and screen print of the ternary conductive nanocomposite. EESs with high comprehensive performance (electrical and mechanical properties) are fabricated to confirm the analytical results and monitor the motion of a human hand. The good agreement between experimental and analytical results paves the way for bettering monitoring of skin growth during wound healing in order to avoid necrosis and scarring. This EES in monitoring the motion of a human exhibit presents a promising application for assisting prosthetic movement.

Direct-Write Stretchable Sensors Using Single-Walled Carbon Nanotube/Polymer Matrix

2013 ◽  
Vol 135 (1) ◽  
Author(s):  
Morteza Vatani ◽  
Yanfeng Lu ◽  
Kye-Shin Lee ◽  
Ho-Chan Kim ◽  
Jae-Won Choi
Keyword(s):  
Large Strain ◽  
Strain Range ◽  
Free Form ◽  
Gauge Factor ◽  
Direct Write ◽  
Wearable Electronics ◽  
Resistance Change ◽  
Single Walled Carbon ◽  
3D Structural Electronics ◽  
Stretchable Sensors

There have been increasing demands and interests in stretchable sensors with the development of flexible or stretchable conductive materials. These sensors can be used for detecting large strain, 3D deformation, and a free-form shape. In this work, a stretchable conductive sensor has been developed using single-walled carbon nanotubes (SWCNTs) and monofunctional acrylate monomers (cyclic trimethylolpropane formal acrylate and acrylate ester). The suggested sensors have been fabricated using a screw-driven microdispensing direct-write (DW) technology. To demonstrate the capabilities of the DW system, effects of dispensing parameters such as the feed rate and material flow rate on created line widths were investigated. Finally, a stretchable conductive sensor was fabricated using proper dispensing parameters, and an experiment for stretchability and resistance change was accomplished. The result showed that the sensor had a large strain range up to 90% with a linear resistance change and gauge factor ∼2.7. Based on the results, it is expected that the suggested DW stretchable sensor can be used in many application areas such as wearable electronics, tactile sensors, 3D structural electronics, etc.

scholarly journals Synergistic Effect of Graphene/Silver Nanowire Hybrid Fillers on Highly Stretchable Strain Sensors Based on Spandex Composites

Nanomaterials ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 2063
Author(s):  
Tan Thong Vo ◽  
Hyeon-Jong Lee ◽  
Sang-Yun Kim ◽  
Ji Won Suk
Keyword(s):  
Synergistic Effect ◽  
High Performance ◽  
Silver Nanowires ◽  
Large Strain ◽  
Strain Range ◽  
Strain Sensors ◽  
Silver Nanowire ◽  
Gauge Factor ◽  
Hybrid Fillers ◽  
Conductive Nanomaterials

Embedding conductive nanomaterials into elastomeric polymer matrices is one of the most promising approaches for fabricating stretchable strain sensors capable of monitoring large mechanical movements or deformation through the detection of resistance changes. Here, hybrid fillers comprising graphene and silver nanowires (AgNWs) are incorporated into extremely stretchable spandex to fabricate strain sensors. Composites containing only graphene and those containing the graphene/AgNW hybrid fillers are systematically investigated by evaluating their electrical and mechanical properties. The synergistic effect between graphene and AgNWs enable the strain sensors based on the composites to experience a large strain range of up to 120%, and low hysteresis with a high gauge factor of 150.3 at a strain of 120%. These reliable strain sensors are utilized for monitoring human motions such as heartbeats and body movements. The findings of this study indicate the significant applicability of graphene/AgNW/spandex composites in future applications that demand high-performance stretchable strain sensors.

3D-Printed Stretchable Strain Sensor With Application to Wind Sensing

2018 ◽  
Author(s):  
Mohammed Al-Rubaiai ◽  
Ryohei Tsuruta ◽  
Umesh Gandhi ◽  
Chuan Wang ◽  
Xiaobo Tan
Keyword(s):  
Wind Speed ◽  
Large Strain ◽  
Thermoplastic Polyurethane ◽  
Strain Sensor ◽  
Strain Range ◽  
Strain Sensors ◽  
Plastic Substrate ◽  
Gauge Factor ◽  
Effective Manner ◽  
3D Printed

Stretchable strain sensors with large strain range, high sensitivity, and excellent reliability are of great interest for applications in soft robotics, wearable devices, and structure-monitoring systems. Unlike conventional template lithography-based approaches, 3D-printing can be used to fabricate complex devices in a simple and cost-effective manner. In this paper, we report 3D-printed stretchable strain sensors that embeds a flexible conductive composite material in a hyper-plastic substrate. Three commercially available conductive filaments are explored, among which the conductive thermoplastic polyurethane (ETPU) shows the highest sensitivity (gauge factor of 5), with a working strain range of 0%–20%. The ETPU strain sensor exhibits an interesting behavior where the conductivity increases with the strain. In addition, an experiment for measuring the wind speed is conducted inside a wind tunnel, where the ETPU sensor shows sensitivity to the wind speed beyond 5.6 m/s.

Embedded 3D Printing of Highly Flexible Nanocomposites With Piezoresistive Sensing Capabilities

2020 ◽  
Author(s):  
Blake Herren ◽  
Mrinal C. Saha ◽  
M. Cengiz Altan ◽  
Yingtao Liu
Keyword(s):  
3D Printing ◽  
Human Skin ◽  
Strain Sensor ◽  
Strain Range ◽  
High Sensitivity ◽  
Curing Temperature ◽  
Gauge Factor ◽  
Strain Sensing ◽  
Sensing Applications ◽  
Human Joints

Abstract In recent years, highly flexible nanocomposite sensors have been developed for the detection of a variety of human body movements. To precisely detect the bending motions of human joints, the sensors must be able to conform well with the human skin and produce signals that effectively describe the amount of deformation applied to the material during bending. In this paper, a carbon nanotube-based piezoresistive strain sensor is developed via the direct ink writing based embedded 3D printing method. The optimum weight concentration range of carbon nanotubes in the nanocomposite inks, appropriate for embedded 3D printing, is identified. Samples with complex 2D and 3D geometries are printed to demonstrate the manufacturing capabilities of the embedded printing process. The sensitivity of the piezoresistive strain sensor is optimized by determining the ideal nanofiller concentration, curing temperature, and nozzle size to produce the highest gauge factor in a wide strain range. The piezoresistive and mechanical properties of the optimized sensors are fully characterized to verify the suitability for skin-attachable strain sensing applications. The developed sensors have a wide sensing range, high sensitivity, and minimal strain rate dependence. In addition, their low elasticity and high biocompatibility allow them to be comfortably bonded on the human skin.

scholarly journals Mechanical and Immunological Regulation in Wound Healing and Skin Reconstruction

2021 ◽  
Vol 22 (11) ◽  
pp. 5474
Author(s):  
Shun Kimura ◽  
Takashi Tsuji
Keyword(s):  
Tissue Engineering ◽  
Wound Healing ◽  
Human Skin ◽  
Developmental Stages ◽  
Control Mechanisms ◽  
Tissue Remodelling ◽  
Skin Equivalents ◽  
Immunological Interactions ◽  
Stress Signals ◽  
Specific Species

In the past decade, a new frontier in scarless wound healing has arisen because of significant advances in the field of wound healing realised by incorporating emerging concepts from mechanobiology and immunology. The complete integumentary organ system (IOS) regeneration and scarless wound healing mechanism, which occurs in specific species, body sites and developmental stages, clearly shows that mechanical stress signals and immune responses play important roles in determining the wound healing mode. Advances in tissue engineering technology have led to the production of novel human skin equivalents and organoids that reproduce cell–cell interactions with tissue-scale tensional homeostasis, and enable us to evaluate skin tissue morphology, functionality, drug response and wound healing. This breakthrough in tissue engineering has the potential to accelerate the understanding of wound healing control mechanisms through complex mechanobiological and immunological interactions. In this review, we present an overview of recent studies of biomechanical and immunological wound healing and tissue remodelling mechanisms through comparisons of species- and developmental stage-dependent wound healing mechanisms. We also discuss the possibility of elucidating the control mechanism of wound healing involving mechanobiological and immunological interaction by using next-generation human skin equivalents.

Flexible Bicolorimetric Polyacrylamide/Chitosan Hydrogels for Smart Real‐Time Monitoring and Promotion of Wound Healing

2021 ◽  
pp. 2102599
Author(s):  
Kaikai Zheng ◽  
Yu Tong ◽  
Shihao Zhang ◽  
Ruiying He ◽  
Lan Xiao ◽  
...  
Keyword(s):  
Wound Healing ◽  
Real Time ◽  
Real Time Monitoring ◽  
Chitosan Hydrogels

scholarly journals Modeling of Personalized Anatomy Using Plastic Strains

2021 ◽  
Vol 40 (2) ◽  
pp. 1-21
Author(s):  
Bohan Wang ◽  
George Matcuk ◽  
Jernej Barbič
Keyword(s):  
Magnetic Resonance Imaging ◽  
Computed Tomography ◽  
Magnetic Resonance ◽  
Large Strain ◽  
Human Anatomy ◽  
Shape Deformation ◽  
Human Hand ◽  
Plastic Strains ◽  
Resonance Imaging ◽  
Deformation Method

We present a method for modeling solid objects undergoing large spatially varying and/or anisotropic strains, and use it to reconstruct human anatomy from medical images. Our novel shape deformation method uses plastic strains and the finite element method to successfully model shapes undergoing large and/or anisotropic strains, specified by sparse point constraints on the boundary of the object. We extensively compare our method to standard second-order shape deformation methods, variational methods, and surface-based methods, and demonstrate that our method avoids the spikiness, wiggliness, and other artifacts of previous methods. We demonstrate how to perform such shape deformation both for attached and un-attached (“free flying”) objects, using a novel method to solve linear systems with singular matrices with a known nullspace. Although our method is applicable to general large-strain shape deformation modeling, we use it to create personalized 3D triangle and volumetric meshes of human organs, based on magnetic resonance imaging or computed tomography scans. Given a medically accurate anatomy template of a generic individual, we optimize the geometry of the organ to match the magnetic resonance imaging or computed tomography scan of a specific individual. Our examples include human hand muscles, a liver, a hip bone, and a gluteus medius muscle (“hip abductor”).

scholarly journals Systematic Review on Human Skin-Compatible Wearable Photoplethysmography Sensors

2021 ◽  
Vol 11 (5) ◽  
pp. 2313
Author(s):  
Inho Lee ◽  
Nakkyun Park ◽  
Hanbee Lee ◽  
Chuljin Hwang ◽  
Joo Hee Kim ◽  
...  
Keyword(s):  
Systematic Review ◽  
Health Care ◽  
Real Time ◽  
Human Skin ◽  
State Of The Art ◽  
Electronic Devices ◽  
Semiconducting Materials ◽  
Physiological Conditions ◽  
Technological Developments ◽  
Monitoring Technologies

The rapid advances in human-friendly and wearable photoplethysmography (PPG) sensors have facilitated the continuous and real-time monitoring of physiological conditions, enabling self-health care without being restricted by location. In this paper, we focus on state-of-the-art skin-compatible PPG sensors and strategies to obtain accurate and stable sensing of biological signals adhered to human skin along with light-absorbing semiconducting materials that are classified as silicone, inorganic, and organic absorbers. The challenges of skin-compatible PPG-based monitoring technologies and their further improvements are also discussed. We expect that such technological developments will accelerate accurate diagnostic evaluation with the aid of the biomedical electronic devices.

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