Smart Prosthetics Research Articles

Advancing Oral Health and Craniofacial Science through Microchip Implants

Microchip implants have emerged as transformative tools in the realm of oral health and craniofacial science, offering novel solutions to longstanding challenges. This paper aims to explore the diverse applications of microchip technology in dentistry and craniofacial medicine, envisioning a future where these implants play a pivotal role in diagnostics, treatment modalities, and ongoing patient care. The integration of microchips enables real-time monitoring of oral conditions, facilitating early detection of dental issues and providing personalized treatment strategies. Additionally, these implants open avenues for smart prosthetics and orthodontic devices, optimizing patient comfort and treatment outcomes. However, ethical considerations, patient perceptions, and the societal impact of such technology should also be addressed. By examining the multifaceted implications and applications of microchip implants in oral health and craniofacial science, this research overview seeks to contribute valuable insights to the intersection of technology and healthcare in the dental domain.

Flexible Ag2Se Thermoelectric Films Enable the Multifunctional Thermal Perception in Electronic Skins.

Skin is critical for shaping our interactions with the environment. The electronic skin (E-skin) has emerged as a promising interface for medical devices to replicate the functions of damaged skin. However, exploration of thermal perception, which is crucial for physiological sensing, has been limited. In this work, a multifunctional E-skin based on flexible thermoelectric Ag2Se films is proposed, which utilizes the Seebeck effect to replicate the sensory functions of natural skin. The E-skin can enable capabilities including temperature perception, tactile perception, contactless perception, and material recognition by analyzing the thermal conduction behaviors of various materials. To further validate the capabilities of constructed E-skins, a wearable device with multiple sensory channels was fabricated and tested for gesture recognition. This work highlights the potential for using flexible thermoelectric materials in advanced biomedical applications including health monitoring and smart prosthetics.

A three-dimensional force/temperature composite flexible sensor

Flexible sensors that mimic human tactile perception are widely used in areas such as smart prosthetics and human-robot interaction, and play a key role in bridging the gap between humans, robots and the environment. The development of tactile sensors with versatile tactile sensing capabilities remains a challenge. In this paper, a three-dimensional force/temperature composite flexible sensor is proposed and developed. The upper part of the sensor is a temperature-sensitive unit completely covered with a hardened layer, which not only protects the temperature-sensitive material, but also reduces pressure interference. The lower part contains a truncated pyramid bump and four arrays of pressure-sensitive units to achieve three-dimensional force detection. When a three-dimensional force is applied on the sensor, four pressure-sensitive units undergo different resistance changes by which normal and shear components of the force can be decoupled. The temperature-sensitive unit is made of graphene/carbon nanotubes/silicone rubber (GR/CNT/SR) conductive nanocomposite and the pressure-sensitive units are made of graphene/silver nanoflakes/silicone rubber (GR/AgNF/SR) conductive nanocomposite. Experimental results show that force sensitivities of the sensor in x-, y- and z- directions are 1.694 N/V, 1.436 V/N and 0.435 N/V in the ranges of − 1.2–1.2 N, − 1.2–1.2 N and 0–7 N, respectively. The temperature sensitivity is 0.067 V/°C in the range of 25–90 °C. In addition, the sensor was mounted on a manipulator for daily grasping and results demonstrate good application potential.

How to Achieve Human–Machine Interaction by Foot Gesture Recognition: A Review

Researchers are investigating how to make machines read our body language to make human-machine interaction (HMI) more intelligent and efficient. The lower limbs contain a variety of gestures, and it is also one of the most effective ways to express body information. Therefore, foot gesture recognition (FGR) has become a popular technology for human-machine interface with simple, fast and accurate features. To give the reader a quick overview of the current state of FGR research, this review takes the sensing methods used in FGR technology as an entry point, introduces different sensing methods, machine learning algorithms and applications, and discusses the limitations and future work on FGR systems. The results show that the mainstream sensing methods for FGR are plantar pressure, inertial, visual, surface electromyography and ultrasound. Current applications of FGR are simplified control, medical rehabilitation, virtual reality, and smart prosthetics. Research on hybrid sensing methods and deep learning algorithms has gradually increased in recent years. Future research will focus on designing sensor hardware that can respond to environmental changes, using multimodal sensing for interaction, and designing more comfortable and portable FGR systems.

Wearable Strain Sensor With a Graphene Localized Warping Structure for Ultra-Wide Range Strain Detection and Bending Direction Recognition

The practical need for the accurate detection of human activities requires wearable flexible strain sensors that can detect subtle and large strains and recognize the bending direction of joints. However, it remains challenging to integrate these detection capabilities into a single strain sensor. Herein, we prepared flexible strain sensors with firmly attached locally warped graphene on the surface of anhydride-grafted styrene-butadiene-styrene triblock copolymer films using a swelling-self-assembly method. The unique localized warpage structure of graphene sheets gives the sensor excellent strain response performance and the ability to recognize the bending direction. The detection limit of the sensor to strain is independent of the sensitivity to strain, which allows it to detect ultralow (0.01%) and large strains (500%). Moreover, the sensor has a large linear response range (0~94%) and good test stability (3000 cycles of strain). The sensor can be used to recognize the bending direction by generating opposite response signals to different bending directions. The excellent response behavior allows the sensor to accurately monitor the joint bending angle, direction of the human body, and subtle tremors of the human skin, which makes it a potential application for wearable devices and smart prosthetics.

A machine learning‐assisted multifunctional tactile sensor for smart prosthetics

AbstractThe absence of tactile perception limits the dexterity of a prosthetic hand and its acceptance by amputees. Recreating the sensing properties of the skin using a flexible tactile sensor could have profound implications for prosthetics, whereas existing tactile sensors often have limited functionality with cross‐interference. In this study, we propose a machine‐learning‐assisted multifunctional tactile sensor for smart prosthetics, providing a human‐like tactile sensing approach for amputations. This flexible sensor is based on a poly(3,4‐ethylenedioxythiophene): poly(styrene sulfonate) (PEDOT:PSS)–melamine sponge, which enables the detection of force and temperature with low cross‐coupling owing to two separate sensing mechanisms: the open‐circuit voltage of the sensor as a force‐insensitive intrinsic variable to measure the absolute temperature and the resistance as a temperature‐insensitive extrinsic variable to measure force. Furthermore, by analyzing the unsteady heat conduction and characterizing it using real‐time thermal imaging, we demonstrated that the process of open‐circuit voltage variation resulting from the unsteady heat conduction is closely correlated with the heat‐conducting capabilities of materials, which can be utilized to discriminate between substances. Assisted by the decision tree algorithm, the device is endowed with thermal conductivity sensing ability, which allows it to identify 10 types of substances with an accuracy of 94.7%. Furthermore, an individual wearing an advanced myoelectric prosthesis equipped with the above sensor can sense pressure, temperature, and recognize different materials. We demonstrated that our multifunctional tactile sensor provides a new strategy to help amputees feel force, temperature and identify the material of objects without the aid of vision. image

Artificial Intelligence in Human Medicine

This editorial reflects on the emergence of artificial intelligence and how it is applied in the field of health. AI is a technology that mimics the functioning of the human brain and uses algorithms, machine learning, pattern recognition and cognitive computing to process large amounts of data and extract useful insights. AI can improve health and well-being of people in various areas of medicine, such as medical image analysis, diagnosis, treatment, genetics, pregnancy and smart prosthetics. These applications can help medical professionals make better clinical decisions, accelerate research and development of new drugs, personalize patient care and reduce costs and human errors. AI can also empower users to access relevant information about their health and actively participate in their care. However, AI also poses ethical, legal and social challenges that must be addressed with responsibility and transparency.

All Resistive Pressure-Temperature Bimodal Sensing E-Skin for Object Classification.

Electronic skin (E-skin) with multimodal sensing ability demonstrates huge prospects in object classification by intelligent robots. However, realizing the object classification capability of E-skin faces severe challenges in multiple types of output signals. Herein, a hierarchical pressure-temperature bimodal sensing E-skin based on all resistive output signals is developed for accurate object classification, which consists of laser-induced graphene/silicone rubber (LIG/SR) pressure sensing layer and NiO temperature sensing layer. The highly conductive LIG is employed as pressure-sensitive material as well as the interdigital electrode. Benefiting from high conductivity of LIG, pressure perception exhibits an excellent sensitivity of -34.15 kPa-1 . Meanwhile, a high temperature coefficient of resistance of -3.84%°C-1 is obtained in the range of 24-40°C. More importantly, based on only electrical resistance as the output signal, the bimodal sensing E-skin with negligible crosstalk can simultaneously achieve pressure and temperature perception. Furthermore, a smart glove based on this E-skin enables classifying various objects with different shapes, sizes, and surface temperatures, which achieves over 92% accuracy under assistance of deep learning. Consequently, the hierarchical pressure-temperature bimodal sensing E-skin demonstrates potential application in human-machine interfaces, intelligent robots, and smart prosthetics.

Overcoming Challenges and Innovations in Orthopedic Prosthesis Design: An Interdisciplinary Perspective.

Recent advances in the orthopedic prostheses design have significantly improved the quality of life for individuals with orthopedic disabilities. However, there are still critical challenges that need to be addressed to further enhance the functionality of orthopedic prostheses improving biocompatibility to promote better integration with natural tissues, enhancing durability to withstand the demands of daily use, and improving sensory feedback for better control of movement are the most pressing issues. To address these challenges, promising emerging solutions such as smart prosthetics, 3D printing, regenerative medicine, and artificial intelligence have been developed. These innovative technologies hold the potential to significantly enhance the functionality of orthopedic prostheses. Realizing the full potential of these next-generation orthopedic prostheses requires addressing several critical factors. These include interdisciplinary collaboration between experts in orthopedics, materials science, biology, and engineering, increased investment in research and development, standardization of components to ensure quality and reliability, and improved access to prosthetics. A comprehensive review of these challenges and considerations for future orthopedic prosthesis design is s provided in this paper addressing the further advances to the field. By addressing these issues, we can continue to improve the lives of individuals with orthopedic disabilities and further enhance the field of orthopedic prosthetics.

Stretchable Sensors for Soft Robotic Grippers in Edge-Intelligent IoT Applications.

The rapid development of electronic material and sensing technology has enabled research to be conducted on liquid metal-based soft sensors. The application of soft sensors is widespread and has many applications in soft robotics, smart prosthetics, and human-machine interfaces, where these sensors can be integrated for precise and sensitive monitoring. Soft sensors can be easily integrated for soft robotic applications, where traditional sensors are incompatible with robotic applications as these types of sensors show large deformation and very flexible. These liquid-metal-based sensors have been widely used for biomedical, agricultural and underwater applications. In this research, we have designed and fabricated a novel soft sensor that yields microfluidic channel arrays embedded with liquid metal Galinstan alloy. First of all, the article presents different fabrication steps such as 3D modeling, printing, and liquid metal injection. Different sensing performances such as stretchability, linearity, and durability results are measured and characterized. The fabricated soft sensor demonstrated excellent stability and reliability and exhibited promising sensitivity with respect to different pressures and conditions.

Dual Mode Strain–Temperature Sensor with High Stimuli Discriminability and Resolution for Smart Wearables

AbstractStrain and temperature are important physiological parameters for health monitoring, providing access to the respiration state, movement of joints, and inflammation processes. The challenge for smart wearables is to unambiguously discriminate strain and temperature using a single sensor element assuring a high degree of sensor integration. Here, a dual‐mode sensor with two electrodes and tubular mechanically heterogeneous structure enabling simultaneous sensing of strain and temperature without cross‐talk is reported. The sensor structure consists of a thermocouple coiled around an elastic strain‐to‐magnetic induction conversion unit, revealing a giant magnetoelastic effect, and accommodating a magnetic amorphous wire. The thermocouple provides access to temperature and its coil structure allows to measure impedance changes caused by the applied strain. The dual‐mode sensor also exhibits interference‐free temperature sensing performance with high coefficient of 54.49 µV °C−1, low strain and temperature detection limits of 0.05% and 0.1 °C, respectively. The use of these sensors in smart textiles to monitor continuously breathing, body movement, body temperature, and ambient temperature is demonstrated. The developed multifunctional wearable sensor is needed for applications in early disease prevention, health monitoring, and interactive electronics as well as for smart prosthetics and intelligent soft robotics.

Design, Fabrication, and Testing of a Fully 3D-Printed Pressure Sensor Using a Hybrid Printing Approach.

Pressure sensing is not a new concept and can be applied by using different transduction mechanisms and manufacturing techniques, including printed electronics approaches. However, very limited efforts have been taken to realise pressure sensors fully using additive manufacturing techniques, especially for personalised guide prosthetics in biomedical applications. In this work, we present a novel, fully printed piezoresistive pressure sensor, which was realised by using Aerosol Jet® Printing (AJP) and Screen Printing. AJ®P was specifically chosen to print silver interconnects on a selective laser sintered (SLS) polyamide board as a customised substrate, while piezoresistive electrodes were manually screen-printed on the top of the interconnects as the sensing layer. The sensor was electromechanically tested, and its response was registered upon the application of given signals, in terms of sensitivity, hysteresis, reproducibility, and time drift. When applying a ramping pressure, the sensor showed two different sensitive regions: (i) a highly sensitive region in the range of 0 to 0.12 MPa with an average sensitivity of 106 Ω/MPa and a low sensitive zone within 0.12 to 1.25 MPa with an average sensitivity of 7.6 Ω/MPa with some indeterminate overlapping regions. Hysteresis was negligible and an electrical resistance deviation of about 14% was observed in time drift experiments. Such performances will satisfy the demands of our application in the biomedical field as a smart prosthetics guide.

Tunable force sensor based on carbon nanotube fiber for fine mechanical and acoustic technologies

Design of new smart prosthetics or robotic grippers gives a major impetus to low-cost manufacturing and rapid prototyping of force sensing devices. In this paper, we examine piezoresistive force sensors based on carbon nanotube fibers fabricated by a novel wet pulling technique. The developed sensor is characterized by an adjustable force range coupled with high sensitivity to enable the detection of a wide range of forces and displacements limited by the experimental setup only. We have demonstrated the applicability of the developed unit in tactile sensing, displacement sensing, and nanophone vibration monitoring system and evaluated its force sensing characteristics, i.e. displacement/force input and resistance/mechanical response. In the experiments it measures 0–115 N force range within 2.5 mm displacement. Moreover, the sensor demonstrates good linearity, low hysteresis, and stability when tested over 10 000 cycles. The developed sensor suits multiple applications in the field of soft and transparent sensors, nanophones, actuators, and other robotics devices for both regular and extreme environments, e.g. deep underwater and radioactive environment.

A Breathable and Stretchable Metastructure for a Versatile Hybrid Electronic Skin Patch with Long‐Term Skin Comfort

AbstractWith increasingly diverse functionalities of electronic skins (E‐skins), components and structures for the E‐skin have also become more diverse and complex. It is extremely challenging to make all the components and devices required for additional functionalities stretchable and breathable to ensure skin comfort. Herein, we report a facile strategy to realize a versatile hybrid E‐skin patch with great skin comfort by developing a breathable and stretchable metastructure to serve as the platform material of the hybrid E‐skin patch. A Kagome‐based mechanical metastructure made of breathable, stretchable medical adhesive integrates and tethers non‐stretchable or stiff components and devices to the skin, allowing for both the breathability and mechanical comfort of skin. A wireless skin sensor system to sense electrocardiogram (ECG) signals and wirelessly transmit ECG signals in an event‐driven manner such as sending R peaks only is developed on a polyimide‐based flexible printed circuit board. The Kagome metastructure‐tethered wireless ECG sensor patch does not cause significant skin discomfort when worn for five days, and successfully enables the event‐driven wireless monitoring of ECG signals. We envision that this facile and versatile approach expands the type of materials and functionalities of E‐skin for digital healthcare, personalized medicine, and smart prosthetics with emerging functionalities.

Biomimetic Skins Enable Strain‐Perception‐Strengthening Soft Morphing

AbstractBiological soft tissues are typically characterized of strain mechanical stiffening for injury prevention, yet the capability to achieve active awareness via perception strengthening still remains a challenge. However, creatures have projected their 2D or 3D deformation in a safe way via perception regulation. In this work, strain‐perception‐strengthening (SPS) enabled soft skins that allow the dynamic transformation from tactile to pain‐sensing are proposed. The synthetic skin featured with elastic, conductive, and adaptive properties is composed of elastomeric thin‐film and assembled graphene nanosheets with an interlocked structural interface. In the SPS‐enabled sensory system, the strain‐perception‐threshold value can be regulated from ≈7.2% to ≈95.3%. The integrated skin‐like system can effectively imitate the normal tactile and pain feeling of soft tissues (e.g., unidirectional stretching of muscle tendon and irregular stretching deformation of hand skin). Furthermore, inspired by the pufferfish, a bionic pufferfish with synthetic skin is designed, enabling it to sensitively capture the external mechanical stimuli such as tiny airflow and finger touch, and further inflate itself to a 3D deformation determined by the SPS effect. The concept of soft skins with SPS effect demonstrates potential fields in safe human‐machine interaction, smart prosthetics and soft robotics.

Bimodal Tactile Sensor without Signal Fusion for User-Interactive Applications

Tactile sensors with multimode sensing ability are cornerstones of artificial skin for applications in humanoid robotics and smart prosthetics. However, the intuitive and interference-free reading of multiple tactile signals without involving complex algorithms and calculations remains a challenge. Herein a pressure-temperature bimodal tactile sensor without any interference is demonstrated by combining the fundamentally different sensing mechanisms of optics and electronics, enabling the simultaneous and independent sensing of pressure and temperature with the elimination of signal separation algorithms and calculations. The bimodal sensor comprises a mechanoluminescent hybrid of ZnS-CaZnOS and a poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) thermoresistant material, endowing the unambiguous transduction of pressure and temperature into optical and electrical signals, respectively. This device exhibits the highest temperature sensitivity of -0.6% °C-1 in the range of 21-60 °C and visual sensing of the applied forces at a low limitation of 2 N. The interference-free and light-emitting characteristics of this device permit user-interactive applications in robotics for encrypted communication as well as temperature and pressure monitoring, along with wireless signal transmission. This work provides an unexplored solution to signal interference of multimodal tactile sensors, which can be extended to other multifunctional sensing devices.

Mutually Noninterfering Flexible Pressure-Temperature Dual-Modal Sensors Based on Conductive Metal-Organic Framework for Electronic Skin.

Pressure and temperature are two important indicators for human skin perception. Electronic skin (E-skin) that mimics human skin within one single flexible sensor is beneficial for detecting and differentiating pressure and temperature and showing immunity from tensile strain disruptions. However, few studies have simultaneously realized these conditions. Herein, a flexible and strain-suppressed pressure-temperature dual-modal sensor based on conductive and microstructured metal-organic framework (MOF) films was reported and mainly prepared by in situ growing Ni3(HiTP)2 onto microstructured mixed cellulose (MSMC) substrates. The sensor exhibits distinguishable and strain-suppressed properties for pressure (sensing range up to 300 kPa, sensitivity of 61.61 kPa-1, response time of 20 ms, and ultralow detection limit of 1 Pa) and temperature sensing (sensitivity of 57.1 μV/K). Theoretical calculations successfully analyzed the mutually noninterfering mechanism between pressure and temperature. Owing to its effective perception in static and dynamic surroundings, this sensor has great potential applications, such as in electronic skin and smart prosthetics.

Transhumanism and Engagement-Facilitating Technologies in Society

Transhumanism is a movement that explores the possibilities that arise from integrating technology in the human body. Neurostimulators and smart prosthetics are some of the technologies that may soon change the way Humans interact with their surrounding environment and enhance their well-being. The current paper presents a framework for stakeholder well-being through transhumanism and engagement-facilitating technologies on four major blocks, namely: reality-virtuality continuum as stimuli, from stimuli to adoption of transhumanism at individual level, stakeholder engagement and technologies at firm level and stakeholder well-being and technologies. Finally, we propose a future research agenda for exploring such changes in society.

Ultrathin Superhydrophobic Flexible Tactile Sensors for Normal and Shear Force Discrimination.

Flexible tactile sensors, with the ability to sense and even discriminate between different mechanical stimuli, can enable real-time and precise monitoring of dexterous and complex robotic motions. However, making them ultrathin and superhydrophobic for practical applications is still a great challenge. Here, superhydrophobic flexible tactile sensors with hierarchical micro- and nanostructures, that is, warped graphene nanosheets adhered to micron-height wrinkled surfaces, were constructed using ultrathin medical tape (40 μm) and graphene. The tactile sensor enables the discrimination of normal and shear forces and senses sliding friction and airflow. Moreover, the tactile sensor exhibits high sensitivity to normal and shear forces, extremely low detection limits (15 Pa for normal forces and 6.4 mN for shear forces), and cyclic robustness. Based on the abovementioned characteristics, the tactile sensor enables real-time and accurate monitoring of the robotic arm's motions, such as moving, gripping, and lifting, during the process of picking up objects. The superhydrophobicity even allows the sensor to monitor the motions of the robotic arm underwater in real time. Our tactile sensors have potential applications in the fields of intelligent robotics and smart prosthetics.

3D Printing of Liquid Metal Based Tactile Sensor for Simultaneously Sensing of Temperature and Forces

ABSTRACT Tactile sensors have been used for haptic perception in intelligent robotics, smart prosthetics, and human-machine interface. The development of multifunctional tactile sensor remains a challenge and limit its application in flexible electronics and devices. We propose a liquid metal based tactile sensor for both temperature and force sensing which is made by 3D printing. The structural design and working principle of liquid metal based tactile sensor are firstly described. A digital light processing-based printing process is developed to print two kinds of photosensitive resins with different hardness, and used to fabricate the tactile sensor. A Wheatstone bridge circuit is designed for decoupling the temperature and forces from the measured output voltages. Characterization tests show that the tactile sensor has relatively high force sensing sensitivity of 0.29 N-1, and temperature sensing sensitivities are 0.55% °C−1 at 20 ~ 50 °C and 0.21% °C−1 at 50 ~ 80 °C, respectively. Then, the fabricated tactile sensor is mounted onto hand finger to measure the contact force and temperature during grasping. Results show that the 3D printed tactile sensor has excellent flexibility and durability and can accurately measure the temperature and contact forces, which demonstrate its potential in robotic manipulation applications.