Challenges and Perspectives in Wearable Bio-Mechanical Sensors and Body Energy Harvesters
With the development of an aging population, the demand for personal health monitoring technology is increasing. Wearable and mobile monitoring technologies enable real-time monitoring, early diagnosis, and protection for chronic disease patients from serious harm. Many modern personal health monitoring devices that are portable, flexible, and wearable have been developed to detect physiological and vital signs, including heart rate, blood pressure, respiratory rate, and local temperature.The Massimo De Vittorio team from the Polytechnic University of Turin’s Center for Biomolecular Nanotechnology published an article titled “Sustainable Electronic Biomaterials for Body-Compliant Devices: Challenges and Perspectives for Wearable Bio-Mechanical Sensors and Body Energy Harvesters” in the journal Nano Energy, highlighting flexible biosensors and energy harvesters based on sustainable biomaterials, and critically discussing the applicability potential of biomaterials.Figure 1: Development and Future Directions of Flexible Functional SensorsFigure 2: (a) Schematic diagram of biodegradable ferroelectric gelatin electronic skin and pulse signals collected from the wrist under different physiological conditions, corresponding to rest, exercise, and sweating; (b) Schematic diagram of the artificial cellulose/PVDF nanofiber membrane wrapped around Chinese chopsticks, and the sensing performance during detecting human motion (i) fist clenching, (ii) finger bending, (iii) sensitive bending, (iv) lightly tapping the foot while walking, (v) bending the elbow at different angles.Figure 3: (a) Schematic diagram of biocompatible chitosan-diatom friction electric BEH and photos of motion sensors, with output voltages obtained during i) wrist, ii) elbow, and iii) knee movements; (b) Method of preparing tea phenol-chitosan diatom hydrogel and optical images of tea phenol-chitosan and tea phenol-chitosan-diatom hydrogel (CCDHG); i) and ii) report the open-circuit voltage of the electronic skin based on CCDHG-TENG under stretching and bending.Figure 4: (a) Schematic diagram of cellulose/PEDOT:PSS hybrid film and its chemical structure, including added glycerol and glucose. Image of the cellulose film attached to the skin (back of the hand) showing stretching capability (up to 300%). The skin sensor’s real-time relative resistance response during i) wrist bending, ii) abdominal breathing, iii) skin stretching, and throat movement (movement of the throat protrusion during drinking). (b) Schematic diagram of a paper-based wearable sensor and various physiological monitoring scenarios. The sensor consists of digital inter-electrodes and MXene/thin paper (the working mechanism is also shown). Additionally, i) shows three different movement states: standing, walking, and jumping, while ii) shows the throat movement when reading “apple” and “banana”. The wrist pulse signals before and after exercise are shown in iii). Simultaneously recorded ECG and arterial pulse signals and pulse transit time (PTT) for blood pressure monitoring are shown in iv). Finally, v) displays the systolic blood pressure (sbp, asterisks) and diastolic pressure calculated using the PTT method before (black) and after (red) exercise.Figure 5: (a) Composition layers and working principle of the piezoresistive-friction electric hybrid electronic device (PTHD) (the manufacturing process of PTHD is also reported below). The figure also shows PTHD attached to the skin, detecting some activities of the human body in different postures, such as wrist pulse before and after exercise, abdominal breathing during normal or deep breathing, as well as further movements such as walking, running, and squatting (reference [108]). (b) Proposed wearable PS-TENG for detecting water molecules, with the measurement device (the figure also reports the absorption and desorption mechanisms of water molecules and shows images of the sensor demonstrating its flexible structure). The left figure shows the sensor’s ability to monitor human breathing, including normal, deep, and rapid breathing states, and identifies joint movements in the human body, such as bending and twisting of the wrist joint.Figure 6: (a) Schematic diagram of the structure of the piezoresistive-friction electric hybrid electronic device (PTHD) (the manufacturing process of PTHD is also reported below). The figure also shows PTHD attached to the skin, detecting some activities of the human body in different postures, such as wrist pulse before and after exercise, abdominal breathing during normal or deep breathing, as well as further movements such as walking, running, and squatting (reference [108]). (b) Proposed wearable PS-TENG for detecting water molecules, with the measurement device (the figure also reports the absorption and desorption mechanisms of water molecules and shows images of the sensor demonstrating its flexible structure). The left figure shows the sensor’s ability to monitor human breathing, including normal, deep, and rapid breathing states, and identifies joint movements in the human body, such as bending and twisting of the wrist joint.Figure 7: (a) Schematic diagram of the flexible electrospun piezoelectric generator device encapsulated with Kapton film and its production. The left side shows the voltage signal produced when detecting a certain bending angle of a finger (from 30° to 90°), corresponding to the movements of three different body parts (elbow, knee, and foot); (b) Schematic diagram of the OSFM-SE pressure sensor, showing the structure of planar electrodes and structural electrodes. The figure also shows the output voltage of the OSFM-SE pressure sensor when attached to the incisors and molars under different occlusal forces (small and large occlusal forces).Figure 8: (a) Breathable, biodegradable, and antibacterial electronic skin conformally attached to the epidermis, with a schematic diagram of its three-dimensional structure; (b) Schematic diagram of signals generated by DF-CNF composites and (left) single and (right) double DF-CNF biocompatible TENG during different breathing rates and coughing.Figure 9: (a) Distribution of sensing mechanisms. (b) Distribution of sensing materials forms.Figure 10: (a) Number of papers related to piezoelectric sensors. (b) Number of papers on triboelectric sensors. (c) Number of papers on piezoresistive sensors. (d) Number of papers on capacitive sensors. (e) Number of papers on hybrid sensors.Figure 11: (a) Number of documents on textile materials. (b) Number of papers on film materials. (c) Number of papers on aerogel materials. (d) Number of papers on hydrogel materials. (e) Number of papers on bulk materials and sponge materials. (e) Number of papers related to nanofiber materials.Figure 12: (a) Distribution of BEH mechanisms. (b) Distribution of material forms of BEH devices.
Original Title: Sustainable electronic biomaterials for body-compliant devices: Challenges and perspectives for wearable bio-mechanical sensors and body energy harvesters
Authors:Gaia de Marzo, et al.
Original Link:https://doi.org/10.1016/j.nanoen.2024.109336
