Skin‐Inspired Thermoreceptors‐Based Electronic Skin for Biomimicking Thermal Pain Reflexes

Abstract

Electronic systems possessing skin‐like morphology and functionalities (electronic skins [e‐skins]) have attracted considerable attention in recent years to provide sensory or haptic feedback in growing areas such as robotics, prosthetics, and interactive systems. However, the main focus thus far has been on the distributed pressure or force sensors. Herein a thermoreceptive e‐skin with biological systems like functionality is presented. The soft, distributed, and highly sensitive miniaturized (≈700 µm2) artificial thermoreceptors (ATRs) in the e‐skin are developed using an innovative fabrication route that involves dielectrophoretic assembly of oriented vanadium pentoxide nanowires at defined locations and high‐resolution electrohydrodynamic printing. Inspired from the skin morphology, the ATRs are embedded in a thermally insulating soft nanosilica/epoxy polymeric layer and yet they exhibit excellent thermal sensitivity (−1.1 ± 0.3% °C−1), fast response (≈1s), exceptional stability (negligible hysteresis for >5 h operation), and mechanical durability (up to 10 000 bending and twisting loading cycles). Finally, the developed e‐skin is integrated on the fingertip of a robotic hand and a biological system like reflex is demonstrated in response to temperature stimuli via localized learning at the hardware level.

Integrated Piezo-Triboelectric Nanogenerators-Based Self-Powered Flexible Temperature and Pressure Sensor

“…earable and flexible electronics have gained significant interest recently because of the wide range of solutions they enable for applications such as health monitoring, robotics, displays and interactive systems etc. [1][2][3][4][5][6]. Energy autonomy is critical for these systems, especially where portability is necessary.…”

V2O5 Nanowires-Coated Yarn-Based Temperature Sensor With Wireless Data Transfer for Smart Textiles

“…In this regard, the one-dimensional (1-D) semiconducting materials like vanadium pentoxide (V2O5) NWs offer better alternative for temperature sensing. Their attractive properties include high crystallinity, high surface area to volume ratio, ease of synthesis and small activation energy [35][36][37]. The modification of yarn with such heat sensitive material is an enticing approach with no trade-off between flexibility and performance of the temperature sensor.…”

“…3d plots the response versus temperature to evaluate the linear working range of the sensor. The degradation in sensors performance below 10°C was due to the condensation of water on the surface of yarn-based temperature sensor [37].…”

“…Device packaging is crucial for smart or e-textile for better durability and stability during bending motions and washing. To this end, we coated the device with a thin layer of nanosilica/epoxy [37]. Fig.…”

Triboelectric Nanogenerators as Power Sources for Chemical Sensors and Biosensors

“…The advancement in micro/nanotechnology has significantly enriched the quality and reliability of miniaturized sensors needed across multiple sectors including health monitoring, , agriculture, aquaculture, environment monitoring, robotics, − rehabilitation, , automation, space, , etc. Complemented by recent progress in flexible and printed electronics, these solutions continue to enrich the above areas and open new opportunities by allowing the detection of various chemical and biological analytes or parameters such as dopamine, glucose, tyrosine, and creatinine for human healthcare. , The rapidly aging society and new forms of lethal diseases have pushed healthcare systems to adopt innovative solutions such as digital healthcare, which have contributed immensely to the rising demand for portable and wearable chemical sensors and biosensors globally. − Numerous selective and sensitive chemical sensors and biosensors have been reported in the literature − using distinct working mechanisms and exploiting the optical, piezoelectric, electrochemical, and enzymatic properties of various sensing materials [e.g., metal–organic frameworks (MOFs), two-dimensional (2D) materials, conducting polymers, carbon nanotubes (CNTs)]. − However, one of the long-standing problems with these sensors is the lack of a suitable source of power.…”