Stretchable and anti-impact iontronic pressure sensor with an ultrabroad linear range for biophysical monitoring and deep learning-aided knee rehabilitation

Abstract

Monitoring biophysical signals such as body or organ movements and other physical phenomena is necessary for patient rehabilitation. However, stretchable flexible pressure sensors with high sensitivity and a broad range that can meet these requirements are still lacking. Herein, we successfully monitored various vital biophysical features and implemented in-sensor dynamic deep learning for knee rehabilitation using an ultrabroad linear range and high-sensitivity stretchable iontronic pressure sensor (SIPS). We optimized the topological structure and material composition of the electrode to build a fully stretching on-skin sensor. The high sensitivity (12.43 kPa−1), ultrabroad linear sensing range (1 MPa), high pressure resolution (6.4 Pa), long-term durability (no decay after 12000 cycles), and excellent stretchability (up to 20%) allow the sensor to maintain operating stability, even in emergency cases with a high sudden impact force (near 1 MPa) applied to the sensor. As a practical demonstration, the SIPS can positively track biophysical signals such as pulse waves, muscle movements, and plantar pressure. Importantly, with the help of a neuro-inspired fully convolutional network algorithm, the SIPS can accurately predict knee joint postures for better rehabilitation after orthopedic surgery. Our SIPS has potential as a promising candidate for wearable electronics and artificial intelligent medical engineering owing to its unique high signal-to-noise ratio and ultrabroad linear range.

Flexible Sensory Systems: Structural Approaches

“…Due to this deformation, the interconnect can have a stretchability that does not break, even in tension. Currently, stretchable interconnects are being manufactured using patterns such as serpentine and fractal designs [ 7 , 14 , 84 , 85 , 86 , 87 , 88 , 89 , 90 , 91 , 92 , 93 , 94 , 95 , 96 , 97 , 98 , 99 , 100 , 101 , 102 , 103 , 104 , 105 , 106 , 107 , 108 ]. The most representative pattern in stretchable interconnects is the former [ 84 , 94 , 102 , 103 , 104 , 105 , 106 , 107 , 108 ], in which two semicircles are repeatedly connected in a straight line.…”

“…Interconnects with improved stretchability through pattern design are being used in various fields, such as wearable devices and biomonitoring [ 14 , 96 , 97 , 98 , 99 , 100 , 101 ]. The device shown in Figure 3 d has improved stretchability, with a serpentine pattern interconnect [ 96 ].…”

“…Stretchable interconnects are used in various fields, such as wearable devices and bioelectronics [ 96 , 97 , 112 , 126 ]. A stretchable interconnect structure is essential in the field of soft electronics, because it has a structure that facilitates the connection of components of the sensor.…”

Monolayer MoS2-Based Flexible and Highly Sensitive Pressure Sensor with Wide Sensing Range

“…Flexible pressure sensors are widely used in human-machine interaction (HMI) [ 1 , 2 , 3 ], electronic skin (E-Skin) [ 4 , 5 , 6 ], and human health monitoring [ 7 , 8 , 9 , 10 , 11 ]. In particular, capacitive pressure sensors have attracted a broad attention with their merits of low power, excellent stability and fast response time.…”

“…The EDL performance depends on many items, among which the electrode materials play a most important role. Currently reported sensitive materials for preparing iontronic pressure sensor is categorized into metal-based electrode materials [ 18 , 19 ], carbon-based materials [ 7 ], metal oxide indium tin oxide (ITO) [ 20 ], and MXene [ 21 ]. Metal electrodes typically exhibit smaller specific surface area and reduced EDL capacitance.…”