Cuticular pad–inspired selective frequency damper for nearly dynamic noise–free bioelectronics

Abstract

Bioelectronics needs to continuously monitor mechanical and electrophysiological signals for patients. However, the signals always include artifacts by patients’ unexpected movement (such as walking and respiration under approximately 30 hertz). The current method to remove them is a signal process that uses a bandpass filter, which may cause signal loss. We present an unconventional bandpass filter material—viscoelastic gelatin-chitosan hydrogel damper, inspired by the viscoelastic cuticular pad in a spider—to remove dynamic mechanical noise artifacts selectively. The hydrogel exhibits frequency-dependent phase transition that results in a rubbery state that damps low-frequency noise and a glassy state that transmits the desired high-frequency signals. It serves as an adaptable passfilter that enables the acquisition of high-quality signals from patients while minimizing signal process for advanced bioelectronics.

Breathable, antifreezing, mechanically skin-like hydrogel textile wound dressings with dual antibacterial mechanisms

“…Gelatin is a natural polymer with excellent biocompatibility, which has been widely used as the raw material for hydrogels [ [30] , [31] , [32] ]. However, the natural gelation of gelatin aqueous solutions is a time- and temperature-dependent process that lacks controllability and is difficult to match with the fast-spinning processes.…”

Motion Artifact‐Resilient Zone for Implantable Sensors

“…As mentioned above, dynamic motion represents a major obstacle in wearable or implantable electronics due to the repeated contraction and relaxation of muscles. [14,24] In other words, a sensor or device implanted in or near the body is also affected by this contraction and relaxation process of muscles, which applies either tensional stretching or compressive force. Figure 1a shows how body motion can affect the signal.…”

“…Therefore, dynamic motion always diminishes the quality of the data and reduces the signal-to-noise ratio. [9,13,14] As an example, a tactile sensor aims to recognize touch. [10,15,16] However, dynamic movement is also a factor that generates signal change without touch, and it results in the user recognizing a virtual touch that does not really exist.…”

“…Meanwhile, unconventional signal filtering using the structures, materials, or designs of electrodes has been suggested as an alternative. [14,[19][20][21][22][23][24][25] Representative examples include bending-insensitive devices using neutral plane, [23,24] unidirectional sensors with precisely aligned patterns to have high sensitivity in one direction, [24,25] and stretching insensitive sensors using wavy or origami forms that enable the sensors to change along with the deformation while maintaining their performance. [21,22,24] However, these methods have faced various problems, including the fact that they concentrated on a single dynamic effect.…”

Spatial information coding with artificially engineered structures for acoustic and elastic wave sensing

“…Acoustic and elastic waves carry a wealth of useful physical information in real world. Sensing acoustic and elastic waves is very important for understanding knowledge in various fields [1][2][3]. However, current wave sensing approaches generally requires multiple expensive sensors and complex hardware systems due to the uniform spatial transmission characteristics of physical field.…”