Hierarchically Structured Flexible Electrode on Polyimide for Highly Sensitive and Reliable Biosignal Acquisition

Abstract

Numerous wearable biomedical devices are developed for the continuous monitoring of personal health or condition. Biosignals acquisition with high sensitivity is important for designing wearable biomedical devices. A sensing electrode between the human body and wearable electronics significantly affects the sensitivity of the sensors. In this study, we fabricated hierarchically structured flexible electrodes on polyimide substrate (HSFE-PI) using micro-casting technique and gold nanoparticles electrodeposition. Polyimides provides robust and outstanding electrical characteristics, and the reliability of HSFE-PI was verified with a cyclic bending test. The integration of hierarchical structures significantly increased the surface area of the electrode by 2.06 times. We applied the HSFE-PI for electromyogram (EMG) and glucose sensing applications and achieved high sensitivity enhancement in both applications. The signal-to-noise ratio (SNR) of measured EMG signals was increased by 2.48 times, and the sensitivity of the glucose detection was increased by 1.42 times compared to the planar counterpart.

Highly Flexible and Conductive Electrodes through Combining Honeycomb and Butterfly Pattern Bio‐Inspired Structure for ECG Signal Recording

“…Flexible electrode is an essential part of biosignal recording and plays a critically important role in health monitoring and medical diagnosis. [1][2][3][4][5] However, conductivity of flexible electronic devices can't be guaranteed due to the lack of reliability of existing flexible electrodes under various deformation and many other fields due to unique auxetic properties and outstanding mechanical properties including stronger shear resistance, fracture toughness and cracks propagation resistance, etc. [27][28][29][30][31][32] It is worth mentioning that the NPR structure has been reported many times to have the ability to improve flexible electrode mechanical performance.…”

“…Flexible electrode is an essential part of biosignal recording and plays a critically important role in health monitoring and medical diagnosis. [ 1–5 ] However, conductivity of flexible electronic devices can't be guaranteed due to the lack of reliability of existing flexible electrodes under various deformation conditions, which hinders the development of flexible electronics as an emerging technology. [ 6–10 ] Ideally, a flexible electrode should be provided reliable conductivity and mechanical flexibility at the same time.…”

Stress‐Free Detachment of Flexible Substrate from Glass Carrier Using CO2 Point Laser for Large‐Area Applications

“…PI is one of the most widely utilized flexible substrate materials in the industry owing to its outstanding heat and chemical resistance, superior insulating properties, and high compatibility with various fabrication processes, compared to other polymeric materials. [9,10] In our approach, a point laser is applied directly on the edge of the PI substrate and not through a transparent carrier. The performance degradation from laser illumination can be minimized, as the laser does not apply to the electronic components.…”