Gold is Poised for a Transformative Role in Reshaping the Future of Wearable Devices

Top Olympic performers receive the esteemed gold medal, symbolizing wealth and honor both in Eastern and Western cultures. This metal, prized for its stability in air, excellent electrical conductivity, and compatibility with living organisms, plays a pivotal role across various domains. It holds significant favor in medical and energy sectors as a ‘preferred catalyst’ and is increasingly utilized in cutting-edge wearable technologies.

Gold’s revolutionary potential in wearables: an integrated wearable sensor device

Under the guidance of Professor Sei Kwang Hahn and Dr. Tae Yeon Kim from the Department of Materials Science and Engineering at Pohang University of Science and Technology (POSTECH), a research team devised an integrated wearable sensor device. This device proficiently captures and processes two bio-signals simultaneously, as detailed in Advanced Materials, a leading international journal in the materials field.

Wearable devices, available in various forms such as attachments and patches, are vital for detecting physical, chemical, and electrophysiological signals used in diagnosing and managing diseases. Recent advancements in research aim to create wearables capable of simultaneously measuring multiple bio-signals.

However, a significant challenge has been the need for different materials for each signal measurement, leading to interface damage, complex fabrication, and decreased device stability. Additionally, analyzing these diverse signals requires additional signal processing systems and algorithms.

To address this challenge, the team employed various gold (Au) nanowire shapes. Although silver (Ag) nanowires, recognized for their extreme thinness, lightness, and conductivity, are commonly used in wearable devices, the team combined them with gold. Initially, they produced bulk gold nanowires by coating silver nanowires externally to mitigate the galvanic effect.

Then, they crafted hollow gold nanowires by selectively removing the silver from the gold-coated nanowires. The bulk gold nanowires exhibited high sensitivity to temperature changes, while the hollow gold nanowires demonstrated sensitivity to minute strain alterations.

Gold’s revolutionary potential in wearables: styrene-ethylene-butylene-styrene (SEBS) polymer

They patterned these nanowires onto a substrate composed of styrene-ethylene-butylene-styrene (SEBS) polymer, seamlessly integrating them without any separations. By employing two types of gold nanowires, each with distinct properties, they engineered an integrated sensor capable of measuring both temperature and strain.

Additionally, they developed a logic circuit for signal analysis, utilizing the negative gauge factor produced by incorporating micrometer-scale corrugations into the pattern. This method resulted in the successful creation of an intelligent wearable device system that captures and analyzes signals simultaneously, all using a single material, Au.

The sensors developed by the team demonstrated exceptional performance in detecting subtle muscle tremors, identifying heartbeat patterns, discerning speech via vocal cord tremors, and monitoring changes in body temperature. Crucially, these sensors maintained high stability without causing damage to the material interfaces. Their flexibility and impressive stretchability allowed them to seamlessly conform to curved skin.

The team arranged these nanowires onto a substrate crafted from styrene-ethylene-butylene-styrene (SEBS) polymer, integrating them smoothly without any separations. By utilizing two types of gold nanowires, each with its own unique properties, they engineered an all-in-one sensor capable of measuring both temperature and strain.

Additionally, they designed a logic circuit for signal analysis, utilizing the negative gauge factor formed by introducing micrometer-scale corrugations into the pattern. This approach successfully developed an intelligent wearable system that captures and analyzes signals simultaneously, all using the single material of Au.

Subtle muscle tremors

Their sensors showcased exceptional performance, detecting subtle muscle tremors, identifying heartbeat patterns, recognizing speech through vocal cord tremors, and monitoring changes in body temperature. Importantly, these sensors maintained remarkable stability without causing any harm to the material interfaces. Their flexibility and outstanding stretchability allowed them to seamlessly conform to curved skin.

Professor Sei Kwang Hahn remarked, “This research emphasizes the potential of creating an advanced bioelectronics platform capable of analyzing a wide array of bio-signals.” He further stated, “We foresee new opportunities across various sectors, including healthcare and integrated electronic systems.”

The study received sponsorship from the Basic Research Program and the Biomedical Technology Development Program of the National Research Foundation of Korea, as well as POSCO Holdings.

Read the original article on sciencedaily.

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