Ki Jun Yu

Long-lasting, high-resolution neural interfaces that are ultrathin and flexible are essential for precise brain mapping and high-performance neuroprosthetic systems. Scaling to sample thousands of sites across large brain regions requires integrating powered electronics to multiplex many electrodes to a few external wires. However, existing multiplexed electrode arrays rely on encapsulation strategies that have limited implant lifetimes. Here, we developed a flexible, multiplexed electrode array

Abstract Recent progress in the synthesis and deterministic assembly of advanced classes of single crystalline inorganic semiconductor nanomaterial establishes a foundation for high-performance electronics on bendable, and even elastomeric, substrates. The results allow for classes of systems with capabilities that cannot be reproduced using conventional wafer-based technologies. Specifically, electronic devices that rely on the unusual shapes/forms/constructs of such semiconductors can offer me

Continuous glucose monitoring (CGM) allows patients with diabetes to manage critical disease effectively and autonomously and prevent exacerbation. A painless, wireless, compact, and minimally invasive device that can provide CGM is essential for monitoring the health conditions of freely moving patients with diabetes. Here, we propose a glucose-responsive fluorescence-based highly sensitive biodegradable microneedle CGM system. These ultrathin and ultralight microneedle sensor arrays continuous

Abstract Monitoring the body temperature with high accuracy provides a fast, facile, yet powerful route about the human body in a wide range of health information standards. Here, the first ever ultrasensitive and stretchable gold‐doped silicon nanomembrane (Au‐doped SiNM) epidermal temperature sensor array is introduced. The ultrasensitivity is achieved by shifting freeze‐out region to intrinsic region in carrier density and modulation of fermi energy level of p‐type SiNM through the developmen

Recently, bioelectronic devices extensively researched and developed through the convergence of flexible biocompatible materials and electronics design that enables more precise diagnostics and therapeutics in human health care and opens up the potential to expand into various fields, such as clinical medicine and biomedical research. To establish an accurate and stable bidirectional bio-interface, protection against the external environment and high mechanical deformation is essential for weara

Neuroscience is an essential field of investigation that reveals the identity of human beings, with a comprehensive understanding of advanced mental activities, through the study of neurobiological structures and functions. Fully understanding the neurotransmission system that allows for connectivity among neuronal circuits has paved the way for the development of treatments for neurodegenerative diseases such as Parkinson's disease, Alzheimer's disease, and depression. The field of flexible imp

Abstract A wearable silent speech interface (SSI) is a promising platform that enables verbal communication without vocalization. The most widely studied methodology for SSI focuses on surface electromyography (sEMG). However, sEMG suffers from low scalability because of signal quality-related issues, including signal-to-noise ratio and interelectrode interference. Hence, here, we present a novel SSI by utilizing crystalline-silicon-based strain sensors combined with a 3D convolutional deep lear

Tactile function is essential for human life as it enables us to recognize texture and respond to external stimuli, including potential threats with sharp objects that may result in punctures or lacerations. Severe skin damage caused by severe burns, skin cancer, chemical accidents, and industrial accidents damage the structure of the skin tissue as well as the nerve system, resulting in permanent tactile sensory dysfunction, which significantly impacts an individual's daily life. Here, we intro

In the rapidly evolving field of human-machine interfaces (HMIs), high-resolution wearable electronic skin (e-skin) is essential for user interaction. However, traditional array-structured tactile interfaces require increased number of interconnects, while soft material-based computational methods have limited functionalities. Here, we introduce a thin and soft e-skin for tactile interfaces, offering high mapping capabilities through electrical impedance tomography (EIT). We employed an organic/

Abstract Transparent implantable devices have received significant attention in neuroscience and biomedical engineering by combining neural recording and optical modalities. Opaque, metal‐based electrode arrays for electrophysiology block optical imaging and cause photoelectric artifacts, making them difficult to integrate with optogenetics. Here, a photoelectric artifact‐free, highly conductive, and transparent poly(3,4‐ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS) electrode array i

Bioresorbable neural implants based on emerging classes of biodegradable materials offer a promising solution to the challenges of secondary surgeries for removal of implanted devices required for existing neural implants. In this study, we introduce a fully bioresorbable flexible hybrid opto-electronic system for simultaneous electrophysiological recording and optogenetic stimulation. The flexible and soft device, composed of biodegradable materials, has a direct optical and electrical interfac

Light-trapping schemes implemented with ultrathin, 3 μm thick silicon solar cells offer excellent opportunities for greatly enhanced absorption and corresponding improvements in efficiency of operation. Optically optimized cells of this type yield energy conversion efficiencies that are higher by ≈190% compared to otherwise identical cells that do not exploit light-trapping features, consistent with optical modeling results.

Recently, flexible pressure sensors have gained substantial research interest in bioelectronics because they can monitor the conditions of various organs, enable early diagnosis of diseases, and provide precise medical treatment by applying them to various parts of the body. In particular, inorganic materials, metal and carbon-based materials are broadly used in novel structured pressure sensors from wearable devices to implantable devices. With the excellent electronic properties, distinctive m

Scientific and engineering progress associated with increased interest in healthcare monitoring, therapy, and human-machine interfaces has rapidly accelerated the development of bio-integrated multifunctional devices. Recently, compensation for the cons of existing materials on electronics for health care systems has been provided by carbon-based nanomaterials. Due to their excellent mechanical and electrical properties, these materials provide benefits such as improved flexibility and stretchab