Yonsei University · Engineering
Professor Hyunjung Yi's research lab specializes in the development of advanced functional materials and wearable electronic systems for biomedical and human-machine interface applications. The lab focuses on integrating nanomaterials—particularly carbon nanotubes and hydrogels—into flexible, biocompatible, and stimuli-responsive devices for real-time sensing and imaging. Key research directions include smart electronic skins, fiber-based optoelectronics, and bio-integrated sensors that enable deep-tissue imaging, pressure sensing, and neural-inspired signal processing for disease diagnosis.
Figures are computed from collected data and may differ slightly.
Second near-infrared (NIR) window light (950-1400 nm) is attractive for in vivo fluorescence imaging due to its deep penetration depth in tissues and low tissue autofluorescence. Here we show genetically engineered multifunctional M13 phage can assemble fluorescent single-walled carbon nanotubes (SWNTs) and ligands for targeted fluorescence imaging of tumors. M13-SWNT probe is detectable in deep tissues even at a low dosage of 2 μg/mL and up to 2.5 cm in tissue-like phantoms. Moreover, targeted
The development of electrically responsive sensors that interact directly with human skin and at the same time produce a visual indication of the temperature is in great demand. Here, we report a highly sensitive electronic skin (E-skin) sensor that measures and visualizes skin temperature simultaneously using a biocompatible hydrogel displaying thermoresponsive transparency and resistivity resulting from a temperature dependence of the strength of the hydrogen bonding between its components. Th
Transfer-printing enables the assembly of functional nanomaterials on unconventional substrates with a desired layout in a controllable manner. However, transfer-printing to substrates with complex surfaces remains a challenge. Herein, we show that hydrogels serve as effective template material platforms for the assembly and transfer-printing of conductive nanonetwork patterns for flexible sensors on various topographic surfaces in a very simple yet versatile manner. The non-adherence, nanoporou
Mechanical properties of biological systems provide useful information about the biochemical status of cells and tissues. Here, an artificial tactile neuron enabling spiking representation of stiffness and spiking neural network (SNN)-based learning for disease diagnosis is reported. An artificial spiking tactile neuron based on an ovonic threshold switch serving as an artificial soma and a piezoresistive sensor as an artificial mechanoreceptor is developed and shown to encode the elastic stiffn
Fiber optoelectronics technology has recently attracted attention as enabling various form factors of wearable electronics, and the issue of how to control and optimize the configuration and physical properties of the electrode micropatterns in the microfiber devices has become important. Here, spirally wrapped carbon nanotube (CNT) microelectrodes with a controlled dimension are demonstrated for high-performance fiber optoelectronic devices. Inkjet-printed CNT microelectrodes with the desired d
Wearable pressure sensors with wide operating pressure ranges and enhanced wearability via seamless integration with circuits can greatly improve the fields of digital healthcare, prosthetic limbs, and human-machine interfaces. Herein, we report an approach based on a conductive-island-bridging nanonetwork to realize wearable resistive pressure sensors that are operative over ultrawide pressure ranges >400 kPa and are circuit-compatible. The sensor has a simple two-layered structure, where nanon
Nanostructured flexible electrodes with biological compatibility and intimate electrochemical coupling provide attractive solutions for various emerging bioelectronics and biosensor applications. Here, we develop all-inkjet-printed flexible nanobio-devices with excellent electrochemical coupling by employing amphiphilic biomaterial, an M13 phage, numerical simulation of single-drop formulation, and rational formulations of nanobio-ink. Inkjet-printed nanonetwork-structured electrodes of single-w
Patchable electrodes are attractive for applications in optoelectronic devices because of their easy and reliable processability. However, development of reliable patchable transparent electrodes (TEs) with high optoelectronic performance is challenging; till now, optoelectronic devices fabricated with patchable TEs have been exhibiting limited performance. In this study, Ag nanowire (AgNW)/poly(methyl methacrylate) (PMMA) patchable TEs are developed and the highly efficient transparent quantum
A hydrodynamic phenomenon is used to assemble a large-scale conductive nanomesh of single-walled carbon nanotubes (SWNTs) with exceptional control of the nanostructure. This is accomplished by a biological material with nanoscale features and a strong binding affinity toward SWNTs. The biological material also presents a unique glue effect for the assembly. Unprecedented material characteristics are observed for the nanomesh.
Abstract With increasingly diverse functionalities of electronic skins (E‐skins), components and structures for the E‐skin have also become more diverse and complex. It is extremely challenging to make all the components and devices required for additional functionalities stretchable and breathable to ensure skin comfort. Herein, we report a facile strategy to realize a versatile hybrid E‐skin patch with great skin comfort by developing a breathable and stretchable metastructure to serve as the
Realizing high-performance electrochemical biosensors in a simple contact-printing-based approach significantly increases the applicability of integrated flexible biosensors. Herein, an enzyme-sticker-based approach that enables flexible and multielectrochemical sensors via simple contact-transfer printing is reported. The enzyme sticker consists of an enzymatic conductive network film and a polymeric support. The enzyme-incorporated nanostructured conductive network showing an efficient electri
Abstract Achieving the nondestructive assembly of carbon nanoelectrodes with multiple components in a scalable manner enables effective electrical interfaces among nanomaterials. Here, a facile nondestructive multiscale assembly of multicomponent nanomaterials using self‐assembled tyrosine‐rich peptide nanofibers (TPFs) as a biological glue is reported. The versatile functionalities of the rationally devised tyrosine‐rich short peptide allow for (1) self‐assembly of the peptide into nanofibers u
Highly [111]-oriented rhombohedral lead zirconate titanate [Pb(Zr1−xTix)O3;PZT] thin films were prepared on Pt(111)∕Ti∕SiO2∕Si substrates by suitably combining pulsed laser deposition with sol-gel coating. Two distinctive types of the backscattering geometry were employed for the polarized Raman scattering study: (i) normal backscattering in which the propagation direction of relevant phonons is parallel to the principal [111] polar axis of the rhombohedral 3m(C3v) point group for observing E(TO
Kinetic stability of transition-metal oxide (TMO) anodes is of significant importance for high-power lithium-ion batteries (LIBs). Stable interfaces between TMOs and electrical nanomaterials could enhance high-power performance. In this study, we report a biotemplate-based approach for securing structural and electrochemical interfaces between active materials and conductive nanomaterials and demonstrate highly stable and high-power Co3O4 anodes for LIBs. Co3O4 nanoflower electrodes are synthesi
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