Sunghwan Kim

Epidermal electronic systems for detecting electrophysiological signals, sensing, therapy, and drug delivery are at the frontier in man-machine interfacing for healthcare. However, it is still a challenge to develop multifunctional bioapplications with minimal invasiveness, biocompatibility, and stable electrical performance under various mechanical deformations of biological tissues. In this study, a natural silk protein with carbon nanotubes (CNTs) is utilized to realize an epidermal electroni

Abstract Triboelectric electronic skins (E‐skins) can be used as primary interactive devices for human–machine interfaces (HMIs). However, devices for seamless on‐skin operations must be soft and deformable, and attachable to and compatible with the skin. In this paper, a substrate‐free, skin‐compatible, skin‐attachable, mechanically deformable, and self‐powered E‐tattoo sticker consisting of carbon nanotubes (CNTs) and silk nanofibers (SNFs) is presented. The E‐tattoo can be imperceptibly tatto

Photonic crystals (PhCs) efficiently manipulate photons at the nanoscale. Applying these crystals to biological tissue that has been subjected to large deformation and humid environments can lead to fascinating bioapplications such as in vivo biosensors and artificial ocular prostheses. These applications require that these PhCs have mechanical durability, deformability, and biocompatibility. Herein, we introduce a deformable and conformal silk hydrogel inverse opal (SHIO); the photonic lattice

A fully biocompatible laser would be attractive in many aspects of biomedical research. Here we report a single-mode biocompatible distributed feedback laser consisting of silk, riboflavin and silver in the form of a freestanding film. The distributed feedback structure has a large surface area and flexibility. The fabricated laser exhibited single-mode lasing at a wavelength of 495 nm.

Biodegradable and physically transient optics represent an emerging paradigm in healthcare devices by harnessing optically active system and obviating issues with chronic uses. Light emitting components that can efficiently interact with their environments have advantages of high sensitivity, visibility, and wireless operation. Here, we report a novel combination of silk biopolymer and optically active organic dyes resulting in versatile fluorescent silk nanofibers (FSNs). FSNs generated by the

We demonstrated biocompatible, optically transparent and flexible electrodes by embedding AgNWs just below the surface of the silk fibroin film.

Skin-actuated self-powered devices based on triboelectric nanogenerators (TENGs) have recently garnered increasing attention, as they can be used to develop electronic skins for healthcare, robotic intelligence, and human interface devices. TENGs typically require tribonegative materials to enable the top layers to either be in contact with or be insulated from other specific materials, resulting in suboptimal performance under practical conditions. Here, we describe the fabrication of a soft, t

Optically activated silk bio-ink is used to realize a physically transient distributed feedback laser. By water-washing and recoating, a fresh single-use laser can be easily obtained. Along with reliable lasing, a chemosensing application to detect a toxic acid vapor is presented. As a service to our authors and readers, this journal provides supporting information supplied by the authors. Such materials are peer reviewed and may be re-organized for online delivery, but are not copy-edited or ty

Abstract Melanin, a biologically occurring pigment featuring broadband optical absorption, ion‐binding affinity including antioxidative and radical‐scavenging properties, and hydration‐dependent electrical conductivity is an ideal natural semiconducting material for interfacing electronics with biological systems. Here, a skin‐mimicking optoelectronic device with a melanin nanoparticle (MNP) dispersion in a protein hydrogel–elastomer hybrid (a mimic of epidermis/dermis layers with melanin) and i

Abstract The ongoing research on printed and flexible electronics is primarily focused on conductive three‐dimensional (3D) print patterning. However, due to the nonhomogeneous distribution of conductive elements in a polymer matrix and their tendency to shrink, 3D‐printed patterns often suffer from low‐printing accuracies and poor mechanical and electrical properties. Herein, poly(vinyl butyral‐ co ‐vinyl alcohol‐ co ‐vinyl acetate) (PVBVA) is reinforced with microwave‐exfoliated graphene to de

Abstract Ultrathin, breathable, and skin‐compatible epidermal electronics are attractive for wearable and implantable healthcare and biomedical applications. However, materializing and integrating all electronic components on ultrathin platforms is still challenging. Here, a charge‐storing electronic tattoo (E‐tattoo) device with ultrathin, breathable, and skin‐compatible properties is reported. Silk protein nanofibers (SNFs) and carbon nanotubes (CNTs) form the top and bottom electrodes that sa