Won‐Gun Koh

Fluorescence-based biosensor platforms have been intensively investigated not only to increase the sensitivity but also to improve the performance of biosensors. By exploiting metal from the macroscopic down to the nanoscopic surface, various architectures have been devised to manipulate fluorescence signals (enhancement, quenching) within near-optical fields. The interaction of a metallic surface with proximal fluorophores (in the range of 5-90 nm) has beneficial effects on optical properties s

We present an easy and effective method for the encapsulation of cells inside PEG-based hydrogel microstructures fabricated using photolithography. High-density arrays of three-dimensional microstructures were created on substrates using this method. Mammalian cells were encapsulated in cylindrical hydrogel microstructures of 600 and 50 micrometers in diameter or in cubic hydrogel structures in microfluidic channels. Reducing lateral dimension of the individual hydrogel microstructure to 50 micr

In the field of tissue engineering, conductive hydrogels have been the most effective biomaterials to mimic the biological and electrical properties of tissues in the human body. The main advantages of conductive hydrogels include not only their physical properties but also their adequate electrical properties, which provide electrical signals to cells efficiently. However, when introducing a conductive material into a non-conductive hydrogel, a conflicting relationship between the electrical an

The development of a lightweight, low-power, user-interactive three-dimensional (3D) touchless display in which a human stimulus can be detected and simultaneously visualized in noncontact mode is of great interest. Here, we present a user-interactive 3D touchless sensing display based on multiorder reflection structural colors (SCs) of a thin, solid-state block copolymer (BCP) photonic crystal (PC). Full-visible-range SCs are developed in a BCP PC consisting of alternating lamellae, one of whic

The fabrication of mammalian cell-containing poly(ethylene glycol) (PEG) hydrogel microstructures on glass and silicon substrates is described. Using photoreaction injection molding in poly(dimethylsiloxane) microfluidic channels, three-dimensional hydrogel microstructures encapsulating cells (fibroblasts, hepatocytes, macrophage) were fabricated with cells uniformly distributed to each hydrogel microstructure, and the number of cells in each hydrogel microstructure was controlled by changing th

Recycling is a fascinating topic in academia due to the environmental and economic benefits in industries. In this paper, we report on the method to recycle cellulose waste papers using a green (eco-friendly) approach based on ionic liquids (ILs) where the regenerated cellulose was converted to carbon dots (CDs). The addition of waste papers to the IL, 1-allyl-3-methylimidazolium chloride ([Amim][Cl]), disrupted the chemical arrangement of cellulose and completely dissolved the waste paper under

A facile approach for the highly luminescent and biocompatible CsPbBr₃@SiO₂ core–shell PNCs was developed. The dual biological roles of these PNCs are demonstrated, offering new directions to the stable PNCs for a variety of biomedical applications.

The extracellular matrix of most natural tissues comprises various types of cells, including fibroblasts, stem cells, and endothelial cells, which communicate with each other directly or indirectly to regulate matrix production and cell functionality. To engineer multicellular interactions in vitro, co-culture systems have achieved tremendous success achieving a more realistic microenvironment of in vivo metabolism than monoculture system in the past several decades. Recently, the fields of tiss

Many layers make light work: Layer-by-layer (LbL) self-assembly of a dendritic porphyrin (red; see picture) and poly(allylamine hydrochloride) (blue) on polystyrene nanoparticles followed by removal of the polystyrene core produces multifunctional hollow nanocapsules. These species can be both loaded with anticancer drugs and used in photodynamic therapy (PDT) and therefore have potential in combined cancer therapy.

A dendrimer porphyrin (DP)-coated gold nanoshell (AuNS-DP) was prepared for the synergistic combination of photodyanmic and photothermal therapy. The resultant AuNS-DP successfully exhibited the generation of reactive oxygen species (ROS) as well as photothermal effect for the simultaneous application of photodynamic therapy (PDT) and photothermal therapy (PTT).