Joonhee Lee

Thermoresponsive polymers exhibiting lower critical solution temperatures (LCSTs) in aqueous solution have garnered considerable attention for the development of smart materials. Herein, we report the synthesis and properties of pH-tunable thermoresponsive poly(ethylene oxide) (PEO)-based functional polymers bearing pendant amine groups with varying cloud points. Well-defined poly(ethylene oxide- co -allyl glycidyl ether) (P(EO- co -AGE)) copolymers were prepared via controlled anionic ring-open

The remarkable underwater adhesion of mussel foot proteins has long been an inspiration in the design of peptidomimetic materials. Although the synergistic wet adhesion of catechol and lysine has been recently highlighted, the critical role of the polymeric backbone has remained largely underexplored. Here, we present a peptidomimetic approach using poly(ethylene glycol) (PEG) as a platform to evaluate the synergistic compositional relation between the key amino acid residues (<i>i.e.</i>, DOPA

Tautomycetin is an antifungal antibiotic retaining potent immunosuppressive function. We have identified the roles of tautomycetin on cellular proliferation and transformation of colorectal cancer cells. The proliferation and anchorage-independent growth of HCT-15, HT-29, and DLD-1 colorectal cancer cells were efficiently inhibited without induction of apoptosis by 150 nmol tautomycetin. These growth inhibitory effects were dependent on p21Cip/WAF induction via the extracellular signal-regulated

Polyethers like poly(ethylene glycol) have been widely used for a variety of valuable applications, although their functionalization still poses challenges due to the absence of functional handles along the polymer backbone. Herein, a series of novel azide-functionalized glycidyl ether monomers are presented as a universal approach to synthesize functional polyethers by post-polymerization modification. Three azide-functionalized glycidyl ether monomers possessing different alkyl spacers (ethyl,

Despite their high potency, the widespread implementation of natural antimicrobial peptides is still challenging due to their low scalability and high hemolytic activities. Herein, we address these issues by employing a modular approach to mimic the key amino acid residues present in antimicrobial peptides, such as lysine, leucine, and serine, but on the highly biocompatible poly(ethylene glycol) (PEG) backbone. A series of these PEG-based peptides (PEGtides) were developed using functional epox

Prodrug-type polymer-drug conjugates based on highly biocompatible functional polyethers are developed through mechanochemical post-polymerization modification. Herein, we design functional epoxide monomers of ethoxyethyl glycidyl ether (EEGE) and azidohexyl glycidyl ether (AHGE) and synthesize diblock copolyethers of PEEGE-<i>b</i>-PAHGE via sequential anionic ring-opening polymerization. Subsequent conversion of the functional monomers to the corresponding hydroxyl and amine groups allows for

Reversible thiol-disulfide exchange chemistry is of particular interest in drug delivery systems. However, high levels of glutathione (GSH) in cancer cells are hard to distinguish from GSH in normal cells, resulting in unmanageable cytotoxic drug release. This study investigates the spatiotemporally-controlled irreversible degradation of Ir-based photosensitizer (TIr3)-encapsulating nanogels (IrNG) through the hyperoxidation of resulting intracellular thiols using reactive oxygen species (ROS).

Despite their superior stability and facile handling, ionic polymers have limited solubility in most organic solvents, restricting the range of substrates and reaction conditions to which they can be applied. To overcome this solubility issue, the present study presents a solvent-free mechanochemical reaction. Specifically, a post-polymerization modification of ammonium-functionalized polyether was demonstrated using a solvent-free vibrational ball-milling technique. The formation of imine bonds

Functional hyperbranched polyglycerols (PGs) have recently garnered considerable interest due to their potential in biomedical applications. Here, we present a one-pot synthesis of hyperbranched PGs possessing amine functionality using a novel amino glycidyl ether monomer. A Boc-protected butanolamine glycidyl ether (BBAG) monomer was designed and polymerized with glycidol (G) through anionic ring-opening multibranching polymerization to yield a series of hyperbranched P(G- co -BBAG) with contro

Mergesort is the most widely-known external sorting algorithm, which is used when the data being sorted do not fit into the available main memory. There have been several attempts to improve mergesort by reducing I/O time, since mergesort is I/O intensive. However, these methods assumed that mergesort runs on hard disk drives (HDDs). Flash-based solid state drives (SSDs) are emerging as next generation storage devices and becoming alternatives to HDDs. SSDs outperform HDDs in access latency, bec

Graphene oxide (GO) and its derivatives are promising metal-free heterogeneous catalysts due to their high surface area and rich chemical properties. We developed a bifunctional boron-doped sulfonated graphene oxide (BS-GO) and demonstrated its excellent catalytic conversion of glucose to 5-hydroxymethylfurfural (HMF) in a one-pot reaction. BS-GO afforded a high HMF yield of 36.0% from glucose without the use of additives or strong acids. Furthermore, the origin of the catalytic active sites of

Abstract Reversible thiol‐disulfide exchange chemistry is of particular interest in drug delivery systems. However, high levels of glutathione (GSH) in cancer cells are hard to distinguish from GSH in normal cells, resulting in unmanageable cytotoxic drug release. This study investigates the spatiotemporally‐controlled irreversible degradation of Ir‐based photosensitizer (TIr3)‐encapsulating nanogels (IrNG) through the hyperoxidation of resulting intracellular thiols using reactive oxygen specie

This paper proposes a nonlinear sliding mode observer for exhaust pressure estimation. A precise estimation of the exhaust pressure is important for the control of a variable geometry turbocharger (VGT) and exhaust gas recirculation (EGR) system. In order to estimate the exhaust pressure accurately, we derive nonlinear dynamic models of the intake and exhaust pressure in diesel engines based on the energy and mass conservation laws. The model parameters which vary with the engine operating condi

Wilderness monitoring tasks, such as poaching surveillance and forest fire detection, require pervasive and high-accuracy sensing. While AIoT offers a promising path, covering vast, inaccessible regions necessitates the massive deployment of maintenance-free, battery-less nodes with limited computational resources. However, these constraints create a critical 'Availability Gap.' Conventional intermittent operations prioritize computation throughput, forcing sensors to sleep during energy bufferi