Publications by authors named "UkJae Lee"

Although chimeric antigen receptor (CAR) T cell therapies have demonstrated promising clinical outcomes, durable remissions remain limited. To extend the efficacy of CAR T cells, we develop a CAR enhancer (CAR-E), comprising a CAR T cell antigen fused to an immunomodulatory molecule. Here we demonstrate this strategy using B cell maturation antigen (BCMA) CAR T cells for the treatment of multiple myeloma, with a CAR-E consisting of the BCMA fused to a low-affinity interleukin 2 (IL-2).

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  • T cells are essential for fighting tumors and clearing infected cells by recognizing specific targets through T-cell receptors (TCRs) that bind to pMHC molecules on these cells.
  • Current methods for creating pMHC molecules may miss important TCRs that target weaker, yet effective peptides, making personalized immunotherapy challenging.
  • A new method using sortase and click chemistry enables the stable generation of pMHC molecules, improving their binding to TCRs and offering a more effective approach to study and target antigen-specific T cells for cancer treatment.
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  • Tyrosinase-mediated protein conjugation is gaining interest for specific protein modifications, but existing enzymes only work on highly exposed tyrosine residues, limiting their effectiveness.
  • The newly discovered tyrosinase from Streptomyces avermitilis (SaTYR) shows significantly higher activity against surface tyrosine residues, with a flat substrate-binding pocket that accommodates protein substrates more effectively.
  • SaTYR enables successful tagging and modification of less accessible tyrosine residues with high efficiency (95.2% conjugation yield in 1 hour), suggesting it could broaden the range of applications in protein bioconjugation.
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  • Exposure to UV radiation causes skin damage by degrading the extracellular matrix and triggering inflammation, leading to melanin production for skin protection.
  • The study introduces a method to enhance skin protection using a combination of tyrosinase and single-walled carbon nanotubes (SWNT), capable of penetrating deep into the skin (about 300 μm).
  • Results show that SaTy-SWNT significantly increases melanin synthesis and UV absorption, effectively reducing inflammation and wrinkles by over 66%, showcasing its potential in tissue engineering.
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  • Polyphenols are bioactive compounds with therapeutic uses, and their effectiveness can be enhanced through hydroxylation and glycosylation, improving their bioavailability and stability.
  • The process of ortho-hydroxylation can be efficiently performed using the enzyme tyrosinase, while less common meta- and para-hydroxylation involves specific enzymes like cytochrome P450s.
  • O-glycosylation, which follows hydroxylation, typically needs NDP-sugar, but amylosucrase has shown promise for large-scale glycosylation of polyphenols without this requirement.
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Carbon-based nanomaterials, such as carbon nanotubes, fullerenes, nanodiamonds, and graphene, have been investigated for various biomedical applications, including biological imaging, photothermal therapy, drug/gene delivery, cancer therapy, biosensors, and electrochemical sensors. Graphene oxide (GO) has unique physicochemical properties and can be used to restore conductivity through oxidation. In this study, we developed poly(-isopropylacrylamide) (PNIPAM)-based nanogel systems containing GO for controlled drug delivery.

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Melanin nanoparticles (MNPs) used for biomedical applications are often synthesized the chemical auto-oxidation of catecholic monomers such as dopamine and 3,4-dihydroxyphenylalanine (DOPA) under alkaline conditions. However, the synthetic method for the chemical synthesis of MNP (cMNP) is relatively straightforward and more robust to control their homogenous particle size and morphology than the corresponding enzymatic synthetic methods. In this study, we demonstrated that the simple enzymatic synthesis of MNPs (eMNPs) with homogenous and soluble (<20 nm diameter) properties is possible using dopamine and tyrosinase (Ty) under acidic conditions (, pH 3.

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Several regiospecific enantiomers of hydroxy-()-equol (HE) were enzymatically synthesized from daidzein and genistein using consecutive reduction (four daidzein-to-equol-converting reductases) and oxidation (4-hydroxyphenylacetate 3-monooxygenase, HpaBC). Despite the natural occurrence of several HEs, most of them had not been studied owing to the lack of their preparation methods. Herein, the one-pot synthesis pathway of 6-hydroxyequol (6HE) was developed using HpaBC (HpaB) from and ()-equol-producing , previously developed by our group.

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Stimuli-responsive nanoparticles are favorable for improving the selective delivery and rational vocation that easily avoids the undesirable barriers or side effects, leading to a further improved therapeutic efficiency. Furthermore, multifunctional nanomaterials have been extensively developed as attractive candidates for theranostic reagents for cancer treatment. In this article, we developed reversibly pH-responsive gold nanoparticles (AuNPs) with an enhanced Raman scattering signal as well as an efficient photothermal effect and demonstrated their applications as a theranostic reagent for cancer treatment.

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Tyrosinase-mediated melanin synthesis is an essential biological process that can protect skin from UV radiation and radical species. This work reports on in situ biosynthesis of artificial melanin in native skin using photoactivatable tyrosinase (PaTy). The I41Y mutant of Streptomyces avermitilis tyrosinase (SaTy) shows enzymatic activity comparable to that of wild-type SaTy.

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Bio-based polyurethane (PU) has recently drawn our attention due to the increasing interest in sustainability and the risks involved with petroleum depletion. Herein, bio-based self-healing PU with a novel polyol, , eugenol glycol dimer (EGD), was synthesized and characterized for the first time. EGD was designed to have pairs of primary, secondary, and aromatic alcohols, which all are able to be involved in urethane bond formation and to show self-healing and antioxidant effects.

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Tyrosinase is generally known as a melanin-forming enzyme, facilitating monooxygenation of phenols, oxidation of catechols into quinones, and finally generating biological melanin. As a homologous form of tyrosinase in plants, plant polyphenol oxidases perform the same oxidation reactions specifically toward plant polyphenols. Recent studies reported synthetic strategies for large scale preparation of hydroxylated plant polyphenols, using bacterial tyrosinases rather than plant polyphenol oxidase or other monooxygenases, by leveraging its robust monophenolase activity and broad substrate specificity.

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Pancreatic β cell therapy for type 1 diabetes is limited by low cell survival rate owing to physical stress and aggressive host immune response. In this study, we demonstrate a multilayer hydrogel nanofilm caging strategy capable of protecting cells from high shear stress and reducing immune response by interfering cell-cell interaction. Hydrogel nanofilm is fabricated by monophenol-modified glycol chitosan and hyaluronic acid that cross-link each other to form a nanothin hydrogel film on the cell surface via tyrosinase-mediated reactions.

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Post-growth graphene transfer to a variety of host substrates for circuitry fabrication has been among the most popular subjects since its successful development via chemical vapor deposition in the past decade. Fast and reliable evaluation tools for its morphological characteristics are essential for the development of defect-free transfer protocols. The implementation of conventional techniques, such as Raman spectroscopy, atomic force microscopy (AFM), and transmission electron microscopy in production quality control at an industrial scale is difficult because they are limited to local areas, are time consuming, and their operation is complex.

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Epigallocatechin gallates (EGCGs), isolated from green tea, have intrinsic properties such as anti-oxidant, anti-inflammation, and radical scavenger effects. In this study, we report a tissue adhesive and anti-inflammatory hydrogel formed by high-affinity enzymatic crosslinking of polyphenolic EGCGs. A mixture of EGCG conjugated hyaluronic acids (HA_E) and tyramine conjugated hyaluronic acids (HA_T) was reacted with tyrosinase isolated from Streptomyces avermitillis (SA_Ty) to form that displayed fast enzyme kinetic to form a crosslinked adhesive hydrogel.

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The enhanced growth of Cu oxides underneath graphene grown on a Cu substrate has been of great interest to many groups. In this work, the strain and doping status of graphene, based on the gradual growth of Cu oxides from underneath, were systematically studied using time evolution Raman spectroscopy. The compressive strain to graphene, due to the thermal expansion coefficient difference between graphene and the Cu substrate, was almost released by the nonuniform CuO growth; however, slight tensile strain was exerted.

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A nuclear environment, including decommissioning activity contains various radioactive nuclides such as pure beta emitters. These radionuclides should be monitored to ensure radiological safety. In particular, beta radionuclides, such as H and C, can cause internal exposures and should be managed more strictly in terms of health physics.

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In heavy water reactors, radionuclides are generated, then removed and treated by ion exchange resin. The disposal cost of spent resin is expected to increase because of the saturation of the existing storage capacity. In this study, a spent resin treatment process using microwaves is proposed, and a radiological safety assessment and cost evaluation of the spent resin treatment process are performed.

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The metal/graphene interface has been one of the most important research topics with regard to charge screening, charge transfer, contact resistance, and solar cells. Chemical bond formation of metal and graphene can be deduced from the defect induced D-band and its second-order mode, 2D band, measured by Raman spectroscopy, as a simple and nondestructive method. However, a phonon mode located at ∼1350 cm, which is normally known as the defect-induced D-band, is intriguing for graphene deposited with noble metals (Ag, Au, and Cu).

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Soy isoflavones are naturally occurring phytochemicals, which are biotransformed into functional derivatives through oxidative and reductive metabolic pathways of diverse microorganisms. Such representative derivatives, ortho-dihydroxyisoflavones (ODIs) and equols, have attracted great attention for their versatile health benefits since they were found from soybean fermented foods and human intestinal fluids. Recently, scientists in food technology, nutrition and microbiology began to understand their correct biosynthetic pathways and nutraceutical values, and have attempted to produce the valuable bioactive compounds using microbial fermentation and whole-cell/enzyme-based biotransformation.

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An on-site, rapid, measurement-based, radiation-distribution visualization system with radionuclide recognition was developed for quick decision making during a radiation emergency. After scanning of the area was complete, radionuclide-specific radiation-distribution contours were displayed in two and three dimensions on a map of the measurement area, in a few tens of seconds, by clicking once on an execution file, which was programmed using MathWorks' MATLAB software. The contours were fundamentally verified using Cs and Co standard sources.

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Graphene derivatives are known to be suitable for biomedical applications, especially for stem cell-based therapies. Herein, we report the size effects of graphene oxide (GO) on differentiation of human adipose-derived mesenchymal stem cells (hADMSCs), using micro-sized (MGO) and nano-sized graphene oxide (NGO) sheets. The MGO and NGO sheets having lateral sizes of 1-10 μm and 100-300 nm, respectively, are coated on glass substrates by drop casting.

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This study presents a real-time measurement-based rapid radiation distribution visualization system for radionuclide recognition, which can quickly scan a contaminated environment. The system combines a portable detector with a digital map and a program for quick data treatment. Radiation information at the measurement location is transferred between a detector and a laptop.

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