Publications by authors named "Youngwon Ju"

Three types of carbon dots (CDs) are synthesized from isomers of phenylenediamine to develop multicolor nanomaterials with low toxicity, high stability, and high quantum yield. The distinctive electronic structures of CDs lead to the characteristic optical transitions, such as three colors of blue, green, and red, which are primarily attributed to the difference in configurations, despite the similar basic structures of conjugated systems. The excitation-independent emission and the single exponential decay of CDs indicate the single chromophore-like nature in each type of CD.

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Nanozymes are nanostructure-based materials which mimic the enzymatic characteristics of natural enzymes. Biological applications of nanozymes have been highlighted in basic research, industry, and translational medicine as a new cutting-edge tool. In this work, and for the first time, we disclose a tumor alleviation property of a nanozyme that is made up of amine-terminated sixth-generation polyamidoamine dendrimers with encapsulated tiny platinum nanoparticles.

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Article Synopsis
  • Researchers utilized 3-D electron tomography to create a detailed 3-D visualization of dendrimer-encapsulated platinum (Pt) nanoparticles, highlighting the complex structure of these hybrid nanostructures.
  • The 3-D reconstruction involved analyzing a series of 2-D images of the Pt nanoparticles that were encapsulated inside dendrimers and negatively stained, providing insight into their encapsulation characteristics.
  • Additional experiments confirmed these characteristics, and the 3-D analysis yielded more accurate size distribution data for the Pt nanoparticles compared to traditional 2-D imaging methods.
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Herein, we report the functional decoration of single-walled carbon nanotubes (swCNTs) with Pt dendrimer-encapsulated nanoparticles (Pt DENs) (dia. (1.78 ± 0.

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The majority of human gut microbiome is comprised of obligate anaerobic bacteria that exert essential metabolic functions in the human colon. These anaerobic gut bacteria constantly crosstalk with the colonic epithelium in a mucosal anoxic-oxic interface (AOI). However, recreation of the metabolically mismatched colonic AOI has been technically challenging.

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Although the deposition of metallic domains on a preformed semiconductor nanocrystal provides an effective pathway to access diverse hybrid nanocrystals with synergistic metal/semiconductor heterojunction interface, those reactions that take place on the surface of semiconductor nanoscrystals have not been investigated thoroughly, because of the impediments caused by the surface-capping organic surfactants. By exploiting the interfacial reactions occurring between the solution and nanoparticles confined with the cavities of hollow nanoparticles, we propose a novel nanospace-confined strategy for assessing the innate reactivity of surfaces of inorganic semiconductor nanoparticles. This strategy was adopted to investigate the newly discovered process of spontaneous Pt deposition on InO nanocrystals.

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Here, we report the size-dependent catalysis of Pt dendrimer-encapsulated nanoparticles (DENs) having well-defined sizes over the range of 1-3 nm with subnanometer accuracy for the highly enhanced chemiluminescence of the luminol/H2O2 system. This size-dependent catalysis is ascribed to the differences in the chemical states of the Pt DENs as well as in their surface areas depending on their sizes. Facile and versatile applications of the Pt DENs in diverse oxidase-based assays are demonstrated as efficient catalysts for sensitive chemiluminescence-based analyses.

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We demonstrate the feasible use of Pt nanoparticles encapsulated inside amine-terminated fourth-generation polyamidoamine dendrimers as peroxidase-mimetic labels for sensitive colorimetric assays. This was performed by utilizing intrinsic dual functionalities of the dendrimer-encapsulated Pt nanoparticles, i.e.

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We report the electrochemical grafting of amine-terminated dendrimers encapsulating nanoparticles onto indium tin oxide (ITO) surfaces.

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