Publications by authors named "Young Geon Kim"

6 Publications

  • Page 1 of 1

Effect of polystyrene nanoplastics and their degraded forms on stem cell fate.

J Hazard Mater 2022 05 2;430:128411. Epub 2022 Feb 2.

School of Chemical Engineering, Sungkyunkwan University, Suwon 16419, Republic of Korea. Electronic address:

Several studies have examined the effects of micro- and nanoplastics on microbes, cells, and the environment. However, only a few studies have examined their effects-especially, those of their reduced cohesiveness-on cell viability and physiology. We synthesized surfactant-free amine-functionalized polystyrene (PS) nanoparticles (NPs) and PS-NPs with decreased crosslinking density (DPS-NPs) without changing other factors, such as size, shape, and zeta potential and examined their effects on cell viability and physiology. PS- and DPS-NPs exhibited reactive oxygen species (ROS) scavenging activity by upregulating GPX3 expression and downregulating HSP70 (ROS-related gene) and XBP1 (endoplasmic reticulum stress-related gene) expression in human bone marrow-derived mesenchymal stem cells (hBM-MSCs). Additionally, they led to upregulation of MFN2 (mitochondrial fusion related gene) expression and downregulation of FIS1 (mitochondrial fission related gene) expression, indicating enhanced mitochondrial fusion in hBM-MSCs. Cell-cycle analysis revealed that PS- and DPS-NPs increased the proportion of cells in the S phase, indicating that they promoted cell proliferation and, specifically, the adipogenic differentiation of hBM-MSCs. However, the cytotoxicity of DPS-NPs against hBM-MSCs was higher than that of PS-NPs after long-term treatment under adipogenic conditions.
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http://dx.doi.org/10.1016/j.jhazmat.2022.128411DOI Listing
May 2022

Enhanced Chemodynamic Therapy by Cu-Fe Peroxide Nanoparticles: Tumor Microenvironment-Mediated Synergistic Fenton Reaction.

ACS Nano 2022 02 26;16(2):2535-2545. Epub 2022 Jan 26.

Center for Nanoparticle Research, Institute for Basic Science (IBS), Seoul 08826, Republic of Korea.

An urgent need in chemodynamic therapy (CDT) is to achieve high Fenton catalytic efficiency at small doses of CDT agents. However, simple general promotion of the Fenton reaction increases the risk of damaging normal cells along with the cancer cells. Therefore, a tailored strategy to selectively enhance the Fenton reactivity in tumors, for example, by taking advantage of the characteristics of the tumor microenvironment (TME), is in high demand. Herein, a heterogeneous CDT system based on copper-iron peroxide nanoparticles (CFp NPs) is designed for TME-mediated synergistic therapy. CFp NPs degrade under the mildly acidic conditions of TME, self-supply HO, and the released Cu and Fe ions, with their larger portions at lower oxidation states, cooperatively facilitate hydroxyl radical production through a highly efficient catalytic loop to achieve an excellent tumor therapeutic efficacy. This is distinct from previous heterogeneous CDT systems in that the synergism is closely coupled with the Cu-assisted conversion of Fe to Fe rather than their independent actions. As a result, almost complete ablation of tumors at a minimal treatment dose is demonstrated without the aid of any other therapeutic modality. Furthermore, CFp NPs generate O during the catalysis and exhibit a TME-responsive T magnetic resonance imaging contrast enhancement, which are useful for alleviating hypoxia and monitoring of tumors, respectively.
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http://dx.doi.org/10.1021/acsnano.1c09171DOI Listing
February 2022

In Vivo Sol-Gel Reaction of Tantalum Alkoxide for Endovascular Embolization.

Adv Healthc Mater 2022 02 23;11(4):e2101908. Epub 2021 Nov 23.

Center for Nanoparticle Research, Institute for Basic Science (IBS), Seoul, 08826, Republic of Korea.

Liquid embolic agents are considered the most promising for various embolization procedures because they enable deep penetration. For realizing effective procedures, the delivery of liquid embolic agents should be guided under X-ray imaging systems and the solidification time should be optimized for the specific indication. The biocompatibility of embolic agents is also crucial because they remain in the vessel after embolization. In this study, new biocompatible embolic agents based on tantalum ethoxide is synthesized. Tantalum alkoxide liquid embolics (TALE) possess the radiopacity for fluoroscopy and can control the penetration depth by modifying the sol-gel kinetics. Furthermore, TALE can serve as drug carriers for synergistic treatment. Using these excellent characteristics, it is demonstrated that TALE agents can be used in various situations including the transarterial chemoembolization of hepatocellular carcinoma and embolotherapy of massive bleeding from the femoral artery.
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http://dx.doi.org/10.1002/adhm.202101908DOI Listing
February 2022

Elastic Photonic Microcapsules Containing Colloidal Crystallites as Building Blocks for Macroscopic Photonic Surfaces.

ACS Nano 2021 May 14. Epub 2021 May 14.

Department of Chemical and Biomolecular Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, Republic of Korea.

Colloidal crystals develop structural colors through wavelength-selective diffraction. Recently, a granular format of colloidal crystals has emerged as building blocks to construct macroscopic photonic surfaces or architectures with high reconfigurability through the secondary assembly. Here, we design elastic photonic microcapsules containing colloidal crystallites along the inner wall as a building block. Water-in-oil-in-water double-emulsion templates are microfluidically prepared to have an aqueous dispersion of polystyrene particles in the inner droplet and polydimethylsiloxane prepolymers in the shell. Colloidal particles are enriched in the presence of depletant and salt by osmotic compression, with the crystallization at the inner interface by depletion attraction. The number of nucleation sites depends on the rate of the enrichment, which enables control over the size and surface coverage of the crystallites with osmotic conditions. The enrichment is ceased by transferring the droplets into an isotonic solution, and the oil shell is cured to form an elastic membrane. As the elastic microcapsules have a large void in the core, they are deformable without structural damage in the crystallites. Therefore, the microcapsules can be closely packed to form macroscopic surfaces while achieving a high quality of structural colors with a collection of crystallites aligned along the flattened membrane.
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http://dx.doi.org/10.1021/acsnano.1c02000DOI Listing
May 2021

Ceria Nanoparticle Systems for Selective Scavenging of Mitochondrial, Intracellular, and Extracellular Reactive Oxygen Species in Parkinson's Disease.

Angew Chem Int Ed Engl 2018 07 22;57(30):9408-9412. Epub 2018 Jun 22.

Center for Nanoparticle Research, Institute for Basic Science (IBS), Seoul, 08826, Republic of Korea.

Oxidative stress induced by reactive oxygen species (ROS) is one of the critical factors that involves in the pathogenesis and progression of many diseases. However, lack of proper techniques to scavenge ROS depending on their cellular localization limits a thorough understanding of the pathological effects of ROS. Here, we demonstrate the selective scavenging of mitochondrial, intracellular, and extracellular ROS using three different types of ceria nanoparticles (NPs), and its application to treat Parkinson's disease (PD). Our data show that scavenging intracellular or mitochondrial ROS inhibits the microglial activation and lipid peroxidation, while protecting the tyrosine hydroxylase (TH) in the striata of PD model mice. These results indicate the essential roles of intracellular and mitochondrial ROS in the progression of PD. We anticipate that our ceria NP systems will serve as a useful tool for elucidating the functions of various ROS in diseases.
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http://dx.doi.org/10.1002/anie.201805052DOI Listing
July 2018

Association between blood glucose level derived using the oral glucose tolerance test and glycated hemoglobin level.

Korean J Intern Med 2016 May 22;31(3):535-42. Epub 2016 Feb 22.

Department of Endocrinology and Metabolism, Ajou University School of Medicine, Suwon, Korea.

Background/aims: Glycated hemoglobin (HbA1c) is widely used as a marker of glycemic control. Translation of the HbA1c level to an average blood glucose level is useful because the latter figure is easily understood by patients. We studied the association between blood glucose levels revealed by the oral glucose tolerance test (OGTT) and HbA1c levels in a Korean population.

Methods: A total of 1,000 subjects aged 30 to 64 years from the Cardiovascular and Metabolic Diseases Etiology Research Center cohort were included. Fasting glucose levels, post-load glucose levels at 30, 60, and 120 minutes into the OGTT, and HbA1c levels were measured.

Results: Linear regression of HbA1c with mean blood glucose levels derived using the OGTT revealed a significant correlation between these measures (predicted mean glucose [mg/dL] = 49.4 × HbA1c [%] - 149.6; R (2) = 0.54, p < 0.001). Our linear regression equation was quite different from that of the Alc-Derived Average Glucose (ADAG) study and Diabetes Control and Complications Trial (DCCT) cohort.

Conclusions: Discrepancies between our results and those of the ADAG study and DCCT cohort may be attributable to differences in the test methods used and the extent of insulin secretion. More studies are needed to evaluate the association between HbA1c and self monitoring blood glucose levels.
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http://dx.doi.org/10.3904/kjim.2015.075DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4855099PMC
May 2016
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