Publications by authors named "Tae-Geol Lee"

The safety screening of manufactured nanomaterials (MNMs) is essential for their adoption by consumers and the marketplace. Lately, animal-based testing has been replaced by mechanistically informative in vitro assays due to the requirements of regulatory agencies. Cell viability assays are widely employed for manufactured nanomaterial hazard screening as a first-tier approach.

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The prospective use of food additive titanium dioxide (E171 TiO) in a variety of fields (food, pharmaceutics, and cosmetics) prompts proper cellular cytotoxicity and transcriptomic assessment. Interestingly, smaller-sized E171 TiO can translocate in bloodstream and induce a diverse immunological response by activating the immune system, which can be either pro-inflammatory or immune-suppressive. Nevertheless, their cellular or immunologic responses in a heterogeneous population of the immune system following exposure of food additive E171 TiO is yet to be elucidated.

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  • - The study addresses the limitations of using undefined basement membrane extracts like Matrigel for cultivating intestinal stem cells (ISCs) by introducing a new xenogeneic-free culture dish called XF-DISC.
  • - XF-DISC significantly increases the growth and maintenance of ISCs, achieving a 24-fold cell number increase within 30 days and sustaining viability over 210 days (30 passages).
  • - This method allows for successful transplantation of cultured human ISCs into mouse models with intestinal injuries, fostering tissue regeneration, making it a promising approach for effective ISC therapy in human intestinal diseases.
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  • This study used time-of-flight secondary ion mass spectrometry (ToF-SIMS) data along with machine learning to classify six different types of plastics.* -
  • The research involved preprocessing measurement data by identifying local maxima, then applying several machine learning techniques, including ensemble analysis with decision trees and gradient boosting.* -
  • The methods employed also included principal component analysis for data visualization, enabling better understanding of the features that differentiate each plastic type and their chemical properties.*
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  • The study focuses on characterizing protein coronas formed on multi-walled carbon nanotubes (MWCNTs) coated with bovine serum albumin (BSA) to improve nanomedicine safety and efficiency.
  • It was found that varying BSA pretreatment concentrations affect cellular uptake rates and induce different biological responses in A549 cells, with significant findings revealed through advanced spectroscopic and spectrometric analyses.
  • Key findings include changes in the composition ratio of proteins based on BSA concentration, an increase in α-helix structure with higher BSA levels, and the activation of distinct biological pathways at different BSA concentrations, highlighting the important link between nano/bio-interface and cellular responses.
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With the growing prevalence of plastic use, the environmental release of plastic waste is escalating, and fragmented nanoscale plastic particles are emerging as significant environmental threats. This study aimed to evaluate the cytotoxic effects of fragmented polyethylene nanoplastics (PE NPs) manufactured using a focused ultrasonic system. The ultrasonic irradiation process generated fragmented PE NPs with a geometric mean diameter of 85.

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Human pluripotent stem cells (hPSCs), encompassing human embryonic stem cells (hESCs) and human induced pluripotent stem cells (hiPSCs), hold immense potential in regenerative medicine, offering new opportunities for personalized cell therapies. However, their clinical translation is hindered by the inevitable reliance on xenogeneic components in culture environments. This study addresses this challenge by engineering a fully synthetic, xeno-free culture substrate, whose surface composition is tailored systematically for xeno-free culture of hPSCs.

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Intravitreal injection of biodegradable implant drug carriers shows promise in reducing the injection frequency for neovascular retinal diseases. However, current intravitreal ocular devices have limitations in adjusting drug release rates for individual patients, thereby affecting treatment effectiveness. Accordingly, we developed mesoporous silica nanoparticles (MSNs) featuring a surface that reverse its charge in response to reactive oxygen species (ROS) for efficient delivery of humanin peptide (HN) to retinal epithelial cells (ARPE-19).

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This study investigates the applicability of six transition metal dichalcogenides to efficient therapeutic drug monitoring of ten antiepileptic drugs using laser desorption/ionization-mass spectrometry. We found that molybdenum ditelluride and tungsten ditelluride are suitable for the sensitive quantification of therapeutic drugs. The contribution of tellurium to the enhanced efficiency of laser desorption ionization was validated through theoretical calculations utilizing an integrated model that incorporates transition-metal dichalcogenides and antiepileptic drugs.

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Cerium oxide nanoparticles (CeO NPs, NM-212) are well-known for their catalytic properties and antioxidant potential, and have many applications in various industries, drug delivery, and cosmetic formulations. CeO NPs exhibit strong antimicrobial activity and can be used to efficiently remove pathogens from different environments. However, knowledge of the toxicological evaluation of CeO NPs is too limited to support their safe use.

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vascularized cancer models utilizing microfluidics have emerged as a promising tool for mechanism study and drug screening. However, the lack of consideration and preparation methods for cancer cellular sources that are capable of adequately replicating the metastatic features of circulating tumor cells contributed to low relevancy with experimental results. Here, we show that the properties of cancer cellular sources have a considerable impact on the validity of the metastasis model.

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ViSiON (visualization materials composed of silicon-based optical nanodisks) is presented, which offers a unique optical combination of near-infrared (NIR) optical properties and biodegradability. Initially, numerical simulations are conducted to calculate the total extinction and scattering effects of ViSiON by the diameter-to-thickness ratio, predicting precise control over its scattering properties in the NIR region. A top-down patterning technique is employed to synthesize ViSiON with accurate diameter and thickness control.

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  • The rising use of nanomaterials has sparked concerns about their safety, leading to the exploration of organoids for testing their toxicity.
  • Traditional organoid systems face challenges, such as uneven sizes and limited nanoparticle penetration due to the extracellular matrix.
  • A new 3D floating organoid system has been developed, enhancing uniformity and structural integrity, which improves nanoparticle internalization and offers a better method for assessing the safety of nanomaterials.
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Lipid alterations in the brain are well-documented in disease and aging, but our understanding of their pathogenic implications remains incomplete. Recent technological advances in assessing lipid profiles have enabled us to intricately examine the spatiotemporal variations in lipid compositions within the complex brain characterized by diverse cell types and intricate neural networks. In this study, we coupled time-of-flight secondary ion mass spectrometry (ToF-SIMS) to an amyotrophic lateral sclerosis (ALS) model, for the first time, to elucidate changes in the lipid landscape and investigate their potential role in the disease process, serving as a methodological and analytical complement to our prior approach that utilized matrix-assisted laser desorption/ionization mass spectrometry.

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The need exists for biosensing technologies capable of sensitively and accurately detecting various biomarkers. In response, the development of nanozymes is actively underway; they have advantages in stability, cost, performance, and functionalization over natural enzymes commonly used for signal amplification in sensing technologies. However, the performance of nanozymes is interdependent with factors such as shape, size, and surface functional moiety, making it challenging to perform quantitative performance comparisons based on the nanozyme material.

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Background: Fibrosis plays an important role in both normal physiological and pathological phenomena as fibroblasts differentiate to myofibroblasts. The activation of fibroblasts is determined through interactions with the surrounding extracellular matrix (ECM). However, how this fibroblast-to-myofibroblast transition (FMT) is regulated and affected by elastin concentration in a three-dimensional (3D) microenvironment has not been investigated.

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This study demonstrated the potential of 50 nm PEGylated Si NPs for high-resolution Si MR imaging, emphasizing their biocompatibility and water dispersibility. The acquisition of Si MR images using the lowest reported dose after subcutaneous and intraperitoneal administration opens new avenues for future Si MR studies.

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We present an integrating hemisphere-based (i.e., a variant of integrating spheres) implementation of the indirect illumination method for absolute photoluminescence quantum yield measurements, which is a recommended method in the international standard IEC 62607-3-1:2014.

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In the study of degenerative brain diseases, changes in lipids, the main component of neurons, are particularly important because they are used as indicators of pathological changes. One method for the sensitive measurement of biomolecules, especially lipids, is time-of-flight secondary ion mass spectrometry (ToF-SIMS) using pulsed argon cluster ions. In this study, biomolecules including various lipids present in normal mouse brain tissue were measured using ToF-SIMS equipped with pulsed argon cluster primary ions.

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  • * The study investigates phospholipid distribution in the brains of valproic acid-induced autistic mice using advanced imaging techniques, finding differences in phospholipid profiles between autistic and control mice.
  • * Key phospholipids identified are critical for cell signaling and brain growth, and understanding these differences may shed light on lipid metabolism changes related to autism spectrum disorder (ASD).
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  • A new International Standard (ISO 20814:2019) for testing the photocatalytic activity of nanomaterials has been released by ISO's Technical Committee 229.
  • The standard introduces a high throughput assay that uses a bio-compatible indicator, NAD, to assess the effectiveness and phototoxicity of nanoparticles.
  • The paper details the measurement principles, the scope of the standard, and the validation process through interlaboratory comparison using a standard reference material (SRM 1898).
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TiO is the most commonly used photocatalyst in water treatment. The particle size of TiO is an important factor that significantly influences its activity during photocatalytic degradation. In the presence of liquid, the properties of nanopowders composed of exactly the same product clearly differ according to their aggregation size.

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Cerium dioxide nanoparticles (CeONPs) have been extensively applied in research for future energy development due to two common oxidation states on their surface. Considering that shape (aspect ratio) is a key determinant of NPs-induced toxicity, we compared the toxicity of hexagonal (H)- and rod-shaped (R)-CeONPs in mice. At 24 h after pharyngeal aspiration, both types of CeONPs recruited surrounding immune cells (monocytes and neutrophils) into the lung, and R-CeONPs induced a more severe pulmonary inflammatory response compared with H-CeONPs.

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Retinal pigment epithelium (RPE) damage is a major factor in age-related macular degeneration (AMD). The RPE in AMD shows mitochondrial dysfunction suggesting an association of AMD with mitochondrial function. Therefore, exogenous mitochondrial transplantation for restoring and replacing dysfunctional mitochondria may be an effective therapeutic strategy for AMD.

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African swine fever virus (ASFV) causes a highly contagious and fatal disease affecting both domesticated and wild pigs. Substandard therapies and inadequate vaccinations cause severe economic damages from pig culling and removal of infected carcasses. Therefore, there is an urgent need to develop a rapid point-of-use approach that assists in avoiding the spread of ASFV and reducing economic loss.

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