Publications by authors named "Sang Ihn Han"

11 Publications

  • Page 1 of 1

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

Highly conductive and elastic nanomembrane for skin electronics.

Science 2021 08;373(6558):1022-1026

School of Mechanical Engineering, Pusan National University, Busan 46241, Republic of Korea.

Skin electronics require stretchable conductors that satisfy metallike conductivity, high stretchability, ultrathin thickness, and facile patternability, but achieving these characteristics simultaneously is challenging. We present a float assembly method to fabricate a nanomembrane that meets all these requirements. The method enables a compact assembly of nanomaterials at the water-oil interface and their partial embedment in an ultrathin elastomer membrane, which can distribute the applied strain in the elastomer membrane and thus lead to a high elasticity even with the high loading of the nanomaterials. Furthermore, the structure allows cold welding and bilayer stacking, resulting in high conductivity. These properties are preserved even after high-resolution patterning by using photolithography. A multifunctional epidermal sensor array can be fabricated with the patterned nanomembranes.
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http://dx.doi.org/10.1126/science.abh4357DOI Listing
August 2021

Durable and Fatigue-Resistant Soft Peripheral Neuroprosthetics for In Vivo Bidirectional Signaling.

Adv Mater 2021 May 19;33(20):e2007346. Epub 2021 Mar 19.

Department of Electrical and Computer Engineering, Sungkyunkwan University, Suwon, 16419, Republic of Korea.

Soft neuroprosthetics that monitor signals from sensory neurons and deliver motor information can potentially replace damaged nerves. However, achieving long-term stability of devices interfacing peripheral nerves is challenging, since dynamic mechanical deformations in peripheral nerves cause material degradation in devices. Here, a durable and fatigue-resistant soft neuroprosthetic device is reported for bidirectional signaling on peripheral nerves. The neuroprosthetic device is made of a nanocomposite of gold nanoshell (AuNS)-coated silver (Ag) flakes dispersed in a tough, stretchable, and self-healing polymer (SHP). The dynamic self-healing property of the nanocomposite allows the percolation network of AuNS-coated flakes to rebuild after degradation. Therefore, its degraded electrical and mechanical performance by repetitive, irregular, and intense deformations at the device-nerve interface can be spontaneously self-recovered. When the device is implanted on a rat sciatic nerve, stable bidirectional signaling is obtained for over 5 weeks. Neural signals collected from a live walking rat using these neuroprosthetics are analyzed by a deep neural network to predict the joint position precisely. This result demonstrates that durable soft neuroprosthetics can facilitate collection and analysis of large-sized in vivo data for solving challenges in neurological disorders.
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http://dx.doi.org/10.1002/adma.202007346DOI Listing
May 2021

Epitaxially Strained CeO /Mn O Nanocrystals as an Enhanced Antioxidant for Radioprotection.

Adv Mater 2020 Aug 10;32(31):e2001566. Epub 2020 Jun 10.

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

Nanomaterials with antioxidant properties are promising for treating reactive oxygen species (ROS)-related diseases. However, maintaining efficacy at low doses to minimize toxicity is a critical for clinical applications. Tuning the surface strain of metallic nanoparticles can enhance catalytic reactivity, which has rarely been demonstrated in metal oxide nanomaterials. Here, it is shown that inducing surface strains of CeO /Mn O nanocrystals produces highly catalytic antioxidants that can protect tissue-resident stem cells from irradiation-induced ROS damage. Manganese ions deposited on the surface of cerium oxide (CeO ) nanocrystals form strained layers of manganese oxide (Mn O ) islands, increasing the number of oxygen vacancies. CeO /Mn O nanocrystals show better catalytic activity than CeO or Mn O alone and can protect the regenerative capabilities of intestinal stem cells in an organoid model after a lethal dose of irradiation. A small amount of the nanocrystals prevents acute radiation syndrome and increases the survival rate of mice treated with a lethal dose of total body irradiation.
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http://dx.doi.org/10.1002/adma.202001566DOI Listing
August 2020

Highly selective microglial uptake of ceria-zirconia nanoparticles for enhanced analgesic treatment of neuropathic pain.

Nanoscale 2019 Oct;11(41):19437-19447

Department of Neuroscience and Physiology, Dental Research Institute, School of Dentistry, Seoul National University, Seoul 08826, Republic of Korea.

Neuropathic pain is a chronic and pathological pain caused by injury or dysfunction in the nervous system. Pro-inflammatory microglial activation with aberrant reactive oxygen species (ROS) generation in the spinal cord plays a critical role in the development of neuropathic pain. However, the efficacy of current therapeutic methods for neuropathic pain is limited because only neurons or neural circuits involved in pain transmission are targeted. Here, an effective strategy to treat pain hypersensitivity using microglia-targeting ceria-zirconia nanoparticles (CZ NPs) is reported. The CZ NPs are coated with microglia-specific antibodies to promote their delivery to microglia, and thus to improve their therapeutic efficacy. The targeted delivery facilitates the elimination of both pro-inflammatory cytokines and ROS in microglia, enabling the rapid and effective inhibition of microglial activation. As a result, greatly ameliorated mechanical allodynia is achieved in a spinal nerve transection (SNT)-induced neuropathic pain mouse model, proving the potent analgesic effect of the microglia-targeting CZ NPs. Given the generality of the approach used in this study, the microglia-targeting CZ NPs are expected to be useful for the treatment of not only neuropathic pain but also other neurological diseases associated with the vicious activation of microglia.
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http://dx.doi.org/10.1039/c9nr02648gDOI Listing
October 2019

High-performance stretchable conductive nanocomposites: materials, processes, and device applications.

Chem Soc Rev 2019 Mar;48(6):1566-1595

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

Highly conductive and intrinsically stretchable electrodes are vital components of soft electronics such as stretchable transistors and circuits, sensors and actuators, light-emitting diode arrays, and energy harvesting devices. Many kinds of conducting nanomaterials with outstanding electrical and mechanical properties have been integrated with elastomers to produce stretchable conductive nanocomposites. Understanding the characteristics of these nanocomposites and assessing the feasibility of their fabrication are therefore critical for the development of high-performance stretchable conductors and electronic devices. We herein summarise the recent advances in stretchable conductors based on the percolation networks of nanoscale conductive fillers in elastomeric media. After discussing the material-, dimension-, and size-dependent properties of conductive fillers and their implications, we highlight various techniques that are used to reduce the contact resistance between the conductive filler materials. Furthermore, we categorize elastomer matrices with different stretchabilities and mechanical properties based on their polymeric chain structures. Then, we discuss the fabrication techniques of stretchable conductive nanocomposites toward their use in soft electronics. Finally, we provide representative examples of stretchable device applications and conclude the review with a brief outlook for future research.
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http://dx.doi.org/10.1039/c8cs00706cDOI Listing
March 2019

Highly conductive, stretchable and biocompatible Ag-Au core-sheath nanowire composite for wearable and implantable bioelectronics.

Nat Nanotechnol 2018 11 13;13(11):1048-1056. Epub 2018 Aug 13.

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

Wearable and implantable devices require conductive, stretchable and biocompatible materials. However, obtaining composites that simultaneously fulfil these requirements is challenging due to a trade-off between conductivity and stretchability. Here, we report on Ag-Au nanocomposites composed of ultralong gold-coated silver nanowires in an elastomeric block-copolymer matrix. Owing to the high aspect ratio and percolation network of the Ag-Au nanowires, the nanocomposites exhibit an optimized conductivity of 41,850 S cm (maximum of 72,600 S cm). Phase separation in the Ag-Au nanocomposite during the solvent-drying process generates a microstructure that yields an optimized stretchability of 266% (maximum of 840%). The thick gold sheath deposited on the silver nanowire surface prevents oxidation and silver ion leaching, making the composite biocompatible and highly conductive. Using the nanocomposite, we successfully fabricate wearable and implantable soft bioelectronic devices that can be conformally integrated with human skin and swine heart for continuous electrophysiological recording, and electrical and thermal stimulation.
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http://dx.doi.org/10.1038/s41565-018-0226-8DOI Listing
November 2018

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

Multiplexible Wash-Free Immunoassay Using Colloidal Assemblies of Magnetic and Photoluminescent Nanoparticles.

ACS Nano 2017 08 11;11(8):8448-8455. Epub 2017 Aug 11.

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

Colloidal assemblies of nanoparticles possess both the intrinsic and collective properties of their constituent nanoparticles, which are useful in applications where ordinary nanoparticles are not well suited. Here, we report an immunoassay technique based on colloidal nanoparticle assemblies made of iron oxide nanoparticles (magnetic substrate) and manganese-doped zinc sulfide (ZnS:Mn) nanoparticles (photoluminescent substrate), both of which are functionalized with antibodies to capture target proteins in a sandwich assay format. After magnetic isolation of the iron oxide nanoparticle assemblies and their bound ZnS:Mn nanoparticle assemblies (MZSNAs), photoluminescence of the remaining MZSNAs is measured for the protein quantification, eliminating the need for washing steps and signal amplification. Using human C-reactive protein as a model biomarker, we achieve a detection limit of as low as 0.7 pg/mL, which is more than 1 order of magnitude lower than that of enzyme-linked immunosorbent assay (9.1 pg/mL) performed using the same pair of antibodies, while using only one-tenth of the antibodies. We also confirm the potential for multiplex detection by using two different types of photoluminescent colloidal nanoparticle assemblies simultaneously.
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http://dx.doi.org/10.1021/acsnano.7b04088DOI Listing
August 2017

Multifunctional nanoparticles as a tissue adhesive and an injectable marker for image-guided procedures.

Nat Commun 2017 07 19;8:15807. Epub 2017 Jul 19.

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

Tissue adhesives have emerged as an alternative to sutures and staples for wound closure and reconnection of injured tissues after surgery or trauma. Owing to their convenience and effectiveness, these adhesives have received growing attention particularly in minimally invasive procedures. For safe and accurate applications, tissue adhesives should be detectable via clinical imaging modalities and be highly biocompatible for intracorporeal procedures. However, few adhesives meet all these requirements. Herein, we show that biocompatible tantalum oxide/silica core/shell nanoparticles (TSNs) exhibit not only high contrast effects for real-time imaging but also strong adhesive properties. Furthermore, the biocompatible TSNs cause much less cellular toxicity and less inflammation than a clinically used, imageable tissue adhesive (that is, a mixture of cyanoacrylate and Lipiodol). Because of their multifunctional imaging and adhesive property, the TSNs are successfully applied as a hemostatic adhesive for minimally invasive procedures and as an immobilized marker for image-guided procedures.
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http://dx.doi.org/10.1038/ncomms15807DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5524935PMC
July 2017

Magnetically recyclable hollow nanocomposite catalysts for heterogeneous reduction of nitroarenes and Suzuki reactions.

Chem Commun (Camb) 2013 May;49(42):4779-81

Center for Nanoparticle Research, Institute for Basic Science (IBS), and School of Chemical and Biological Engineering, Seoul National University, Seoul 151-744, Korea.

Highly active magnetically recyclable hollow nanocomposite catalysts with a permeable carbon surface have been prepared by a simple, economical and scalable process. The designed nanocomposite exhibited excellent catalytic activities in the selective reduction of nitroarenes and Suzuki cross-coupling reactions. The catalysts could be easily separated by a magnet, and recycled consecutively.
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http://dx.doi.org/10.1039/c3cc41034jDOI Listing
May 2013
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