Taeghwan Hyeon abstract

Chemistry for Nano, and Nano for Medicine & Energy

Taeghwan Hyeon^1,2

¹ Center for Nanoparticle Research, Institute for Basic Science (IBS), ² School of Chemical and Biological Engineering, Seoul National University, Seoul 08826, Republic of Korea. thyeon@snu.ac.kr

 

For the last 20 years, I have been focused on designed synthesis, assembly and medical & energy applications of uniform-sized nanocrystals and related nanomaterials.¹ We reported that uniform 2 nm iron oxide nanoclusters can be successfully used as T1 MRI contrast agent for high-resolution MR angiography of monkeys.² We demonstrated that ceria nanoparticles and ceria–zirconia nanoparticles can work as therapeutic antioxidants to treat various nasty diseases including ischemic stroke, Alzheimer’s disease, sepsis, and Parkinson’s disease.³ CeO₂/Mn₃O₄ nanocrystals possessing surface strains protect tissue-resident stem cells from irradiation-induced ROS damage, significantly increasing the survival rate of the animals (67% up to 150 days after 13 Gy total body irradiation).⁴ We developed a click reaction-assisted immune cell targeting (CRAIT) strategy to deliver drug-loaded nanoparticles deep into tumor interiors, reducing tumor burden in an aggressive 4T1 breast cancer model without any systemic toxicity.⁵ We report a highly sensitive and selective K⁺ nanosensor that can quantitatively monitor extracellular K⁺ concentration changes in the brains of freely moving mice experiencing epileptic seizures.⁶ We introduced electromechanical cardioplasty using an epicardial mesh made of electrically conductive and elastic Ag nanowire-rubber composite material to resemble the innate cardiac tissue and confer cardiac conduction system function.⁷

Recently we have focused on the architecture engineering of nanomaterials for their applications to fuel cell electrocatalysis, lithium ion battery, and photocatalysis. We present a synthesis of highly durable and active electrocatalysts based on ordered fct-PtFe nanoparticles and FeP nanoparticles coated with N-doped carbon shell.⁸ The effect of porous structures on the electrocatalytic activity of N-doped carbon is studied by using electrochemical analysis techniques, and the results are applied to synthesize highly active and stable Fe-N-C catalyst for oxygen reduction reaction (ORR).⁹ We also report on the design and synthesis of highly active and stable Co-N₄(O) moiety incorporated in nitrogen-doped graphene (Co₁-NG(O)) that exhibits a record-high kinetic current density (2.84 mA cm^-2 at 0.65 V vs. RHE) and mass activity (277.3 A g^-1 at 0.65 V vs. RHE) with unprecedented stability (>110 h) for electrochemical hydrogen peroxide (H₂O₂) production.¹⁰ We report on the design and synthesis of highly active TiO₂ photocatalysts incorporated with site-specific single copper atoms (Cu/TiO₂) that exhibit reversible & cooperative photoactivation process, and enhancement of photocatalytic hydrogen generation activity.¹¹ We synthesized multigrain nanocrystals consisting of Co₃O₄ nanocube cores and Mn₃O₄ shells. At the sharp edges of the Co₃O₄ nanocubes, we observed that tilt boundaries of the Mn₃O₄ grains exist in the form of disclinations, and we obtained a correlation between the defects and the resulting electrocatalytic behavior for the oxygen reduction reaction.¹²

1. “Ultra-Large Scale Syntheses of Monodisperse Nanocrystals,” Nature Mater. 2004, 3, 891; “Galvanic Replacement Reactions in Metal Oxide Nanocrystals,” Science 2013, 340, 964; “Highly luminescent and catalytically active suprastructures of magic-sized semiconductor nanoclusters,” Nature Mater. 2021, DOI: 10.1038/s41563-020-00880-6.
2. “Iron oxide nanoclusters for T1 MRI of nonhuman primates,” Nature Biomed. Eng. 2017, 1, 637.
3. “Ceria Nanoparticles that can Protect against Ischemic Stroke,” Angew. Chem. Int. Ed. 2012, 51, 11039; “Mitochondria-Targeting Ceria Nanoparticles as Antioxidants for Alzheimer’s Disease,” ACS Nano, 2016, 10, 2860; “Ceria–Zirconia Nanoparticles as Enhanced Multi-Antioxidant for Sepsis Treatment,” Angew. Chem. Int. Ed. 2017, 56, 11399; “Ceria nanoparticle systems for selective scavenging of mitochondrial, intracellular, & extracellular ROS in Parkinson’s disease,” Angew. Chem. Int. Ed. 2018, 57, 9408; “Magnetite/Ceria Nanoparticle Assemblies for Extracorporeal Cleansing of Amyloid-β in Alzheimer’s Disease,” Adv. Mater. 2018, 30, 1807965.
4. “Epitaxially Strained CeO₂/Mn₃O₄ Nanocrystals as an Enhanced Antioxidant for Radioprotection,” Adv. Mater. 2020, 32, 2001566.
5. “Deep tumor penetration of drug-loaded nanoparticles by click reaction-assisted immune cell targeting strategy,” JACS 2019, 141, 13829.
6. “A sensitive and specific nanosensor for monitoring extracellular potassium levels in brain,” Nature Nanotech. 2020, 15, 321.
7. Highly conductive, stretchable & biocompatible Ag-Au core-sheath nanowire composite for wearable & implantable bioelectronics, Nature Nanotech. 2018, 13, 1048; Electromechanical cardioplasty using elasto-conductive epicardial mesh, Science Transl. Med. 2016, 8, 344ra86.
8. “Highly durable and active PtFe nanocatalyst for electrochemical oxygen reduction reaction,” J. Am. Chem. Soc. 2015, 137, 15478; “Direct Synthesis of Intermetallic Platinum-Alloy Nanoparticles Highly-Loaded on Carbon Supports for Efficient Electrocatalysis,” J. Am. Chem. Soc. 2020, 142, 14190; “Direct Synthesis of Intermetallic Platinum-Alloy Nanoparticles Highly-Loaded on Carbon Supports for Efficient Electrocatalysis,” J. Am. Chem. Soc. 2020, 142, 14190; “Large-scale Synthesis of Carbon Shell-coated FeP Nanoparticles for Robust Hydrogen Evolution Reaction Electrocatalyst,” J. Am. Chem. Soc. 2017, 139, 6669.
   9. “Design Principle of Fe–N–C Electrocatalysts: How to Optimize Multimodal Porous Structures?” JACS 2019, 141, 2035.

10.“Atomic-level tuning of Co-N-C catalyst for high-performance electrochemical H₂O₂ production,” Nature Mater. 2020, 19, 436.

11. “Reversible and cooperative photoactivation of single-atom Cu/TiO2 photocatalysts,” Nature Mater. 2019, 18, 620.
12. “Design and Synthesis of Multigrain Nanocrystals via Geometric Misfit Strain,” Nature 2020, 359, 577 (Cover article).