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Colloquium | Nanoscience and Technology Division

Designing Inorganic Nanomaterials for Medical and Energy Applications

NST Colloquium

Abstract: Over the last 20 years, our laboratory has focused on designed chemical synthesis, assembly, and applications of uniform-sized nanocrystals. Especially, we developed a novel generalized procedure, called the heat-up process” for the direct synthesis of uniform-sized nanocrystals of many metals, oxides, and chalcogenides. For the last 10 years, our group has been focused on medical applications of various uniform-sized nanoparticles. We reported that uniform 2-nm iron oxide nanoclusters can be used as a T1 MRI contrast agent for high-resolution MR angiography of monkeys. We also reported the first successful demonstration of high-resolution in vivo three-photon imaging using biocompatible and bright Mn2+/ZnS nanocrystals. 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. 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. We reported 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. 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.

Recently we have focused on the architecture engineering of nanomaterials for application to lithium-ion battery, fuel cell electrocatalysts, solar cells, and thermoelectrics. We reported the first demonstration of galvanic replacement reactions in metal-oxide nanocrystals and were able to synthesize hollow nanocrystals of various multimetallic oxides, including Mn3O4/γ-Fe2O3. We report a simple synthetic method of carbon-based hybrid cellular nanosheets loaded with SnO2 nanoparticles. 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. 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. We report on the design and synthesis of highly active TiO2 photocatalysts incorporated with site-specific single copper atoms (Cu/TiO2) that exhibit reversible and cooperative photoactivation process, and enhancement of photocatalytic hydrogen generation activity.