Publications by authors named "Dong Shin Choi"

10 Publications

  • Page 1 of 1

Polyselenide Anchoring Using Transition-Metal Disulfides for Enhanced Lithium-Selenium Batteries.

Inorg Chem 2018 Feb 27;57(4):2149-2156. Epub 2018 Jan 27.

Graduate School of Energy, Environment, Water, and Sustainability, Korea Advanced Institute of Science and Technology , 291 Daehak-ro, Daejeon 34141, Republic of Korea.

While selenium has recently been proposed as a lithium battery cathode as a promising alternative to a lithium-sulfur battery, dissolution of intermediate species should be resolved to improve its cycle stability. Here, we report the promising results of transition-metal disulfides as an anchoring material and the underlying origin for preventing active material loss from the electrode using density functional theory calculations. Group 5 and 4 disulfides (VS, NbS, TaS, TiS, ZrS, and HfS) in particular show anchoring capabilities superior to those of group 6 disulfides (CrS, MoS, and WS). The governing interaction controlling the latter relative anchoring strengths is shown to be charge transfer as understood by crystal-field theory. The current findings and methodologies provide novel chemical insight for the further design of inorganic anchoring materials for both lithium-selenium and lithium-sulfur batteries.
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http://dx.doi.org/10.1021/acs.inorgchem.7b03001DOI Listing
February 2018

Porous cationic polymers: the impact of counteranions and charges on CO2 capture and conversion.

Chem Commun (Camb) 2016 Jan;52(5):934-7

Graduate School of Energy, Environment, Water and Sustainability (EEWS), Korea Advanced Institute of Science and Technology (KAIST), 373-1 Guesong Dong, Daejeon, 305-701, Republic of Korea. and Department of Chemistry, KAIST, Daejeon, Republic of Korea.

Porous cationic polymers (PCPs) with surface areas up to 755 m(2) g(-1) bearing positively charged viologen units in their backbones and different counteranions have been prepared. We have demonstrated that by simply varying counteranions both gas sorption and catalytic properties of PCPs can be tuned for metal-free capture and conversion of CO2 into value-added products such as cyclic carbonates with excellent yields.
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http://dx.doi.org/10.1039/c5cc08132gDOI Listing
January 2016

M13 Bacteriophage and Adeno-Associated Virus Hybrid for Novel Tissue Engineering Material with Gene Delivery Functions.

Adv Healthc Mater 2016 Jan 22;5(1):88-93. Epub 2015 May 22.

Department of Bioengineering, University of California, Berkeley, Physical Biosciences Division, Lawrence Berkeley National Laboratory, Berkeley Nanoscience and Nanoengineering Institute, Berkeley, CA, 94720, USA.

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http://dx.doi.org/10.1002/adhm.201500179DOI Listing
January 2016

Skeletal octahedral nanoframe with Cartesian coordinates via geometrically precise nanoscale phase segregation in a [email protected] core-shell nanocrystal.

ACS Nano 2015 Mar 5;9(3):2856-67. Epub 2015 Mar 5.

⊥Graduate School of Energy Environment Water and Sustainability (EEWS), Korea Advanced Institute of Science and Technology (KAIST), Daejeon 305-701, Republic of Korea.

Catalytic properties of nanoparticles can be significantly enhanced by controlling nanoscale alloying and its structure. In this work, by using a facet-controlled [email protected] core-shell octahedron nanoparticle, we show that the nanoscale phase segregation can have directionality and be geometrically controlled to produce a Ni octahedron that is penetrated by Pt atoms along three orthogonal Cartesian axes and is coated by Pt atoms along its edges. This peculiar anisotropic diffusion of Pt core atoms along the ⟨100⟩ vertex, and then toward the ⟨110⟩ edges, is explained via the minimum strain energy for Ni-Ni pair interactions. The selective removal of the Ni-rich phase by etching then results in structurally fortified Pt-rich skeletal PtNi alloy framework nanostructures. Electrochemical evaluation of this hollow nanoframe suggests that the oxygen reduction reaction (ORR) activity is greatly improved compared to conventional Pt catalysts.
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http://dx.doi.org/10.1021/nn5068539DOI Listing
March 2015

Cyclic RGD peptide incorporation on phage major coat proteins for improved internalization by HeLa cells.

Bioconjug Chem 2014 Feb 13;25(2):216-23. Epub 2014 Jan 13.

Department of Bioengineering, University of California , Berkeley, California 94720, United States.

Delivering therapeutic materials or imaging reagents into specific tumor tissues is critically important for development of novel cancer therapeutics and diagnostics. Genetically engineered phages possess promising structural features to develop cancer therapeutic materials. For cancer targeting purposes, we developed a novel engineered phage that expressed cyclic RGD (cRGD) peptides on the pVIII major coat protein using recombinant DNA technology. Using a type 88 phage engineering approach, which inserts a new gene to express additional major coat protein in the noncoding region of the phage genome, we incorporated an additional pVIII major coat protein with relatively bulky cRGD and assembled heterogeneous major coat proteins on the F88.4 phage surfaces. With IPTG control, we could tune different numbers of cRGD peptide displayed on the phage particles up to 140 copies. The resulting phage with cRGD on the recombinant pVIII protein exhibited enhanced internalization efficiency into HeLa cells in a ligand density and conformational structure dependent manner when comparing with the M13 phages modified with either linear RGD on pVIII or cRGD on pIII. Our cRGD peptide engineered phage could be useful for cancer therapy or diagnostic purposes after further modifying the phage with drug molecules or contrast reagents in the future.
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http://dx.doi.org/10.1021/bc4003234DOI Listing
February 2014

Phage-based nanomaterials for biomedical applications.

Acta Biomater 2014 Apr 30;10(4):1741-50. Epub 2013 Jun 30.

Department of Bioengineering, University of California, Berkeley and Physical Biosciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA. Electronic address:

Recent advances in nanotechnology enable us to manipulate and produce materials with molecular level control. In the newly emerging field of bionanomedicine, it is essential to precisely control the physical, chemical and biological properties of materials. Among other biological building blocks, viruses are a promising nanomaterial that can be functionalized with great precision. Since the production of viral particles is directed by the genetic information encapsulated in their protein shells, the viral particles create precisely defined sizes and shapes. In addition, the composition and surface properties of the particles can be controlled through genetic engineering and chemical modification. In this manuscript, we review the advances of virus-based nanomaterials for biomedical applications in three different areas: phage therapy, drug delivery and tissue engineering. By exploiting and manipulating the original functions of viruses, viral particles hold great possibilities in these biomedical applications to improve human health.
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http://dx.doi.org/10.1016/j.actbio.2013.06.037DOI Listing
April 2014

Electrical control of kinesin-microtubule motility using a transparent functionalized-graphene substrate.

Nanotechnology 2013 May 17;24(19):195102. Epub 2013 Apr 17.

Department of Biophysics and Chemical Biology, Seoul National University, Seoul, Korea.

We report a new strategy to selectively localize and control microtubule translocation via electrical control of microtubules using a microfabricated channel on a functionalized-graphene electrode with high transparency and conductivity. A patterned SU-8 film acts as an insulation layer which shields the electrical field generated by the graphene underneath while the localized electric field on the exposed graphene surface guides the negatively charged microtubules. This is the first report showing that functionalized graphene can support and control microtubule motility.
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http://dx.doi.org/10.1088/0957-4484/24/19/195102DOI Listing
May 2013

Graphene-polymer hybrid nanostructure-based bioenergy storage device for real-time control of biological motor activity.

ACS Nano 2011 Nov 28;5(11):8656-64. Epub 2011 Oct 28.

Department of Physics and Astronomy, Seoul National University, Seoul, 151-742 Korea.

We report a graphene-polymer hybrid nanostructure-based bioenergy storage device to turn on and off biomotor activity in real-time. In this strategy, graphene was functionalized with amine groups and utilized as a transparent electrode supporting the motility of biomotors. Conducting polymer patterns doped with adenosine triphosphate (ATP) were fabricated on the graphene and utilized for the fast release of ATP by electrical stimuli through the graphene. The controlled release of biomotor fuel, ATP, allowed us to control the actin filament transportation propelled by the biomotor in real-time. This strategy should enable the integrated nanodevices for the real-time control of biological motors, which can be a significant stepping stone toward hybrid nanomechanical systems based on motor proteins.
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http://dx.doi.org/10.1021/nn202421nDOI Listing
November 2011

Polarization-controlled differentiation of human neural stem cells using synergistic cues from the patterns of carbon nanotube monolayer coating.

ACS Nano 2011 Jun 13;5(6):4704-11. Epub 2011 May 13.

Interdisciplinary Program in Nano-Science and Technology, Seoul National University, Seoul 151-747, Korea.

We report a method for selective growth and structural-polarization-controlled neuronal differentiation of human neural stem cells (hNSCs) into neurons using carbon nanotube network patterns. The CNT patterns provide synergistic cues for the differentiation of hNSCs in physiological solution and an optimal nanotopography at the same time with good biocompatibility. We demonstrated a polarization-controlled neuronal differentiation at the level of individual NSCs. This result should provide a stable and versatile platform for controlling the hNSC growth because CNT patterns are known to be stable in time unlike commonly used organic molecular patterns.
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http://dx.doi.org/10.1021/nn2006128DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3125501PMC
June 2011

Dual transport systems based on hybrid nanostructures of microtubules and actin filaments.

Small 2011 Jul 12;7(13):1755-60. Epub 2011 May 12.

Department of Nano Science and Engineering, Seoul National University, Seoul, 151-747, Korea.

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http://dx.doi.org/10.1002/smll.201002267DOI Listing
July 2011