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Kinetically Controlled Growth of Gold Nanoplates and Nanorods via a One-Step Seed-Mediated Method
Hong, Soonchang,Acapulco, Jesus A.I. Jr.,Jang, Hee-Jeong,Kulkarni, Akshay S.,Park, Sungho Korean Chemical Society 2014 Bulletin of the Korean Chemical Society Vol.35 No.6
In this research, we further developed the one-step seed mediated method to synthesize gold nanoparticles (GNPs) and control their resulting shapes to obtain hexagonal, triangular, rod-shaped, and spherical gold nanostructures. Our method reveals that the reaction kinetics of formation of GNPs with different shapes can be controlled by the rate of addition of ascorbic acid, because this is the critical factor that dictates the energy barrier that needs to be overcome. This in turn affects the growth mechanism process, which involves the adsorption of growth species to gold nanoseeds. There were also observable trends in the dimensions of the GNPs according to different rates of addition of ascorbic acid. We performed further analyses to investigate and confirm the characteristics of the synthesized GNPs.
Hong, Soonchang,Shuford, Kevin L,Park, Sungho Wiley-VCH 2013 Chemistry, an Asian journal Vol.8 No.6
<P>This paper describes how the surface roughness and synthetic methods of Au nanorods affect the optical properties that are often associated with localized surface plasmon resonances. We synthesized Au nanorods with different aspect ratios and surface roughness by using two different synthetic strategies to observe surface plasmon resonance bands. One set of nanorods was prepared in high yield by using a seed-mediated dropwise-addition method with a growth-directing surfactant in aqueous solution (Au nanorods in aqueous phase, GNRA). The other set of Au nanorods were synthesized by the electrochemical deposition of Au onto an anodized aluminum oxide (AAO) template (Au nanorods by AAO template, GNRT). The length of the nanorods was controlled by changing the total charge that was passed through the cell and their diameter was monitored by changing the diameter of the template channel. The as-prepared Au nanorods were optimized to observe a quadrupole mode, which is one of the higher-order surface plasmon bands. Our results showed differences between the optical properties of GNRA and GNRT. The roughness and crystal structure of the Au nanorods affected their optical properties. Smooth and single-crystal surface on GNRA had larger and sharper peaks than GNRT. The discrete dipole approximation (DDA) method was used to calculate the optical properties of the Au nanorods and these results were in good agreement with our experimental results.</P>
Hong, Soonchang,Acapulco, Jesus A. I.,Jang, Ho Young,Park, Sungho American Chemical Society 2014 Chemistry of materials Vol.26 No.12
<P>Au nanodisk-core multishell nanoparticles (NDCMS-NPs) were synthesized using a Au nanodisk core as a seed to deposit a controlled number of surrounding Ag layers, followed by galvanic replacement reactions with Au ions in water. Uniform Au NDCMS-NPs with controllable shell numbers and intershell distances exhibited unique surface plasmon mode shifts, which were found to be dependent on the thickness of the Ag layer. The number of shells was tuned by controlling the multistep reactions from one to five. The Au core played a critical role in terms of holding the multishell structure during the experimental procedures. We systematically followed their shape evolution by monitoring the surface plasmon resonance bands, as well as by viewing these physical changes with electron microscopy.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/cmatex/2014/cmatex.2014.26.issue-12/cm500846w/production/images/medium/cm-2014-00846w_0009.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/cm500846w'>ACS Electronic Supporting Info</A></P>
Shape Control of Ag ShellGrowth on Au Nanodisks
Hong, Soonchang,Choi, Yoonjung,Park, Sungho American ChemicalSociety 2011 Chemistry of materials Vol.23 No.24
<P>Core-shell (Au@Ag) bimetallic nanoparticles containing a Au nanodisk in the core were synthesized using Au nanodisks as seeds. The growth direction of the Ag shell on the gold nanodisks could be tuned by the presence of iodide ions. Without the I(-) ions, the Ag shell was formed homogeneously over the entire surface of the flat Au nanodisks, while the presence of I(-) induced the selective coating of the Ag shell in the direction perpendicular to the basal plane of the nanodisks. The resulting core-shell (Au@Ag) bimetallic nanoparticles could be further converted to hollow nanostructures containing a central Au nanodisk via galvanic replacement reactions.</P>
Hong, Soonchang,Shuford, Kevin L.,Park, Sungho American Chemical Society 2011 Chemistry of materials Vol.23 No.8
<P>We present a simple synthetic method for hexagonal Au nanoplates. Selective etching of specific facets of triangular nanoplates has led to the shape transformation. Also, the high quality of hexagonal Au nanoplates allows one to identify the higher-order plasmon resonance bands in addition to the dipole mode.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/cmatex/2011/cmatex.2011.23.issue-8/cm103273c/production/images/medium/cm-2010-03273c_0007.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/cm103273c'>ACS Electronic Supporting Info</A></P>
( Min Sun Park ),( Soonchang Hong ),( Yoo Li Lim ),( Seong Hee Kang ),( Soon Koo Baik ),( Moon Young Kim ) 대한간학회 2018 Gut and Liver Vol.12 No.5
Background/Aims: Acute hepatic dysfunction combined with alcoholic hepatitis (AH) in alcoholic cirrhosis is related to hepatic hypo-perfusion secondary to intrahepatic necroinflammation, neoangiogenesis, and shunt. The hepatic vein arrival time (HVAT) assessed by microbubble contrastenhanced ultrasonography (CEUS) is closely correlated with the severity of intrahepatic changes. We investigated the usefulness of HVAT to predict short-term mortality of AH in cirrhosis. Methods: Thirty-nine patients with alcoholic cirrhosis (27 males) and AH were prospectively enrolled. HVAT study was performed within 3 days after admission using ultrasonic contrast (SonoVue®). The primary outcome was 12- week mortality. Results: Twelve-week mortality developed in nine patients. HVAT was significantly different between the mortality and survival groups (9.3±2.0 seconds vs 12.6±3.5 seconds, p=0.002). The odds ratio of a shortened HVAT for 12-week mortality was 1.481 (95% confidence interval, 1.050-2.090; p=0.025). The area under the receiver operating characteristic curve of HVAT for 12-week mortality was 0.787 (p=0.010). The combination of MDF and HVAT ≥11.0 seconds resulted in an 87.5% survival rate even if the MDF score ≥32; however, HVAT <11.0 seconds was related with mortality despite a MDF score<32. Conclusions: HVAT using microbubble CEUS could be a useful additional index to predict short-term mortality in patients with AH and cirrhosis. (Gut Liver 2018;12:555-561)