Department of Chemistry

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Shigeru Amemiya

Professor

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803A CHVRN
Chevron Science Center, 219 Parkman Avenue

Pittsburgh, PA 15260
412-624-1217

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Research Overview

Our studies are focused on electrochemistry and analytical applications of charge- and molecular-transport processes at liquid/liquid interfaces, such as water/organic solution, water/polymer membrane, and biomembrane interfaces. Especially, our projects are directed toward (1) understanding membrane transport phenomena of chemical and biological importance and (2) developing electrochemical sensors based on the interfacial transport processes. In addition to conventional electrochemical techniques, we use scanning probe microscopy, such as scanning electrochemical microscopy (SECM) and atomic force microscopy (AFM), in order to investigate the interfacial transport processes with high spatial resolutions. We also use computational simulation approaches to quantitatively understand these transport processes.

Chemical Imaging of Biomembranes by SECM

It is well known that biomembrane surface is laterally highly heterogeneous in nanometer scale. Thus, high-resolution imaging of membrane structure and function is urgently required in various biological contexts. We will develop very small electrochemical sensors for studying the ion- and molecular-transport processes through biomembrane nanostructures, e.g., ion-channel pores (0.2-10 nm) and lipid domains (100-500 nm). A scanning electrochemical microscope is used to position the sensors very close to a biomembrane surface and measure their response simultaneously. As the response indicates how fast the transport processes are at the local position, a plot of the response against the x,y-positions gives a chemical image of the membrane surface.

Electrochemical Sensors Based on Interfacial Molecular Recognition

In our second project, electrochemical sensors with high selectivity and sensitivity will be developed on the basis of molecular recognition (or host-guest chemistry) at liquid/liquid interfaces. Interfacial transfer of an analyte ion from a sample solution into a sensor membrane can be facilitated selectively by a receptor (ionophore) that forms complexes with the analyte in the membrane phase. This process can be directly detected as electrical signals, i.e., potential and current, allowing for simple construction of ion sensors, so called potentiometric and voltammetric ion-selective electrodes (ISEs), respectively. We are interested in miniaturization of the sensors for biomembrane studies (Figure 1) and in improving and understanding their response properties for clinical and environmental analysis. For both purposes, we will try to widen the range of detectable analytes by applying different types of receptors and by sophisticating detection principles.

Computational Simulations of Electrochemical Problems

We use PC-based numerical simulation methods to quantitatively understand important processes in the above-mentioned projects and more generally those in electrochemical problems, which have not been accessible analytically or numerically within reasonable computation time. A special emphasis will be on comprehensive understanding of diffusion and other kinetic processes at microenvironments such as intra- and extracellular spaces, biomembrane surfaces, and microelectrodes.

Awards

  • NSF CAREER Award 2007-2012; Research Corporation Research Innovation Award 2002; The Japan Society for the Promotion of Science Postdoctoral Fellowship 1998-2001.

Publications

“Scanning Electrochemical Microscopy of Carbon Nanomaterials and Graphite,” Amemiya S, Chen R, Nioradze N, and Kim J , Acc. Chem. Res., Vol. 49, 2016, Pages 2007–2014
“Origin of Asymmetry of Paired Nanogap Voltammograms Based on Scanning Electrochemical Microscopy: Contamination Not Adsorption,”  Chen R, Balla RJ, Li Z, Liu H, and Amemiya S , Anal. Chem., Vol. 88, 2016, Pages 8323–8331
“Voltammetric Mechanism of Multiion Detection with Thin Ionophore-Based Polymeric Membrane,” Greenawalt PJ, and Amemiya S , Anal. Chem., Vol. 88, 2016, Pages 5827–5834
“Focused-Ion-Beam-Milled Carbon Nanoelectrodes for Scanning Electrochemical Microscopy,” Chen R, Hu K, Yu Y, Mirkin MV, and Amemiya S , J. Electrochem. Soc., Vol. 163, 2016, Pages H3032–H3037
“Water Protects Graphitic Surface from Airborne Hydrocarbon Contamination,” Li Z, Kozbial A, Nioradze N, Parobek DG, Shenoy GJ, Salim M, Amemiya S, Li L and Liu H , ACS Nano, Vol. 10, 2016, Pages 349-359
“Ultrafast Electron Transfer Kinetics of Graphene Grown by Chemical Vapor Deposition,” Chen R, Nioradze N, Santhosh P, Li Z, Surwade SP, Shenoy GJ, Parobek DG, Kim MA, Liu H, and Amemiya S , Angew. Chem., Int. Ed., Vol. 54, 2015, Pages 15134–15137
“Voltammetric Characterization of Ion–Ionophore Complexation Using Thin Polymeric Membranes: Asymmetric Thin-Layer Responses,” Greenawalt PJ, Garada MB and Amemiya S , Anal. Chem., Vol. 87, 2015, Pages 8564–8572
“Nanoscale Scanning Electrochemical Microscopy,” Amemiya, S, Eds. Bard AJ, and Zoski CG, Taylor and Francis , Electroanalytical Chemistry, Vol. 26, 2015, Pages 1-72
“Extraction or Adsorption? Voltammetric Assessment of Protamine Transfer at Ionophore-Based Polymeric Membranes,” Garada MB, Kabagambe B, and Amemiya S , Anal. Chem., Vol. 87, 2015, Pages 5348–5355
“Organic Contamination of Highly Oriented Pyrolytic Graphite as Studied by Scanning Electrochemical Microscopy,” Nioradze N, Chen R, Kurapati N, Khvataeva-Domanov A, Mabi S, and Amemiya S , Anal. Chem., Vol. 87, 2015, Pages 4836–4843
“Scanning Electrochemical Microscopy of Nanopores, Nanocarbons, and Nanoparticles,” Amemiya S, Eds. Mirkin MV, and Amemiya S, Taylor and Francis , Nanoelectrochemistry, 2015, Pages 621-653
“Ion-Transfer Voltammetry of Perfluoroalkanesulfonates and Perfluoroalkanecarboxylates: Picomolar Detection Limit and High Lipophilicity,” Garada MB, Kabagambe B, Kim Y, and Amemiya S , Anal. Chem., Vol. 86, 2014, Pages 11230-11237
“Subnanomolar Detection Limit of Stripping Voltammetric Ca2+-Selective Electrode: Effects of Analyte Charge and Sample Contamination,” Kabagambe B, Garada MB, Ishimatsu R, and Amemiya S , Anal. Chem. , Vol. 86, 2014, Pages 7939–7946
“Nanoscale Mechanism of Molecular Transport through the Nuclear Pore Complex as Studied by Scanning Electrochemical Microscopy,” Kim J, Izadyar A, Nioradze N, Amemiya S, J.Am.Chem.Soc., Vol. 135, 2013, Pages 2321-2329