Keisuke Yokoyama
NSK Ltd.
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Publication
Featured researches published by Keisuke Yokoyama.
ACS Nano | 2011
Tae Hyun Kim; Byung Yang Lee; Justyn Jaworski; Keisuke Yokoyama; Woo Jae Chung; Eddie Wang; Seunghun Hong; Arun Majumdar; Seung-Wuk Lee
Miniaturized smart sensors that can perform sensitive and selective real-time monitoring of target analytes are tremendously valuable for various sensing applications. We developed selective nanocoatings by combining trinitrotoluene (TNT) receptors bound to conjugated polydiacetylene (PDA) polymers with single-walled carbon nanotube field-effect transistors (SWNT-FET). Selective binding events between the TNT molecules and phage display derived TNT receptors were effectively transduced to sensitive SWNT-FET conductance sensors through the PDA coating layers. The resulting sensors exhibited an unprecedented 1 fM sensitivity toward TNT in real time, with excellent selectivity over various similar aromatic compounds. Our biomimetic receptor coating approach may be useful for the development of sensitive and selective micro- and nanoelectronic sensor devices for various other target analytes.
Langmuir | 2011
Justyn Jaworski; Keisuke Yokoyama; Chris Zueger; Woo-Jae Chung; Seung-Wuk Lee; Arun Majumdar
Because of their unique optical and stimuli-response properties, polydiacetylene-based platforms have been explored as an alternative to complex mechanical and electrical sensing systems. We linked chromic responsive polydiacetylene (PDA) onto a peptide-based molecular recognition element for trinitrotoluene (TNT) molecules in order to provide a system capable of responding to the presence of a TNT target. We first identified the trimer peptide receptor that could induce chromic changes on a PDA backbone. We then investigated the multivalent interactions between TNT and our peptide-based receptor by nuclear magnetic resonance (NMR) spectroscopy. We further characterized various parameters that affected the conjugated PDA system and hence the chromic response, including the size of end-group motifs, the surface density of receptors, and the length of alkane side chains. Taking these necessary design parameters into account, we demonstrated a modular system capable of transducing small-molecule TNT binding into a detectable signal. Our conjugated PDA-based sensor coupled with molecular recognition elements has already proven useful recently in the development of another sensitive and selective electronic sensor, though we expect that our results will also be valuable in the design of colorimetric sensors for small-molecule detection.
Archive | 2001
Hiromitsu Asai; Toshimi Takagi; Takahiko Uchiyama; Keisuke Yokoyama; 貴彦 内山; 景介 横山; 拡光 浅井; 敏己 高城
Archive | 2004
Toshikazu Yabe; Toshimi Takajo; Takahiko Uchiyama; Keisuke Yokoyama
Archive | 2007
Koichi Morita; Toshiaki Oguchi; Keisuke Yokoyama
Archive | 2007
Koichi Morita; Toshiaki Oguchi; Keisuke Yokoyama
Archive | 2012
Keisuke Yokoyama; Hideki Furukawa; Kunihiko Sasao; Nobuko Okutani; Toshiaki Oguchi
Archive | 2003
Shigeaki Aihara; Hiromitsu Asai; Takahiko Uchiyama; Keisuke Yokoyama; 貴彦 内山; 景介 横山; 拡光 浅井; 成明 相原
한국진공학회 학술발표회초록집 | 2011
Justyn Jaworski; Tae Hyun Kim; Keisuke Yokoyama; Woo-Jae Chung; Eddie Wang; Byung Yang Lee; Seunghun Hong; Arun Majumdar; Seung-Wuk Lee; Ki-Young Kwon
Archive | 2005
Keisuke Yokoyama; 景介 横山