匂いクラスターによるマッチング情報サービスに関する研究
キーワード：匂いコード，匂いクラスター，マッチング，匂いマップ，情報サービス，匂いデータベース，メタ情報
2009.04.

匂い空間の可視化
キーワード：可視化，匂い，蛍光プローブ，分子認識
2010.03.

匂いの定量的な測定と記録，再現に関する研究．
キーワード：匂いセンサ，部分構造，匂いコード，匂い再生
2008.04.

分子ワイアと有機エレクトロニクス材料による新規デバイスに関する研究
キーワード：分子ワイア，トンネル電流，匂い，センサ
2007.04～2019.03.

匂いによるバイオメトリクスに関する研究
キーワード：バイオメトリクス，生体認証，匂い，センサ，匂いタイプ
2004.04.

異臭と悪臭の超高感度検出技術の開発
キーワード：超高感度匂いセンサ，分子認識
2005.04～2015.03.

匂いの定量的な測定と客観的な質の表現方法に関する研究
キーワード：匂いセンサ，部分構造，匂いコード
1998.04～2007.03.

分子認識のための表面ナノ構造の構築
キーワード：ナノ構造，分子認識，分子間相互作用
2003.01.

環境汚染物質の高感度センシングに関する研究
キーワード：環境ホルモン，環境汚染，水質汚染，電気化学，センサ
1999.04～2007.03.

味のセンシング技術に関する研究
キーワード：味覚センサ，基本味，うま味，辛味
1986.04～2011.03.

匂いの時空間揺らぎ情報による人探索
2022.04～2027.03, 代表者：林 健司
科学研究費 基盤研究Sの研究開発課題として取り組んでいる匂いの時空間情報を用いた人探索プロジェクト研究である。.

匂いイメージ情報のプロファイル分解
2018.04～2021.03, 代表者：林　健司, 九州大学
匂いを数値化し，時空間イメージとして可視化する。その際、混在情報を要素プロファイルに分解することで視覚情報として理解可能な情報とする。また、センサの同時・高速・多項目キャリブレーションを実現する。
JST 科学研究費 基盤研究A匂いイメージセンサによる匂い痕跡画像の要素臭プロファイル分解.

匂いセンサロボットによる匂い痕跡の追跡
2017.09～2019.09, 代表者：林健司
匂いの痕跡を可視化するセンサをロボットに搭載し、痕跡を追跡する研究を、セコム科学技術財団による一般研究助成テーマとして実施している。.

電気的制御可能でリコンフィギュアラブルな分子認識デバイス
2014.03～2019.03, 代表者：林　健司, 九州大学大学院　システム情報科学研究院, JST 科学研究費 挑戦的萌芽（電気的制御可能でリコンフィギュアラブルな分子認識デバイス）
電気的に分子認識能力を制御可能な分子認識デバイスを開発し、様々な化学物質を検知できるデバイスを開発する。.

人の匂い検知のためのインテリジェント匂いセンサアレイe-noseの開発
2012.11～2014.10, 代表者：林　健司, 九州大学大学院　システム情報科学研究院, 独立行政法人　日本学術振興会
匂いセンサは食品や環境の匂いを定量的に測定することを目的としている．しかしながら，それらの測定量は匂いとしての表現方法が曖昧で定量性に欠けており，センサの開発の明確な目標設定や，センサの実用化に障害をもたらし，匂いセンサの幅広い利用は実現していない．本研究は匂いセンサの実用的な応用を図るため，その目標を人の匂いの探知に設定した．現在，匂いセンサの実現方法の一つである，非選択的なガスセンサアレイとパターン認識ソフトウェアを組み合わせたe-noseは広く研究が行われおり，技術的には対象をガスとして測定が可能なレベルに到達しているが，上述の理由により実用化は遅れている．そのため，本研究は定量対象は人を探知し，識別できる揮発性化学物質に限定し，人の検知をe-noseにより行うことを目的とする．.

匂いイメージセンシング
2011.04, 代表者：林　健司, 九州大学
匂いを数値化し，時空間イメージとして可視化する．また，脳内の匂いクラスターマップとして処理可能な情報として可視化する．
JST 科学研究費 基盤研究B（匂い分子を認識するプローブにより匂いを可視化する）
総務省 SCOPE（匂いイメージセンサの開発）
JST 科学研究費 基盤研究A（匂いの質と空間の可視化センシング）
JST 科学研究費 基盤研究A（匂いイメージセンサによる匂い痕跡画像の要素臭プロファイル分解 ）.

匂いセンシングによる人の探知とバイオメトリクスに関する研究
2006.05, 代表者：林　健司, システム情報科学研究院, 株式会社ユーエスイー
匂いによる人の探知と個人認証（バイオメトリクス）に関するセンサ開発を行う．.

化学センシングMT-FETの創成
2011.04～2013.03, 代表者：林　健司, 九州大学
JST 科学研究費 挑戦的萌芽研究
Mott-Hubbard転移に基づく化学物質を検知するFETデバイスを開発する．.

匂いセンシングシステムと匂い情報の応用に関する研究
2009.04～2015.03, 代表者：林　健司, 九州大学大学院システム情報科学研究院
匂い分離測定装置により得られる匂い情報により生物に関する情報を計測する．また，匂い情報のマッチングとメタ情報による情報サービスに関する研究を行う．.

安全・安心のためのバイオエレクトロニクス技術の研究開発とセンシングLSI化
2007.06～2012.03, 代表者：都甲 潔, 九州大学, 文部科学省
知的クラスター シリコンシーベルト福岡プロジェクト第二ステージ
表記プロジェクト研究テーマのサブプロジェクトである「匂いセンサ開発」に関する研究
異臭悪臭を検知することで人の状態を測定するための高機能匂いセンサを開発する（プロジェクトリーダー）.

感性バイオセンサの開発
2006.04～2013.03, 代表者：都甲 潔, 九州大学, JST　科学研究費　基盤研究S（2006-2010）
JST　科学研究費　基盤研究A（2011-2013）
脂質膜を用いた味覚センサ，機能性表面を持った匂いセンサの開発により感性の計測を行うセンサシステムを開発する．.

微小電気化学セルアレイによる匂いコードセンシング
2008.04～2011.03, 代表者：林　健司, 九州大学, 文部科学省
科学研究費 基盤研究B
匂い分子認識表面を有する匂いセンサアレイを作成し，電気化学法により測定することで，匂い情報としての匂いコードを得るセンサシステムを構築する．.

辛味センサの開発
2007.05～2010.03, 代表者：林　健司, 九州大学, 株式会社インテリジェントセンサーテクノロジー，農林水産省
辛味センサのための受容表面を設計する．.

セキュリティー用途向け超高感度匂いセンサシステムの開発
2005.10～2011.03, 代表者：都甲　潔, 九州大学, 科学技術振興機構
バイオセンサによるポータブル爆発物検知用センサの開発．.

食品の異臭検知バイオセンサの開発
2006.04～2009.03, 代表者：松本　潔, 九州大学, NEDO
バイオセンサによる着香物質検知用センサの開発．.

匂い検出・再生通信システムの開発研究
2006.04～2007.03, 代表者：林　健司, システム情報科学研究院, 関西電力株式会社
匂いのコードにより匂いの再生を行うシステムと方式を開発する．.

オンサイト型環境汚染物質高感度迅速分析システムの開発
2005.05～2007.03, 代表者：国武豊喜, 北九州市立大学, 九州経済産業局，北九州産業学術推進機構
土壌中の重金属を超高感度に分析するシステムを開発する．.

バイオミメティック匂いセンサの開発
2005.04～2007.03, 代表者：都甲潔，I. Lundstrom, 九州大学，Linkoping大学, 科学技術振興機構
バイオミメティック匂いセンサのための表面開発.

分子認識による超高感度火災検知センサの開発
2004.06～2007.03, 代表者：都甲　潔, 九州大学, 消防庁防災研究所 消防防災科学技術研究推進制度
初期火災時に発生する異臭物質を超高感度に分子認識するセンサを開発する．.

主要著書

主要原著論文

1.	Bin Chen, Chuanjun Liu, Lingpu Ge, Liang Shang, Hao Guo, Kenshi Hayashi, AuNU Dimers on ITO Substrate With the Highest Refractive Index Sensitivity as Chemical Sensor, IEEE Sensors Journal, 10.1109/JSEN.2022.3155792, 22, 8, 7580-7589, 2022.04, We synthesized gold (Au) nano-urchins (AuNUs) and deposited these AuNUs on indium tin oxide (ITO) glass. We compared the influence of the resistance of ITO glass and the deposition density of NUs on refractive index sensitivity (RIS) of these ITO substrates, and found that ITO glass with resistance of 8-12/sq and substrates with many AuNU dimers gave the highest RIS which was as high as 455 nm/RIU (refractive index unit), which is the highest on substrate as we known. Compared with AuNUs deposited on quartz glass, the extinction peak intensity and RIS were enhanced on ITO glass. The RIS enhancement is mainly attributed to the considerably enhanced electric field at the tips of AuNUs, electrical hot spots generated by AuNU aggregates (such as dimers), and the repulsive forces decrease in each AuNU by the ITO layer. It is thought that further shape, distribution, and size change of AuNUs and dimers on ITO glass will greatly affect the RIS and spectral characteristics. AuNU substrate is then proposed for heparin detection through Au etching. The results showed that heparin detection was realized in a linear range of 0.05 to 5μ g/mL with a detection limit of 8 ng/mL, which has potential to be applied in the practical environment..
2.	Chuanjun Liu, Hitoshi Miyauchi, Kenshi Hayashi, DeepSniffer: A meta-learning-based chemiresistive odor sensor for recognition and classification of aroma oils, Sensors and Actuators B: Chemical, 10.1016/j.snb.2021.130960, 351, 2022.01, A meta-learning algorithm, conventionally used for visual recognition, was applied to the recognition and classification of aroma oils. A printable chemiresistive sensor array was fabricated, based on composites of carbon black with various active materials. Standard aromatherapy kits with 30 types of essential oils were used as targets in an odor sensing experiment. Benefiting from the pattern recognition ability of the fabricated sensor array, a high-quality dataset was obtained with 30 aroma oil classes, in which each class had nine replicate samples. A deep metric learning model, based on a Siamese neural network and a multilayer perceptron, was used to perform the N-way k-shot meta-learning. A test accuracy of over 98.7% was obtained for 31-way 9-shot learning, on discriminating whether the input pair samples were taken from similar or dissimilar classes. The model was effective in extracting meta-features of the aroma oils; this was proved by the improved clustering effect of samples in the spaces of principal components analysis and t-distributed stochastic neighbor embedding. The 30 aroma oils were divided into two datasets according to 6-fold cross-validation: 25 aroma oil classes (plus one blank class) as seen classes for constructing 26-way 9-shot learning models and the remaining five aroma oils as unseen classes for prediction. Average accuracies of 93.5% and 93.9% were achieved for recognition of the unseen aroma oils from the seen classes and classification of the unseen aroma oils themselves, respectively, demonstrating the effectiveness of the developed sensor and model for odor recognition and classification..
3.	Sunil Kumar Jha, Jian Zhang, Kenshi Hayashi, Chuanjun Liu, Identification of discriminating chemical compounds in banana species and their odor characterization using GC–MS, statistical, and clustering analysis, Journal of Food Science and Technology, 10.1007/s13197-021-05298-9, 59, 1, 402-408, 2022.01, The study aims identification of discriminating chemical constituents in the banana odor grown in Philippines and Ecuador using GC–MS characterization. Ester is recognized as a major chemical class in selected banana odor. Odors discriminating compounds like, 2-hexenal, ethyl acetate, and hexanoic acid, ethyl ester, etc. have been identified. Besides, other odors generating chemical compounds (alcohols, esters, aldehydes, and ketones) have been recognized. Furthermore, principal component analysis (PCA) and hierarchical cluster analysis were implemented to differentiate banana odors. PCA achieved 100% discrimination of selected bananas odors using the peak area information about recognizing chemical compounds. Odor identity and discrimination of selected bananas have been achieved successfully..
4.	Shiyi Zhang, Joseph Wang, Kenshi Hayashi, Fumihiro Sassa, Monolithic processing of a layered flexible robotic actuator film for kinetic electronics, Scientific Reports, 10.1038/s41598-021-99500-9, 11, 1, 2021.12, Low-invasive soft robotic techniques can potentially be used for developing next-generation body–machine interfaces. Most soft robots require complicated fabrication processes involving 3D printing and bonding/assembling. In this letter, we describe a monolithic soft microrobot fabrication process for the mass production of soft film robots with a complex structure by simple 2D processing of a robotic actuator film. The 45 µg/mm2 lightweight film robot can be driven at a voltage of CMOS compatible 5 V with 0.15 mm−1 large curvature changes; it can generate a force 5.7 times greater than its self-weight. In a durability test, actuation could be carried out over 8000 times without degradation. To further demonstrate this technique, three types of film robots with multiple degrees of freedom and a moving illuminator robot were fabricated. This technique can easily integrate various electrical circuits developed in the past to robotic systems and can be used for developing advanced wearable sensing devices; it can be called “Kinetic electronics”..
5.	Arata Sawada, Fumihiro Sassa, Kenshi Hayashi, Estimation of Distributed Concentration of Mixed Gases Using Au/Ag Core-Shell 2D LSPR Gas Sensor, Proceedings of IEEE Sensors, 10.1109/SENSORS47087.2021.9639593, 2021-October, 2021.10, A two-dimensional gas sensor with distributed response characteristics was fabricated by depositing silver in a pattern on an AuNPs substrate, and a method to estimate multiple mixed gas concentrations using the fabricated substrate was proposed. We also proposed a method to estimate multiple gas concentrations using the fabricated substrates with linear analysis. The gas concentrations were calculated using the different response characteristics distributed on the fabricated Au/AgNPs LSPR (Localized Surface Plasmon Resonance) 2D gas sensor elements having sub-pixel patterns adjusted by image analysis. Linear regression analysis was employed to successfully estimate the gas concentration. This sensor device is expected to be applied to gas image sensors that can visualize odor and gas distribution..
6.	Xiao Ye, Tianshu Jiang, Lingpu Ge, Fumihiro Sassa, Chuanjun Liu, Kenshi Hayashi, Paper-based Chemiresistive Gas Sensor Using Molecularly Imprinted Sol-Gels for Volatile Organic Acids Detection, Proceedings of IEEE Sensors, 10.1109/SENSORS47087.2021.9639251, 2021-October, 2021.10, Volatile organic acids are important compounds related to specific diseases from human body odor. In this research, paper-based chemiresistive gas sensor was proposed based on inkjet printing technology using desktop inkjet printer. We formulated an alcoholic-based ketjen black ink to construct conductive layer. In addition, molecularly imprinted sol-gels ink was synthesized to realize specific selectivity. To obtain best sensor performance, the main two parameters, template concentration and crosslinker/monomer ratio, were optimized. This work demonstrated that the paper-based MISG gas sensor have a great potential for rapid, sensitive, and selective gas detection..
7.	Lin Chen, Hao Guo, Fumihiro Sassa, Bin Chen, Kenshi Hayashi, Sers gas sensors based on multiple polymer films with high design flexibility for gas recognition, Sensors, 10.3390/s21165546, 21, 16, 2021.08, The Surface-Enhanced Raman Scattering (SERS) technique is utilized to fabricate sensors for gas detection due to its rapid detection speed and high sensitivity. However, gases with similar molecular structures are difficult to directly discriminate using SERS gas sensors because there are characteristic peak overlaps in the Raman spectra. Here, we proposed a multiple SERS gas sensor matrix via a spin-coating functional polymer to enhance the gas recognition capability. Poly (acrylic acid) (PAA), Poly (methyl methacrylate) (PMMA) and Polydimethylsiloxane (PDMS) were employed to fabricate the polymer film. The high design flexibility of the two-layer film was realized by the layer-by-layer method with 2 one-layer films. The SERS gas sensor coated by different polymer films showed a distinct affinity to target gases. The principle component analysis (PCA) algorithm was used for the further clustering of gas molecules. Three target gases, phenethyl alcohol, acetophenone and anethole, were perfectly discriminated, as the characteristic variables in the response matrix constructed by the combination of gas responses obtained 3 one-layer and 3 two-layer film-coated sensors. This research provides a new SERS sensing approach for recognizing gases with similar molecular structures..
8.	Lingpu Ge, Xiao Ye, Bin Chen, Chuanjun Liu, Hao Guo, Fumihiro Sassa, Kenshi Hayashi, Chemiresistor sensor matrix prepared by full-printing processes, Flexible and Printed Electronics, 10.1088/2058-8585/abec19, 6, 1, 2021.03, Herein, we report a novel full printing process for fabricating chemiresistor gas sensor matrixes on photographic paper with an inkjet printer. Sensor matrices, which can increase a number of sensors significantly compared to a serial sensor array, were printed on one piece of A4 photographic paper. Each sensor matrix contains 36 interdigital electrodes in an area of less than 11 mm2, which greatly improves the density of the sensor. The basic architecture of the sensor matrix is electrodes that row and column intersecting. In order to insulate the row and column electrodes from meeting each other, an insulating layer needs to be fabricated at the point of intersection between the row and column electrodes. The insulation layer was produced by adjusting the number of printing passes and shape of the printing pattern of color pigment ink. Carbon black (CB) was used to form a chemosensitive composite by changing its resistivity with a specific polymer for the preparation of sensing material. In order to make the sensing material can be printed, it is necessary to disperse CB first. CB was dispersed in aqueous solution with sodium dodecyl sulfate added as a surfactant to lower the surface tension, which enabled printing of CB using an inkjet printer. Some polymers have certain adsorption characteristics for gases. According to the different gas properties, the adsorption characteristics are also different. By adding polyethylene glycol polymer to the CB layer, the response to four gases with different properties is improved. Compared with the drop coating, the full-printing sensors not only reduces the production time significantly, but also improves the gas response magnitude to ethanol by about three times. The results demonstrate that the developed sensor can be used as a low cost, disposable, and easily printable chemical sensor..
9.	Bin Chen, Hao Guo, Chuanjun Liu, Liang Shang, Xiao Ye, Lin Chen, Changhao Feng, Kenshi Hayashi, Molecularly imprinted sol-gel/Au@Ag core-shell nano-urchin localized surface plasmon resonance sensor designed in reflection mode for detection of organic acid vapors, Biosensors and Bioelectronics, 10.1016/j.bios.2020.112639, 169, 2020.12, A molecularly imprinted sol-gel (MISG)/Au@Ag core-shell NU sensor is proposed for organic vapor detection in an optical fiber-based reflection mode. The compact structure design of the system in the reflection model is promising for practical use as a portable and rapid responsivity sensing probe. Volatile organic acids (OAs) are analogs to biogenetic volatile organic vapors related to specific human diseases. Here, Au@Ag core-shell nano-urchins exhibiting branched tips were synthesized and deposited on indium tin oxide (ITO) glass in small dimer and trimmer clusters to generate an enhanced electric field. A MISG solution was then spin-coated on the substrate to fabricate MISG-LSPR sensors, and three types of MISGs were developed for the detection of hexanoic acid, heptanoic acid and octanoic acid. The normalized spectral response indicated selectivity of the MISG-LSPR sensors for the corresponding template OAs. With Native Bayes and linear discriminant analysis of the sensor responses, where the latter were detected by the proposed system, single- and mixed-OA vapors could be classified into separate clusters. This signified that the proposed MISG-LSPR sensor can be applied toward pattern recognition of single vapors or multiple vapor mixtures..
10.	Bin Chen, Chuanjun Liu, Liang Shang, Hao Guo, Jiongming Qin, Lingpu Ge, Chun Ju Jing, Changhao Feng, Kenshi Hayashi, Electric-field enhancement of molecularly imprinted sol–gel-coated Au nano-urchin sensors for vapor detection of plant biomarkers, Journal of Materials Chemistry C, 10.1039/c9tc05522c, 8, 1, 262-269, 2020.11, [URL], The response of MISG@Au nano-urchin sensors indicated that selectivities of the MISG@Au nano-urchin sensors to the corresponding plant biomarker VOCs were generated via the branched tips of Au nano-urchins and their electric field coupling effects. .
11.	Kohei Semasa, Fumihiro Sassa, Kenshi Hayashi, 2D LSPR gas sensor with Au/Ag core-shell structure coated by fluorescent dyes, Proceedings of IEEE Sensors, 10.1109/SENSORS47125.2020.9278828, 2020-October, 2020.10, LSPR (Localized Surface Plasmon Resonance) based 2D (Two-dimensional) gas sensor system which can measure and identify multi-gases with high spatial resolution have been developed. The gas sensor detects optical changes promoted by the gas on the LSPR substrate with hyperspectral camera. Basically, LSPR gas sensor does not have a molecular selectivity, then the identification of gas species is difficult. To overcome the disadvantage, LSPR substrates based on Au/Ag core-shell structure with spectral gas-discriminating ability through optical interaction were fabricated by spin coating fluorescent dyes. Using the LSPR coupled with fluorescent dyes, this sensor provides rich spectral information about the detecting molecules and can discriminates gas species..
12.	Yasuhiro Kusuda, Zhongyuan Yang, Kohei Semasa, Fumihiro Sassa, Kenshi Hayashi, Odor Source Detection with High Speed Multi Gas Sensing Robot System using AuNPs-Fluorescent Molecular coupling Opt-Chemical LSPR Sensor, Proceedings of IEEE Sensors, 10.1109/SENSORS47125.2020.9278605, 2020-October, 2020.10, The Localized Surface Plasmon Resonance (LSPR) gas sensor is a promising for mounting on the robot due to an advantage of high-speed response speed and low power consumption. In addition, it is possible to change the characteristic by coating fluorescent dye on the LSPR surface. In this research, we have developed a robot equipped with multi LSPR gas sensor module for the purpose of the identification of gas species..
13.	Lin Chen, Noriko Shiramatsu, Bin Chen, Fumihiro Sassa, Shoichi Sameshima, Tatsuya Seki, Kenshi Hayashi, Ultra-high Sensitive SERS Gas Sensor to detect Geosmin, Proceedings of IEEE Sensors, 10.1109/SENSORS47125.2020.9278909, 2020-October, 2020.10, Geosmin (GSM) with an earthy odor resembling is often accompanied by 2-methylisoborneol (MIB), which caused the earthy and musty taste of drinking water. To detect trace GSM solution, we designed gas sensor by Surface-enhanced Raman Scattering (SERS) technology which has the capacity of single molecule detection. With our ultra-high sensitivity detection system, response range from 10 ppt to 10 ppb geosmin in ultrapure water was confirmed. Additionally, 100 ppt geosmin in tap water was detectable..
14.	Shoffi Izza Sabilla, Riyanarto Sarno, Kuwat Triyana, Kenshi Hayashi, Deep learning in a sensor array system based on the distribution of volatile compounds from meat cuts using GC–MS analysis, Sensing and Bio-Sensing Research, 10.1016/j.sbsr.2020.100371, 29, 2020.08, Generally, people distinguish the type of meat by looking at the color, texture, and even aroma of meat. These three methods have less effective approaches to distinguish the types of meat from meat cuts. Some researchers analyze the differences in the aroma of meats by using laboratory equipment, which is gas chromatography–mass spectrometry (GC–MS). This tool is mostly accurate, but it requires some time to determine the meat types completely. Moreover, the analysis process using GC–MS is also complicated. Nowadays, the electronic nose (e-nose) is a promising technology because it has a faster process of identifying various food types with reasonable production costs. Hence, the development of an e-nose for distinguishing volatile compounds from some meat types is appealing. Not only to determine the type of meat, but this study can also differentiate the part of the body from the meat, which has never been done by previous researchers. GC–MS was used as ground truth for the e-nose system, which helped the results to meet the standards. To achieve the objective in differentiating two meat cuts from three types of meat, this study uses statistical parameters for extraction feature, PCA for reducing the dimension, and deep learning. Furthermore, to get more improvements from the previous researches, this study aims to optimize the parameters of deep learning. The result of the proposed method was compared to several machine learning algorithms that were used in previous studies, i.e., k-nearest neighbor (k−NN), support vector machine (SVM), Multi-Layer Perceptron (MLP), and basic deep learning. The experimental results showed that e-nose could detect meat cuts for 120 s, and the proposed method provides a significant improvement..
15.	Takaaki Soeda, Zhongyuan Yang, Fumihiro Sassa, Yoichi Tomiura, Kenshi Hayashi, 2D LSPR multi gas sensor array with 4-segmented subpixel using Au/Ag core shell structure, Proceedings of IEEE Sensors, 10.1109/SENSORS43011.2019.8956635, 2019-October, 2019.10, LSPR (Localized Surface Plasmon Resonance) based 2D (2 Dimensional) gas imaging sensor system which can capture spatial distribution of each constituent of mixed gas have been developed. The gas image sensor detects the gas promoted optical changes occurred on the LSPR substrate by CCD camera. Basically, LSPR gas sensor does not have a molecular selectivity, then the identification of gas species is difficult. To overcome the disadvantage, pixelated LSPR substrate based on Au/Ag core-shell structure which has different gas response properties is fabricated by photo-induced metal growth by mask-less exposure system using a commercial video projector..
16.	Lingpu Ge, Bin Chen, Hiroki Kawano, Fumihiro Sassa, Kenshi Hayashi, Inkjet-printed Gas Sensor Matrix with Molecularly Imprinted Gas Selective Materials, Proceedings of IEEE Sensors, 10.1109/SENSORS43011.2019.8956795, 2019-October, 2019.10, This paper introduces a new method to fabricate a large - scale sensor array. By printing electrodes on photographic paper and making insulating layers, 6×6 arrays of sensors were obtained. Different gas selective can be printed in different units to detect different gases. Thus, production of multiple sensors in a small area with low cost was realized. On a piece of A4 photo paper, 30 sensor matrices can be printed at the same time. Each sensor array has 36 sensing units, thus theoretically identifying up to 36 gases. The sensor is suitable to be used in wearable devices to identify human skin gases due to its flexible substrate, low production cost and simple manufacturing process. In this experiment, molecular imprinted polymer (MIP) solution [1], carbon black (C.B.) conductive solution and insulating solution are prepared as ink, which can be used for ink-jet printer printing. This makes the method of developing the sensor more flexible. Compared with the sensor developed by micropipette to drop the MIP solution and C.B. conductive solution, the sensor developed by a printer has better uniformity..
17.	Yasuhiro Kusuda, Zhongyuan Yang, Takaaki Soeda, Fumihiro Sassa, Kenshi Hayashi, Invisible Odor Trace Tracking with LSPR based High Speed Gas Sensor Robot System, Proceedings of IEEE Sensors, 10.1109/SENSORS43011.2019.8956599, 2019-October, 2019.10, Various odor robots have been developed for finding gas sources. However, the response speed of sensors is now a major limit for the promotion of odor robot using chemical substances information. In this research, we have developed a robot equipped with two LSPR (Localized Surface Plasmon Resonance) gas sensor module that can quickly respond to gas molecules at a high speed of above 25 Hz and set a specific algorithm for tracking the invisible odor line on the ground..
18.	Lin Chen, Bin Chen, Fumihiro Sassa, Kenshi Hayashi, Multi-layer Filter Structure for Molecular Selective SERS Gas Sensor, Proceedings of IEEE Sensors, 10.1109/SENSORS43011.2019.8956884, 2019-October, 2019.10, Mixture of gas molecules must be accurately detected for gas sensor. However, there are certain difficulties in identifying the type of gas and detecting its concentration by chemical sensors. SERS (Surface Enhanced Raman Scattering) is a promising method for high sensitive gas detection because of its ability of molecule discrimination. However, it is difficult for SERS sensor to identify gases with the similar structure. In this research, we have developed a more selective SERS sensor with molecular filter layers. Molecular filter property is studied by coating a filter polymer film on the SERS substrate. The characteristics of the sensor with two membrane structures were also studied and different filtering properties were obtained..
19.	Bin Chen, Chuanjun Liu, Liang Shang, Ying Huang, Shaohua Yang, Xiaoyan Sun, Changhao Feng, Kenshi Hayashi, Electron transfer during binding processes between thiolate molecules and Au nano-islands, Applied Surface Science, 10.1016/j.apsusc.2018.12.138, 473, 49-54, 2019.04, [URL], We investigated electron transfer during the time-dependent binding processes between thiolate molecules and Au nano-islands by observing tunneling current with an interdigitated microelectrode supporting the sputtered Au nano-islands (IME@AuNI). The time-dependent optical and electrical signal variation during the binding process was examined for five kinds of thiolates. As the immersion time was prolonged, the optical absorbance increased, whereas the current passing through the IME@AuNI decreased. Importantly, the spectral and current characteristics depended on the thiolate structure, because of the formation of capping layer in accordance with thiolate structure. These results are mainly attributed to synergistic effects of electron transfer from Au nano-islands to thiolate molecules and bridging effects of thiolate molecules among Au nano-islands..
20.	Fumihiro Sassa, Chuanjun Liu, Kenshi Hayashi, Visualization of odor space and quality, Chemical, Gas, and Biosensors for Internet of Things and Related Applications, 10.1016/B978-0-12-815409-0.00018-8, 253-269, 2019.01, Our living environment is surrounded by a variety of odors. The visualized detection of odorant molecules may explore many new applications that cannot be realized by conventional sensors. This chapter introduces some novel sensing technologies that can be used to visualize both the odor space and odor quality. Fluorescence imaging sensors are developed to record the shape of odor sources and the spatiotemporal distribution of odor flows. Multispectral imaging-based odor visualization shows power in the structure-related discrimination of different odorant molecules. Localized surface plasmon resonance (LSPR) sensors based on metal nanoparticles show advantages in high-speed response and recovery in gas or vapor sensing. A sensor robot based on the LSPR sensors is developed to visualize the odor information from on-ground odor sources. In addition, data analysis based on physicochemical parameters of odorant molecules is carried out to demonstrate the difference of odor quality by using network-graph techniques..
21.	Liang Shang, Chuanjun Liu, Bin Chen, Kenshi Hayashi, Plant Biomarker Recognition by Molecular Imprinting Based Localized Surface Plasmon Resonance Sensor Array Performance Improvement by Enhanced Hotspot of Au Nanostructure, ACS Sensors, 10.1021/acssensors.8b00329, 3, 8, 1531-1538, 2018.08, [URL], Detection of plant volatile organic compounds (VOCs) enables monitoring of pests and diseases in agriculture. We previously revealed that a localized surface plasmon resonance (LSPR) sensor coated with a molecularly imprinted sol-gel (MISG) can be used for cis-jasmone vapor detection. Although the selectivity of the LSPR sensor was enhanced by the MISG coating, its sensitivity was decreased. Here, gold nanoparticles (AuNPs) were doped in the MISG to enhance the sensitivity of the LSPR sensor through hot spot generation. The size and amount of AuNPs added to the MISG were investigated and optimized. The sensor coated with the MISG containing 20 μL of 30 nm AuNPs exhibited higher sensitivity than that of the sensors coated with other films. Furthermore, an optical multichannel sensor platform containing different channels that were bare and coated with four types of MISGs was developed to detect plant VOCs in single and binary mixtures. Linear discriminant analysis, k-nearest neighbor (KNN), and naïve Bayes classifier approaches were used to establish plant VOC identification models. The results indicated that the KNN model had good potential to identify plant VOCs quickly and efficiently (96.03%). This study demonstrated that an LSPR sensor array coated with a AuNP-embedded MISG combined with a pattern recognition approach can be used for plant VOC detection and identification. This research is expected to provide useful technologies for agricultural applications..
22.	Zhongyuan Yang, Fumihiro Sassa, Kenshi Hayashi, A robot equipped with a high-speed LSPR gas sensor module for collecting spatial odor information from on-ground invisible odor sources, ACS Sensors, 10.1021/acssensors.8b00214, 3, 6, 1174-1181, 2018.06, [URL], Improving the efficiency of detecting the spatial distribution of gas information with a mobile robot is a great challenge that requires rapid sample collection, which is basically determined by the speed of operation of gas sensors. The present work developed a robot equipped with a highspeed gas sensor module based on localized surface plasmon resonance. The sensor module is designed to sample gases from an on-ground odor source, such as a footprint material or artificial odor marker, via a fine sampling tubing. The tip of the sampling tubing was placed close to the ground to reduce the sampling time and the effect of natural gas diffusion. On-ground ethanol odor sources were detected by the robot at high resolution (i.e., 2.5 cm when the robot moved at 10 cm/s), and the reading of gas information was demonstrated experimentally. This work may help in the development of environmental sensing robots, such as the development of odor source mapping and multirobot systems with pheromone tracing..
23.	Zhongyuan Yang, Fumihiro Sassa, Kenshi Hayashi, A Robot Equipped with a High-Speed LSPR Gas Sensor Module for Collecting Spatial Odor Information from On-Ground Invisible Odor Sources, ACS SENSORS, 10.1021/acssensors.8b00214, 3, 6, 1174-1181, 2018.06, [URL], Improving the efficiency of detecting the spatial distribution of gas information with a mobile robot is a great challenge that requires rapid sample collection, which is basically determined by the speed of operation of gas sensors. The present work developed a robot equipped with a highspeed gas sensor module based on localized surface plasmon resonance. The sensor module is designed to sample gases from an on-ground odor source, such as a footprint material or artificial odor marker, via a fine sampling tubing. The tip of the sampling tubing was placed close to the ground to reduce the sampling time and the effect of natural gas diffusion. On-ground ethanol odor sources were detected by the robot at high resolution (i.e., 2.5 cm when the robot moved at 10 cm/s), and the reading of gas information was demonstrated experimentally. This work may help in the development of environmental sensing robots, such as the development of odor source mapping and multirobot systems with pheromone tracing..
24.	Xiaoguang Ying, Hiro-Taka Yoshioka, Chuanjun Liu, Fumihiro Sassa, Kenshi Hayashi, Molecular imprinting technique in putrescine visualized detection, SENSORS AND ACTUATORS B-CHEMICAL, 10.1016/j.snb.2017.11.128, 258, 870-880, 2018.04, [URL], This work is an exploration into visualizing measurement of putrescine specific adsorption by photographing colorized molecule imprinting chromogenic hydrogel. Membranes are prepared with imitate templates 1,4-butylene glycol, adipic acid or succinic acid, respectively and ninhydrin is used as chromogenic agent for target molecule putrescine. The adsorbing concentration on MIP is reflected in the form of visible violet-colored stain differed in shape and shade, which are recorded by hyper spectral camera and proceeded into intuitive 3D isohypse surfaces plot. By quantifying the height of surface peaks, imprinting efficiency is estimated in accordance with polyvinyl alcohol concentration and crosslinking degree. The imprinting efficiency of three imitate molecule templates is also discussed. (C) 2017 Elsevier B.V. All rights reserved..
25.	Chuanjun Liu, Liang Shang, Hiro Taka Yoshioka, Bin Chen, Kenshi Hayashi, Preparation of molecularly imprinted polymer nanobeads for selective sensing of carboxylic acid vapors, Analytica Chimica Acta, 10.1016/j.aca.2018.01.004, 1010, 1-10, 2018.01, [URL], The detection and discrimination of volatile carboxylic acid components, which are the main contributors to human body odor, have a wide range of potential applications. Here, a quartz crystal microbalance (QCM) sensor array based on molecularly imprinted polymer (MIP) nanobeads is developed for highly sensitive and selective sensing of typical carboxylic acid vapors, namely: propionic acid (PA), hexanoic acid (HA) and octanoic acid (OA). The MIP nanobeads were prepared by precipitation polymerization with methacrylic acid (MAA) as a functional monomer, trimethylolproane trimethacrylate (TRIM) as a crosslinker, and carboxylic acids (PA, HA and OA) as the template molecules. The precipitation polymerization resulted in nano-sized (150-200 nm) polymer beads with a regular shape. The polymerization conditions were optimized to give a functional monomer, crosslinker, and template ratio of 1:1:2. We investigated the imprinting effect using both QCM and GC/MS measurements comparing vapor absorption characteristics between the imprinted and non-imprinted (NIP) nanobeads. A four-channel QCM sensory array based on the NIP and the three types of MIP nanobeads was fabricated for sensing the three types of carboxylic acid vapor at concentrations on the ppm level. The output of the sensor array was analyzed by both a non-supervised method (principle component analysis: PCA) and supervised method (linear discrimination analysis: LDA). LDA showed a better discrimination ability than PCA. A 96%-classification rate was achieved by applying leave-one-out cross-validation to the LDA model. The high sensitivity and selectivity of the sensor array was attributed to the imprinting effect of the nano-sized polymer beads. The developed MIP nanobeads, together with other types of MIPs, show promise as materials for artificial receptors in vapor and odorant sensing..
26.	Liang Shang, Chuanjun Liu, Yoichi Tomiura, Kenshi Hayashi, Machine-Learning-Based Olfactometer Prediction of Odor Perception from Physicochemical Features of Odorant Molecules, Analytical Chemistry, 10.1021/acs.analchem.7b02389, 89, 22, 11999-12005, 2017.11, [URL], Gas chromatography/olfactometry (GC/O) has been used in various fields as a valuable method to identify odor-active components from a complex mixture. Since human assessors are employed as detectors to obtain the olfactory perception of separated odorants, the GC/O technique is limited by its subjectivity, variability, and high cost of the trained panelists. Here, we present a proof-of-concept model by which odor information can be obtained by machine-learning-based prediction from molecular parameters (MPs) of odorant molecules. The odor prediction models were established using a database of flavors and fragrances including 1026 odorants and corresponding verbal odor descriptors (ODs). Physicochemical parameters of the odorant molecules were acquired by use of molecular calculation software (DRAGON). Ten representative ODs were selected to build the prediction models based on their high frequency of occurrence in the database. The features of the MPs were extracted via either unsupervised (principal component analysis) or supervised (Boruta, BR) approaches and then used as input to calibrate machine-learning models. Predictions were performed by various machine-learning approaches such as support vector machine (SVM), random forest, and extreme learning machine. All models were optimized via parameter tuning and their prediction accuracies were compared. A SVM model combined with feature extraction by BR-C (confirmed only) was found to afford the best results with an accuracy of 97.08%. Validation of the models was verified by using the GC/O data of an apple sample for comparison between the predicted and measured results. The prediction models can be used as an auxiliary tool in the existing GC/O by suggesting possible OD candidates to the panelists and thus helping to give more objective and correct judgment. In addition, a machine-based GC/O in which the panelist is no longer needed might be expected after further development of the proposed odor prediction technique..
27.	Liang Shang, Chuanjun Liu, Bin Chen, Kenshi Hayashi, Development of molecular imprinted sol-gel based LSPR sensor for detection of volatile cis-jasmone in plant, Sensors and Actuators, B: Chemical, 10.1016/j.snb.2017.12.123, 260, 617-626, 2017.11, [URL], Detection of cis-jasmone (CJ) enables monitoring of growth pressure in plants, which is especially useful for sensing attacks by herbivores. Here, a sensitive and selective nanocomposite-imprinted, localized surface plasmon resonance (LSPR) sensor for CJ vapor was fabricated. Gold (Au) nano-islands were prepared by vacuum sputtering of Au nanoparticles on a glass substrate, followed by thermal annealing. Titanium molecularly imprinted sol-gels (MISGs) were spin-coated on the Au nano-islands as an adsorption layer for enhancing the selectivity of the optical sensor. Gas molecules were detected by using a small spectrometer to monitor variations in absorption spectra. In addition, the functional monomer and the ratio of matrix materials to functional monomers in the MISGs were investigated and optimized. MISGs that contained the functional monomer trimethoxyphenylsilane at a 3:1(v:v) ratio exhibited a higher sensitivity and selectivity than other films. The optical sensor would have advantages of low cost, selectivity, sensitivity, and repeatability. The limit of CJ detection in air was 3.5 ppm (signal/noise = 3). Thus, the sensor is expected to be a potential tool for CJ monitoring in agriculture applications..
28.	Liang Shang, Chuanjun Liu, Yoichi Tomiura, Kenshi Hayashi, Odorant clustering based on molecular parameter-feature extraction and imaging analysis of olfactory bulb odor maps, Sensors and Actuators, B: Chemical, 10.1016/j.snb.2017.08.024, 255, 508-518, 2017.08, [URL], Progress in the molecular biology of olfaction has revealed a close relationship between the structural features of odorants and the response patterns they elicit in the olfactory bulb. Molecular feature-related response patterns, termed odor maps (OMs), may represent information related to basic odor quality. Thus, studying the relationship between OMs and the molecular features of odorants is helpful for better understanding the relationships between odorant structure and odor. Here, we explored the correlation between OMs and the molecular parameters (MPs) of odorants by taking OMs from rat olfactory bulbs and extracting feature profiles of the corresponding odorant molecules. 178 images of glomerular activities in olfactory bulb that are corresponding to odorants were taken from the OdorMapDB, a publicly accessible database. The gray value of each pixel was extracted from the images (178 × 357 pixels) to fabricate an image matrix for each odorant. Forty-six molecular feature parameters were calculated using BioChem3D software, which was used to construct a second matrix for each odorant. Correlation analysis between the two matrixes was first carried out by establishing coefficient maps. Results from hierarchical clustering showed that all parameters could be segregated into seven clusters, and each cluster showed a relatively similar response pattern in the olfactory bulb. Using the information from the OMs and MPs, we mapped odorants in 2D space by incorporating dimension-reducing techniques based on principal component analysis (PCA) and t-distributed stochastic neighbor embedding (t-SNE). Artificial neural network models based on the OM and MP feature values were proposed as a means to identify odorant functional groups. An OM-PCA-based model calibrated via extreme learning machine (ELM) was 94.81% and 93.02% accuracy for the calibration and validation sets, respectively. Similarly, an MP-t-SNE-based model calibrated by ELM was 86.67% and 93.35% accuracy for the calibration set and the validation set, respectively. Thus, this research supports a structure-odor relationship from a data-analysis perspective..
29.	Bin Chen, Chuanjun Liu, Lingpu Ge, Kenshi Hayashi, Electrical conduction and gas sensing characteristics of P3HT/Au nano-islands composite, Sensors and Actuators B: Chemical, 10.1016/j.snb.2016.10.030, 241, 1099-1105, 2017.03, [URL], Poly (3-hexylthiophene) (P3HT)/Au nano-islands composite was deposited on the interdigital microelectrode (IME) for the electrical conduction and gas sensing characteristics measurement. The conduction characteristic was verified to be Au nano-islands sputtering time dependent. Long sputtering time would form large-sized, closely-packed, and inter-connected Au nano-islands with irregular shape. As discussed in our previous work, there existed the mutual effects between the surface plasmon resonance of Au nano-islands and P3HT, which helped to increase the conduction. Herein, IME under 90 s Au sputtering and 60 °C heating presented the best gas sensing performance instead of longer sputtering time such as 150 s. This result implied that gas sensing characteristics of P3HT/Au nano-islands composite depended on the coupling condition between the localized surface plasmon resonance of Au nano-islands and P3HT molecules instead of the conductance characteristics..
30.	Masashi Watanabe, Chuanjun Liu, Kenshi Hayashi, Growth orientation control of metal nanostructures using linearly polarized light irradiation, THIN SOLID FILMS, 10.1016/j.tsf.2016.11.039, 621, 137-144, 2017.01, Controlled orientation of metal nanostructures on a solid substrate was realized by irradiating a pre-deposited nanoseed layer with linearly polarized light in a growth solution containing metal cations. The resulted nanostructures showed the different transmittance spectra for two orthogonal polarized lights, which indicated an anisotropic growth induced by polarized light. The investigation on the growth conditions demonstrated that the wavelength of the irradiated light and the existence of cetyl cetyltrimethylammonium bromide used as surfactant could affect the anisotropic degree of the oriented nanostructures. It was suggested that the polarized lights enhanced the anisotropic local electric field of Au seed nanoparticles, which resulted in the oriented growth of metal nanostructures during the reduction process in the solution. The approach reported in this work can be used in the device fabrication based on oriented metal nanostructures, such as photocatalysts or optical sensors..
31.	Liang Shang, Chuanjun Liu, Masashi Watanabe, Bin Chen, Kenshi Hayashi, LSPR sensor array based on molecularly imprinted sol-gels for pattern recognition of volatile organic acids, Sensors and Actuators, B: Chemical, 10.1016/j.snb.2017.04.048, 249, 14-21, 2017.01, [URL], Volatile organic acids are important compounds contained in human body odor. The detection and recognition of volatile organic acids in human body odor are significant in many areas. The present study explored a possibility to use localized surface plasmon resonance (LSPR) of Au nanoparticles (AuNPs) and molecularly imprinted sol-gels (MISGs) as the sensitive layer to recognize typical organic acid odorants, propanoic acid (PA), hexanoic acid (HA), heptanoic acid (HPA) and octanoic acid (OA), from human body. The LSPR layer was prepared by vacuum sputtering of AuNPs on a glass substrate and consequently thermal annealing. The sensitive layer was fabricated by spin-coating molecularly imprinted titanate sol-gel on the AuNPs layer. A homemade optical device was developed to detect the change of transmittance, which was caused by the index changes of organic acid vapors where selecting absorbed by the MISG layers. It was found that compared with MISG coated samples, samples coated with non-imprinted sol gel (NISG) shown no responses to any acid vapors. For the MISG coated sensors, the LSPR sensitivity was affected by the spin coating speed. In addition, a sensor array based on MISGs with different templates (HA, HPA and OA) was constructed to detect the organic acids in single and their binary mixtures. The sensor response was analyzed by principal component analysis (PCA) and linear discriminant analysis (LDA). A 100% classification rate was achieved by leave-one-out cross-validation technique for LDA model. This work demonstrated that the MISGs coated LSPR sensor array has a great potential in organic acid odor recognition of human body odor..
32.	Bin Chen, Chuanjun Liu, Lingpu Ge, Kenshi Hayashi, Localized surface plasmon resonance gas sensor of Au nano-islands coated with molecularly imprinted polymer: Influence of polymer thickness on sensitivity and selectivity, SENSORS AND ACTUATORS B-CHEMICAL, 10.1016/j.snb.2016.03.117, 231, 787-792, 2016.08, α-Pinene is a kind of biomarker vapors emitted by plant during metabolism process. In this work, A localized surface plasmon resonance (LSPR) sensors based on the large and closely-packed Au nano-islands were propose to be coupled with the molecularly imprinted polymer (MIP) film for α-pinene vapor detection. Au nano-island film was prepared through repeated Au sputtering and annealing with cycles as many as 18. MIPα-pinene was prepared using methacylic acid as monomer, ethylene glycol dimethylacrylate as cross-linker, and α-pinene as the template molecule. Pre-polymerized MIPα-pinene solution was spin-coated on Au nano-island films at a series of speeds. The influence of spin coating speed on polymer thickness and target vapor binding capability was investigated. The result demonstrated that thick polymer layer could bind more template molecules than the thin one, which verified our speculation that there were more specific template binding sites in thick polymer layer. In addition, the in-situ response of MIPα-pinene coated Au nano-island film to α-pinene vapor was verified to be rapid (in less than 10 s) and reversible. The selective α-pinene vapor adsorption and absorption characteristics of MIPα-pinene coated Au nano-islands film to α-pinene vapor was observed comparing with the responses to γ-terpinene and limonene vapors..
33.	Bin Chen, Chuanjun Liu, Yiyuan Xie, Pengfei Jia, Kenshi Hayashi, Localized Surface Plasmon Resonance Gas Sensor based on Molecularly Imprinted Polymer Coated Au Nano-island Films: Influence of Nanostructure on Sensing Characteristics, IEEE Sensors Journal, 10.1109/JSEN.2016.2536629, 16, 10, 3532-3540, 2016.05, A localized surface plasmon resonance gas sensor based on Au nano-island films coated with molecularly imprinted polymer (MIP) layer was developed to selectively detect terpene vapor emitted from plants. Au nano-islands were deposited on a glass substrate through repeated Au sputtering and annealing. The MIP layer was coated on Au nano-island films by spin-coating a pre-polymerized solution containing methacrylic acid as monomer, ethylene glycol dimethylacrylate as crosslinker, and α-pinene as the template molecule. The influence of nanostructure on the refractive index (RI) sensing characteristics was mainly investigated in this paper. The result demonstrated that the structure of Au nano-island films could be controlled by Au sputtering-annealing cycle. Increase in the sputteringannealing cycle induced the size increase and the inter-particle distance decrease of Au nano-island films. In addition, spectral red shift, decrease in transmittance, and increase in absorbance were observed under this procedure as well. The typical RI sensing evaluation parameters Δλmax, ΔTmin, and ΔAmax achieved the maximum values: 9.75 nm, and 9%, 0.42 under 3 and 18 Au sputtering-annealing cycles. Au nano-island films under 3 and 18 Au sputtering-annealing cycles were coated with the MIP, and the response of MIP-coated Au nano-island sensor to α-pinene vapor was verified to be fast, reversible, and reproducible..
34.	Bin Chen, Masami Mokume, Chuanjun Liu, Kenshi Hayashi, Irradiation Wavelength Dependent Photocurrent Sensing Characteristics of AuNPs/P3HT Composites on Volatile Vapor, IEEE Sensors Journal, 10.1109/JSEN.2015.2487278, 16, 3, 596-602, 2016.02, Gas sensing characteristics of Au nanoparticles (AuNPs)/3-hexylthiophene-2, 5-diyl (P3HT) composite based on photocurrent detection under different irradiation wavelengths were investigated. AuNPs with different structures were prepared either by the vacuum sputtering/annealing method or by the wet chemical synthesis based on seed growth. AuNPs/P3HT composites were prepared by the dip coating method. The optical features of P3HT and Au nanostructure/P3HT composite were investigated. The optical absorption increase of AuNPs film was observed after P3HT coating, which was attributed to the interaction between the P3HT and the Au nano-islands. New shoulder peaks and the phenomenon of one spectral peak splitting into two were observed in the absorption spectra of the composite film, which confirmed the interaction between the AuNPs and the P3HT further. The photoconductivity characteristics of the P3HT and AuNPs with spectral peak position at 580-nm (AuNPs580)/P3HT composite films were investigated utilizing LED light source with different dominate wavelengths. The wavelength-dependent photocurrent change ratio I/I0 of both the P3HT and the AuNPs580/P3HT composite films was observed. The maximum I/I0 of the P3HT and AuNPs580 composite films emerged under LED irradiation with a dominate wavelength 590 nm, which was mainly ascribed to the antenna effect from the Au nano-islands, the carrier injection from nanostucture to P3HT, localized surface plasmon resonance coupling among Au nanostructures, and plasmon coupling between the Au nano-islands and the P3HT molecules. The response of Au nano-island/P3HT composite to ethanol vapor showed that the response and recovery time was shorter than 2 s. Furthermore, gas sensing characteristics were verified to be irradiation wavelength dependent. Irradiation light source with a dominate wavelength 590 nm produced the largest I/I0 1.07..
35.	Hiro-Taka Yoshioka, Chuanjun Liu, Kenshi Hayashi, Multispectral fluorescence imaging for odorant discrimination and visualization, SENSORS AND ACTUATORS B-CHEMICAL, 10.1016/j.snb.2015.07.073, 220, 1297-1304, 2015.12, A concept based on multispectral fluorescence imaging was proposed in this paper for the discrimination and visualization of odorants. Fluorescent dyes with different excitation/emission spectra were mixed into agarose gel to prepare a multiple probe sensing film. Odorants remained in environment were recorded on the sensing film via a process called odorant exposure. The odorant-induced fluorescence change of the film under various excitation lights was captured by a CCD camera to obtain multispectral images. It was demonstrated that the use of multiple fluorescence probes provided discrete emission bands, which increased the dimensions of vector space of the multispectral images. Complicated interactions between probes and probes, probes and odorants resulted in the diversiform fluorescence change patterns of the images. Combined with principal component analysis (PCA), different odorants could be discriminated and clustered in the principal component spaces in association with their molecular structures. A hand-shape odorant mark with region-segmented components was visualized with high spatial resolution. Additionally, the technique also succeeded in the visualized demonstration of an airflow containing mixed odorants. Compared with the existing gas and odor sensing technologies, the multispectral fluorescence imaging can be used not only to discriminate different odorants, but also to visualize their time-averaged spatial distribution in environment. Due to its novelty and high information acquisition ability, it can be expected as a new and powerful tool in odor sensing. (C) 2015 Elsevier By. All rights reserved..
36.	Bin Chen, Masami Mokume, Chuanjun Liu, Kenshi Hayashi, Structure and localized surface plasmon tuning of sputtered Au nano-islands through thermal annealing, Vacuum, 10.1016/j.vacuum.2014.09.005, 110, 94-101, 2014.12, Localized surface plasmon resonance of noble metallic nanoparticles has been widely used in the fabrication of various sensors. Turning the nanostructure of localized surface plasmon resonance is significant because the resonance induced localized surface plasmon resonance shift is found to be strongly dependent on the structural characteristics, and thus the performance of the sensors. A simple sputtering, annealing, re-sputtering, and re-annealing process was proposed to tune the structural and optical characteristics of Au nano-islands deposited on the glass substrate. It was found that the size and inter-particle distance of nano-islands depend on annealing time and temperature. High temperature annealing tended to increase the size and inter-islands distance of Au islands. Re-sputtering and re-annealing under different conditions made size and inter-particle distance further tuning possible. Investigations on the optical characteristics of Au nano-islands demonstrated that the surface plasmon resonance peak and the spectral bandwidth of islands were tunable from 510 nm to 620 nm and from 50 nm to approximately 400 nm, respectively. The refractive index sensitivity of Au nano-islands determined by the surface plasmon band position change in different surrounding medium was compared. 500 °C 5 h annealing increased the value of refractive index sensitivity to approximately 58 nm/RIU from 26 nm/RIU under 100 °C 5 h annealing. Besides, Au nano-islands with the same re-sputtering condition but different re-annealing conditions showed the maximum value when the re-annealing temperature is at 500 °C for 5 h. In addition, the refractive index sensitivity, surface plasmon band position, and figure of merit were dependent with each other. These results suggest that the scheme "sputtering, annealing, re-sputtering, and re-annealing" is an effective method to adjust the structure and increase the refractive index sensitivity of sputtered Au islands..
37.	Masahiro Imahashi, Masashi Watanabe, S. K. Jha, Kenshi Hayashi, Olfaction-inspired Sensing using a Sensor System with Molecular Recognition and Optimal Classification Ability for Comprehensive Detection of Gases, Sensors, 14, 5221-5238, 2014.03.
38.	Bin Chen, Chuanjun Liu, Masashi Watanabe, Kenshi Hayashi, Layer-by-Layer Structured AuNP Sensors for Terpene Vapor Detection, IEEE SENSORS JOURNAL, 10.1109/JSEN.2013.2264803, 13, 11, 4212-4219, 2013.11.
39.	Masahiro Imahashi, Kenshi Hayashi, Concentrating materials covered by molecular imprinted nanofiltration layer with reconfigurability prepared by a surface sol-gel process for gas-selective detection, JOURNAL OF COLLOID AND INTERFACE SCIENCE, 10.1016/j.jcis.2013.05.051, 406, 186-195, 2013.09.
40.	Chuanjun Liu, Yudai Furusawa, Kenshi Hayashi, Development of a fluorescent imaging sensor for the detection of human body sweat odor, SENSORS AND ACTUATORS B-CHEMICAL, 10.1016/j.snb.2013.03.111, 183, 117-123, 2013.07.
41.	Chen Bin, Ota Manami, Mokume Masami, LIU Chuanjun, HAYASHI Kenshi, High-speed Gas Sensing using Localized Surface Plasmon Resonance of Sputtered Noble Metal Nanoparticles, 電気学会論文誌. E, センサ・マイクロマシン準部門誌 = The transactions of the Institute of Electrical Engineers of Japan. A publication of Sensors and Micromachines Society, 10.1541/ieejsmas.133.90, 133, 3, 90-95, 2013.03, High speed gas sensing devices can be applied in a number of areas where a better understanding of gas distribution is needed, such as in environmental monitoring and safety- and security-related fields. In this paper, we present a localized surface plasmon resonance (LSPR) sensor that was realized using sputtered Au and Ag nanoparticles (NPs), which can be used in robots for high-speed gas detection. The NPs' LSPR response, a red-shift of the minimum transmittance in wavelength (Δλmin), and a decrease in the minimum transmittance (ΔTmin) for ethanol gas, were investigated and compared using Au and Ag NPs under the same sputtering conditions but using a different thermal annealing process for the reshaping of the NPs. The results obtained show that NPs with a larger aspect ratio can generate a large LSPR response. The response characteristics confirmed that this LSPR sensor can be used for high-speed gas detection..
42.	Bin Chen, Chuanjun Liu, Manami Ota, Kenshi Hayashi, Terpene detection based on localized surface plasma resonance of thiolate-modified Au nanoparticles, IEEE Sensors Journal, 10.1109/JSEN.2012.2231672, 13, 4, 1307-1314, 2013.02, [URL], The detection of terpene vapors, a group of biomarker vapors emitted by plants during their growth process, is an efficient way to monitor plant growth status and control plant pests and disease. In this study, a gas sensor based on the localized surface plasma resonance (LSPR) of Au nanoparticles (Au NPs) is proposed for the terpene vapors detection. Au ion sputtering method is used to deposit Au NPs on transparent glass substrates. The dependence of transmission spectra on the morphology of Au NPs prepared by different sputtering conditions is investigated. In order to enhance the sensitivity and selectivity of the sensor, thiolate modification is applied to form the selective soluble monolayer on the surface of Au NPs. The results indicate that different thiolates could form different steric capping layers, and the responding ability of the LSPR sensor is verified by a red-shift of the minimum transmittance in wavelength (Δλmin) and a decrease in the minimum transmittance (ΔTmin) upon exposure to terpene vapors..
43.	Chuanjun Liu, Zhiyun Noda, Kazunori Sasaki, Kenshi Hayashi, Development of a polyanilinenanofibe-based carbon monoxide sensor for hydrogen fuel cell application,, International Journal of Hydrogen Energy, 10.1016/j.ijhydene.2012.06.096, 37, 13529-13535, 2012.07.
44.	Masahiro Imahashi, Kenshi Hayashi, Odor clustering and discrimination using an odor separating system, Sensors and Actuators B:Chemical, 10.1016/j.snb.2012.03.041, 166, 685-694, 2012.03, In this study, odor evaluation and discrimination are examined. First, an odor separating system that imitates the odor receptive mechanism of biological olfaction is developed. This system enables a rough detection of odor by measuring the molecular size and polarity of odorants. Using representative odor materials that belong to different biological glomeruli clusters, odor information extracted on time course patterns can be obtained by the system. The extracted features can be used for creating an odor map similar to the one created in the receptive mechanism, which can classify qualities by their odor-cluster attributes. Mixed odors can be discriminated and decomposed into their elemental clusters. The map obtained from this study can be used for odor matching analysis. © 2012 Elsevier B.V. All rights reserved..
45.	C. Liu, K. Hayashi, K. Toko, Template-Free Deposition of Polyaniline Nanostructures on Solid Substrates with Horizontal Orientation, Macromolecules, 10.1021/ma1023878, 44, 7, 2212-2219, 2011.03, By investigating the electrochemical nucleation and growth of polyaniline (PANI) on the insulating gap area of an interdigitated electrode, a template-free, in-situ approach is developed to obtain PANI nanowires and nanofibers with horizontal orientation on solid substrates. Experimental results show that the deposition process of PANI on the gap area is significantly influenced by polymerization conditions (such as polymerization current and time) and surface characteristics of the substrates (such as hydrophilicity/hydrophobicity and roughness). The concentration of solution-formed oligomers and the nucleation amount of the oligomers on the solid surface determine the morphology and orientation of the nanostructures. Controlling the deposition with high oligomer concentrations and limited nucleation amounts on the substrate is the key to the horizontal orientation. Gas sensing experiments confirm that the horizontal orientation of the nanostructures helps to improve the sensitivity and response time of sensor devices. Because of its simplicity, the approach proposed in this paper can be used in the fabrication of nanostructured conducting polymer chemiresistive gas sensor with high sensitivity but low cost. © 2011 American Chemical Society..
46.	Hirotaka Matsuo, Kenshi Hayashi, Detection of odor map image using optical method, Proceeding of International Conference on Advanced Mechatronics, 165-170, 2010.10.
47.	Hirotaka Matsuo, Kenshi Hayashi, Detection of odor map image using optical method, The Abstracts of the international conference on advanced mechatronics : toward evolutionary fusion of IT and mechatronics : ICAM, 10.1299/jsmeicam.2010.5.165, 2010, 0, 165-170, 2010.06, [URL], Odor gas detection is important in explosives detection, environmental sensing, biometrics, foodstuff and more comfortable life. In this paper, we tried to detect odor chemicals with optical method. We used five kinds of fluorescence dyes, fluorescenin, acridine orange, pyrene, quinine sulfate, and tryptophan. As analyte, we used following four compounds, benezen, vanillin, and NPOE. It is supposed that PET or FRET mechanism will occur between fluorescence dyes and odor compounds, then fluorescence quenching will observed. Indeed, we could detect odor substances using fluorescence dyes by fluorescent quenching. Odor information could be obtained by response patterns across the fluorescence dyes. Moreover, we captured odor shape image and odor spatiotemporal images with cooled CCD camera. Shapes of target which emit odor could be roughly recognized by odor shape image. From the odor spatiotemporal images, two-dimensional odor expanse could be obtained..
48.	C. Liu, K. Hayashi, K. Toko, Electrochemical Deposition of Nanostructured Polyaniline on an Insulating Substrate, Electrochemistry Communications, 10.1016/j.elecom.2009.10.030, 12, 1, 36-39, 2010.01, In order to obtain practicable nano-conducting polymer resistive sensors, we investigated the electrochemical deposition of polyaniline (PANI) on the insulating gap area of an interdigitated electrode with a gap width as great as 100 μm. We revealed that the nucleation and growth of PANI on the insulating substrate were influenced by the surface character of the substrate such as hydrophilicity and roughness. By controlling the polymerization conditions, homogeneous PANI films with various nanostructures could be obtained across the insulating gap to form resistive junctions. Among them, a loose 2D nanowire network structure showed the best sensing performance upon exposure to ammonia gas with a low concentration. © 2009 Elsevier B.V. All rights reserved..

主要総説, 論評, 解説, 書評, 報告書等

1.	林 健司, 劉 傳軍, 体臭を可視化するイメージセンサの開発と応用の可能性, Vol.43, No.8, pp.52-58, 2015.08.
2.	林 健司, 劉 傳軍, 匂いイメージセンサの開発と匂いの可視化, 2014.03.
3.	林 健司, 匂いコードセンサによる匂いの測定と可視化, 2013.02.
4.	林 健司, 分子認識型センサによる匂いコードセンシング, 2008.11.
5.	林 健司, 匂いセンサ・嗅覚を模倣した包括的化学物質センシング, 2008.10.
6.	林 健司, 分子情報による匂いコードのセンシングとその応用, 2008.10.
7.	林 健司, 匂いコードセンサの開発と応用, 2008.01.

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