| 1. |
Junya Sato, Tatsuya Matsumoto, Ryuta Nakao, Hideo Tanaka, Hajime Nagahara, Hirohiko Niioka, Tetsuro Takamatsu, Deep UV-excited fluorescence microscopy installed with CycleGAN-assisted image translation enhances precise detection of lymph node metastasis towards rapid intraoperative diagnosis, Scientific Reports, 10.1038/s41598-023-48319-7, 13, 1, 2023.12, Abstract
Rapid and precise intraoperative diagnosing systems are required for improving surgical outcomes and patient prognosis. Because of the poor quality and time-intensive process of the prevalent frozen section procedure, various intraoperative diagnostic imaging systems have been explored. Microscopy with ultraviolet surface excitation (MUSE) is an inexpensive, maintenance-free, and rapid imaging technique that yields images like thin-sectioned samples without sectioning. However, pathologists find it nearly impossible to assign diagnostic labels to MUSE images of unfixed specimens; thus, AI for intraoperative diagnosis cannot be trained in a supervised learning manner. In this study, we propose a deep-learning pipeline model for lymph node metastasis detection, in which CycleGAN translate MUSE images of unfixed lymph nodes to formalin-fixed paraffin-embedded (FFPE) sample, and diagnostic prediction is performed using deep convolutional neural network trained on FFPE sample images. Our pipeline yielded an average accuracy of 84.6% when using each of the three deep convolutional neural networks, which is a 18.3% increase over the classification-only model without CycleGAN. The modality translation to FFPE sample images using CycleGAN can be applied to various intraoperative diagnostic imaging systems and eliminate the difficulty for pathologists in labeling new modality images in clinical sites. We anticipate our pipeline to be a starting point for accurate rapid intraoperative diagnostic systems for new imaging modalities, leading to healthcare quality improvement.. |
| 2. |
Masaya Nagai, Yuhei Higashitani, Masaaki Ashida, Koichi Kusakabe, Hirohiko Niioka, Azusa N. Hattori, Hidekazu Tanaka, Goro Isoyama, Norimasa Ozaki, Martensite transformation triggered with intense THz pulses, 2023 48th International Conference on Infrared, Millimeter, and Terahertz Waves (IRMMW-THz), 10.1109/irmmw-thz57677.2023.10298936, 2023.09. |
| 3. |
Masaya Nagai, Yuhei Higashitani, Masaaki Ashida, Koichi Kusakabe, Hirohiko Niioka, Azusa N. Hattori, Hidekazu Tanaka, Goro Isoyama, Norimasa Ozaki, Terahertz-induced martensitic transformation in partially stabilized zirconia, Communications Physics, 10.1038/s42005-023-01207-y, 6, 1, 2023.04. |
| 4. |
Mitsuyoshi Hirokawa, Hirohiko Niioka, Ayana Suzuki, Masatoshi Abe, Yusuke Arai, Hajime Nagahara, Akira Miyauchi, Takashi Akamizu, Application of deep learning as an ancillary diagnostic tool for thyroid FNA cytology, Cancer Cytopathology, 10.1002/cncy.22669, 131, 4, 217-225, 2022.12, This paper was one of the most downloaded* during its first 12 months
of publication in:
CANCER CYTOPATHOLOGY
Application of deep learning as an ancillary diagnostic tool for thyroid FNA cytology
*Among work published in an issue between 1 January 2022 – 31 December 2022.. |
| 5. |
Hirohiko Niioka, Teruyoshi Kume, Takashi Kubo, Tsunenari Soeda, Makoto Watanabe, Ryotaro Yamada, Yasushi Sakata, Yoshihiro Miyamoto, Bowen Wang, Hajime Nagahara, Jun Miyake, Takashi Akasaka, Yoshihiko Saito, Shiro Uemura, Automated diagnosis of optical coherence tomography imaging on plaque vulnerability and its relation to clinical outcomes in coronary artery disease, Scientific Reports, 10.1038/s41598-022-18473-5, 12, 1, 2022.08, Abstract
This study sought to develop a deep learning-based diagnostic algorithm for plaque vulnerability by analyzing intravascular optical coherence tomography (OCT) images and to investigate the relation between AI-plaque vulnerability and clinical outcomes in patients with coronary artery disease (CAD). A total of 1791 study patients who underwent OCT examinations were recruited from a multicenter clinical database, and the OCT images were first labeled as either normal, a stable plaque, or a vulnerable plaque by expert cardiologists. A DenseNet-121-based deep learning algorithm for plaque characterization was developed by training with 44,947 prelabeled OCT images, and demonstrated excellent differentiation among normal, stable plaques, and vulnerable plaques. Patients who were diagnosed with vulnerable plaques by the algorithm had a significantly higher rate of both events from the OCT-observed segments and clinical events than the patients with normal and stable plaque (log-rank p |
| 6. |
廣川満良, 新岡宏彦, 鈴木彩菜, 安部政俊, 式見彰浩, 長原一, 宮内昭, AI を用いた甲状腺細胞診支援システムの開発と利用, Journal of the Japanese Society of Clinical Cytology, 10.5795/jjscc.61.200, 61, 3, 200-207, 2022.05. |
| 7. |
Naoki Yamato, Hirohiko Niioka, Jun Miyake, Mamoru Hashimoto, Near real-time nerve visualization using coherent Raman scattering rigid endoscope and deep learning-based image processing for nerve-sparing surgery, Biomedical Vibrational Spectroscopy 2022: Advances in Research and Industry, 10.1117/12.2609483, 2022.03. |
| 8. |
Masahiro Yanagawa, Hirohiko Niioka, Masahiko Kusumoto, Kazuo Awai, Mitsuko Tsubamoto, Yukihisa Satoh, Tomo Miyata, Yuriko Yoshida, Noriko Kikuchi, Akinori Hata, Shohei Yamasaki, Shoji Kido, Hajime Nagahara, Jun Miyake, Noriyuki Tomiyama, Diagnostic performance for pulmonary adenocarcinoma on CT: comparison of radiologists with and without three-dimensional convolutional neural network, European Radiology, 10.1007/s00330-020-07339-x, 31, 4, 1978-1986, 2021.04, OBJECTIVES: To compare diagnostic performance for pulmonary invasive adenocarcinoma among radiologists with and without three-dimensional convolutional neural network (3D-CNN). METHODS: Enrolled were 285 patients with adenocarcinoma in situ (AIS, n = 75), minimally invasive adenocarcinoma (MIA, n = 58), and invasive adenocarcinoma (IVA, n = 152). A 3D-CNN model was constructed with seven convolution-pooling and two max-pooling layers and fully connected layers, in which batch normalization, residual connection, and global average pooling were used. Only the flipping process was performed for augmentation. The output layer comprised two nodes for two conditions (AIS/MIA and IVA) according to prognosis. Diagnostic performance of the 3D-CNN model in 285 patients was calculated using nested 10-fold cross-validation. In 90 of 285 patients, results from each radiologist (R1, R2, and R3; with 9, 14, and 26 years of experience, respectively) with and without the 3D-CNN model were statistically compared. RESULTS: Without the 3D-CNN model, accuracy, sensitivity, and specificity of the radiologists were as follows: R1, 70.0%, 52.1%, and 90.5%; R2, 72.2%, 75%, and 69%; and R3, 74.4%, 89.6%, and 57.1%, respectively. With the 3D-CNN model, accuracy, sensitivity, and specificity of the radiologists were as follows: R1, 72.2%, 77.1%, and 66.7%; R2, 74.4%, 85.4%, and 61.9%; and R3, 74.4%, 93.8%, and 52.4%, respectively. Diagnostic performance of each radiologist with and without the 3D-CNN model had no significant difference (p > 0.88), but the accuracy of R1 and R2 was significantly higher with than without the 3D-CNN model (p |
| 9. |
Naoki Yamato, Hirohiko Niioka, Jun Miyake, Mamoru Hashimoto, Improvement of nerve imaging speed with coherent anti-Stokes Raman scattering rigid endoscope using deep-learning noise reduction, Scientific Reports, 10.1038/s41598-020-72241-x, 10, 1, 2020.12, AbstractA coherent anti-Stokes Raman scattering (CARS) rigid endoscope was developed to visualize peripheral nerves without labeling for nerve-sparing endoscopic surgery. The developed CARS endoscope had a problem with low imaging speed, i.e. low imaging rate. In this study, we demonstrate that noise reduction with deep learning boosts the nerve imaging speed with CARS endoscopy. We employ fine-tuning and ensemble learning and compare deep learning models with three different architectures. In the fine-tuning strategy, deep learning models are pre-trained with CARS microscopy nerve images and retrained with CARS endoscopy nerve images to compensate for the small dataset of CARS endoscopy images. We propose using the equivalent imaging rate (EIR) as a new evaluation metric for quantitatively and directly assessing the imaging rate improvement by deep learning models. The highest EIR of the deep learning model was 7.0 images/min, which was 5 times higher than that of the raw endoscopic image of 1.4 images/min. We believe that the improvement of the nerve imaging speed will open up the possibility of reducing postoperative dysfunction by intraoperative nerve identification.. |
| 10. |
Arno Germond, Yulia Panina, Mikio Shiga, Hirohiko Niioka, Tomonobu M. Watanabe, Following Embryonic Stem Cells, Their Differentiated Progeny, and Cell-State Changes During iPS Reprogramming by Raman Spectroscopy, Analytical Chemistry, 10.1021/acs.analchem.0c01800, 92, 22, 14915-14923, 2020.11, Monitoring cell-state transition in pluripotent cells is invaluable for application and basic research. In this study, we demonstrate the pertinence of noninvasive, label-free Raman spectroscopy to monitor and characterize the cell-state transition of mouse stem cells undergoing reprogramming. Using an isogenic cell line of mouse stem cells, reprogramming from neuronal cells was performed, and we showcase a comparative analysis of living single-cell spectral data of the original stem cells, their neuronal progenitors, and reprogrammed cells. Neural network, regression models, and ratiometric analyses were used to discriminate the cell states and extract several important biomarkers specific to differentiation or reprogramming. Our results indicated that the Raman spectrum allowed us to build a low-dimensional space allowing us to monitor and characterize the dynamics of cell-state transition at a single-cell level, scattered in heterogeneous populations. The ability of monitoring pluripotency by Raman spectroscopy and distinguishing differences between ES and reprogrammed cells is also discussed.. |
| 11. |
Shin-ichi Tanaka, Hiroki Wadati, Kazuhisa Sato, Hidehiro Yasuda, Hirohiko Niioka, Red-Fluorescent Pt Nanoclusters for Detecting and Imaging HER2 in Breast Cancer Cells, ACS Omega, 10.1021/acsomega.0c02578, 5, 37, 23718-23723, 2020.09, Overexpression of human epidermal growth factor receptor 2 (HER2) is associated with more frequent cancer recurrence and metastasis. Sensitive sensing of HER2 in living breast cancer cells is crucial in the early stages of cancer and to further understand its role in cells. Biomedical imaging has become an indispensable tool in the fields of early cancer diagnosis and therapy. In this study, we designed and synthesized platinum (Pt) nanocluster bionanoprobes with red emission (Ex/Em = 535/630 nm) for fluorescence imaging of HER2. Our Pt nanoclusters, which were synthesized using polyamidoamine (PAMAM) dendrimer and preequilibration, exhibited approximately 1% quantum yield and possessed low cytotoxicity, ultrasmall size, and excellent photostability. Furthermore, combined with ProteinA as an adapter protein, we developed Pt bionanoprobes with minimal nonspecific binding and utilized them as fluorescent probes for highly sensitive optical imaging of HER2 at the cellular level. More importantly, molecular probes with long-wavelength emission have allowed visualization of deep anatomical features because of enhanced tissue penetration and a decrease in background noise from tissue scattering. Our Pt nanoclusters are promising fluorescent probes for biomedical applications.. |
| 12. |
Naoki Yamato, Mana Matsuya, Hirohiko Niioka, Jun Miyake, Mamoru Hashimoto, Nerve Segmentation with Deep Learning from Label-Free Endoscopic Images Obtained Using Coherent Anti-Stokes Raman Scattering, Biomolecules, 10.3390/biom10071012, 10, 7, 1012-1012, 2020.07, Semantic segmentation with deep learning to extract nerves from label-free endoscopic images obtained using coherent anti-Stokes Raman scattering (CARS) for nerve-sparing surgery is described. We developed a CARS rigid endoscope in order to identify the exact location of peripheral nerves in surgery. Myelinated nerves are visualized with a CARS lipid signal in a label-free manner. Because the lipid distribution includes other tissues as well as nerves, nerve segmentation is required to achieve nerve-sparing surgery. We propose using U-Net with a VGG16 encoder as a deep learning model and pre-training with fluorescence images, which visualize the lipid distribution similar to CARS images, before fine-tuning with a small dataset of CARS endoscopy images. For nerve segmentation, we used 24 CARS and 1,818 fluorescence nerve images of three rabbit prostates. We achieved label-free nerve segmentation with a mean accuracy of 0.962 and an F 1 value of 0.860. Pre-training on fluorescence images significantly improved the performance of nerve segmentation in terms of the mean accuracy and F 1 value ( p |
| 13. |
Kiminori Yanagisawa, Masayasu Toratani, Ayumu Asai, Masamitsu Konno, Hirohiko Niioka, Tsunekazu Mizushima, Taroh Satoh, Jun Miyake, Kazuhiko Ogawa, Andrea Vecchione, Yuichiro Doki, Hidetoshi Eguchi, Hideshi Ishii, Convolutional Neural Network Can Recognize Drug Resistance of Single Cancer Cells., International journal of molecular sciences, 10.3390/ijms21093166, 21, 9, 2020.04, It is known that single or isolated tumor cells enter cancer patients' circulatory systems. These circulating tumor cells (CTCs) are thought to be an effective tool for diagnosing cancer malignancy. However, handling CTC samples and evaluating CTC sequence analysis results are challenging. Recently, the convolutional neural network (CNN) model, a type of deep learning model, has been increasingly adopted for medical image analyses. However, it is controversial whether cell characteristics can be identified at the single-cell level by using machine learning methods. This study intends to verify whether an AI system could classify the sensitivity of anticancer drugs, based on cell morphology during culture. We constructed a CNN based on the VGG16 model that could predict the efficiency of antitumor drugs at the single-cell level. The machine learning revealed that our model could identify the effects of antitumor drugs with ~0.80 accuracies. Our results show that, in the future, realizing precision medicine to identify effective antitumor drugs for individual patients may be possible by extracting CTCs from blood and performing classification by using an AI system.. |
| 14. |
Tatsuya Matsumoto, Hirohiko Niioka(equally contributed), Yasuaki Kumamoto, Junya Sato, Osamu Inamori, Ryuta Nakao, Yoshinori Harada, Eiichi Konishi, Eigo Otsuji, Hideo Tanaka, Jun Miyake, Tetsuro Takamatsu, Deep-UV excitation fluorescence microscopy for detection of lymph node metastasis using deep neural network, Scientific Reports, 10.1038/s41598-019-53405-w, 9, 1, 16912-1-16912-12, 2019.11. |
| 15. |
Yamanaka, M., Niioka, H., Furukawa, T., Nishizawa, N., Excitation of erbium-doped nanoparticles in 1550-nm wavelength region for deep tissue imaging with reduced degradation of spatial resolution, Journal of Biomedical Optics, 10.1117/1.JBO.24.7.070501, 24, 7, 070501-1-070501-4, 2019.07. |
| 16. |
Masahiro Yanagawa, Hirohiko Niioka, Akinori Hata, Noriko Kikuchi, Osamu Honda, Hiroyuki Kurakami, Eiichi Morii, Masayuki Noguchi, Yoshiyuki Watanabe, Jun Miyake, Noriyuki Tomiyama, Application of deep learning (3-dimensional convolutional neural network) for the prediction of pathological invasiveness in lung adenocarcinoma: A preliminary study., Medicine, 10.1097/MD.0000000000016119, 98, 25, e16119, 2019.06, To compare results for radiological prediction of pathological invasiveness in lung adenocarcinoma between radiologists and a deep learning (DL) system.Ninety patients (50 men, 40 women; mean age, 66 years; range, 40-88 years) who underwent pre-operative chest computed tomography (CT) with 0.625-mm slice thickness were included in this retrospective study. Twenty-four cases of adenocarcinoma in situ (AIS), 20 cases of minimally invasive adenocarcinoma (MIA), and 46 cases of invasive adenocarcinoma (IVA) were pathologically diagnosed. Three radiologists of different levels of experience diagnosed each nodule by using previously documented CT findings to predict pathological invasiveness. DL was structured using a 3-dimensional (3D) convolutional neural network (3D-CNN) constructed with 2 successive pairs of convolution and max-pooling layers, and 2 fully connected layers. The output layer comprises 3 nodes to recognize the 3 conditions of adenocarcinoma (AIS, MIA, and IVA) or 2 nodes for 2 conditions (AIS and MIA/IVA). Results from DL and the 3 radiologists were statistically compared.No significant differences in pathological diagnostic accuracy rates were seen between DL and the 3 radiologists (P >.11). Receiver operating characteristic analysis demonstrated that area under the curve for DL (0.712) was almost the same as that for the radiologist with extensive experience (0.714; P = .98). Compared with the consensus results from radiologists, DL offered significantly inferior sensitivity (P = .0005), but significantly superior specificity (P = .02).Despite the small training data set, diagnostic performance of DL was almost the same as the radiologist with extensive experience. In particular, DL provided higher specificity than radiologists.. |
| 17. |
Hirose, K., Fukushima, S., Furukawa, T., Niioka, H., Hashimoto, M., Invited Article: Label-free nerve imaging with a coherent anti-Stokes Raman scattering rigid endoscope using two optical fibers for laser delivery, APL Photonics, 10.1063/1.5031817, 3, 9, 092407-1-092407-8, 2018.09, A coherent anti-Stokes Raman scattering (CARS) rigid endoscope using two optical fibers to deliver excitation beams individually is developed. The use of two optical fibers allows the correction of longitudinal chromatic aberration and enhances the CARS signal by a factor of 2.59. The endoscope is used to image rat sciatic nerves with an imaging time of 10 s. Imaging of the rabbit prostatic fascia without sample slicing is also demonstrated, which reveals the potential for the application of the CARS endoscope to robot-assisted surgery.
. |
| 18. |
Jun Miyake, Yuhei Kaneshita, Satoshi Asatani, Seiichi Tagawa, Hirohiko Niioka, Takashi Hirano, Graphical classification of DNA sequences of HLA alleles by deep learning, Human Cell, 10.1007/s13577-017-0194-6, 31, 2, 102-105, 2018.04, Alleles of human leukocyte antigen (HLA)-A DNAs are classified and expressed graphically by using artificial intelligence “Deep Learning (Stacked autoencoder)”. Nucleotide sequence data corresponding to the length of 822 bp, collected from the Immuno Polymorphism Database, were compressed to 2-dimensional representation and were plotted. Profiles of the two-dimensional plots indicate that the alleles can be classified as clusters are formed. The two-dimensional plot of HLA-A DNAs gives a clear outlook for characterizing the various alleles.. |
| 19. |
K. Hirose, T. Aoki, T. Furukawa, S. Fukushima, H. Niioka, S. Deguchi, M. Hashimoto, Coherent anti-stokes Raman scattering rigid endoscope toward robot-assisted surgery, Biomedical Optics Express, 10.1364/BOE.9.000387, 9, 2, 387-396, 2018.02, Label-free visualization of nerves and nervous plexuses will improve the preservation of neurological functions in nerve-sparing robot-assisted surgery. We have developed a coherent anti-Stokes Raman scattering (CARS) rigid endoscope to distinguish nerves from other tissues during surgery. The developed endoscope, which has a tube with a diameter of 12 mm and a length of 270 mm, achieved 0.91% image distortion and 8.6% non-uniformity of CARS intensity in the whole field of view (650 µm diameter). We demonstrated CARS imaging of a rat sciatic nerve and visualization of the fine structure of nerve fibers.. |
| 20. |
Hirohiko Niioka, Satoshi Asatani, Aina Yoshimura, Hironori Ohigashi, Seiichi Tagawa, Jun Miyake, Classification of C2C12 cells at differentiation by convolutional neural network of deep learning using phase contrast images, Human Cell, 10.1007/s13577-017-0191-9, 31, 1, 87-93, 2018.01, In the field of regenerative medicine, tremendous numbers of cells are necessary for tissue/organ regeneration. Today automatic cell-culturing system has been developed. The next step is constructing a non-invasive method to monitor the conditions of cells automatically. As an image analysis method, convolutional neural network (CNN), one of the deep learning method, is approaching human recognition level. We constructed and applied the CNN algorithm for automatic cellular differentiation recognition of myogenic C2C12 cell line. Phase-contrast images of cultured C2C12 are prepared as input dataset. In differentiation process from myoblasts to myotubes, cellular morphology changes from round shape to elongated tubular shape due to fusion of the cells. CNN abstract the features of the shape of the cells and classify the cells depending on the culturing days from when differentiation is induced. Changes in cellular shape depending on the number of days of culture (Day 0, Day 3, Day 6) are classified with 91.3% accuracy. Image analysis with CNN has a potential to realize regenerative medicine industry.. |
| 21. |
Daisuke Onoshima, Naoko Kawakita, Daiki Takeshita, Hirohiko Niioka, Hiroshi Yukawa, Jun Miyake, Yoshinobu Baba, Measurement of DNA Length Changes Upon CpG Hypermethylation by Microfluidic Molecular Stretching., Cell medicine, 10.3727/215517916X693087, 9, 1-2, 61-66, 2017.01, Abnormal DNA methylation in CpG-rich promoters is recognized as a distinct molecular feature of precursor lesions to cancer. Such unintended methylation can occur during in vitro differentiation of stem cells. It takes place in a subset of genes during the differentiation or expansion of stem cell derivatives under general culture conditions, which may need to be monitored in future cell transplantation studies. Here we demonstrate a microfluidic device for investigating morphological length changes in DNA methylation. Arrayed polymer chains of single DNA molecules were fluorescently observed by parallel trapping and stretching in the microfluidic channel. This observational study revealed that the shortened DNA length is due to the increased rigidity of the methylated DNA molecule. The trapping rate of the device for DNA molecules was substantially unaffected by changes in the CpG methylation.. |
| 22. |
Hirohiko Niioka, Jumpei Yamasaki, Doan Thi Kim Dung, Jun Miyake, Enhancement of Near-infrared Luminescence of Y2O3:Ln, Yb (Ln = Tm, Ho, Er) by Li-ion Doping for Cellular Bioimaging, CHEMISTRY LETTERS, 10.1246/cl.160754, 45, 12, 1406-1408, 2016.12, Bioimaging probes, which can emit near-infrared (NIR) light and are excitable with NIR light, are promising for deep tissue imaging in vivo. Lanthanide-doped phosphors, such as Y2O3:Tm,Yb; Y2O3:Ho,Yb; and Y2O3:Er,Yb, are candidates for the probes. We enhanced the NIR emission of the three kinds of lanthanide-doped phosphor by using Li-ion doping. The probes were applied to cellular imaging.. |
| 23. |
Doan Thi Kim Dung, Shoichiro Fukushima, Taichi Furukawa, Hirohiko Niioka, Takumi Sannomiya, Kaori Kobayashi, Hiroshi Yukawa, Yoshinobu Baba, Mamoru Hashimoto, Jun Miyake, Multispectral Emissions of Lanthanide-Doped Gadolinium Oxide Nanophosphors for Cathodoluminescence and Near-Infrared Upconversion/Downconversion Imaging, NANOMATERIALS, 10.3390/nano6090163, 6, 9, 2016.09, Comprehensive imaging of a biological individual can be achieved by utilizing the variation in spatial resolution, the scale of cathodoluminescence (CL), and near-infrared (NIR), as favored by imaging probe Gd2O3 co-doped lanthanide nanophosphors (NPPs). A series of Gd2O3:Ln(3+)/Yb3+ (Ln(3+): Tm3+, Ho3+, Er3+) NPPs with multispectral emission are prepared by the sol-gel method. The NPPs show a wide range of emissions spanning from the visible to the NIR region under 980 nm excitation. The dependence of the upconverting (UC)/downconverting (DC) emission intensity on the dopant ratio is investigated. The optimum ratios of dopants obtained for emissions in the NIR regions at 810 nm, 1200 nm, and 1530 nm are applied to produce nanoparticles by the homogeneous precipitation (HP) method. The nanoparticles produced from the HP method are used to investigate the dual NIR and CL imaging modalities. The results indicate the possibility of using Gd2O3 co-doped Ln(3+)/Yb3+ (Ln(3+): Tm3+, Ho3+, Er3+) in correlation with NIR and CL imaging. The use of Gd2O3 promises an extension of the object dimension to the whole-body level by employing magnetic resonance imaging (MRI).. |
| 24. |
S. Fukushima, T. Furukawa, H. Niioka, M. Ichimiya, T. Sannomiya, N. Tanaka, D. Onoshima, H. Yukawa, Y. Baba, M. Ashida, J. Miyake, T. Araki, M. Hashimoto, Correlative near-infrared light and cathodoluminescence microscopy using Y2O3:Ln, Yb (Ln = Tm, Er) nanophosphors for multiscale, multicolour bioimaging, SCIENTIFIC REPORTS, 10.1038/srep25950, 6, 2016.05, This paper presents a new correlative bioimaging technique using Y2O3:Tm, Yb and Y2O3:Er, Yb nanophosphors (NPs) as imaging probes that emit luminescence excited by both near-infrared (NIR) light and an electron beam. Under 980 nm NIR light irradiation, the Y2O3:Tm, Yb and Y2O3:Er, Yb NPs emitted NIR luminescence (NIRL) around 810 nm and 1530 nm, respectively, and cathodoluminescence at 455 nm and 660 nm under excitation of accelerated electrons, respectively. Multimodalities of the NPs were confirmed in correlative NIRL/CL imaging and their locations were visualized at the same observation area in both NIRL and CL images. Using CL microscopy, the NPs were visualized at the single-particle level and with multicolour. Multiscale NIRL/CL bioimaging was demonstrated through in vivo and in vitro NIRL deep-tissue observations, cellular NIRL imaging, and high-spatial resolution CL imaging of the NPs inside cells. The location of a cell sheet transplanted onto the back muscle fascia of a hairy rat was visualized through NIRL imaging of the Y2O3:Er, Yb NPs. Accurate positions of cells through the thickness (1.5 mm) of a tissue phantom were detected by NIRL from the Y2O3:Tm, Yb NPs. Further, locations of the two types of NPs inside cells were observed using CL microscopy.. |
| 25. |
Shoichiro Fukushima, Taichi Furukawa, Hirohiko Niioka, Masayoshi Ichimiya, Takumi Sannomiya, Jun Miyake, Masaaki Ashida, Tsutomu Araki, Mamoru Hashimoto, Synthesis of Y2O3 nanophosphors by homogeneous precipitation method using excessive urea for cathodoluminescence and upconversion luminescence bioimaging, OPTICAL MATERIALS EXPRESS, 10.1364/OME.6.000831, 6, 3, 831-843, 2016.03, Yttrium oxide-based nanophosphors that emit both upconversion luminescence (UPL) and cathodoluminescence (CL) were synthesized by a precipitation method using excessive urea. Precursors of Y2O3 nanophosphors were synthesized with size control to less than 50 nm and a chemical yield greater than 90%. Concentrations of rare-earth co-dopants in nanophosphors were controlled with optimal molar ratios. Co-dopants Tm, Yb/Er, Yb enabled NPs to emit UPL at wavelengths around 810/660 nm and CL at wavelengths around 450/660 nm via excitation with 980 nm NIR light and an electron beam. Synthesized NPs were imaged by NIR and CL microscopy. (C) 2016 Optical Society of America. |
| 26. |
Mamoru Hashimoto, Hirohiko Niioka, Koichiro Ashida, Keisuke Yoshiki, Tsutomu Araki, High-sensitivity and high-spatial-resolution imaging of self-assembled monolayer on platinum using radially polarized beam excited second-harmonic-generation microscopy, APPLIED PHYSICS EXPRESS, 10.7567/APEX.8.112401, 8, 11, 2015.11, High-sensitivity, high-spatial-resolution imaging of organic monolayers on platinum with second harmonic generation (SHG) microscopy using radially polarized beam excitation is investigated. A tightly focused, radially polarized beam forms a longitudinal electric field at the focus. The longitudinal field is enhanced at a metal surface and increases the intensity of SHG from the molecules on the metal surface. The SHG signal from a self-assembled monolayer (SAM) on a platinum surface excited by a radially polarized beam is approximately 3.7 times higher than that obtained with a linearly polarized beam. Improved spatial resolution is also demonstrated using a SAM patterned by electron beam lithography. (C) 2015 The Japan Society of Applied Physics. |
| 27. |
Taichi Furukawa, Shoichiro Fukushima, Hirohiko Niioka, Naoki Yamamoto, Jun Miyake, Tsutomu Araki, Mamoru Hashimoto, Rare-earth-doped nanophosphors for multicolor cathodoluminescence nanobioimaging using scanning transmission electron microscopy, JOURNAL OF BIOMEDICAL OPTICS, 10.1117/1.JBO.20.5.056007, 20, 5, 2015.05, We describe rare-earth-doped nanophosphors (RE-NPs) for biological imaging using cathodoluminescence (CL) microscopy based on scanning transmission electron microscopy (STEM). We report the first demonstration of multicolor CL nanobioimaging using STEM with nanophosphors. The CL spectra of the synthesized nanophosphors (Y2O3:Eu, Y2O3:Tb) were sufficiently narrow to be distinguished. From CL images of RE-NPs on an elastic carbon-coated copper grid, the spatial resolution was beyond the diffraction limit of light. Y2O3:Tb and Y2O3:Eu RE-NPs showed a remarkable resistance against electron beam exposure even at high acceleration voltage (80 kV) and retained a CL intensity of more than 97% compared with the initial intensity for 1 min. In biological CL imaging with STEM, heavy-metal-stained cell sections containing the RE-NPs were prepared, and both the CL images of RE-NPs and cellular structures, such as mitochondria, were clearly observed from STEM images with high contrast. The cellular CL imaging using RE-NPs also had high spatial resolution even though heavy-metal-stained cells are normally regarded as highly scattering media. Moreover, since the RE-NPs exhibit photoluminescence (PL) excited by UV light, they are useful for multimodal correlative imaging using CL and PL. (C) 2015 Society of Photo-Optical Instrumentation Engineers (SPIE). |
| 28. |
Shoichiro Fukushima, Taichi Furukawa, Hirohiko Niioka, Masayoshi Ichimiya, Jun Miyake, Masaaki Ashida, Tsutomu Araki, Mamoru Hashimoto, Y2O3:Tm,Yb nanophosphors for correlative upconversion luminescence and cathodoluminescence imaging, MICRON, 10.1016/j.micron.2014.07.002, 67, 90-95, 2014.12, We present a phosphor nanoparticle that shows both upconversion luminescence (UCL) and cathodoluminescence (CL). With this particle, low-autofluorescence, deep-tissue and wide-field fluorescence imaging can be achieved with nanometer-order high-spatial-resolution imaging. We synthesized Y2O3:Tm,Yb nanophosphors that emit visible and near-infrared UCL under 980 nm irradiation and blue CL via electron beam excitation. The phosphors were applied to fluorescent imaging of HeLa cells. The photostability of the phosphors was superior to that of a conventional organic dye. We show that after uptake by HeLa cells, the particles can be imaged with SEM and CL contrast in a cellular section. This indicates that correlative UCL and CL imaging of biological samples could be realized. (C) 2014 Elsevier Ltd. All rights reserved.. |
| 29. |
Nicholas I. Smith, Kentaro Mochizuki, Hirohiko Niioka, Satoshi Ichikawa, Nicolas Pavillon, Alison J. Hobro, Jun Ando, Katsumasa Fujita, Yutaro Kumagai, Laser-targeted photofabrication of gold nanoparticles inside cells, NATURE COMMUNICATIONS, 10.1038/ncomms6144, 5, 2014.10, Nanoparticle manipulation is of increasing interest, since they can report single molecule-level measurements of the cellular environment. Until now, however, intracellular nanoparticle locations have been essentially uncontrollable. Here we show that by infusing a gold ion solution, focused laser light-induced photoreduction allows in situ fabrication of gold nanoparticles at precise locations. The resulting particles are pure gold nanocrystals, distributed throughout the laser focus at sizes ranging from 2 to 20 nm, and remain in place even after removing the gold solution. We demonstrate the spatial control by scanning a laser beam to write characters in gold inside a cell. Plasmonically enhanced molecular signals could be detected from nanoparticles, allowing their use as nano-chemical probes at targeted locations inside the cell, with intracellular molecular feedback. Such light-based control of the intracellular particle generation reaction also offers avenues for in situ plasmonic device creation in organic targets, and may eventually link optical and electron microscopy.. |
| 30. |
Taichi Furukawa, Hirohiko Niioka, Masayoshi Ichimiya, Tomohiro Nagata, Masaaki Ashida, Tsutomu Araki, Mamoru Hashimoto, High-resolution microscopy for biological specimens via cathodoluminescence of Eu- and Zn-doped Y2O3 nanophosphors, Optics Express, 10.1364/OE.21.025655, 21, 22, 25655-25663, 2013.11, High-resolution microscopy for biological specimens was performed using cathodoluminescence (CL) of Y2O3:Eu, Zn nanophosphors, which have high CL intensity due to the incorporation of Zn. The intensity of Y2O3:Eu nanophosphors at low acceleration voltage (3 kV) was increased by adding Zn. The CL intensity was high enough for imaging even with a phosphor size as small as about 30 nm. The results show the possibility of using CL microscopy for biological specimens at single-protein-scale resolution. CL imaging of HeLa cells containing laserablated Y2O 3:Eu, Zn nanophosphors achieved a spatial resolution of a few tens of nanometers. Y2O3:Eu, Zn nanophosphors in HeLa cells were also imaged with 254 nm ultraviolet light excitation. The results suggest that correlative microscopy using CL, secondary electrons and fluorescence imaging could enable multi-scale investigation of molecular localization from the nanoscale to the microscale. ©2013 Optical Society of America.. |
| 31. |
Harsono Cahyadi, Junichi Iwatsuka, Takeo Minamikawa, Hirohiko Niioka, Tsutomu Araki, Mamoru Hashimoto, Fast spectral coherent anti-Stokes Raman scattering microscopy with high-speed tunable picosecond laser, JOURNAL OF BIOMEDICAL OPTICS, 10.1117/1.JBO.18.9.096009, 18, 9, 2013.09, We develop a coherent anti-Stokes Raman scattering (CARS) microscopy system equipped with a tunable picosecond laser for high-speed wavelength scanning. An acousto-optic tunable filter (AOTF) is integrated in the laser cavity to enable wavelength scanning by varying the radio frequency waves applied to the AOTF crystal. An end mirror attached on a piezoelectric actuator and a pair of parallel plates driven by galvanometer motors are also introduced into the cavity to compensate for changes in the cavity length during wavelength scanning to allow synchronization with another picosecond laser. We demonstrate fast spectral imaging of 3T3-L1 adipocytes every 5 cm(-1) in the Raman spectral region around 2850 cm(-1) with an image acquisition time of 120 ms. We also demonstrate fast switching of Raman shifts between 2100 and 2850 cm(-1), corresponding to CD2 symmetric stretching and CH2 symmetric stretching vibrations, respectively. The fast-switching CARS images reveal different locations of recrystallized deuterated and nondeuterated stearic acid. (C) The Authors. Published by SPIE under a Creative Commons Attribution 3.0 Unported License. Distribution or reproduction of this work in whole or in part requires full attribution of the original publication, including its DOI.. |
| 32. |
Takeo Minamikawa, Tatsuro Takagi, Hirohiko Niioka, Makoto Kurihara, Nobuyuki Hashimoto, Tsutomu Araki, Mamoru Hashimoto, Molecular Orientation Imaging of Liquid Crystals by Tunable-Polarization-Mode Coherent Anti-Stokes Raman Scattering Microscopy, APPLIED PHYSICS EXPRESS, 10.7567/APEX.6.072401, 6, 7, 2013.07, We have developed a tunable-polarization-mode coherent anti-Stokes Raman scattering (CARS) microscope with compact polarization mode converters constructed using eight-segmented liquid-crystal spatial light modulators. The polarization modes, such as linear, radial, and azimuthal polarizations, of two excitation beams are controlled independently and are switched without any mechanical tuning in less than 300 ms. We use the system to detect the molecular orientation of 4-cyano-4'-octylbiphenyl (8CB) liquid crystals aligned parallel and perpendicular to the optical axis. We also observe CARS images of liquid crystal defects known as focal conic domains, demonstrating the potential of our molecular orientation imaging system. (C) 2013 The Japan Society of Applied Physics. |
| 33. |
Hideo Kohno, Takuya Komine, Takayuki Hasegawa, Hirohiko Niioka, Satoshi Ichikawa, Formation of a carbon nanoribbon by spontaneous collapse of a carbon nanotube grown from a γ-Fe nanoparticle via an origami mechanism, Nanoscale, 10.1039/c2nr32607h, 5, 2, 570-573, 2013.01, We report a simple method of fabricating graphite nanoribbons by utilizing a self-collapsing mechanism of multi-walled carbon nanotubes during their growth. In the growth process, a nanotube is expelled from a γ-Fe seed nanoparticle, and then collapses spontaneously forming a nanoribbon. Our microscopic analysis of the structures and crystal orientations of γ-Fe nanoparticles and graphite nanoribbons suggests a possible mechanism of the collapse of nanotubes into nanoribbons, an origami mechanism. Our approach can be developed toward the fabrication of bi-layered graphene nanoribbons. Furthermore, the origami mechanism also yields graphitic nano-tetrahedrons. © The Royal Society of Chemistry.. |
| 34. |
Zhuo Li, Shoji Kawahito, Keita Yasutomi, Keiichiro Kagawa, Juichiro Ukon, Mamoru Hashimoto, Hirohiko Niioka, A Time-Resolved CMOS Image Sensor With Draining-Only Modulation Pixels for Fluorescence Lifetime Imaging, IEEE TRANSACTIONS ON ELECTRON DEVICES, 10.1109/TED.2012.2209179, 59, 10, 2715-2722, 2012.10, This paper presents a time-resolved CMOS image sensor with draining-only modulation (DOM) pixels, for time-domain fluorescence lifetime imaging. In the DOM pixels using a pinned photodiode (PPD) technology, a time-windowed signal charge transfer from a PPD to a pinned storage diode (PSD) is controlled by a draining gate only, without a transfer gate between the two diodes. This structure allows a potential barrierless and trapless charge transfer from the PPD to the PSD. A 256 x 256 pixel time-resolved CMOS imager with 7.5 x 7.5 mu m(2) DOM pixels has been implemented using 0.18-mu m CMOS image sensor process technology with PPD option. The prototype demonstrates high sensitivity for weak signal of less than one electron per light pulse and accurate measurement of fluorescence decay process with subnanosecond time resolution.. |
| 35. |
Hirohiko Niioka, Taichi Furukawa, Masayoshi Ichimiya, Masaaki Ashida, Tsutomu Araki, Mamoru Hashimoto, Multicolor Cathodoluminescence Microscopy for Biological Imaging with Nanophosphors, APPLIED PHYSICS EXPRESS, 10.1143/APEX.4.112402, 4, 11, 2011.11, We report the first demonstration of a multicolor high-spatial-resolution imaging technique for observation of biological cells using cathodoluminescence from nanophosphors. Three kinds of rare-earth-doped nanophosphors were injected into J744A.1 macrophages, and the spatial distribution of nanophosphors was visualized by using a scanning electron microscope cathodoluminescence (SEM-CL) system. The spectral bandwidth of the phosphors was narrow enough to distinguish the types of the phosphors. CL images of the nanophosphors on Si substrates were obtained with high resolution comparable to that of SEM images. These nanophosphors will be candidates to image more than two kinds of biological molecules at high resolution. (C) 2011 The Japan Society of Applied Physics. |
| 36. |
Takeo Minamikawa, Hirohiko Niioka, Tsutomu Araki, Mamoru Hashimoto, Real-time imaging of laser-induced membrane disruption of a living cell observed with multifocus coherent anti-Stokes Raman scattering microscopy, JOURNAL OF BIOMEDICAL OPTICS, 10.1117/1.3533314, 16, 2, 2011.02, We demonstrate the real-time imaging of laser-induced disruption of the cellular membrane in a living HeLa cell and its cellular response with a multifocus coherent anti-Stokes Raman scattering (CARS) microscope. A near-infrared pulsed laser beam tightly focused on the cellular membrane of a living cell induces ablation at the focal point causing a local disruption of the cellular membrane. After the membrane disruption a dark spot decreasing CARS intensity of 2840 cm(-1) Raman shift at the disrupted site appears. This dark spot immediately disappears and a strong CARS signal is observed around the disrupted site. This increase of the CARS signal might be caused by resealing of the disrupted site via aggregation of the patch lipid vesicles in the cytoplasm. The accumulation of lipids around the disrupted site is also confirmed with three-dimensional CARS images of a cell before and after membrane disruption. The temporal behavior of the CARS signal at the disrupted site is observed to detect the fusion dynamics of patch vesicles. (C) 2011 Society of Photo-Optical Instrumentation Engineers (SPIE). [DOI:10.1117/1.3533314]. |
| 37. |
Hideo Kohno, Kazuki Yagi, Hirohiko Niioka, Graphene/Graphite-Coated SiC Nanowires Grown by Metal-Organic Chemical Vapor Deposition in One Step, JAPANESE JOURNAL OF APPLIED PHYSICS, 10.1143/JJAP.50.018001, 50, 1, 2011.01, Graphene/graphite-coated SiC nanowires are fabricated from diethylsilane or divinyldimethylsilane by Fe-assisted metal-organic chemical vapor deposition. When diethylsilane is used, a few layers of graphene are formed, while 30-40-nm-thick graphite is formed from divinyldimethylsilane. (C) 2011 The Japan Society of Applied Physics. |
| 38. |
Hirohiko Niioka, Nanocommunication Design in Graduate-Level Education and Research Training, J. Korean Vacuum Society, 10.5757/jkvs.2010.19.6.423, 19, 6, 423-431, 2010.11. |
| 39. |
H. Niioka, N. I. Smith, K. Fujita, Y. Inouye, S. Kawata, Femtosecond laser nano-ablation in fixed and non-fixed cultured cells, OPTICS EXPRESS, 10.1364/OE.16.014476, 16, 19, 14476-14495, 2008.09, To understand the onset and morphology of femtosecond laser submicron ablation in cells and to study physical evidence of intracellular laser irradiation, we used transmission electron microscopy (TEM). The use of partial fixation before laser irradiation provides for clear images of sub-micron intracellular laser ablation, and we observed clear evidence of bubble-type physical changes induced by femtosecond laser irradiation at pulse energies as low as 0.48 nJ in the nucleus and cytoplasm. By taking ultrathin sliced sections, we reconstructed the laser affected subcellular region, and found it to be comparable to the point spread function of the laser irradiation. Laser-induced bubbles were observed to be confined by the surrounding intracellular structure, and bubbles were only observed with the use of partial pre-fixation. Without partial pre-fixation, laser irradiation of the nucleus was found to produce observable aggregation of nanoscale electron dense material, while irradiation of cytosolic regions produced swollen mitochondria but residual local physical effects were not observed. This was attributed to the rapid collapse of bubbles and/or the diffusion of any observable physical effects from the irradiation site following the laser exposure. (c) 2008 Optical Society of America.. |
