The Experts below are selected from a list of 2328 Experts worldwide ranked by ideXlab platform
Takehiko Kitamori - One of the best experts on this subject based on the ideXlab platform.
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fabrication of infrared compatible nanofluidic devices for plasmon enhanced infrared absorption spectroscopy
Micromachines, 2020Co-Authors: Takumi Matsushita, Ryoichi Ohta, Yuta Shimoda, Hiroaki Matsui, Takehiko KitamoriAbstract:Nanofluidic devices have offered us fascinating analytical platforms for chemical and bioanalysis by exploiting unique properties of liquids and molecules confined in nanospaces. The increasing interests in nanofluidic analytical devices have triggered the development of new robust and sensitive detection techniques, especially label-free ones. IR absorption spectroscopy is one of the most powerful biochemical analysis methods for identification and quantitative measurement of chemical species in the label-free and non-invasive fashion. However, the low sensitivity and the difficulties in fabrication of IR-compatible nanofluidic devices are major obstacles that restrict the applications of IR spectroscopy in Nanofluidics. Here, we realized the bonding of CaF2 and SiO2 at room temperature and demonstrated an IR-compatible nanofluidic device that allowed the IR spectroscopy in a wide range of mid-IR regime. We also performed the integration of metal-insulator-metal perfect absorber metamaterials into nanofluidic devices for plasmon-enhanced infrared absorption spectroscopy with ultrahigh sensitivity. This study also shows a proof-of-concept of the multi-band absorber by combining different types of nanostructures. The results indicate the potential of implementing metamaterials in tracking several characteristic molecular vibrational modes simultaneously, making it possible to identify molecular species in mixture or complex biological entities.
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implementation of a nanochannel open close valve into a glass nanofluidic device
Microfluidics and Nanofluidics, 2020Co-Authors: Hiroki Sano, Kyojiro Morikawa, Yutaka Kazoe, Takehiko KitamoriAbstract:In micro-/Nanofluidics, channel open/close valves are fundamental to integrating fluid operations and realizing highly integrated analytical devices. Recently, we proposed a nanochannel open/close valve utilizing glass deformation and verified the principle of opening and closing nanochannels. Glass deformation sufficient to close the valve was achieved using a 45-µm-thick glass sheet as a material of a nanofluidic device. However, since the device incorporates the thin glass sheet and is not robust enough to be used for repeated analyses, fluid operations utilizing the valve have not been verified sufficiently. Thus, in the present study, we fabricated a nanofluidic device implemented with a nanochannel open/close valve using rigid glass substrates of thicknesses on the order of 100 μm, and verified fluid operations utilizing the valve. On a small part of the substrate, we designed and fabricated a 30-µm-thick deformation section for the valve. The open/close operation and the performance of the valve were verified. The leakage of the valve was measured to be 2%, the response time was 0.9 s, and the number of repetitions was over 100,000. By utilizing the fabricated valve, we demonstrated fluid operations with femtoliter to picoliter volumes. Flow-switching within approximately 1 s and a flow control rate in the 63-1341 fL/s range was achieved. In addition, the fluid resistance of the valve was investigated both experimentally and numerically to establish a guideline for designing the valve. The valve developed and the design guidelines obtained will greatly contribute to integrated nanofluidic analytical devices.
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femtoliter volumetric pipette and flask utilizing Nanofluidics
Analyst, 2020Co-Authors: Tatsuro Nakao, Kyojiro Morikawa, Kazuma Mawatari, Yutaka Kazoe, Ling Lin, Takehiko KitamoriAbstract:Microfluidics has achieved integration of analytical processes in microspaces and realized miniaturized analyses in fields such as chemistry and biology. We have proposed a general concept of integration and extended this concept to the 10-1000 nm scale exploring ultimate analytical performances (e.g. immunoassay of a single-protein molecule). However, a sampling method is still challenging for Nanofluidics despite its importance in analytical chemistry. In this study, we developed a femtoliter (fL) sampling method for volume measurement and sample transport. Traditionally, sampling has been performed using a volumetric pipette and flask. In this research, a nanofluidic device consisting of a femtoliter volumetric pipette and flask was fabricated on glass substrates. Since gravity, which is exploited in bulk fluidic operations, becomes less dominant than surface effects on the nanometer scale, fluidic operation of the femtoliter sampling was designed utilizing surface tension and air pressure control. The working principle of an 11 fL volumetric pipette and a 50 fL flask, which were connected by a nanochannel, was verified. It was found that evaporation of the sample solution by air flow was a significant source of error because of the ultra-small volumes being processed. Thus, the evaporation issue was solved by suppressing the air flow. As a result, the volumetric measurement error was decreased to ±0.06 fL (CV 0.6%), which is sufficiently low for use in nanofluidic analytical applications. This study will present a fundamental technology for the development of novel analytical methods for femtoliter volume samples such as single molecule analyses.
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cytokine analysis on a countable number of molecules from living single cells on nanofluidic devices
Analyst, 2019Co-Authors: Tatsuro Nakao, Emi Mori, Kyojiro Morikawa, Takemichi Fukasawa, Ayumi Yoshizaki, Yutaka Kazoe, Takehiko KitamoriAbstract:Analysis of proteins released from living single cells is strongly required in the fields of biology and medicine to elucidate the mechanism of gene expression, cell–cell communication and cytopathology. However, as living single-cell analysis involves fL sample volumes with ultra-small amounts of analyte, comprehensive integration of entire chemical processing for single cells and proteins into spaces smaller than single cells (pL) would be indispensable to prevent dispersion-associated analyte loss. In this study, we proposed and developed a living single-cell protein analysis device based on micro/Nanofluidics and demonstrated analysis of cytokines released from living single B cells by enzyme-linked immunosorbent assay. Based on our integration method and technologies including top-down nanofabrication, surface modifications and pressure-driven flow control, we designed and prepared the device where pL-microfluidic- and fL-nanofluidic channels are hierarchically allocated for cellular and molecular processing, respectively, and succeeded in micro/nanofluidic control for manipulating single cells and molecules. 13-unit operations for pL-cellular processing including single-cell trapping and stimulation and fL-molecular processing including fL-volumetry, antigen–antibody reactions and detection were entirely integrated into a microchip. The results suggest analytical performances for countable interleukin (IL)-6 molecules at the limit of detection of 5.27 molecules and that stimulated single B cells secrete 3.41 IL-6 molecules per min. The device is a novel tool for single-cell targeted proteomics, and the methodology of device integration is applicable to other single-cell analyses such as single-cell shotgun proteomics. This study thus provides a general approach and technical breakthroughs that will facilitate further advances in micro/Nanofluidics, single-cell life science research, and other fields.
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metamaterials enhanced infrared spectroscopic study of nanoconfined molecules by plasmonics Nanofluidics hydrid device
ACS Photonics, 2018Co-Authors: Kazuma Mawatari, Takehiko Kitamori, Akihiro Morita, Takuo TanakaAbstract:The behavior of molecules under nanoconfinement is crucial for understanding the chemical processes in biological and nanomaterial systems. We demonstrated here an infrared spectroscopic method to characterize the molecular structures of molecules confined in several tens of nanometer cavities by employing the plasmonics–Nanofluidics hybrid device. This device consists of an array of metal nanostructures and a metal mirror separated by a nanofluidic cavity. Its configuration enables the confinement of both molecules and light energy as localized surface plasmons inside the physicochemically well-defined nanocavity. Exploiting the plasmons–molecular coupling, the vibrational modes of the nanoconfined molecules are selectively detected with a prominent sensitivity. Applying water as a proof-of-concept sample, we have successfully measured the infrared absorption characteristic and elucidated the molecular structures of water confined in a 10 nm cavity. They unveiled the presence of a strong H-bond network w...
Lei Jiang - One of the best experts on this subject based on the ideXlab platform.
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Nanofluidics for osmotic energy conversion
Nature Reviews Materials, 2021Co-Authors: Liping Wen, Zhen Zhang, Lei JiangAbstract:The osmotic pressure difference between river water and seawater is a promising source of renewable energy. However, current osmotic energy conversion processes show limited power output, mainly owing to the low performance of commercial ion-exchange membranes. Nanofluidic channels with tailored ion transport dynamics enable high-performance reverse electrodialysis to efficiently harvest renewable osmotic energy. In this Review, we discuss ion diffusion through nanofluidic channels and investigate the rational design and optimization of advanced membrane architectures. We highlight how the structure and charge distribution can be tailored to minimize resistance and promote energy conversion, and examine the possibility of integrating nanofluidic osmotic energy conversion with other technologies, such as desalination and water splitting. Finally, we give an outlook to future applications and discuss challenges that need to be overcome to enable large-scale, real-world applications. Osmotic energy conversion is a promising renewable energy source. This Review discusses Nanofluidics-based osmotic energy conversion systems, investigating the principles of ion diffusion in nanofluidic systems, optimization of membrane architectures to increase energy conversion and possible integration with other technologies, such as water splitting.
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ultraselective monovalent metal ion conduction in a three dimensional sub 1 nm nanofluidic device constructed by metal organic frameworks
ACS Nano, 2021Co-Authors: Huacheng Zhang, Lei Jiang, Binbin Qian, Jue Hou, Li Han, Yinlong Zhu, Chenghua Sun, Huanting WangAbstract:Construction of nanofluidic devices with an ultimate ion selectivity analogue to biological ion channels has been of great interest for their versatile applications in energy harvesting and conversion, mineral extraction, and ion separation. Herein, we report a three-dimensional (3D) sub-1 nm nanofluidic device to achieve high monovalent metal ion selectivity and conductivity. The 3D nanofluidic channel is constructed by assembly of a carboxyl-functionalized metal-organic framework (MOF, UiO-66-COOH) crystals with subnanometer pores into an ethanediamine-functionalized polymer nanochannel via a nanoconfined interfacial growth method. The 3D UiO-66-COOH nanofluidic channel achieves an ultrahigh K+/Mg2+ selectivity up to 1554.9, and the corresponding K+ conductivity is one to three orders of magnitude higher than that in bulk. Drift-diffusion experiments of the nanofluidic channel further reveal an ultrahigh charge selectivity (K+/Cl-) up to 112.1, as verified by the high K/Cl content ratio in UiO-66-COOH. The high metal ion selectivity is attributed to the size-exclusion, charge selectivity, and ion binding of the negatively charged MOF channels. This work will inspire the design of diverse MOF-based nanofluidic devices for ultimate ion separation and energy conversion.
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light powered directional nanofluidic ion transport in kirigami made asymmetric photonic ionic devices
Small, 2020Co-Authors: Meijuan Jia, Lei Jiang, Lili Wang, Liping Ding, Yanbing Zhang, Xian Kong, Di Quan, Wei GuoAbstract:Nacre-mimetic 2D nanofluidic materials with densely packed sub-nanometer-height lamellar channels find widespread applications in water-, energy-, and environment-related aspects by virtue of their scalable fabrication methods and exceptional transport properties. Recently, light-powered nanofluidic ion transport in synthetic materials gained considerable attention for its remote, noninvasive, and active control of the membrane transport property using the energy of light. Toward practical application, a critical challenge is to overcome the dependence on inhomogeneous or site-specific light illumination. Here, asymmetric photonic-ionic devices based on kirigami-tailored graphene oxide paper are fabricated, and directional nanofluidic ion transport properties therein powered by full-area light illumination are demonstrated. The in-plane asymmetry of the graphene oxide paper is essential to the generation of photoelectric driving force under homogeneous illumination. This light-powered ion transport phenomenon is explained based on a modified carrier diffusion model. In asymmetric nanofluidic structures, enhanced recombination of photoexcited charge carriers at the membrane boundary breaks the electric potential balance in the horizontal direction, and thus drives the ion transport in that direction under symmetric illumination. The kirigami-based strategy provides a facile and scalable way to fabricate paper-like photonic-ionic devices with arbitrary shapes, working as fundamental elements for large-scale light-harvesting nanofluidic circuits.
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Asymmetric Electrokinetic Proton Transport through 2D Nanofluidic Heterojunctions.
ACS Nano, 2019Co-Authors: Xiaopeng Zhang, Lei Jiang, Qi Wen, Lili Wang, Liping Ding, Jinlei Yang, Yanbing Zhang, Wei GuoAbstract:Nanofluidic ion transport in nacre-like 2D layered materials attracts broad research interest due to subnanometer confined space and versatile surface chemistry for precisely ionic sieving and ultrafast water permeation. Currently, most of the 2D-material-based nanofluidic systems are homogeneous, and the investigations of proton conduction therein are restricted to symmetric transport behaviors. It remains a great challenge to endow the 2D nanofluidic systems with asymmetric proton transport characteristics and adaptive responsibilities. Herein, we report the asymmetric proton transport phenomena through a 2D nanofluidic heterojunction membrane under three different types of electrokinetic driving force, that is, the external electric field, the transmembrane concentration gradient, and the hydraulic pressure difference. The heterogeneous 2D nanofluidic membrane comprises of sequentially stacked negatively and positively charged graphene oxide (n-GO and p-GO) multilayers. We find that the preferential direction for proton transport is opposite under the three types of electrokinetic driving force. The preferential direction for electric-field-driven proton transport is from the n-GO multilayers to the p-GO multilayers, showing rectified behaviors. Intriguingly, when the transmembrane concentration difference and the hydraulic flow are used as the driving force, a preferred diffusive and streaming proton current is found in the reverse direction, from the p-GO to the n-GO multilayers. The asymmetric proton transport phenomena are explained in terms of asymmetric proton concentration polarization and difference in proton selectivity. The membrane-scale heterogeneous 2D nanofluidic devices with electrokinetically controlled asymmetric proton flow provide a facile and general strategy for potential applications in biomimetic energy conversion and chemical sensing.
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Asymmetric Electrokinetic Proton Transport through 2D Nanofluidic Heterojunctions
2019Co-Authors: Xiaopeng Zhang, Lei Jiang, Qi Wen, Lili Wang, Liping Ding, Jinlei Yang, Yanbing Zhang, Wei GuoAbstract:Nanofluidic ion transport in nacre-like 2D layered materials attracts broad research interest due to subnanometer confined space and versatile surface chemistry for precisely ionic sieving and ultrafast water permeation. Currently, most of the 2D-material-based nanofluidic systems are homogeneous, and the investigations of proton conduction therein are restricted to symmetric transport behaviors. It remains a great challenge to endow the 2D nanofluidic systems with asymmetric proton transport characteristics and adaptive responsibilities. Herein, we report the asymmetric proton transport phenomena through a 2D nanofluidic heterojunction membrane under three different types of electrokinetic driving force, that is, the external electric field, the transmembrane concentration gradient, and the hydraulic pressure difference. The heterogeneous 2D nanofluidic membrane comprises of sequentially stacked negatively and positively charged graphene oxide (n-GO and p-GO) multilayers. We find that the preferential direction for proton transport is opposite under the three types of electrokinetic driving force. The preferential direction for electric-field-driven proton transport is from the n-GO multilayers to the p-GO multilayers, showing rectified behaviors. Intriguingly, when the transmembrane concentration difference and the hydraulic flow are used as the driving force, a preferred diffusive and streaming proton current is found in the reverse direction, from the p-GO to the n-GO multilayers. The asymmetric proton transport phenomena are explained in terms of asymmetric proton concentration polarization and difference in proton selectivity. The membrane-scale heterogeneous 2D nanofluidic devices with electrokinetically controlled asymmetric proton flow provide a facile and general strategy for potential applications in biomimetic energy conversion and chemical sensing
Wei Guo - One of the best experts on this subject based on the ideXlab platform.
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light powered directional nanofluidic ion transport in kirigami made asymmetric photonic ionic devices
Small, 2020Co-Authors: Meijuan Jia, Lei Jiang, Lili Wang, Liping Ding, Yanbing Zhang, Xian Kong, Di Quan, Wei GuoAbstract:Nacre-mimetic 2D nanofluidic materials with densely packed sub-nanometer-height lamellar channels find widespread applications in water-, energy-, and environment-related aspects by virtue of their scalable fabrication methods and exceptional transport properties. Recently, light-powered nanofluidic ion transport in synthetic materials gained considerable attention for its remote, noninvasive, and active control of the membrane transport property using the energy of light. Toward practical application, a critical challenge is to overcome the dependence on inhomogeneous or site-specific light illumination. Here, asymmetric photonic-ionic devices based on kirigami-tailored graphene oxide paper are fabricated, and directional nanofluidic ion transport properties therein powered by full-area light illumination are demonstrated. The in-plane asymmetry of the graphene oxide paper is essential to the generation of photoelectric driving force under homogeneous illumination. This light-powered ion transport phenomenon is explained based on a modified carrier diffusion model. In asymmetric nanofluidic structures, enhanced recombination of photoexcited charge carriers at the membrane boundary breaks the electric potential balance in the horizontal direction, and thus drives the ion transport in that direction under symmetric illumination. The kirigami-based strategy provides a facile and scalable way to fabricate paper-like photonic-ionic devices with arbitrary shapes, working as fundamental elements for large-scale light-harvesting nanofluidic circuits.
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Asymmetric Electrokinetic Proton Transport through 2D Nanofluidic Heterojunctions.
ACS Nano, 2019Co-Authors: Xiaopeng Zhang, Lei Jiang, Qi Wen, Lili Wang, Liping Ding, Jinlei Yang, Yanbing Zhang, Wei GuoAbstract:Nanofluidic ion transport in nacre-like 2D layered materials attracts broad research interest due to subnanometer confined space and versatile surface chemistry for precisely ionic sieving and ultrafast water permeation. Currently, most of the 2D-material-based nanofluidic systems are homogeneous, and the investigations of proton conduction therein are restricted to symmetric transport behaviors. It remains a great challenge to endow the 2D nanofluidic systems with asymmetric proton transport characteristics and adaptive responsibilities. Herein, we report the asymmetric proton transport phenomena through a 2D nanofluidic heterojunction membrane under three different types of electrokinetic driving force, that is, the external electric field, the transmembrane concentration gradient, and the hydraulic pressure difference. The heterogeneous 2D nanofluidic membrane comprises of sequentially stacked negatively and positively charged graphene oxide (n-GO and p-GO) multilayers. We find that the preferential direction for proton transport is opposite under the three types of electrokinetic driving force. The preferential direction for electric-field-driven proton transport is from the n-GO multilayers to the p-GO multilayers, showing rectified behaviors. Intriguingly, when the transmembrane concentration difference and the hydraulic flow are used as the driving force, a preferred diffusive and streaming proton current is found in the reverse direction, from the p-GO to the n-GO multilayers. The asymmetric proton transport phenomena are explained in terms of asymmetric proton concentration polarization and difference in proton selectivity. The membrane-scale heterogeneous 2D nanofluidic devices with electrokinetically controlled asymmetric proton flow provide a facile and general strategy for potential applications in biomimetic energy conversion and chemical sensing.
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Asymmetric Electrokinetic Proton Transport through 2D Nanofluidic Heterojunctions
2019Co-Authors: Xiaopeng Zhang, Lei Jiang, Qi Wen, Lili Wang, Liping Ding, Jinlei Yang, Yanbing Zhang, Wei GuoAbstract:Nanofluidic ion transport in nacre-like 2D layered materials attracts broad research interest due to subnanometer confined space and versatile surface chemistry for precisely ionic sieving and ultrafast water permeation. Currently, most of the 2D-material-based nanofluidic systems are homogeneous, and the investigations of proton conduction therein are restricted to symmetric transport behaviors. It remains a great challenge to endow the 2D nanofluidic systems with asymmetric proton transport characteristics and adaptive responsibilities. Herein, we report the asymmetric proton transport phenomena through a 2D nanofluidic heterojunction membrane under three different types of electrokinetic driving force, that is, the external electric field, the transmembrane concentration gradient, and the hydraulic pressure difference. The heterogeneous 2D nanofluidic membrane comprises of sequentially stacked negatively and positively charged graphene oxide (n-GO and p-GO) multilayers. We find that the preferential direction for proton transport is opposite under the three types of electrokinetic driving force. The preferential direction for electric-field-driven proton transport is from the n-GO multilayers to the p-GO multilayers, showing rectified behaviors. Intriguingly, when the transmembrane concentration difference and the hydraulic flow are used as the driving force, a preferred diffusive and streaming proton current is found in the reverse direction, from the p-GO to the n-GO multilayers. The asymmetric proton transport phenomena are explained in terms of asymmetric proton concentration polarization and difference in proton selectivity. The membrane-scale heterogeneous 2D nanofluidic devices with electrokinetically controlled asymmetric proton flow provide a facile and general strategy for potential applications in biomimetic energy conversion and chemical sensing
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Nanofluidics in two-dimensional layered materials: inspirations from nature
Chemical Society Reviews, 2017Co-Authors: Jun Gao, Yaping Feng, Wei Guo, Lei JiangAbstract:With the advance of chemistry, materials science, and nanotechnology, significant progress has been achieved in the design and application of synthetic nanofluidic devices and materials, mimicking the gating, rectifying, and adaptive functions of biological ion channels. Fundamental physics and chemistry behind these novel transport phenomena on the nanoscale have been explored in depth on single-pore platforms. However, toward real-world applications, one major challenge is to extrapolate these single-pore devices into macroscopic materials. Recently, inspired partially by the layered microstructure of nacre, the material design and large-scale integration of artificial nanofluidic devices have stepped into a completely new stage, termed 2D Nanofluidics. Unique advantages of the 2D layered materials have been found, such as facile and scalable fabrication, high flux, efficient chemical modification, tunable channel size, etc. These features enable wide applications in, for example, biomimetic ion transport manipulation, molecular sieving, water treatment, and nanofluidic energy conversion and storage. This review highlights the recent progress, current challenges, and future perspectives in this emerging research field of “2D Nanofluidics”, with emphasis on the thought of bio-inspiration.
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asymmetric ion transport through ion channel mimetic solid state nanopores
Accounts of Chemical Research, 2013Co-Authors: Wei Guo, Ye Tian, Lei JiangAbstract:Both scientists and engineers are interested in the design andfabrication of synthetic nanofluidic architectures that mimic the gating functions of biological ion channels. The effort to build such structures requires interdisciplinary efforts at the intersection of chemistry, materials science, and nanotechnology. Biological ion channels and synthetic nanofluidic devices have some structural and chemical similarities, and therefore, they share some common features in regulating the traverse ionic flow. In the past decade, researchers have identified two asymmetric ion transport phenomena in synthetic nanofluidic structures, the rectified ionic current and the net diffusion current. The rectified ionic current is a diode-like current–voltage response that occurs when switching the voltage bias. This phenomenon indicates a preferential direction of transport in the nanofluidic system. The net diffusion current occurs as a direct product of charge selectivity and is generated from the asymmetric diffusion t...
Kazuma Mawatari - One of the best experts on this subject based on the ideXlab platform.
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concentration determination at a countable molecular level in Nanofluidics by solvent enhanced photothermal optical diffraction
Analytical Chemistry, 2020Co-Authors: Yoshiyuki Tsuyama, Kazuma MawatariAbstract:Nanofluidic devices have become a powerful tool for extremely precise analyses at a single-molecule/nanoparticle level. However, a simple and sensitive molecular detection method is essential for nanofluidic devices because of ultrasmall volume (fL-aL). One such technology is photothermal spectroscopy (PTS), which utilizes light absorption and thermal relaxation by target molecules. Recently, we developed a photothermal optical diffraction (POD) detection method as PTS for nanofluidic devices. However, the detectable concentration range was in the order of μM (102 to 104 molecules), and further improvement in detection performance is strongly required. Here, we demonstrate solvent-enhanced POD with optimized experimental conditions and show its capability of concentration determination of nonfluorescent molecules in nanochannels at a countable molecular level. A relationship between the POD signal and thermal/optical properties of solvents is elucidated. We estimate the diffraction factor and photothermal factor of the solvent enhancement effect by thermal simulations and theoretical calculations. Experimental results show good agreement with the prediction, and the detection performance of the POD is successfully improved. At the optimized condition, we demonstrate the concentration determination with the limit of detection of 75 nM, which corresponds to an average of 10 molecules in a detection volume of 0.23 fL. Our sensitive nonfluorescent molecule detection method will be applied to a wide range of chemical/biological analyses utilizing Nanofluidics.
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femtoliter volumetric pipette and flask utilizing Nanofluidics
Analyst, 2020Co-Authors: Tatsuro Nakao, Kyojiro Morikawa, Kazuma Mawatari, Yutaka Kazoe, Ling Lin, Takehiko KitamoriAbstract:Microfluidics has achieved integration of analytical processes in microspaces and realized miniaturized analyses in fields such as chemistry and biology. We have proposed a general concept of integration and extended this concept to the 10-1000 nm scale exploring ultimate analytical performances (e.g. immunoassay of a single-protein molecule). However, a sampling method is still challenging for Nanofluidics despite its importance in analytical chemistry. In this study, we developed a femtoliter (fL) sampling method for volume measurement and sample transport. Traditionally, sampling has been performed using a volumetric pipette and flask. In this research, a nanofluidic device consisting of a femtoliter volumetric pipette and flask was fabricated on glass substrates. Since gravity, which is exploited in bulk fluidic operations, becomes less dominant than surface effects on the nanometer scale, fluidic operation of the femtoliter sampling was designed utilizing surface tension and air pressure control. The working principle of an 11 fL volumetric pipette and a 50 fL flask, which were connected by a nanochannel, was verified. It was found that evaporation of the sample solution by air flow was a significant source of error because of the ultra-small volumes being processed. Thus, the evaporation issue was solved by suppressing the air flow. As a result, the volumetric measurement error was decreased to ±0.06 fL (CV 0.6%), which is sufficiently low for use in nanofluidic analytical applications. This study will present a fundamental technology for the development of novel analytical methods for femtoliter volume samples such as single molecule analyses.
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metamaterials enhanced infrared spectroscopic study of nanoconfined molecules by plasmonics Nanofluidics hydrid device
ACS Photonics, 2018Co-Authors: Kazuma Mawatari, Takehiko Kitamori, Akihiro Morita, Takuo TanakaAbstract:The behavior of molecules under nanoconfinement is crucial for understanding the chemical processes in biological and nanomaterial systems. We demonstrated here an infrared spectroscopic method to characterize the molecular structures of molecules confined in several tens of nanometer cavities by employing the plasmonics–Nanofluidics hybrid device. This device consists of an array of metal nanostructures and a metal mirror separated by a nanofluidic cavity. Its configuration enables the confinement of both molecules and light energy as localized surface plasmons inside the physicochemically well-defined nanocavity. Exploiting the plasmons–molecular coupling, the vibrational modes of the nanoconfined molecules are selectively detected with a prominent sensitivity. Applying water as a proof-of-concept sample, we have successfully measured the infrared absorption characteristic and elucidated the molecular structures of water confined in a 10 nm cavity. They unveiled the presence of a strong H-bond network w...
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nano x ray diffractometry device for Nanofluidics
Lab on a Chip, 2018Co-Authors: Kazuma Mawatari, Hiroki Koreeda, Koji Ohara, Shinji Kohara, Koji Yoshida, Toshio Yamaguchi, Takehiko KitamoriAbstract:Nanofluidics is gaining attention because it has unique liquid and fluidic properties that are not observed in microfluidics. It has been reported that many liquid properties change when the size of a fluidic channel is reduced below 500-800 nm. To discuss the underlying mechanism, information on the microscopic liquid structure must be obtained (e.g., by X-ray diffractometry). However, the very small volume (attoliters to femtoliters) of a nanochannel and the large volume of its glass substrate prevent measurement of signals from the nanochannel liquid. In this study, we report a novel nanofluidic device that can be used in conjunction with X-ray diffractometry to analyze the structure of water confined in nanochannels. Top-down and bottom-up micro- and nano-fabrication processes were established, and the substrate thickness of the measurement area was reduced to only 2.7 μm, which was almost 1000 times smaller than that of conventional substrates (millimeter scale). With this new device, X-ray diffraction signals were clearly observed in nanochannels 500 nm wide and deep. Based on the X-ray diffraction pattern, the radial distribution function was calculated, which showed a structure nearly similar to that of a bulk sample. Therefore, X-ray diffractometry in nanochannels was realized. This method will provide important information on how a liquid behaves when confined in a nanospace and contribute to chemistry and biology on scales of 10-100 nm (e.g., inter- and intra-cellular spaces). It is also important for designing chemical reactions and fluidic circuits in nanochannels for realizing highly functional devices.
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bonding of glass nanofluidic chips at room temperature by a one step surface activation using an o2 cf4 plasma treatment
Lab on a Chip, 2013Co-Authors: Yan Xu, Lixiao Li, Kihoon Jang, Kazuma Mawatari, Tadatomo Suga, Yiyang Dong, Nobuhiro Matsumoto, Chenxi Wang, Takehiko KitamoriAbstract:A technical bottleneck to the broadening of applications of glass nanofluidic chips is bonding, due to the strict conditions, especially the extremely high temperatures (∼1000 °C) and the high vacuum required in the current glass-to-glass fusion bonding method. Herein, we report a strong, nanostructure-friendly, and high pressure-resistant bonding method, performed at room temperature (RT, ∼25 °C) for glass nanofluidic chips, using a one-step surface activation process with an O2/CF4 gas mixture plasma treatment. The developed RT bonding method is believed to be able to conquer the technical bottleneck in bonding in nanofluidic fields.
Peidong Yang - One of the best experts on this subject based on the ideXlab platform.
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Inorganic nanotubes: a novel platform for Nanofluidics.
Accounts of Chemical Research, 2006Co-Authors: Joshua E. Goldberger, Rong Fan, Peidong YangAbstract:Templating approaches are being developed for the synthesis of inorganic nanotubes, a novel platform for Nanofluidics. Single crystalline semiconductor GaN nanotubes have been synthesized using an epitaxial casting method. The partial thermal oxidation of silicon nanowires leads to the synthesis of silica nanotubes. The dimension of these nanotubes can be precisely controlled during the templating process. These inorganic nanotubes can be integrated into metal-oxide solution field effect transistors (MOSolFETs), which exhibit rapid field effect modulation of ionic conductance. These nanofluidic devices have been further demonstrated to be useful for single-molecule sensing, as single DNA molecules can be readily detected either by charge effect or by geometry effect. These inorganic nanotubes will have great implications in subfemtoliter analytical technology and large-scale nanofluidic integration.
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dna translocation in inorganic nanotubes
Nano Letters, 2005Co-Authors: Rong Fan, Rohit Karnik, Arun Majumdar, Min Yue, Peidong YangAbstract:Inorganic nanotubes were successfully integrated with microfluidic systems to create nanofluidic devices for single DNA molecule sensing. Inorganic nanotubes are unique in their high aspect ratio and exhibit translocation characteristics in which the DNA is fully stretched. Transient changes of ionic current indicate DNA translocation events. A transition from current decrease to current enhancement during translocation was observed on changing the buffer concentration, suggesting interplay between electrostatic charge and geometric blockage effects. These inorganic nanotube nanofluidic devices represent a new platform for the study of single biomolecule translocation with the potential for integration into nanofluidic circuits.
