Research

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24 pages, 13005 KiB

Open AccessArticle

Size Distribution Analysis with On-Chip Multi-Imaging Cell Sorter for Unlabeled Identification of Circulating Tumor Cells in Blood

by Masao Odaka, Hyonchol Kim, Yoshiyasu Nakamura, Akihiro Hattori, Kenji Matsuura, Moe Iwamura, Yohei Miyagi and Kenji Yasuda

Micromachines 2019, 10(2), 154; https://doi.org/10.3390/mi10020154 - 25 Feb 2019

Cited by 3 | Viewed by 3958

Abstract

We report a change of the imaging biomarker distribution of circulating tumor cell (CTC) clusters in blood over time using an on-chip multi-imaging flow cytometry system, which can obtain morphometric parameters of cells and those clusters, such as cell number, perimeter, total cross-sectional [...] Read more.

We report a change of the imaging biomarker distribution of circulating tumor cell (CTC) clusters in blood over time using an on-chip multi-imaging flow cytometry system, which can obtain morphometric parameters of cells and those clusters, such as cell number, perimeter, total cross-sectional area, aspect ratio, number of nuclei, and size of nuclei, as “imaging biomarkers”. Both bright-field (BF) and fluorescent (FL) images were acquired at 200 frames per second and analyzed within the intervals for real-time cell sorting. A green fluorescent protein-transfected prostate cancer cell line (MAT-LyLu-GFP) was implanted into Copenhagen rats, and the blood samples of these rats were collected 2 to 11 days later and measured using the system. The results showed that cells having BF area of 90 μm² or larger increased in number seven days after the cancer cell implantation, which was specifically detected as a shift of the cell size distribution for blood samples of implanted rats, in comparison with that for control blood. All cells with BF area of 150 μm² or larger were arranged in cell clusters composed of at least two cells, as confirmed by FL nucleus number and area measurements, and they constituted more than 1% of all white blood cells. These results indicate that the mapping of cell size distribution is useful for identifying an increase of irregular cells such as cell clusters in blood, and show that CTC clusters become more abundant in blood over time after malignant tumor formation. The results also reveal that a blood sample of only 50 μL is sufficient to acquire a stable size distribution map of all blood cells to predict the presence of CTC clusters. Full article

(This article belongs to the Special Issue State-of-the-Art Lab-on-a-Chip Technology in Japan)

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9 pages, 2499 KiB

Open AccessArticle

Transport of a Micro Liquid Plug in a Gas-Phase Flow in a Microchannel

by Yutaka Kazoe, Takumi Matsuno, Ippei Yamashiro, Kazuma Mawatari and Takehiko Kitamori

Micromachines 2018, 9(9), 423; https://doi.org/10.3390/mi9090423 - 23 Aug 2018

Cited by 5 | Viewed by 3383

Abstract

Micro liquid droplets and plugs in the gas-phase in microchannels have been utilized in microfluidics for chemical analysis and synthesis. While higher velocities of droplets and plugs are expected to enable chemical processing at higher efficiency and higher throughput, we recently reported that [...] Read more.

Micro liquid droplets and plugs in the gas-phase in microchannels have been utilized in microfluidics for chemical analysis and synthesis. While higher velocities of droplets and plugs are expected to enable chemical processing at higher efficiency and higher throughput, we recently reported that there is a limit of the liquid plug velocity owing to splitting caused by unstable wetting to the channel wall. This study expands our experimental work to examine the dynamics of a micro liquid plug in the gas phase in a microchannel. The motion of a single liquid plug, 0.4–58 nL in volume, with precise size control in 39- to 116-m-diameter hydrophobic microchannels was investigated. The maximum velocity of the liquid plug was 1.5 m/s, and increased to 5 m/s with splitting. The plug velocity was 20% of that calculated using the Hagen-Poiseuille equation. It was found that the liquid plug starts splitting when the inertial force exerted by the fluid overcomes the surface tension, i.e., the Weber number (ratio of the inertial force to the surface tension) is higher than 1. The results can be applied in the design of microfluidic devices for various applications that utilize liquid droplets and plugs in the gas phase. Full article

(This article belongs to the Special Issue State-of-the-Art Lab-on-a-Chip Technology in Japan)

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9 pages, 2653 KiB

Open AccessFeature PaperArticle

Design and Fabrication of a Visible-Light-Compatible, Polymer-Based Photonic Crystal Resonator and Waveguide for Sensing Applications

by Jiayi Sun, Kenichi Maeno, Shoma Aki, Kenji Sueyoshi, Hideaki Hisamoto and Tatsuro Endo

Micromachines 2018, 9(8), 410; https://doi.org/10.3390/mi9080410 - 17 Aug 2018

Cited by 2 | Viewed by 3355

Abstract

In this paper, we have proposed a polymer-based photonic crystal (PhC) resonator, with multiple sizes of cavities, and a waveguide to be used as highly sensitive optical sensor components. Properties of the proposed PhC were simulated by the finite-difference time-domain method, and the [...] Read more.

In this paper, we have proposed a polymer-based photonic crystal (PhC) resonator, with multiple sizes of cavities, and a waveguide to be used as highly sensitive optical sensor components. Properties of the proposed PhC were simulated by the finite-difference time-domain method, and the polymer-based PhC resonator and waveguide were fabricated on a photoresist (polymer) by electron beam lithography, which was prepared on an Au-layer-deposited Si substrate. We detected the resonant light that penetrated through the waveguide and was trapped in the PhC resonator. Optical characteristics of the fabricated PhC were evaluated by detecting the polymer layer deposition process by using the layer-by-layer (LbL) method to deposit polymer layers. As a result, by using an optimized design of a polymer-based PhC resonator with a long cavity (equivalent to a defect of three holes), the PhC structure changes caused by LbL deposition lead to changes in resonant light wavelength (peak shift: 5.26 nm/layer). Therefore, we suggest that a PhC resonator and a waveguide is applicable as an optical sensor. Full article

(This article belongs to the Special Issue State-of-the-Art Lab-on-a-Chip Technology in Japan)

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11 pages, 3294 KiB

Open AccessArticle

A Closed System for Pico-Liter Order Substance Transport from a Giant Liposome to a Cell

by Shohei Miyakawa, Kaoru Uesugi and Keisuke Morishima

Micromachines 2018, 9(7), 331; https://doi.org/10.3390/mi9070331 - 02 Jul 2018

Cited by 3 | Viewed by 3602

Abstract

In single cell analysis, transport of foreign substances into a cell is an important technique. In particular, for accurate analysis, a method to transport a small amount (pico-liter order) of substance into the cell without leakage while retaining the cell shape is essential. [...] Read more.

In single cell analysis, transport of foreign substances into a cell is an important technique. In particular, for accurate analysis, a method to transport a small amount (pico-liter order) of substance into the cell without leakage while retaining the cell shape is essential. Because the fusion of the cell and the giant liposome is a closed system to the outside, it may be possible to transport a precise, small amount of substances into the cell. Additionally, there is no possibility that a leaked substance would affect other systems. To develop the liposome-cell transportation system, knowledge about the behavior of substances in the liposome and the cell is important. However, only a few studies have observed the substance transport between a liposome and a cell. Here, we report observation of small amount of substance transport into a single C2C12 cell by using a giant liposome. Substance transport occurred by electrofusion between the cell and the giant liposome containing the substance, which is a closed system. First, to observe the electrofusion and substance transport from the moment of voltage application, we fabricated a microfluidic device equipped with electrodes. We introduced suspensions of cells and liposomes into the microfluidic device and applied alternating current (AC) and direct current (DC) voltages for electrofusion. We observed a small amount (22.4 ± 0.1%, 10.3 ± 0.4% and 9.1 ± 0.1%) of fluorescent substance (Calcein) contained in the liposomes was transported into the cell without leakage outside the cell, and we obtained the diffusion coefficient of Calcein in the cell as 137 ± 18 μm²/s. We anticipate that this system and the knowledge acquired will contribute to future realization of more accurate single cell analysis in a wide range of fields. Full article

(This article belongs to the Special Issue State-of-the-Art Lab-on-a-Chip Technology in Japan)

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14 pages, 5525 KiB

Open AccessArticle

Developing a MEMS Device with Built-in Microfluidics for Biophysical Single Cell Characterization

by Yuki Takayama, Grégoire Perret, Momoko Kumemura, Manabu Ataka, Samuel Meignan, Stanislav L. Karsten, Hiroyuki Fujita, Dominique Collard, Chann Lagadec and Mehmet Cagatay Tarhan

Micromachines 2018, 9(6), 275; https://doi.org/10.3390/mi9060275 - 01 Jun 2018

Cited by 10 | Viewed by 4548

Abstract

This study combines the high-throughput capabilities of microfluidics with the sensitive measurements of microelectromechanical systems (MEMS) technology to perform biophysical characterization of circulating cells for diagnostic purposes. The proposed device includes a built-in microchannel that is probed by two opposing tips performing compression [...] Read more.

This study combines the high-throughput capabilities of microfluidics with the sensitive measurements of microelectromechanical systems (MEMS) technology to perform biophysical characterization of circulating cells for diagnostic purposes. The proposed device includes a built-in microchannel that is probed by two opposing tips performing compression and sensing separately. Mechanical displacement of the compressing tip (up to a maximum of 14 µm) and the sensing tip (with a quality factor of 8.9) are provided by two separate comb-drive actuators, and sensing is performed with a capacitive displacement sensor. The device is designed and developed for simultaneous electrical and mechanical measurements. As the device is capable of exchanging the liquid inside the channel, different solutions were tested consecutively. The performance of the device was evaluated by introducing varying concentrations of glucose (from 0.55 mM (0.1%) to 55.5 mM (10%)) and NaCl (from 0.1 mM to 10 mM) solutions in the microchannel and by monitoring changes in the mechanical and electrical properties. Moreover, we demonstrated biological sample handling by capturing single cancer cells. These results show three important capabilities of the proposed device: mechanical measurements, electrical measurements, and biological sample handling. Combined in one device, these features allow for high-throughput multi-parameter characterization of single cells. Full article

(This article belongs to the Special Issue State-of-the-Art Lab-on-a-Chip Technology in Japan)

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11 pages, 1016 KiB

Open AccessArticle

Effects of Microchannel Shape and Ultrasonic Mixing on Microfluidic Padlock Probe Rolling Circle Amplification (RCA) Reactions

by Yuri Ishigaki and Kae Sato

Micromachines 2018, 9(6), 272; https://doi.org/10.3390/mi9060272 - 30 May 2018

Cited by 4 | Viewed by 3553

Abstract

The fluorescence in situ hybridization (FISH)-based padlock probe and rolling circle amplification (RCA) method allows for the detection of point mutations. However, it requires multiple reaction steps and solution exchanges, making it costly, labor-intensive, and time-consuming. In this study, we aimed to improve [...] Read more.

The fluorescence in situ hybridization (FISH)-based padlock probe and rolling circle amplification (RCA) method allows for the detection of point mutations. However, it requires multiple reaction steps and solution exchanges, making it costly, labor-intensive, and time-consuming. In this study, we aimed to improve the efficiency of padlock/RCA by determining the effects of microchannel shape and ultrasonic solution mixing. Using a circular-shaped microchamber and ultrasonic mixing, the efficiency of microfluidic padlock/RCA was improved, and the consumption of the expensive probe solution was reduced from 10 µL to approximately 3.5 µL. Moreover, the fluorescent probe hybridization time was reduced to 5 min, which is four times faster than that of the standard protocol. We used this method to successfully detect mitochondrial DNA and transcripts of β-actin and K-ras proto-oncogene codon 12 in cells. Our method offers improvements over current padlock/RCA methods and will be helpful in optimizing other microfluidics-based FISH-related analyses. Full article

(This article belongs to the Special Issue State-of-the-Art Lab-on-a-Chip Technology in Japan)

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10 pages, 2431 KiB

Open AccessFeature PaperCommunication

Assembly and Connection of Micropatterned Single Neurons for Neuronal Network Formation

by Shotaro Yoshida, Midori Kato-Negishi and Shoji Takeuchi

Micromachines 2018, 9(5), 235; https://doi.org/10.3390/mi9050235 - 15 May 2018

Cited by 20 | Viewed by 10457

Abstract

Engineering of neuronal network geometry by micropatterning technology is a key future technology for creating artificial brains on a chip. However, engineering of network geometry at the single-cell-level with functional morphology (axon/dendrite) and connectivity (synapses) is still challenging. Here, we describe a method [...] Read more.

Engineering of neuronal network geometry by micropatterning technology is a key future technology for creating artificial brains on a chip. However, engineering of network geometry at the single-cell-level with functional morphology (axon/dendrite) and connectivity (synapses) is still challenging. Here, we describe a method for controlling the axon and dendrite morphology of single primary-cultured neurons and assembling a neural circuit using mobile microplates. The microplates enabled morphological control of neurons by their shapes and bringing their ends into contact caused the formation of physical connections. Functional synapse formation at the connection was indicated by immunostaining of synapse-related proteins and intracellular Ca²⁺ imaging of neural activity. We believe that the method will be useful in engineering neural circuits with selected neurons and defined morphology. Full article

(This article belongs to the Special Issue State-of-the-Art Lab-on-a-Chip Technology in Japan)

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9 pages, 10663 KiB

Open AccessArticle

Quantitative Evaluation of Dielectric Breakdown of Silicon Micro- and Nanofluidic Devices for Electrophoretic Transport of a Single DNA Molecule

by Mamiko Sano, Noritada Kaji, Qiong Wu, Toyohiro Naito, Takao Yasui, Masateru Taniguchi, Tomoji Kawai and Yoshinobu Baba

Micromachines 2018, 9(4), 180; https://doi.org/10.3390/mi9040180 - 13 Apr 2018

Cited by 4 | Viewed by 3594

Abstract

In the present study, we quantitatively evaluated dielectric breakdown in silicon-based micro- and nanofluidic devices under practical electrophoretic conditions by changing the thickness of the insulating layer. At higher buffer concentration, a silicon nanofluidic device with a 100 nm or 250 nm silicon [...] Read more.

In the present study, we quantitatively evaluated dielectric breakdown in silicon-based micro- and nanofluidic devices under practical electrophoretic conditions by changing the thickness of the insulating layer. At higher buffer concentration, a silicon nanofluidic device with a 100 nm or 250 nm silicon dioxide layer tolerated dielectric breakdown up to ca. 10 V/cm, thereby allowing successful electrophoretic migration of a single DNA molecule through a nanochannel. The observed DNA migration behavior suggested that parameters, such as thickness of the insulating layer, tolerance of dielectric breakdown, and bonding status of silicon and glass substrate, should be optimized to achieve successful electrophoretic transport of a DNA molecule through a nanopore for nanopore-based DNA sequencing applications. Full article

(This article belongs to the Special Issue State-of-the-Art Lab-on-a-Chip Technology in Japan)

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21 pages, 13091 KiB

Open AccessArticle

Analytical Model and Experimental Evaluation of the Micro-Scale Thermal Property Sensor for Single-Sided Measurement

by Takashi Katayama, Kaoru Uesugi and Keisuke Morishima

Micromachines 2018, 9(4), 168; https://doi.org/10.3390/mi9040168 - 05 Apr 2018

Cited by 4 | Viewed by 4144

Abstract

We report a new analytical model of the MEMS-based thermal property sensor for samples which are difficult to handle and susceptible to damage by thermal stimulus, such as living cells. Many sensor designs had been reported for thermal property measurements, but only a [...] Read more.

We report a new analytical model of the MEMS-based thermal property sensor for samples which are difficult to handle and susceptible to damage by thermal stimulus, such as living cells. Many sensor designs had been reported for thermal property measurements, but only a few of them have considered the analytical model of the single-sided measurement in which a measurement sample is placed on the sensor substrate. Even in the few designs that have considered the analytical model, their applicable limits are restricted to more than 1 mm length in practical situations. Our new model considers both the sample and the sensor substrate thermal properties and is applicable to a sensor length less than 1 µm. In order to minimize the influence of the heat stimulus to the sample, the model formulates the required heat dissipating time for different sensor geometries. We propose fast and precise detection circuit architecture to realize our model, and we discuss the sensor performance for a number of different designs. Full article

(This article belongs to the Special Issue State-of-the-Art Lab-on-a-Chip Technology in Japan)

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Review

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25 pages, 4490 KiB

Open AccessReview

Recent Microdevice-Based Aptamer Sensors

by Donny Nugraha Mazaafrianto, Masatoshi Maeki, Akihiko Ishida, Hirofumi Tani and Manabu Tokeshi

Micromachines 2018, 9(5), 202; https://doi.org/10.3390/mi9050202 - 25 Apr 2018

Cited by 26 | Viewed by 5903

Abstract

Since the systematic evolution of ligands by exponential enrichment (SELEX) method was developed, aptamers have made significant contributions as bio-recognition sensors. Microdevice systems allow for low reagent consumption, high-throughput of samples, and disposability. Due to these advantages, there has been an increasing demand [...] Read more.

Since the systematic evolution of ligands by exponential enrichment (SELEX) method was developed, aptamers have made significant contributions as bio-recognition sensors. Microdevice systems allow for low reagent consumption, high-throughput of samples, and disposability. Due to these advantages, there has been an increasing demand to develop microfluidic-based aptasensors for analytical technique applications. This review introduces the principal concepts of aptasensors and then presents some advanced applications of microdevice-based aptasensors on several platforms. Highly sensitive detection techniques, such as electrochemical and optical detection, have been integrated into lab-on-a-chip devices and researchers have moved towards the goal of establishing point-of-care diagnoses for target analyses. Full article

(This article belongs to the Special Issue State-of-the-Art Lab-on-a-Chip Technology in Japan)

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