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Micromachines
Volume 7
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Micromachines, Volume 7, Issue 2 (February 2016) – 17 articles

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858 KiB  
Article
Combined Forced and Thermocreep Convection through a Long Horizontal Microchannel
by Huei Chu Weng
Micromachines 2016, 7(2), 33; https://doi.org/10.3390/mi7020033 - 19 Feb 2016
Cited by 5 | Viewed by 4447
Abstract
This study examines how thermal creep affects the mixed convection in a long horizontal parallel-plate microchannel under a pressure drop and a temperature rise. The analytical solutions of the fully developed thermal-flow fields and the corresponding characteristics are derived based on the Maxwell [...] Read more.
This study examines how thermal creep affects the mixed convection in a long horizontal parallel-plate microchannel under a pressure drop and a temperature rise. The analytical solutions of the fully developed thermal-flow fields and the corresponding characteristics are derived based on the Maxwell boundary conditions with thermal creep and presented for the physical properties of air at the standard reference state. The calculated thermal-flow characteristics reveal that thermal creep has an appreciable effect on the velocity slip, flow rate, and heat transfer rate but a negligible effect on the flow drag. Such a creep effect could be further magnified by decreasing the pressure drop or increasing the Knudsen number. Full article
(This article belongs to the Special Issue Recent Advances in Smart System)
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923 KiB  
Review
Challenges and Opportunities of Centrifugal Microfluidics for Extreme Point-of-Care Testing
by Issac J. Michael, Tae-Hyeong Kim, Vijaya Sunkara and Yoon-Kyoung Cho
Micromachines 2016, 7(2), 32; https://doi.org/10.3390/mi7020032 - 19 Feb 2016
Cited by 35 | Viewed by 10888
Abstract
The advantages offered by centrifugal microfluidic systems have encouraged its rapid adaptation in the fields of in vitro diagnostics, clinical chemistry, immunoassays, and nucleic acid tests. Centrifugal microfluidic devices are currently used in both clinical and point-of-care settings. Recent studies have shown that [...] Read more.
The advantages offered by centrifugal microfluidic systems have encouraged its rapid adaptation in the fields of in vitro diagnostics, clinical chemistry, immunoassays, and nucleic acid tests. Centrifugal microfluidic devices are currently used in both clinical and point-of-care settings. Recent studies have shown that this new diagnostic platform could be potentially used in extreme point-of-care settings like remote villages in the Indian subcontinent and in Africa. Several technological inventions have decentralized diagnostics in developing countries; however, very few microfluidic technologies have been successful in meeting the demand. By identifying the finest difference between the point-of-care testing and extreme point-of-care infrastructure, this review captures the evolving diagnostic needs of developing countries paired with infrastructural challenges with technological hurdles to healthcare delivery in extreme point-of-care settings. In particular, the requirements for making centrifugal diagnostic devices viable in developing countries are discussed based on a detailed analysis of the demands in different clinical settings including the distinctive needs of extreme point-of-care settings. Full article
(This article belongs to the Special Issue Centrifugal (Compact-Disc) Microfluidics for Extreme POC)
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5198 KiB  
Article
Height Resolution of Antibody Spots Measured by Spinning-Disk Interferometry on the BioCD
by Kevin O’Brien, Ming Zhao and David Nolte
Micromachines 2016, 7(2), 31; https://doi.org/10.3390/mi7020031 - 17 Feb 2016
Viewed by 4641
Abstract
Spinning-disc interferometry (SDI) is a high-speed laser scanning approach to surface metrology that uses common-path interferometry to measure protein spots on a BioCD disk. The measurement sensitivity depends on the scanning pitch and on the time-base. Based on high-resolution laser scanning images of [...] Read more.
Spinning-disc interferometry (SDI) is a high-speed laser scanning approach to surface metrology that uses common-path interferometry to measure protein spots on a BioCD disk. The measurement sensitivity depends on the scanning pitch and on the time-base. Based on high-resolution laser scanning images of printed antibody spots, we quantify the protein sensitivity as a function of the scan parameters. For smoothly printed antibody spots scanned with a transverse spatial resolution of 1 μm, the surface height precision for a single 100 μm diameter protein spot is approximately 1 pm. This detection sensitivity sets the fundamental limit of detection for label-free BioCD biosensors performing immunoassays. Full article
(This article belongs to the Special Issue Centrifugal (Compact-Disc) Microfluidics for Extreme POC)
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3655 KiB  
Article
CMOS-NEMS Copper Switches Monolithically Integrated Using a 65 nm CMOS Technology
by Jose Luis Muñoz-Gamarra, Arantxa Uranga and Nuria Barniol
Micromachines 2016, 7(2), 30; https://doi.org/10.3390/mi7020030 - 15 Feb 2016
Cited by 14 | Viewed by 6224
Abstract
This work demonstrates the feasibility to obtain copper nanoelectromechanical (NEMS) relays using a commercial complementary metal oxide semiconductor (CMOS) technology (ST 65 nm) following an intra CMOS-MEMS approach. We report experimental demonstration of contact-mode nano-electromechanical switches obtaining low operating voltage (5.5 V), good [...] Read more.
This work demonstrates the feasibility to obtain copper nanoelectromechanical (NEMS) relays using a commercial complementary metal oxide semiconductor (CMOS) technology (ST 65 nm) following an intra CMOS-MEMS approach. We report experimental demonstration of contact-mode nano-electromechanical switches obtaining low operating voltage (5.5 V), good ION/IOFF (103) ratio, abrupt subthreshold swing (4.3 mV/decade) and minimum dimensions (3.50 μm × 100 nm × 180 nm, and gap of 100 nm). With these dimensions, the operable Cell area of the switch will be 3.5 μm (length) × 0.2 μm (100 nm width + 100 nm gap) = 0.7 μm2 which is the smallest reported one using a top-down fabrication approach. Full article
(This article belongs to the Special Issue CMOS-MEMS Sensors and Devices)
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3032 KiB  
Review
Opto-Microfluidic Immunosensors: From Colorimetric to Plasmonic
by Jie-Long He, Da-Shin Wang and Shih-Kang Fan
Micromachines 2016, 7(2), 29; https://doi.org/10.3390/mi7020029 - 15 Feb 2016
Cited by 14 | Viewed by 7614
Abstract
Optical detection has long been the most popular technique in immunosensing. Recent developments in the synthesis of luminescent probes and the fabrication of novel nanostructures enable more sensitive and efficient optical detection, which can be miniaturized and integrated with microfluidics to realize compact [...] Read more.
Optical detection has long been the most popular technique in immunosensing. Recent developments in the synthesis of luminescent probes and the fabrication of novel nanostructures enable more sensitive and efficient optical detection, which can be miniaturized and integrated with microfluidics to realize compact lab-on-a-chip immunosensors. These immunosensors are portable, economical and automated, but their sensitivity is not compromised. This review focuses on the incorporation and implementation of optical detection and microfluidics in immunosensors; it introduces the working principles of each optical detection technique and how it can be exploited in immunosensing. The recent progress in various opto-microfluidic immunosensor designs is described. Instead of being comprehensive to include all opto-microfluidic platforms, the report centers on the designs that are promising for point-of-care immunosensing diagnostics, in which ease of use, stability and cost-effective fabrication are emphasized. Full article
(This article belongs to the Special Issue Optofluidics 2015)
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1666 KiB  
Article
Development of a Whole Blood Paper-Based Device for Phenylalanine Detection in the Context of PKU Therapy Monitoring
by Robert Robinson, Liam Wong, Raymond J. Monnat and Elain Fu
Micromachines 2016, 7(2), 28; https://doi.org/10.3390/mi7020028 - 15 Feb 2016
Cited by 38 | Viewed by 7968
Abstract
Laboratory-based testing does not allow for the sufficiently rapid return of data to enable optimal therapeutic monitoring of patients with metabolic diseases such as phenylketonuria (PKU). The typical turn-around time of several days for current laboratory-based testing is too slow to be practically [...] Read more.
Laboratory-based testing does not allow for the sufficiently rapid return of data to enable optimal therapeutic monitoring of patients with metabolic diseases such as phenylketonuria (PKU). The typical turn-around time of several days for current laboratory-based testing is too slow to be practically useful for effective monitoring or optimizing therapy. This report describes the development of a rapid, paper-based, point-of-care device for phenylalanine detection using a small volume (40 μL) of whole blood. The quantitative resolution and reproducibility of this device with instrumented readout are described, together with the potential use of this device for point-of-care monitoring by PKU patients. Full article
(This article belongs to the Special Issue Paper-Based Microfluidic Devices for Point-of-Care Diagnostics)
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613 KiB  
Article
Oocytes Polar Body Detection for Automatic Enucleation
by Di Chen, Mingzhu Sun and Xin Zhao
Micromachines 2016, 7(2), 27; https://doi.org/10.3390/mi7020027 - 14 Feb 2016
Cited by 11 | Viewed by 6566
Abstract
Enucleation is a crucial step in cloning. In order to achieve automatic blind enucleation, we should detect the polar body of the oocyte automatically. The conventional polar body detection approaches have low success rate or low efficiency. We propose a polar body detection [...] Read more.
Enucleation is a crucial step in cloning. In order to achieve automatic blind enucleation, we should detect the polar body of the oocyte automatically. The conventional polar body detection approaches have low success rate or low efficiency. We propose a polar body detection method based on machine learning in this paper. On one hand, the improved Histogram of Oriented Gradient (HOG) algorithm is employed to extract features of polar body images, which will increase success rate. On the other hand, a position prediction method is put forward to narrow the search range of polar body, which will improve efficiency. Experiment results show that the success rate is 96% for various types of polar bodies. Furthermore, the method is applied to an enucleation experiment and improves the degree of automatic enucleation. Full article
(This article belongs to the Special Issue Micro/Nano Robotics)
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3531 KiB  
Article
Microfluidic-Based Droplet and Cell Manipulations Using Artificial Bacterial Flagella
by Yun Ding, Famin Qiu, Xavier Casadevall i Solvas, Flora Wing Yin Chiu, Bradley J. Nelson and Andrew DeMello
Micromachines 2016, 7(2), 25; https://doi.org/10.3390/mi7020025 - 8 Feb 2016
Cited by 42 | Viewed by 11797
Abstract
Herein, we assess the functionality of magnetic helical microswimmers as basic tools for the manipulation of soft materials, including microdroplets and single cells. Their ability to perform a range of unit operations is evaluated and the operational challenges associated with their use are [...] Read more.
Herein, we assess the functionality of magnetic helical microswimmers as basic tools for the manipulation of soft materials, including microdroplets and single cells. Their ability to perform a range of unit operations is evaluated and the operational challenges associated with their use are established. In addition, we also report on interactions observed between the head of such helical swimmers and the boundaries of droplets and cells and discuss the possibilities of assembling an artificial swimming microorganism or a motorized cell. Full article
(This article belongs to the Collection Lab-on-a-Chip)
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6612 KiB  
Review
A Review of Biomedical Centrifugal Microfluidic Platforms
by Minghui Tang, Guanghui Wang, Siu-Kai Kong and Ho-Pui Ho
Micromachines 2016, 7(2), 26; https://doi.org/10.3390/mi7020026 - 6 Feb 2016
Cited by 145 | Viewed by 16693
Abstract
Centrifugal microfluidic or lab-on-a-disc platforms have many advantages over other microfluidic systems. These advantages include a minimal amount of instrumentation, the efficient removal of any disturbing bubbles or residual volumes, and inherently available density-based sample transportation and separation. Centrifugal microfluidic devices applied to [...] Read more.
Centrifugal microfluidic or lab-on-a-disc platforms have many advantages over other microfluidic systems. These advantages include a minimal amount of instrumentation, the efficient removal of any disturbing bubbles or residual volumes, and inherently available density-based sample transportation and separation. Centrifugal microfluidic devices applied to biomedical analysis and point-of-care diagnostics have been extensively promoted recently. This paper presents an up-to-date overview of these devices. The development of biomedical centrifugal microfluidic platforms essentially covers two categories: (i) unit operations that perform specific functionalities, and (ii) systems that aim to address certain biomedical applications. With the aim to provide a comprehensive representation of current development in this field, this review summarizes progress in both categories. The advanced unit operations implemented for biological processing include mixing, valving, switching, metering and sequential loading. Depending on the type of sample to be used in the system, biomedical applications are classified into four groups: nucleic acid analysis, blood analysis, immunoassays, and other biomedical applications. Our overview of advanced unit operations also includes the basic concepts and mechanisms involved in centrifugal microfluidics, while on the other hand an outline on reported applications clarifies how an assembly of unit operations enables efficient implementation of various types of complex assays. Lastly, challenges and potential for future development of biomedical centrifugal microfluidic devices are discussed. Full article
(This article belongs to the Special Issue Centrifugal (Compact-Disc) Microfluidics for Extreme POC)
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6632 KiB  
Review
Scanning Micromirror Platform Based on MEMS Technology for Medical Application
by Eakkachai Pengwang, Kanty Rabenorosoa, Micky Rakotondrabe and Nicolas Andreff
Micromachines 2016, 7(2), 24; https://doi.org/10.3390/mi7020024 - 6 Feb 2016
Cited by 72 | Viewed by 12983
Abstract
This topical review discusses recent development and trends on scanning micromirrors for biomedical applications. This also includes a biomedical micro robot for precise manipulations in a limited volume. The characteristics of medical scanning micromirror are explained in general with the fundamental of microelectromechanical [...] Read more.
This topical review discusses recent development and trends on scanning micromirrors for biomedical applications. This also includes a biomedical micro robot for precise manipulations in a limited volume. The characteristics of medical scanning micromirror are explained in general with the fundamental of microelectromechanical systems (MEMS) for fabrication processes. Along with the explanations of mechanism and design, the principle of actuation are provided for general readers. In this review, several testing methodology and examples are described based on many types of actuators, such as, electrothermal actuators, electrostatic actuators, electromagnetic actuators, pneumatic actuators, and shape memory alloy. Moreover, this review provides description of the key fabrication processes and common materials in order to be a basic guideline for selecting micro-actuators. With recent developments on scanning micromirrors, performances of biomedical application are enhanced for higher resolution, high accuracy, and high dexterity. With further developments on integrations and control schemes, MEMS-based scanning micromirrors would be able to achieve a better performance for medical applications due to small size, ease in microfabrication, mass production, high scanning speed, low power consumption, mechanical stable, and integration compatibility. Full article
(This article belongs to the Special Issue Micro/Nano Robotics)
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2812 KiB  
Article
A New XYZ Compliant Parallel Mechanism for Micro-/Nano-Manipulation: Design and Analysis
by Haiyang Li, Guangbo Hao and Richard C. Kavanagh
Micromachines 2016, 7(2), 23; https://doi.org/10.3390/mi7020023 - 1 Feb 2016
Cited by 17 | Viewed by 7943
Abstract
Based on the constraint and position identification (CPI) approach for synthesizing XYZ compliant parallel mechanisms (CPMs) and configuration modifications, this paper proposes a new fully-symmetrical XYZ CPM with desired motion characteristics such as reduced cross-axis coupling, minimized lost motion, and relatively small parasitic [...] Read more.
Based on the constraint and position identification (CPI) approach for synthesizing XYZ compliant parallel mechanisms (CPMs) and configuration modifications, this paper proposes a new fully-symmetrical XYZ CPM with desired motion characteristics such as reduced cross-axis coupling, minimized lost motion, and relatively small parasitic motion. The good motion characteristics arise from not only its symmetric configuration, but also the rigid linkages between non-adjacent rigid stages. Comprehensive kinematic analysis is carried out based on a series of finite element simulations over a motion range per axis less than ±5% of the beam length, which reveals that the maximum cross-axis coupling rate is less than 0.86%, the maximum lost motion rate is less than 1.20%, the parasitic rotations of the motion stage (MS) are in the order of 10−5 rad, and the parasitic translations of the three actuated stages (ASs) are in the order of 10−4 of the beam length (less than 0.3% of the motion range), where the beam slenderness ratio is larger than 20. Furthermore, the nonlinear analytical models of the primary translations of the XYZ CPM, including the primary translations of the MS and the ASs, are derived and validated to provide a quick design synthesis. Moreover, two practical design schemes of the proposed XYZ CPM are discussed with consideration of the manufacturability. The practical designs enable the XYZ CPM to be employed in many applications such as micro-/nano-positioning, micro-/nano-manufacturing and micro-/nano-assembly. Finally, a spatial high-precision translational system is presented based on the practical design schemes, taking the actuator and sensor integration into account. Full article
(This article belongs to the Special Issue Micro/Nano Robotics)
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6987 KiB  
Review
CD-Based Microfluidics for Primary Care in Extreme Point-of-Care Settings
by Suzanne Smith, Dario Mager, Alexandra Perebikovsky, Ehsan Shamloo, David Kinahan, Rohit Mishra, Saraí M. Torres Delgado, Horacio Kido, Satadal Saha, Jens Ducrée, Marc Madou, Kevin Land and Jan G. Korvink
Micromachines 2016, 7(2), 22; https://doi.org/10.3390/mi7020022 - 29 Jan 2016
Cited by 95 | Viewed by 19053
Abstract
We review the utility of centrifugal microfluidic technologies applied to point-of-care diagnosis in extremely under-resourced environments. The various challenges faced in these settings are showcased, using areas in India and Africa as examples. Measures for the ability of integrated devices to effectively address [...] Read more.
We review the utility of centrifugal microfluidic technologies applied to point-of-care diagnosis in extremely under-resourced environments. The various challenges faced in these settings are showcased, using areas in India and Africa as examples. Measures for the ability of integrated devices to effectively address point-of-care challenges are highlighted, and centrifugal, often termed CD-based microfluidic technologies, technologies are presented as a promising platform to address these challenges. We describe the advantages of centrifugal liquid handling, as well as the ability of a standard CD player to perform a number of common laboratory tests, fulfilling the role of an integrated lab-on-a-CD. Innovative centrifugal approaches for point-of-care in extremely resource-poor settings are highlighted, including sensing and detection strategies, smart power sources and biomimetic inspiration for environmental control. The evolution of centrifugal microfluidics, along with examples of commercial and advanced prototype centrifugal microfluidic systems, is presented, illustrating the success of deployment at the point-of-care. A close fit of emerging centrifugal systems to address a critical panel of tests for under-resourced clinic settings, formulated by medical experts, is demonstrated. This emphasizes the potential of centrifugal microfluidic technologies to be applied effectively to extremely challenging point-of-care scenarios and in playing a role in improving primary care in resource-limited settings across the developing world. Full article
(This article belongs to the Special Issue Centrifugal (Compact-Disc) Microfluidics for Extreme POC)
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3270 KiB  
Review
Magnetic Bead—Magic Bullet
by Christine Ruffert
Micromachines 2016, 7(2), 21; https://doi.org/10.3390/mi7020021 - 28 Jan 2016
Cited by 45 | Viewed by 10674
Abstract
Microfluidics is assumed to be one of the leading and most promising areas of research since the early 1990s. In microfluidic systems, small spherical magnetic particles with superparamagnetic properties, called magnetic beads, play an important role in the design of innovative methods and [...] Read more.
Microfluidics is assumed to be one of the leading and most promising areas of research since the early 1990s. In microfluidic systems, small spherical magnetic particles with superparamagnetic properties, called magnetic beads, play an important role in the design of innovative methods and tools, especially in bioanalysis and medical sciences. The intention of this review paper is to address main aspects from the state-of-the-art in the area of magnetic bead research, while demonstrating the broad variety of applications and the huge potential to solve fundamental biological and medical problems in the fields of diagnostics and therapy. Basic issues and demands related to the fabrication of magnetic particles and physical properties of nanosize magnets are discussed in Section 2. Of main interest are the control and adjustment of the nanoparticles’ properties and the availability of adequate approaches for particle detection via their magnetic field. Section 3 presents an overview of magnetic bead applications in nanomedicine. In Section 4, practical aspects of sample manipulation and separation employing magnetic beads are described. Finally, the benefits related to the use of magnetic bead-based microfluidic systems are summarized, illustrating ongoing questions and open tasks to be solved on the way to an approaching microfluidic age. Full article
(This article belongs to the Special Issue Magnetic MEMS)
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3017 KiB  
Article
Mental Fatigue Monitoring Using a Wearable Transparent Eye Detection System
by Kota Sampei, Miho Ogawa, Carlos Cesar Cortes Torres, Munehiko Sato and Norihisa Miki
Micromachines 2016, 7(2), 20; https://doi.org/10.3390/mi7020020 - 26 Jan 2016
Cited by 27 | Viewed by 7888
Abstract
We propose mental fatigue measurement using a wearable eye detection system. The system is capable of acquiring movement of the pupil and blinking from the light reflected from the eye. The reflection is detected by dye-sensitized photovoltaic cells. Since these cells are patterned [...] Read more.
We propose mental fatigue measurement using a wearable eye detection system. The system is capable of acquiring movement of the pupil and blinking from the light reflected from the eye. The reflection is detected by dye-sensitized photovoltaic cells. Since these cells are patterned onto the eyeglass and do not require external input power, the system is notable for its lightweight and low power consumption and can be combined with other wearable devices, such as a head mounted display. We performed experiments to correlate information obtained by the eye detection system with the mental fatigue of the user. Since it is quite difficult to evaluate mental fatigue objectively and quantitatively, we assumed that the National Aeronautics and Space Administration Task Load Index (NASA-TLX) had a strong correlation with te mental fatigue. While a subject was requested to conduct calculation tasks, the eye detection system collected his/her information that included position, velocity and total movement of the eye, and amount and frequency of blinking. Multiple regression analyses revealed the correlation between NASA-TLX and the information obtained for 3 out of 5 subjects. Full article
(This article belongs to the Special Issue Sensors and Systems for Medical Applications and Personal Health Monitoring)
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5050 KiB  
Article
Two-Layer Microstructures Fabricated by One-Step Anisotropic Wet Etching of Si in KOH Solution
by Han Lu, Hua Zhang, Mingliang Jin, Tao He, Guofu Zhou and Lingling Shui
Micromachines 2016, 7(2), 19; https://doi.org/10.3390/mi7020019 - 25 Jan 2016
Cited by 17 | Viewed by 8002
Abstract
Anisotropic etching of silicon in potassium hydroxide (KOH) is an important technology in micromachining. The residue deposition from KOH etching of Si is typically regarded as a disadvantage of this technology. In this report, we make use of this residue as a second [...] Read more.
Anisotropic etching of silicon in potassium hydroxide (KOH) is an important technology in micromachining. The residue deposition from KOH etching of Si is typically regarded as a disadvantage of this technology. In this report, we make use of this residue as a second masking layer to fabricate two-layer complex structures. Square patterns with size in the range of 15–150 μm and gap distance of 5 μm have been designed and tested. The residue masking layer appears when the substrate is over-etched in hydrofluoric acid (HF) solution over a threshold. The two-layer structures of micropyramids surrounded by wall-like structures are obtained according to the two different masking layers of SiO2 and residue. The residue masking layer is stable and can survive over KOH etching for long time to achieve deep Si etching. The process parameters of etchant concentration, temperature, etching time and pattern size have been investigated. With well-controlled two-layer structures, useful structures could be designed for applications in plasmonic and microfluidic devices in the future. Full article
(This article belongs to the Special Issue Optofluidics 2015)
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1082 KiB  
Review
Devices Based on Co-Integrated MEMS Actuators and Optical Waveguide: A Review
by Franck Chollet
Micromachines 2016, 7(2), 18; https://doi.org/10.3390/mi7020018 - 25 Jan 2016
Cited by 44 | Viewed by 13471
Abstract
The convergence of Micro Electro Mechanical Systems (MEMS) and optics was, at the end of the last century, a fertile ground for a new breed of technological and scientific achievements. The weightlessness of light has been identified very early as a key advantage [...] Read more.
The convergence of Micro Electro Mechanical Systems (MEMS) and optics was, at the end of the last century, a fertile ground for a new breed of technological and scientific achievements. The weightlessness of light has been identified very early as a key advantage for micro-actuator application, giving rise to optical free-space MEMS devices. In parallel to these developments, the past 20 years saw the emergence of a less pursued approach relying on guided optical wave, where, pushed by the similarities in fabrication process, researchers explored the possibilities offered by merging integrated optics and MEMS technology. The interest of using guided waves is well known (absence of diffraction, tight light confinement, small size, compatibility with fiber optics) but it was less clear how they could be harnessed with MEMS technology. Actually, it is possible to use MEMS actuators for modifying waveguide properties (length, direction, index of refraction) or for coupling light between waveguide, enabling many new devices for optical telecommunication, astronomy or sensing. With the recent expansion to nanophotonics and optomechanics, it seems that this field still holds a lot of promises. Full article
(This article belongs to the Special Issue Optical Microsystems)
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6730 KiB  
Article
Numerical Investigation of Cell Encapsulation for Multiplexing Diagnostic Assays Using Novel Centrifugal Microfluidic Emulsification and Separation Platform
by Yong Ren and Wallace Woon Fong Leung
Micromachines 2016, 7(2), 17; https://doi.org/10.3390/mi7020017 - 25 Jan 2016
Cited by 25 | Viewed by 9199
Abstract
In the present paper, we report a novel centrifugal microfluidic platform for emulsification and separation. Our design enables encapsulation and incubation of multiple types of cells by droplets, which can be generated at controlled high rotation speed modifying the transition between dripping-to-jetting regimes. [...] Read more.
In the present paper, we report a novel centrifugal microfluidic platform for emulsification and separation. Our design enables encapsulation and incubation of multiple types of cells by droplets, which can be generated at controlled high rotation speed modifying the transition between dripping-to-jetting regimes. The droplets can be separated from continuous phase using facile bifurcated junction design. A three dimensional (3D) model was established to investigate the formation and sedimentation of droplets using the centrifugal microfluidic platform by computational fluid dynamics (CFD). The simulation results were compared to the reported experiments in terms of droplet shape and size to validate the accuracy of the model. The influence of the grid resolution was investigated and quantified. The physics associated with droplet formation and sedimentation is governed by the Bond number and Rossby number, respectively. Our investigation provides insight into the design criteria that can be used to establish centrifugal microfluidic platforms tailored to potential applications, such as multiplexing diagnostic assays, due to the unique capabilities of the device in handling multiple types of cells and biosamples with high throughput. This work can inspire new development of cell encapsulation and separation applications by centrifugal microfluidic technology. Full article
(This article belongs to the Special Issue Centrifugal (Compact-Disc) Microfluidics for Extreme POC)
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