共查询到20条相似文献，搜索用时 0 毫秒
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Rohollah Nasiri Amir Shamloo Samad Ahadian Leyla Amirifar Javad Akbari Marcus J. Goudie KangJu Lee Nureddin Ashammakhi Mehmet R. Dokmeci Dino Di Carlo Ali Khademhosseini 《Small (Weinheim an der Bergstrasse, Germany)》2020,16(29)
Cell separation is a key step in many biomedical research areas including biotechnology, cancer research, regenerative medicine, and drug discovery. While conventional cell sorting approaches have led to high‐efficiency sorting by exploiting the cell's specific properties, microfluidics has shown great promise in cell separation by exploiting different physical principles and using different properties of the cells. In particular, label‐free cell separation techniques are highly recommended to minimize cell damage and avoid costly and labor‐intensive steps of labeling molecular signatures of cells. In general, microfluidic‐based cell sorting approaches can separate cells using “intrinsic” (e.g., fluid dynamic forces) versus “extrinsic” external forces (e.g., magnetic, electric field, etc.) and by using different properties of cells including size, density, deformability, shape, as well as electrical, magnetic, and compressibility/acoustic properties to select target cells from a heterogeneous cell population. In this work, principles and applications of the most commonly used label‐free microfluidic‐based cell separation methods are described. In particular, applications of microfluidic methods for the separation of circulating tumor cells, blood cells, immune cells, stem cells, and other biological cells are summarized. Computational approaches complementing such microfluidic methods are also explained. Finally, challenges and perspectives to further develop microfluidic‐based cell separation methods are discussed. 相似文献
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Masahiro Takinoue Hiroaki Onoe Shoji Takeuchi 《Small (Weinheim an der Bergstrasse, Germany)》2010,6(21):2374-2377
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Myeongwoo Kang Woohyun Park Sangcheol Na Sang‐Min Paik Hyunjae Lee Jae Woo Park Ho‐Young Kim Noo Li Jeon 《Small (Weinheim an der Bergstrasse, Germany)》2015,11(23):2789-2797
Soft lithography and other techniques have been developed to investigate biological and chemical phenomena as an alternative to photolithography‐based patterning methods that have compatibility problems. Here, a simple approach for nonlithographic patterning of liquids and gels inside microchannels is described. Using a design that incorporates strategically placed microstructures inside the channel, microliquids or gels can be spontaneously trapped and patterned when the channel is drained. The ability to form microscale patterns inside microfluidic channels using simple fluid drain motion offers many advantages. This method is geometrically analyzed based on hydrodynamics and verified with simulation and experiments. Various materials (i.e., water, hydrogels, and other liquids) are successfully patterned with complex shapes that are isolated from each other. Multiple cell types are patterned within the gels. Capillarity guided patterning (CGP) is fast, simple, and robust. It is not limited by pattern shape, size, cell type, and material. In a simple three‐step process, a 3D cancer model that mimics cell–cell and cell–extracellular matrix interactions is engineered. The simplicity and robustness of the CGP will be attractive for developing novel in vitro models of organ‐on‐a‐chip and other biological experimental platforms amenable to long‐term observation of dynamic events using advanced imaging and analytical techniques. 相似文献
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Hashimoto M Shevkoplyas SS Zasońska B Szymborski T Garstecki P Whitesides GM 《Small (Weinheim an der Bergstrasse, Germany)》2008,4(10):1795-1805
This paper describes the mechanism of formation of bubbles of nitrogen in water containing Tween 20 as a surfactant, and of droplets of water in hexadecane containing Span 80 as a surfactant. The study of these microfluidic systems compares two or four flow-focusing generators coupled through shared inlets, supplying the continuous phase, and through a common outlet channel. The processes that form bubbles in neighboring generators interact for a wide range of flow parameters; the formation of bubbles alternates in time and space, and the bubbles assemble into complex patterns in the outlet channel. The dynamics of formation of bubbles in these systems are stable for long time (at least 10 min). For a certain range of flow parameters, the coupled flow-focusing generators exhibit two stable modes of operation for a single set of flow parameters. The dynamics of formation of droplets of water in hexadecane by the coupled flow-focusing generators are simpler--the adjacent generators produce only monodisperse droplets over the entire range of flow parameters that are explored. These observations suggest that the mechanism of interaction between coupled flow-focusing generators relies on the compressibility of the dispersed phase (e.g., the gas or liquid), and on variations in pressure at the flow-focusing orifices induced by the breakup of bubbles or droplets. 相似文献
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Guillermo J. Amador Ziyu Ren Ahmet F. Tabak Yunus Alapan Oncay Yasa Metin Sitti 《Small (Weinheim an der Bergstrasse, Germany)》2019,15(21)
Surface tension gradients induce Marangoni flow, which may be exploited for fluid transport. At the micrometer scale, these surface‐driven flows can be quite significant. By introducing fluid–fluid interfaces along the walls of microfluidic channels, bulk fluid flows driven by temperature gradients are observed. The temperature dependence of the fluid–fluid interfacial tension appears responsible for these flows. In this report, the design concept for a biocompatible microchannel capable of being powered by solar irradiation is provided. Using microscale particle image velocimetry, a bulk flow generated by apparent surface tension gradients along the walls is observed. The direction of flow relative to the imposed temperature gradient agrees with the expected surface tension gradient. The phenomenon's ability to replace bulky peripherals, like traditional syringe pumps, on a diagnostic microfluidic device that captures and detects leukocyte subpopulations within blood is demonstrated. Such microfluidic devices may be implemented for clinical assays at the point of care without the use of electricity. 相似文献
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We might be at the turning point where research in microfluidics undertaken in academia and industrial research laboratories, and substantially sponsored by public grants, may provide a range of portable and networked diagnostic devices. In this Progress Report, an overview on microfluidic devices that may become the next generation of point-of-care (POC) diagnostics is provided. First, we describe gaps and opportunities in medical diagnostics and how microfluidics can address these gaps using the example of immunodiagnostics. Next, we conceptualize how different technologies are converging into working microfluidic POC diagnostics devices. Technologies are explained from the perspective of sample interaction with components of a device. Specifically, we detail materials, surface treatment, sample processing, microfluidic elements (such as valves, pumps, and mixers), receptors, and analytes in the light of various biosensing concepts. Finally, we discuss the integration of components into accurate and reliable devices. 相似文献
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Chen GD Fachin F Fernandez-Suarez M Wardle BL Toner M 《Small (Weinheim an der Bergstrasse, Germany)》2011,7(8):1061-1067
Solid materials, such as silicon, glass, and polymers, dominate as structural elements in microsystems including microfluidics. Porous elements have been limited to membranes sandwiched between microchannel layers or polymer monoliths. This paper reports the use of micropatterned carbon-nanotube forests confined inside microfluidic channels for mechanically and/or chemically capturing particles ranging over three orders of magnitude in size. Nanoparticles below the internanotube spacing (80 nm) of the forest can penetrate inside the forest and interact with the large surface area created by individual nanotubes. For larger particles (>80 nm), the ultrahigh porosity of the nanotube elements reduces the fluid boundary layer and enhances particle-structure interactions on the outer surface of the patterned nanoporous elements. Specific biomolecular recognition is demonstrated using cells (≈10 μm), bacteria (≈1 μm), and viral-sized particles (≈40 nm) using both effects. This technology can provide unprecedented control of bioseparation processes to access bioparticles of interest, opening new pathways for both research and point-of-care diagnostics. 相似文献
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Glass NR Shilton RJ Chan PP Friend JR Yeo LY 《Small (Weinheim an der Bergstrasse, Germany)》2012,8(12):1881-1888
A miniaturized centrifugal microfluidic platform for lab-on-a-chip applications is presented. Unlike its macroscopic Lab-on-a-CD counterpart, the miniature Lab-on-a-Disc (miniLOAD) device does not require moving parts to drive rotation of the disc, is inexpensive, disposable, and significantly smaller, comprising a 10-mm-diameter SU-8 disc fabricated through two-step photolithography. The disc is driven to rotate using surface acoustic wave irradiation incident upon a fluid coupling layer from a pair of offset, opposing single-phase unidirectional transducers patterned on a lithium niobate substrate. The irradiation causes azimuthally oriented acoustic streaming with sufficient intensity to rotate the disc at several thousand revolutions per minute. In this first proof-of-concept, the capability of the miniLOAD platform to drive capillary-based valving and mixing in microfluidic structures on a disc similar to much larger Lab-on-a-CD devices is shown. In addition, the ability to concentrate aqueous particle suspensions at radial positions in a channel in the disc dependent on the particles' size is demonstrated. To the best of our knowledge, the miniLOAD concept is the first centrifugal microfluidic platform small enough to be self-contained in a handheld device. 相似文献
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Luc Gervais Nico de Rooij Emmanuel Delamarche 《Advanced materials (Deerfield Beach, Fla.)》2011,23(24):H208-H208
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Pagra Truman Petra Uhlmann Ralf Frenzel Manfred Stamm 《Advanced materials (Deerfield Beach, Fla.)》2009,21(35):3601-3604
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Ata Tuna Ciftlik Maxime Ettori Martin A. M. Gijs 《Small (Weinheim an der Bergstrasse, Germany)》2013,9(16):2764-2773
Matching the scale of microfluidic flow systems with that of microelectronic chips for realizing monolithically integrated systems still needs to be accomplished. However, this is appealing only if such re‐scaling does not compromise the fluidic throughput. This is related to the fact that the cost of microelectronic circuits primarily depends on the layout footprint, while the performance of many microfluidic systems, like flow cytometers, is measured by the throughput. The simple operation of inertial particle focusing makes it a promising technique for use in such integrated flow cytometer applications, however, microfluidic footprints demonstrated so far preclude monolithic integration. Here, the scaling limits of throughput‐per‐footprint (TPFP) in using inertial focusing are explored by studying the interplay between theory, the effect of channel Reynolds numbers up to 1500 on focusing, the entry length for the laminar flow to develop, and pressure resistance of the microchannels. Inertial particle focusing is demonstrated with a TPFP up to 0.3 L/(min cm2) in high aspect‐ratio rectangular microfluidic channels that are readily fabricated with a post‐CMOS integratable process, suggesting at least a 100‐fold improvement compared to previously demonstrated techniques. Not only can this be an enabling technology for realizing cost‐effective monolithically integrated flow cytometry devices, but the methodology represented here can also open perspectives for miniaturization of many biomedical microfluidic applications requiring monolithic integration with microelectronics without compromising the throughput. 相似文献