Open microfluidics

Last updated

Microfluidics refers to the flow of fluid in channels or networks with at least one dimension on the micron scale. [1] [2] In open microfluidics, also referred to as open surface microfluidics or open-space microfluidics, at least one boundary confining the fluid flow of a system is removed, exposing the fluid to air or another interface such as a second fluid. [1] [3] [4]

Contents

Types of open microfluidics

Open microfluidics can be categorized into various subsets. Some examples of these subsets include open-channel microfluidics, paper-based, and thread-based microfluidics. [1] [5] [6]

Open-channel microfluidics

In open-channel microfluidics, a surface tension-driven capillary flow occurs and is referred to as spontaneous capillary flow (SCF). [1] [7] SCF occurs when the pressure at the advancing meniscus is negative. [1] The geometry of the channel and contact angle of fluids has been shown to produce SCF if the following equation is true.

Where pf is the free perimeter of the channel (i.e., the interface not in contact with the channel wall), and pw is the wetted perimeter [8] (i.e., the walls in contact with the fluid), and θ is the contact angle of the fluid on the material of the device. [1] [5]

Paper-based microfluidics

Paper-based microfluidics utilizes the wicking ability of paper for functional readouts. [9] [10] Paper-based microfluidics is an attractive method because paper is cheap, easily accessible, and has a low environmental impact. Paper is also versatile because it is available in various thicknesses and pore sizes. [9] Coatings such as wax have been used to guide flow in paper microfluidics. [11] In some cases, dissolvable barriers have been used to create boundaries on the paper and control the fluid flow. [12] The application of paper as a diagnostic tool has shown to be powerful because it has successfully been used to detect glucose levels, [13] bacteria, [14] viruses, [15] and other components in whole blood. [16] Cell culture methods within paper have also been developed. [17] [18] Lateral flow immunoassays, such as those used in pregnancy tests, are one example of the application of paper for point of care or home-based diagnostics. [19] Disadvantages include difficulty of fluid retention and high limits of detection.

Thread-based microfluidics

Thread-based microfluidics, an offshoot from paper-based microfluidics, utilizes the same capillary based wicking capabilities. [20] Common thread materials include nitrocellulose, rayon, nylon, hemp, wool, polyester, and silk. [21] Threads are versatile because they can be woven to form specific patterns. [22] Additionally, two or more threads can converge together in a knot bringing two separate ‘streams’ of fluid together as a reagent mixing method. [23] Threads are also relatively strong and difficult to break from handling which makes them stable over time and easy to transport. [21] Thread-based microfluidics has been applied to 3D tissue engineering and analyte analysis. [24] [20]

Capillary filaments in open microfluidics

Open capillary microfluidics are channels that expose fluids to open air by excluding the ceiling and/or floor of the channel. [5] Rather than rely on using pumps or syringes to maintain flow, open capillary microfluidics uses surface tension to facilitate the flow. [25] The elimination of and infusion source reduces the size of the device and associated apparatus, along with other aspects that could obstruct their use. The dynamics of capillary-driven flow in open microfluidics are highly reliant on two types of geometric channels commonly known as either rectangular U-grooves or triangular V-grooves. [26] [25] The geometry of the channels dictates the flow along the interior walls fabricated with various ever-evolving processes. [7]

Capillary filaments in U-groove

SCF in V-groove (left) V-groove open microfluidic channel (right) Wiki final-2.png
SCF in V-groove (left) V-groove open microfluidic channel (right)

Rectangular open-surface U-grooves are the easiest type of open microfluidic channel to fabricate. This design can maintain the same order of magnitude velocity in comparison to V-groove. [27] [26] [28] Channels are made of glass or high clarity glass substitutes such as polymethyl methacrylate (PMMA), [25] polycarbonate (PC), or cyclic olefin copolymer (COC). [25] [ citation needed ] To eliminate the remaining resistance after etching, channels are given hydrophilic treatment using oxygen plasma or deep reactive-ion etching(DRIE). [29] [30] [31]

Capillary filaments in V-groove

SCF in U-groove (left) U-groove open microfluidic channel SCF (right) Wiki final.png
SCF in U-groove (left) U-groove open microfluidic channel SCF (right)

V-groove, unlike U-groove, allows for a variety of velocities depending on the groove angle. [28] V-grooves with sharp groove angle result in the interface curvature at the corners explained by reduced Concus-Finn conditions. [32] In a perfect inner corner of a V-groove, the filament will advance indefinitely in the groove allowing the formation of capillary filament depending on the wetting conditions. [33] The width of the groove plays an important role in controlling the fluid flow. The narrower the V-groove is, the better the capillary flow of liquids is even for highly viscous liquids such as blood; this effect has been used to produce an autonomous assay. [5] [34] The fabrication of a V-groove is more difficult than a U-groove as it poses a higher risk for faulty construction, since the corner has to be tightly sealed. [29]

Advantages

One of the main advantages of open microfluidics is ease of accessibility which enables intervention (i.e., for adding or removing reagents) to the flowing liquid in the system. [35] Open microfluidics also allows simplicity of fabrication thus eliminating the need to bond surfaces. When one of the boundaries of a system is removed, a larger liquid-gas interface results, which enables liquid-gas reactions. [1] [36] Open microfluidic devices enable better optical transparency because at least one side of the system is not covered by the material which can reduce autofluorescence during imaging. [37] Further, open systems minimize and sometimes eliminate bubble formation, a common problem in closed systems. [1]

In closed system microfluidics, the flow in the channels is driven by pressure via pumps (syringe pumps), valves (trigger valves), or electrical field. [38] An example of one of these methods for achieving low flow rates using temperature-controlled evaporation has been described for an open microfluidics system, allowing for long incubation hours for biological applications and requiring small sample volumes. [39] Open system microfluidics enable surface-tension driven flow in channels thereby eliminating the need for external pumping methods. [35] [40] For example, some open microfluidic devices consist of a reservoir port and pumping port that can be filled with fluid using a pipette. [1] [5] [35] Eliminating external pumping requirements lowers cost and enables device use in all laboratories with pipettes. [36]

Materials Solutions

Thankfully, while many problems exist with PDMS, many solutions have also been developed. To address the negative hydrophobicity and porosity that PDMS exhibits, researchers have started to use coatings such as BSA [41] (bovine serum albumin) or charged molecules [42] to create a layer between the native PDMS and the cells. Other researchers have successfully employed several of the Pluronic surfactants, [43] a tri-block copolymer that has two hydrophilic blocks surrounding a hydrophobic core often used to increase the hydrophilic nature of numerous substrates, and even borosilicate glass coatings [44] to address the hydrophobicity problem. Interestingly, treatment with either of the prior two compounds can result in prevention of non-specific protein adsorption, as they (and other coatings) form stable adsorption interactions with the PDMS, which aides in reducing PDSM interference with cell culture media. These compounds and materials can affect surface properties and should be carefully tested to note the impact on cultured cells. Researchers developed 3D scaffolding systems to mimic in vivo environments so that more cells and cell types can grow [45] in an effort to address the problem that not all cell types can grow on PDMS. Like coating the PDMS, 3D scaffolding systems employ alternatives materials like ECM (extracellular matrix) proteins [46] so rather than not binding the native PDMS, cells are more likely to bind to the proteins. Lastly, researchers have addressed the permeability of PDMS to water vapor using some elegant solutions. For example, a portion of the microfluidic system can be designated for humidification and cast in PDMS, or other material like glass.

Disadvantages

Some drawbacks of open microfluidics include evaporation, [47] contamination, [48] and limited flow rate. [4] Open systems are susceptible to evaporation which can greatly affect readouts when fluid volumes are on the microscale. [47] Additionally, due to the nature of open systems, they are more susceptible to contamination than closed systems. [48] Cell culture and other methods where contamination or small particulates are a concern must be carefully performed to prevent contamination. Lastly, open systems have a limited flow rate because induced pressures cannot be used to drive flow. [4]

Materials

Polydimethylsiloxane (PDMS) is an ideal material to fabricate microfluidic devices for cell culture applications due to several advantageous properties such as low processing costs, ease of manufacture, rapid prototyping, ease of surface modification, and cellular non-toxicity. [49] [42] While there are several benefits that arise from using native Polydimethylsiloxane (PDMS), there are also some drawbacks that researchers must account for in their experiments. First, PDMS is both hydrophobic and porous, meaning that small molecules or other hydrophobic molecules can be adsorbed onto it. [50] Such molecules include anything from methyl- or alkyl-containing molecules, [51] and even certain dyes like Nile Red. [52] Researchers identified in 2008 that plasma could be used to reduce the hydrophobicity of PDMS, though it returned about two weeks after treatment. [53] Some researchers postulate that integrating removable polycaprolactone (PCL) fiber-based electrospun scaffolds under NaOH treatment enhances hydrophilicity as well as mitigating hydrophobicity, while promoting more efficient cell communication. [54] Another problem that arises with PDMS is that it can interfere with the media that circulates in the channels. Incomplete curing of PDMS channels can lead to PDMS leaching into the media [55] and, even when complete curing takes place, components of the media can still unintentionally attach to free hydrophobic sites on the PDMS walls. [56] Yet another problem arises with the gas permeability of PDMS. Most researchers take advantage of this to oxygenate both the PDMS and the circulating media, but this trait also makes the microfluidic system especially vulnerable to water vapor loss. Lastly, not all cell types can grow, or will grow at the same levels, on native PDMS. [57] For instance, high levels of rapid cell death in two fibroblast types grown on native PDMS were observed as early as 1994, which posed problems for the widespread use of PDMS in microfluidic cell culture.

Applications

Like many microfluidic technologies, open system microfluidics has been applied to nanotechnology, biotechnology, fuel cells, and point of care (POC) testing. [1] [4] [58] For cell-based studies, open-channel microfluidic devices enable access to cells for single cell probing within the channel. [59] Other applications include capillary gel electrophoresis, water-in-oil emulsions, and biosensors for POC systems. [3] [60] [61] Suspended microfluidic devices, open microfluidic devices where the floor of the device is removed, have been used to study cellular diffusion and migration of cancer cells. [5] Suspended and rail-based microfluidics have been used for micropatterning and studying cell communication. [1]

Materials Solutions Applications

Applications of these solutions are still in use today, as seen by the following examples. In 2014, Lei et al was testing the impedance of human oral cancer cells in the presence of cisplatin, a known anti-cancer drug, by molding the cells into a 3D scaffolding. [62] The authors had noted from previous studies that cellular impedance could be correlated to cellular viability and proliferation in 2D cell culture and hoped to translate that correlation into 3D cell culture. Using agarose to create the 3D scaffolding, the researchers measured the growth and proliferation of human oral cancer cells in the presence and absence of cisplatin using fluorescent DNA assays and observed that there was indeed a correlation like that observed in 2D model. Not only did this prove that principles from 2D cell culture could be translated to 3D open microfluidic cell culture, but it also potentially lays the foundation for a more personalized treatment plan for cancer patients. They postulated that future developments could transform this method into an assay that could test patient cancer cell response to known anti-cancer drugs.

Another group used a similar method, but instead of creating a 3D scaffolding, they employed several different PDMS coatings to determine the best option for studying cancer stem cells. [63] The group looked at BSA and ECM proteins and found that, while their experimental evidence supported BSA as the best coating for circulating cancer cells (CSC’s), phenotypic changes did occur to the cells (namely, elongation), but did not impact the cells’ ability to perform normal cell functions. A key caveat to note here is that BSA is not a blanket solution that works for every cell type- different coatings work better or worse for certain cell types [46] and these differences should be considered when developing an experiment.

Related Research Articles

Microfluidics refers to a system that manipulates a small amount of fluids using small channels with sizes ten to hundreds micrometres. It is a multidisciplinary field that involves molecular analysis, molecular biology, and microelectronics. It has practical applications in the design of systems that process low volumes of fluids to achieve multiplexing, automation, and high-throughput screening. Microfluidics emerged in the beginning of the 1980s and is used in the development of inkjet printheads, DNA chips, lab-on-a-chip technology, micro-propulsion, and micro-thermal technologies.

<span class="mw-page-title-main">Digital microfluidics</span>

Digital microfluidics (DMF) is a platform for lab-on-a-chip systems that is based upon the manipulation of microdroplets. Droplets are dispensed, moved, stored, mixed, reacted, or analyzed on a platform with a set of insulated electrodes. Digital microfluidics can be used together with analytical analysis procedures such as mass spectrometry, colorimetry, electrochemical, and electrochemiluminescense.

<span class="mw-page-title-main">Surface acoustic wave</span> Sound wave which travels along the surface of an elastic material

A surface acoustic wave (SAW) is an acoustic wave traveling along the surface of a material exhibiting elasticity, with an amplitude that typically decays exponentially with depth into the material, such that they are confined to a depth of about one wavelength.

A lab-on-a-chip (LOC) is a device that integrates one or several laboratory functions on a single integrated circuit of only millimeters to a few square centimeters to achieve automation and high-throughput screening. LOCs can handle extremely small fluid volumes down to less than pico-liters. Lab-on-a-chip devices are a subset of microelectromechanical systems (MEMS) devices and sometimes called "micro total analysis systems" (µTAS). LOCs may use microfluidics, the physics, manipulation and study of minute amounts of fluids. However, strictly regarded "lab-on-a-chip" indicates generally the scaling of single or multiple lab processes down to chip-format, whereas "µTAS" is dedicated to the integration of the total sequence of lab processes to perform chemical analysis.

<span class="mw-page-title-main">Polydimethylsiloxane</span> Chemical compound

Polydimethylsiloxane (PDMS), also known as dimethylpolysiloxane or dimethicone, is a silicone polymer with a wide variety of uses, from cosmetics to industrial lubrication.

In fluid statics, capillary pressure is the pressure between two immiscible fluids in a thin tube, resulting from the interactions of forces between the fluids and solid walls of the tube. Capillary pressure can serve as both an opposing or driving force for fluid transport and is a significant property for research and industrial purposes. It is also observed in natural phenomena.

<span class="mw-page-title-main">Plasma cleaning</span>

Plasma cleaning is the removal of impurities and contaminants from surfaces through the use of an energetic plasma or dielectric barrier discharge (DBD) plasma created from gaseous species. Gases such as argon and oxygen, as well as mixtures such as air and hydrogen/nitrogen are used. The plasma is created by using high frequency voltages to ionise the low pressure gas, although atmospheric pressure plasmas are now also common.

<span class="mw-page-title-main">Nanofluidics</span> Dynamics of fluids confined in nanoscale structures

Nanofluidics is the study of the behavior, manipulation, and control of fluids that are confined to structures of nanometer characteristic dimensions. Fluids confined in these structures exhibit physical behaviors not observed in larger structures, such as those of micrometer dimensions and above, because the characteristic physical scaling lengths of the fluid, very closely coincide with the dimensions of the nanostructure itself.

<span class="mw-page-title-main">Micropump</span>

Micropumps are devices that can control and manipulate small fluid volumes. Although any kind of small pump is often referred to as a micropump, a more accurate definition restricts this term to pumps with functional dimensions in the micrometer range. Such pumps are of special interest in microfluidic research, and have become available for industrial product integration in recent years. Their miniaturized overall size, potential cost and improved dosing accuracy compared to existing miniature pumps fuel the growing interest for this innovative kind of pump.

<span class="mw-page-title-main">Bio-MEMS</span>

Bio-MEMS is an abbreviation for biomedical microelectromechanical systems. Bio-MEMS have considerable overlap, and is sometimes considered synonymous, with lab-on-a-chip (LOC) and micro total analysis systems (μTAS). Bio-MEMS is typically more focused on mechanical parts and microfabrication technologies made suitable for biological applications. On the other hand, lab-on-a-chip is concerned with miniaturization and integration of laboratory processes and experiments into single chips. In this definition, lab-on-a-chip devices do not strictly have biological applications, although most do or are amenable to be adapted for biological purposes. Similarly, micro total analysis systems may not have biological applications in mind, and are usually dedicated to chemical analysis. A broad definition for bio-MEMS can be used to refer to the science and technology of operating at the microscale for biological and biomedical applications, which may or may not include any electronic or mechanical functions. The interdisciplinary nature of bio-MEMS combines material sciences, clinical sciences, medicine, surgery, electrical engineering, mechanical engineering, optical engineering, chemical engineering, and biomedical engineering. Some of its major applications include genomics, proteomics, molecular diagnostics, point-of-care diagnostics, tissue engineering, single cell analysis and implantable microdevices.

Cell sorting is the process through which a particular cell type is separated from others contained in a sample on the basis of its physical or biological properties, such as size, morphological parameters, viability and both extracellular and intracellular protein expression. The homogeneous cell population obtained after sorting can be used for a variety of applications including research, diagnosis, and therapy.

<span class="mw-page-title-main">Centrifugal micro-fluidic biochip</span>

The centrifugal micro-fluidic biochip or centrifugal micro-fluidic biodisk is a type of lab-on-a-chip technology, also known as lab-on-a-disc, that can be used to integrate processes such as separating, mixing, reaction and detecting molecules of nano-size in a single piece of platform, including a compact disk or DVD. This type of micro-fluidic biochip is based upon the principle of microfluidics; to take advantage of noninertial pumping for lab-on-a-chip devices using noninertial valves and switches under centrifugal force and Coriolis effect to distribute fluids about the disks in a highly parallel order.

An organ-on-a-chip (OOC) is a multi-channel 3-D microfluidic cell culture, integrated circuit (chip) that simulates the activities, mechanics and physiological response of an entire organ or an organ system. It constitutes the subject matter of significant biomedical engineering research, more precisely in bio-MEMS. The convergence of labs-on-chips (LOCs) and cell biology has permitted the study of human physiology in an organ-specific context. By acting as a more sophisticated in vitro approximation of complex tissues than standard cell culture, they provide the potential as an alternative to animal models for drug development and toxin testing.

Microfluidics in chemical biology is the application of microfluidics in the study of chemical biology.

Suman Chakraborty is a professor at the Indian Institute of Technology Kharagpur and Sir J. C. Bose National Fellow. He has been the first in the history of IIT Kharagpur to be bestowed by the National Award for Teachers in the Higher Education Category by the honourable President of India. He is also Institute Chair Professor Awardee of 2023. He has served as the Dean, Research and Development, Associate Dean and the Head of the School of Medical Science and Technology of the Institute. He has also been National Academy of Engineering Chair Professor. He joined the Institute in 2002 as Assistant Professor and has been a Full Professor since 2008.

<span class="mw-page-title-main">Off-stoichiometry thiol-ene polymer</span>

An off-stoichiometry thiol-ene polymer is a polymer platform comprising off-stoichiometry thiol-enes (OSTE) and off-stoichiometry thiol-ene-epoxies (OSTE+).

Microfluidic cell culture integrates knowledge from biology, biochemistry, engineering, and physics to develop devices and techniques for culturing, maintaining, analyzing, and experimenting with cells at the microscale. It merges microfluidics, a set of technologies used for the manipulation of small fluid volumes within artificially fabricated microsystems, and cell culture, which involves the maintenance and growth of cells in a controlled laboratory environment. Microfluidics has been used for cell biology studies as the dimensions of the microfluidic channels are well suited for the physical scale of cells. For example, eukaryotic cells have linear dimensions between 10 and 100 μm which falls within the range of microfluidic dimensions. A key component of microfluidic cell culture is being able to mimic the cell microenvironment which includes soluble factors that regulate cell structure, function, behavior, and growth. Another important component for the devices is the ability to produce stable gradients that are present in vivo as these gradients play a significant role in understanding chemotactic, durotactic, and haptotactic effects on cells.

Droplet-based microfluidics manipulate discrete volumes of fluids in immiscible phases with low Reynolds number and laminar flow regimes. Interest in droplet-based microfluidics systems has been growing substantially in past decades. Microdroplets offer the feasibility of handling miniature volumes of fluids conveniently, provide better mixing, encapsulation, sorting, sensing and are suitable for high throughput experiments. Two immiscible phases used for the droplet based systems are referred to as the continuous phase and dispersed phase.

Paper-based microfluidics are microfluidic devices that consist of a series of hydrophilic cellulose or nitrocellulose fibers that transport fluid from an inlet through the porous medium to a desired outlet or region of the device, by means of capillary action. This technology builds on the conventional lateral flow test which is capable of detecting many infectious agents and chemical contaminants. The main advantage of this is that it is largely a passively controlled device unlike more complex microfluidic devices. Development of paper-based microfluidic devices began in the early 21st century to meet a need for inexpensive and portable medical diagnostic systems.

Open microfluidics can be employed in the multidimensional culturing of cell types for various applications including organ-on-a-chip studies, oxygen-driven reactions, neurodegeneration, cell migration, and other cellular pathways.

References

  1. 1 2 3 4 5 6 7 8 9 10 11 Berthier J, Brakke KA (2016). Open microfluidics. Hoboken, NJ: Wiley. ISBN   9781118720936. OCLC   953661963.
  2. ↑ Whitesides GM (July 2006). "The origins and the future of microfluidics". Nature. 442 (7101): 368–73. Bibcode:2006Natur.442..368W. doi:10.1038/nature05058. PMID   16871203. S2CID   205210989.
  3. 1 2 Pfohl T, Mugele F, Seemann R, Herminghaus S (December 2003). "Trends in microfluidics with complex fluids". ChemPhysChem. 4 (12): 1291–8. doi:10.1002/cphc.200300847. PMID   14714376.
  4. 1 2 3 4 Kaigala GV, Lovchik RD, Delamarche E (November 2012). "Microfluidics in the "open space" for performing localized chemistry on biological interfaces". Angewandte Chemie. 51 (45): 11224–40. doi:10.1002/anie.201201798. PMID   23111955.
  5. 1 2 3 4 5 6 Casavant BP, Berthier E, Theberge AB, Berthier J, Montanez-Sauri SI, Bischel LL, et al. (June 2013). "Suspended microfluidics". Proceedings of the National Academy of Sciences of the United States of America. 110 (25): 10111–6. Bibcode:2013PNAS..11010111C. doi: 10.1073/pnas.1302566110 . PMC   3690848 . PMID   23729815.
  6. ↑ Yamada K, Shibata H, Suzuki K, Citterio D (March 2017). "Toward practical application of paper-based microfluidics for medical diagnostics: state-of-the-art and challenges". Lab on a Chip. 17 (7): 1206–1249. doi:10.1039/c6lc01577h. PMID   28251200.
  7. 1 2 Yang D, Krasowska M, Priest C, Popescu MN, Ralston J (2011-09-07). "Dynamics of Capillary-Driven Flow in Open Microchannels". The Journal of Physical Chemistry C. 115 (38): 18761–18769. doi:10.1021/jp2065826. ISSN   1932-7447.
  8. ↑ "Wetted perimeter", Wikipedia, 2018-11-27, retrieved 2019-04-16
  9. 1 2 Hosseini S, Vázquez-Villegas P, Martínez-Chapa SO (2017-08-22). "Paper and Fiber-Based Bio-Diagnostic Platforms: Current Challenges and Future Needs". Applied Sciences. 7 (8): 863. doi: 10.3390/app7080863 .
  10. ↑ Swanson C, Lee S, Aranyosi AJ, Tien B, Chan C, Wong M, et al. (2015-09-01). "Rapid light transmittance measurements in paper-based microfluidic devices". Sensing and Bio-Sensing Research. 5: 55–61. doi: 10.1016/j.sbsr.2015.07.005 . ISSN   2214-1804.
  11. ↑ Müller RH, Clegg DL (September 1949). "Automatic Paper Chromatography". Analytical Chemistry. 21 (9): 1123–1125. doi:10.1021/ac60033a032. ISSN   0003-2700.
  12. ↑ Fu E, Lutz B, Kauffman P, Yager P (April 2010). "Controlled reagent transport in disposable 2D paper networks". Lab on a Chip. 10 (7): 918–20. doi:10.1039/b919614e. PMC   3228840 . PMID   20300678.
  13. ↑ Martinez AW, Phillips ST, Carrilho E, Thomas SW, Sindi H, Whitesides GM (May 2008). "Simple telemedicine for developing regions: camera phones and paper-based microfluidic devices for real-time, off-site diagnosis". Analytical Chemistry. 80 (10): 3699–707. doi:10.1021/ac800112r. PMC   3761971 . PMID   18407617.
  14. ↑ Shih CM, Chang CL, Hsu MY, Lin JY, Kuan CM, Wang HK, et al. (December 2015). "Paper-based ELISA to rapidly detect Escherichia coli". Talanta. 145: 2–5. doi:10.1016/j.talanta.2015.07.051. PMID   26459436.
  15. ↑ Wang HK, Tsai CH, Chen KH, Tang CT, Leou JS, Li PC, et al. (February 2014). "Cellulose-based diagnostic devices for diagnosing serotype-2 dengue fever in human serum". Advanced Healthcare Materials. 3 (2): 187–96. doi: 10.1002/adhm.201470008 . PMID   23843297.
  16. ↑ Yang X, Forouzan O, Brown TP, Shevkoplyas SS (January 2012). "Integrated separation of blood plasma from whole blood for microfluidic paper-based analytical devices". Lab on a Chip. 12 (2): 274–80. doi:10.1039/c1lc20803a. PMID   22094609.
  17. ↑ Tao FF, Xiao X, Lei KF, Lee IC (2015-03-18). "Paper-based cell culture microfluidic system". BioChip Journal. 9 (2): 97–104. doi:10.1007/s13206-015-9202-7. ISSN   1976-0280. S2CID   54718125.
  18. ↑ Walsh DI, Lalli ML, Kassas JM, Asthagiri AR, Murthy SK (June 2015). "Cell chemotaxis on paper for diagnostics". Analytical Chemistry. 87 (11): 5505–10. doi:10.1021/acs.analchem.5b00726. PMID   25938457.
  19. ↑ Lam T, Devadhasan JP, Howse R, Kim J (April 2017). "A Chemically Patterned Microfluidic Paper-based Analytical Device (C-µPAD) for Point-of-Care Diagnostics". Scientific Reports. 7 (1): 1188. Bibcode:2017NatSR...7.1188L. doi:10.1038/s41598-017-01343-w. PMC   5430703 . PMID   28446756.
  20. 1 2 Erenas MM, de Orbe-Payá I, Capitan-Vallvey LF (May 2016). "Surface Modified Thread-Based Microfluidic Analytical Device for Selective Potassium Analysis". Analytical Chemistry. 88 (10): 5331–7. doi:10.1021/acs.analchem.6b00633. PMID   27077212. S2CID   30339215.
  21. 1 2 Reches M, Mirica KA, Dasgupta R, Dickey MD, Butte MJ, Whitesides GM (June 2010). "Thread as a matrix for biomedical assays". ACS Applied Materials & Interfaces. 2 (6): 1722–8. CiteSeerX   10.1.1.646.8048 . doi:10.1021/am1002266. PMID   20496913.
  22. ↑ Li X, Tian J, Shen W (January 2010). "Thread as a versatile material for low-cost microfluidic diagnostics". ACS Applied Materials & Interfaces. 2 (1): 1–6. doi:10.1021/am9006148. PMID   20356211.
  23. ↑ Ballerini DR, Li X, Shen W (March 2011). "Flow control concepts for thread-based microfluidic devices". Biomicrofluidics. 5 (1): 14105. doi:10.1063/1.3567094. PMC   3073008 . PMID   21483659.
  24. ↑ Mostafalu P, Akbari M, Alberti KA, Xu Q, Khademhosseini A, Sonkusale SR (2016-07-18). "A toolkit of thread-based microfluidics, sensors, and electronics for 3D tissue embedding for medical diagnostics". Microsystems & Nanoengineering. 2 (1): 16039. doi:10.1038/micronano.2016.39. PMC   6444711 . PMID   31057832.
  25. 1 2 3 4 Berthier J, Brakke KA, Gosselin D, Navarro F, Belgacem N, Chaussy D (July 2016). "Spontaneous capillary flow in curved, open microchannels". Microfluidics and Nanofluidics. 20 (7): 100. doi:10.1007/s10404-016-1766-6. ISSN   1613-4982. S2CID   100099081.
  26. 1 2 Berthier J, Brakke KA, Gosselin D, Huet M, Berthier E (2014). "Metastable capillary filaments in rectangular cross-section open microchannels". AIMS Biophysics. 1 (1): 31–48. doi: 10.3934/biophy.2014.1.31 . ISSN   2377-9098.
  27. ↑ Berthier J, Brakke KA, Gosselin D, Bourdat AG, Nonglaton G, Villard N, et al. (2014-09-18). "Suspended microflows between vertical parallel walls". Microfluidics and Nanofluidics. 18 (5–6): 919–929. doi:10.1007/s10404-014-1482-z. ISSN   1613-4982. S2CID   97022174.
  28. 1 2 Han A, Mondin G, Hegelbach NG, de Rooij NF, Staufer U (January 2006). "Filling kinetics of liquids in nanochannels as narrow as 27 nm by capillary force" (PDF). Journal of Colloid and Interface Science. 293 (1): 151–7. Bibcode:2006JCIS..293..151H. doi:10.1016/j.jcis.2005.06.037. PMID   16023663.
  29. 1 2 Kitron-Belinkov M, Marmur A, Trabold T, Dadheech GV (July 2007). "Groovy drops: effect of groove curvature on spontaneous capillary flow". Langmuir. 23 (16): 8406–10. doi:10.1021/la700473m. PMID   17608505.
  30. ↑ Gambino J (2011). "Process Challenges for Integration of Copper Interconnects with Low-k Dielectrics". ECS Transactions. 35 (4). Montreal, QC, Canada: 687–699. Bibcode:2011ECSTr..35d.687G. doi:10.1149/1.3572313. S2CID   137479649.{{cite journal}}: Cite journal requires |journal= (help)
  31. ↑ Schilp A, Hausner M, Puech M, Launay N, Karagoezoglu H, Laermer F (2001). Advanced Etch Tool for High Etch Rate Deep Reactive Ion Etching in Silicon Micromachining Production Environment. Berlin Heidelberg: Springer. pp. 229–236. ISBN   978-3-642-62124-6.{{cite book}}: |work= ignored (help)
  32. ↑ Berthier J, Brakke KA, Berthier E (2013-11-06). "A general condition for spontaneous capillary flow in uniform cross-section microchannels". Microfluidics and Nanofluidics. 16 (4): 779–785. doi:10.1007/s10404-013-1270-1. ISSN   1613-4982. S2CID   95256291.
  33. ↑ Yost FG, Rye RR, Mann Jr JA (December 1997). "Solder wetting kinetics in narrow V-grooves". Acta Materialia. 45 (12): 5337–5345. Bibcode:1997AcMat..45.5337Y. doi:10.1016/s1359-6454(97)00205-x. ISSN   1359-6454.
  34. ↑ Faivre M, Peltié P, Planat-Chrétien A, Cosnier ML, Cubizolles M, Nougier C, et al. (May 2011). "Coagulation dynamics of a blood sample by multiple scattering analysis". Journal of Biomedical Optics. 16 (5): 057001–057001–9. Bibcode:2011JBO....16e7001F. doi: 10.1117/1.3573813 . PMID   21639579.
  35. 1 2 3 Lee JJ, Berthier J, Brakke KA, Dostie AM, Theberge AB, Berthier E (May 2018). "Droplet Behavior in Open Biphasic Microfluidics". Langmuir. 34 (18): 5358–5366. doi:10.1021/acs.langmuir.8b00380. PMID   29692173.
  36. 1 2 Zhao B, Moore JS, Beebe DJ (February 2001). "Surface-directed liquid flow inside microchannels". Science. 291 (5506): 1023–6. Bibcode:2001Sci...291.1023Z. doi:10.1126/science.291.5506.1023. PMID   11161212.
  37. ↑ Young EW, Berthier E, Beebe DJ (January 2013). "Assessment of enhanced autofluorescence and impact on cell microscopy for microfabricated thermoplastic devices". Analytical Chemistry. 85 (1): 44–9. doi:10.1021/ac3034773. PMC   4017339 . PMID   23249264.
  38. ↑ Sackmann EK, Fulton AL, Beebe DJ (March 2014). "The present and future role of microfluidics in biomedical research". Nature. 507 (7491): 181–9. Bibcode:2014Natur.507..181S. doi:10.1038/nature13118. PMID   24622198. S2CID   4459357.
  39. ↑ Zimmermann M, Bentley S, Schmid H, Hunziker P, Delamarche E (December 2005). "Continuous flow in open microfluidics using controlled evaporation". Lab on a Chip. 5 (12): 1355–9. doi:10.1039/B510044E. PMID   16286965.
  40. ↑ Brakke KA (2015-01-31). The Motion of a Surface by Its Mean Curvature. (MN-20). Princeton: Princeton University Press. doi:10.1515/9781400867431. ISBN   9781400867431.
  41. ↑ Zhang W, Choi DS, Nguyen YH, Chang J, Qin L (December 2013). "Studying cancer stem cell dynamics on PDMS surfaces for microfluidics device design". Scientific Reports. 3 (1): 2332. Bibcode:2013NatSR...3E2332Z. doi:10.1038/srep02332. PMC   3728601 . PMID   23900274.
  42. 1 2 Halldorsson S, Lucumi E, Gómez-Sjöberg R, Fleming RM (January 2015). "Advantages and challenges of microfluidic cell culture in polydimethylsiloxane devices". Biosensors & Bioelectronics. 63: 218–231. doi: 10.1016/j.bios.2014.07.029 . PMID   25105943.
  43. ↑ Wong I, Ho CM (September 2009). "Surface molecular property modifications for poly(dimethylsiloxane) (PDMS) based microfluidic devices". Microfluidics and Nanofluidics. 7 (3): 291–306. doi:10.1007/s10404-009-0443-4. PMC   2847407 . PMID   20357909.
  44. ↑ Orhan JB, Parashar VK, Flueckiger J, Gijs MA (August 2008). "Internal modification of poly(dimethylsiloxane) microchannels with a borosilicate glass coating". Langmuir. 24 (16): 9154–61. doi:10.1021/la801317x. PMID   18652427.
  45. ↑ Wu J, Chen Q, Liu W, He Z, Lin JM (February 2017). "Recent advances in microfluidic 3D cellular scaffolds for drug assays". TrAC Trends in Analytical Chemistry. 87: 19–31. doi:10.1016/j.trac.2016.11.009.
  46. 1 2 Lee JN, Jiang X, Ryan D, Whitesides GM (December 2004). "Compatibility of mammalian cells on surfaces of poly(dimethylsiloxane)". Langmuir. 20 (26): 11684–91. doi:10.1021/la048562+. PMID   15595798.
  47. 1 2 Kachel S, Zhou Y, Scharfer P, Vrančić C, Petrich W, Schabel W (February 2014). "Evaporation from open microchannel grooves". Lab on a Chip. 14 (4): 771–8. doi:10.1039/c3lc50892g. PMID   24345870.
  48. 1 2 Ogawa M, Higashi K, Miki N (August 2015). "Development of hydrogel microtubes for microbe culture in open environment". 2015 37th Annual International Conference of the IEEE Engineering in Medicine and Biology Society (EMBC). Vol. 2015. pp. 5896–5899. doi:10.1109/EMBC.2015.7319733. ISBN   978-1-4244-9271-8. PMID   26737633. S2CID   4089852.
  49. ↑ Firpo G, Angeli E, Guida P, Lo Savio R, Repetto L, Valbusa U (April 2018). "Gas permeation through rubbery polymer nano-corrugated membranes". Scientific Reports. 8 (1): 6345. Bibcode:2018NatSR...8.6345F. doi:10.1038/s41598-018-24551-4. PMC   5910414 . PMID   29679013.
  50. ↑ Gomez-Sjoberg R, Leyrat AA, Houseman BT, Shokat K, Quake SR (November 2010). "Biocompatibility and reduced drug absorption of sol-gel-treated poly(dimethyl siloxane) for microfluidic cell culture applications". Analytical Chemistry. 82 (21): 8954–60. doi:10.1021/ac101870s. PMC   3032040 . PMID   20936785.
  51. ↑ Kuncová-Kallio J, Kallio PJ (August 2006). "PDMS and its suitability for analytical microfluidic devices". 2006 International Conference of the IEEE Engineering in Medicine and Biology Society. Vol. 2006. IEEE. pp. 2486–9. doi:10.1109/IEMBS.2006.260465. ISBN   978-1-4244-0032-4. PMID   17946118. S2CID   28786760.
  52. ↑ Toepke MW, Beebe DJ (December 2006). "PDMS absorption of small molecules and consequences in microfluidic applications". Lab on a Chip. 6 (12): 1484–6. doi:10.1039/B612140C. PMID   17203151.
  53. ↑ Bodas D, Khan-Malek C (2007-04-10). "Hydrophilization and hydrophobic recovery of PDMS by oxygen plasma and chemical treatment—An SEM investigation". Sensors and Actuators B: Chemical. 123 (1): 368–373. doi:10.1016/j.snb.2006.08.037.
  54. ↑ Guida P, Piscitelli E, Marrese M, Martino V, Cirillo V, Guarino V, et al. (June 2020). "Integrating Microstructured Electrospun Scaffolds in an Open Microfluidic System for in Vitro Studies of Human Patient-Derived Primary Cells". ACS Biomaterials Science & Engineering. 6 (6): 3649–3663. doi:10.1021/acsbiomaterials.0c00352. PMID   33463182. S2CID   219093089.
  55. ↑ Regehr KJ, Domenech M, Koepsel JT, Carver KC, Ellison-Zelski SJ, Murphy WL, et al. (August 2009). "Biological implications of polydimethylsiloxane-based microfluidic cell culture". Lab on a Chip. 9 (15): 2132–9. doi:10.1039/b903043c. PMC   2792742 . PMID   19606288.
  56. ↑ Zhou J, Khodakov DA, Ellis AV, Voelcker NH (January 2012). "Surface modification for PDMS-based microfluidic devices". Electrophoresis. 33 (1): 89–104. doi:10.1002/elps.201100482. PMID   22128067. S2CID   31284154.
  57. ↑ Ertel SI, Ratner BD, Kaul A, Schway MB, Horbett TA (June 1994). "In vitro study of the intrinsic toxicity of synthetic surfaces to cells". Journal of Biomedical Materials Research. 28 (6): 667–75. doi:10.1002/jbm.820280603. PMID   8071377.
  58. ↑ Dak P, Ebrahimi A, Swaminathan V, Duarte-Guevara C, Bashir R, Alam MA (April 2016). "Droplet-based Biosensing for Lab-on-a-Chip, Open Microfluidics Platforms". Biosensors. 6 (2): 14. doi: 10.3390/bios6020014 . PMC   4931474 . PMID   27089377.
  59. ↑ Hsu CH, Chen C, Folch A (October 2004). ""Microcanals" for micropipette access to single cells in microfluidic environments". Lab on a Chip. 4 (5): 420–4. doi:10.1039/b404956j. PMID   15472724.
  60. ↑ Li C, Boban M, Tuteja A (April 2017). "Open-channel, water-in-oil emulsification in paper-based microfluidic devices". Lab on a Chip. 17 (8): 1436–1441. doi:10.1039/c7lc00114b. PMID   28322402.
  61. ↑ Gutzweiler L, Gleichmann T, Tanguy L, Koltay P, Zengerle R, Riegger L (July 2017). "Open microfluidic gel electrophoresis: Rapid and low cost separation and analysis of DNA at the nanoliter scale". Electrophoresis. 38 (13–14): 1764–1770. doi:10.1002/elps.201700001. PMID   28426159. S2CID   24074609.
  62. ↑ Lei KF, Wu MH, Hsu CW, Chen YD (January 2014). "Real-time and non-invasive impedimetric monitoring of cell proliferation and chemosensitivity in a perfusion 3D cell culture microfluidic chip". Biosensors & Bioelectronics. 51: 16–21. doi:10.1016/j.bios.2013.07.031. PMID   23920091.
  63. ↑ Zhang W, Choi DS, Nguyen YH, Chang J, Qin L (2013-07-31). "Studying cancer stem cell dynamics on PDMS surfaces for microfluidics device design". Scientific Reports. 3 (1): 2332. Bibcode:2013NatSR...3E2332Z. doi:10.1038/srep02332. PMC   3728601 . PMID   23900274.
This page is based on this Wikipedia article
Text is available under the CC BY-SA 4.0 license; additional terms may apply.
Images, videos and audio are available under their respective licenses.