Microfluidic cell culture

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.[1][2] It merges microfluidics, a set of technologies used for the manipulation of small fluid volumes (μL, nL, pL) within artificially fabricated microsystems, and cell culture, which involves the maintenance and growth of cells in a controlled laboratory environment.[3][4] Microfluidics has been used for cell biology studies as the dimensions of the microfluidic channels are well suited for the physical scale of cells (in the order of magnitude of 10 micrometers).[2] For example, eukaryotic cells have linear dimensions between 10 and 100 μm which falls within the range of microfluidic dimensions.[4] 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.[2] 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.[2]

Fabrication

Some considerations for microfluidic devices relating to cell culture include:

Fabrication material is crucial as not all polymers are biocompatible, with some materials such as PDMS causing undesirable adsorption or absorption of small molecules.[9][10] Additionally, uncured PDMS oligomers can leach into the cell culture media, which can harm the microenvironment.[9] As an alternative to commonly used PDMS, there have been advances in the use of thermoplastics (e.g., polystyrene) as a replacement material.[11][12]

Spatial organization of cells in microscale devices largely depends on the culture region geometry for cells to perform functions in vivo.[13][14] For example, long, narrow channels may be desired to culture neurons.[13] The perfusion system chosen might also affect the geometry chosen. For example, in a system that incorporates syringe pumps, channels for perfusion inlet, perfusion outlet, waste, and cell loading would need to be added for the cell culture maintenance.[15] Perfusion in microfluidic cell culture is important to enable long culture periods on-chip and cell differentiation.[16]

Other critical aspects for controlling the microenvironment include: cell seeding density, reduction of air bubbles as they can rupture cell membranes, evaporation of media due to an insufficiently humid environment, and cell culture maintenance (i.e. regular, timely media changes).[17][16][18]

Cell's health is defined as the collective equilibrium activities of essential and specialized cellular processes; while a cell stressor is defined as a stimulus that causes excursion from its equilibrium state. Hence, cell health may be perturbed within microsystems based on platform design or operating conditions. Exposure to stressors within microsystems can impact cells through direct and indirect ways. Therefore, it is important to design the microfluidics system for cell culture in a manner that minimizes cell stress situations. For example, by minimizing cell suspension, by avoiding abrupt geometries (which tend to favor bubble formation), designing higher and wider channels (to avoid shear stress), avoid thermosensitive hydrogels...[19]

Advantages

Some of the major advantages of microfluidic cell culture include reduced sample volumes (especially important when using primary cells, which are often limited) and the flexibility to customize and study multiple microenvironments within the same device.[3] A reduced cell population can also be used in a microscale system (e.g., a few hundred cells) in comparison to macroscale culture systems (which often require 105 – 107 cells); this can make studying certain cell-cell interactions more accessible.[10] These reduced cell numbers make studying non-dividing or slow dividing cells (e.g., stem cells) easier than traditional culture methods (e.g., flasks, petri dishes, or well plates) due to the smaller sample volumes.[10][20] Given the small dimensions in microfluidics, laminar flow can be achieved, allowing manipulations with the culture system to be done easily without affecting other culture chambers.[20] Laminar flow is also useful as is it mimics in vivo fluid dynamics more accurately, often making microscale culture more relevant than traditional culture methods.[21] Compartmentalized microfluidic cultures have also been combined with live cell calcium imaging, where depolarizing stimuli have been delivered to the peripheral terminals of neurons, and calcium responses recorded in the cell body.[22] This technique has demonstrated a stark difference in the sensitivity of the peripheral terminals compared to the neuronal cell body to certain stimuli such as protons.[22] This gives an excellent example as to why it is so important to study the peripheral terminals in isolation using microfluidic cell culture devices.

Culture Platforms

Traditional cell culture

Traditional two-dimensional (2D) cell culture is cell culture that takes place on a flat surface, e.g. the bottom of a well-plate, and is known as the conventional method.[1] While these platforms are useful for growing and passaging cells to be used in subsequent experiments, they are not ideal environments to monitor cell responses to stimuli as cells cannot freely move or perform functions as observed in vivo that are dependent on cell-extracellular matrix material interactions.[1] To address this issue many methods have been developed to create a three-dimensional (3D) native cell environment. One example of a 3D method is the hanging drop, where a droplet with growing cells is suspended and hangs downwards, which allows cells to grow around and atop of one another, forming a spheroid.[23] The hanging drop method has been used to culture tumor cells but is limited to the geometry of a sphere.[24] Since the advent of poly(dimethylsiloxane) (PDMS) microfluidic device fabrication through soft lithography[25] microfluidic devices have progressed and have proven to be very beneficial for mimicking a natural 3D environment for cell culture.[26]

Microfluidic cell culture

Microfluidic devices make possible the study of a single cell to a few hundred cells in a 3D environment. Comparatively, macroscopic 2D cultures have 104 to 107 cells on a flat surface.[10] Microfluidics also allow for chemical gradients, the continuous flow of fresh media, high through put testing, and direct output to analytical instruments.[10] Additionally, open microfluidic cell cultures such as "microcanals" allow for direct physical manipulation of cells with micropipettes.[27] Many microfluidic systems employ the use of hydrogels as the extracellular matrix (ECM) support which can be modulated for fiber thickness and pore size and have been demonstrated to allow the growth of cancer cells.[28] Gel free 3D cell cultures have been developed to allow cells to grow in either a cell dense environment or an ECM poor environment.[29] Although these devices have proven very useful, there are certain disadvantages such as cells sticking to the PDMS surface, small molecules diffusing into the PDMS, and unreacted PDMS polymers washing into cell culture media.[10]

The use of 3D cell cultures in microfluidic devices has led to a field of study called organ-on-a-chip. The first report of these types of microfluidic cultures was used to study the toxicity of naphthalene metabolites on the liver and lung (Viravaidya et al.). These devices can grow a stripped-down version of an organ-like system that can be used to understand many biological processes.[1] By adding an additional dimension, more advanced cell architectures can be achieved, and cell behavior is more representative of in vivo dynamics; cells can engage in enhanced communication with neighboring cells and cell-extracellular matrix interactions can be modeled.[1][30] In these devices, chambers or collagen layers containing different cell types can interact with one another for multiple days while various channels deliver nutrients to the cells.[1][31] An advantage of these devices is that tissue function can be characterized and observed under controlled conditions (e.g., effect of shear stress on cells, effect of cyclic strain or other forces) to better understand the overall function of the organ.[1][32] While these 3D models offer better model organ function on a cellular level compared with 2D models, there are still challenges. Some of the challenges include: imaging of the cells, control of gradients in static models (i.e., without a perfusion system), and difficulty recreating vasculature.[32] Despite these challenges, 3D models are still used as tools for studying and testing drug responses in pharmacological studies.[1] In recent years, there are microfluidic devices reproducing the complex in vivo microvascular network. Organs-on-a-chip have also been used to replicate very complex systems like lung epithelial cells in an exposed airway and provides valuable insight for how multicellular systems and tissues function in vivo.[33] These devices are able to create a physiologically realistic 3D environment, which is desirable as a tool for drug screening, drug delivery, cell-cell interactions, tumor metastasis etc.[34][35] In one study, researchers grew tumor cells and tested the drug delivery of cis platin, resveratrol, tirapazamine (TPZ) and then measured the effects the drugs have on cell viability.[36]

Applications of Cells in microfluidic systems

Microfluidic systems can be used to culture several cell types.

Culture of mammalian cells

Mammalian cell cultures can be seeded, grown for several weeks, detached, and passaged to a fresh culture medium ad nauseam by digital microfluidic (DMF) devices on a macro-scale.[37]

Algae

Algae can be incubated, and their growth rate and lipid production can be monitored in a hanging-drop microfluidic system. For example, Mishra et al. developed a 25x75 mm, easily accessible microfluidic device. This design is used to optimize the conditions by changing well diameters, UV light exposure (causing mutagenesis), and light/no light tests for culturing Botryococcus braunii, which is one of the most common freshwater microalgae for biofuel production.[38]

Bacteria and Yeast

Microfluidic systems can be used to incubate high volumes of bacteria and yeast colonies.[39] The two-layer microchemostat device is made to allow scientists to culture cells under chemostatic and thermostatic conditions without moving cells around and causing intercellular interaction.[39] Yeast cell suspension droplets can be placed on a plate with patterned hydrophilic areas and incubated for 24 hours; then the droplets are split the produced proteins from yeast are analyzed by MALDI-MS without killing the cells in the original droplets.[40]

Multi-culture in microfluidics

Compared to the highly complex microenvironment in vivo, traditional mono-culture of single cell types in vitro only provides limited information about cellular behavior due to the lack of interactions with other cell types. Typically, cell-to-cell signaling can be divided into four categories depending on the distance: endocrine signaling, paracrine signaling, autocrine signaling, and juxtacrine signaling.[41] For example, in paracrine signaling, growth factors secreted from one cell diffuse over a short distance to the neighboring target cell,[42] whereas in juxtacrine signaling, membrane-bound ligands of one cell directly bind to surface receptors of adjacent cells.[43] There are three conventional approaches to incorporate cell signaling in in vitro cell culture: conditioned media transfer, mixed (or direct) co-culture, and segregated (or indirect) co-culture.[44] The use of conditioned media, where the cultured medium of one cell type (the effector) is introduced to the culture of another cell type (the responder), is a traditional way to include the effects of soluble factors in cell signaling.[45] However, this method only allows one-way signaling, does not apply to short-lived factors (which often degrade before transfer to the responder cell culture), and does not allow temporal observations of the secreted factors.[46] Recently, co-culture has become the predominant approach to study the effect of cellular communication by culturing two biologically related cell types together. Mixed co-culture is the simplest co-culture method, where two types of cells are in direct contact within a single culture compartment at the desired cell ratio.[47] Cells can communicate by paracrine and juxtacrine signaling, but separated treatments and downstream analysis of a single cell type are not readily feasible due to the completely mixed population of cells.[48][49] The more common method is segregated co-culture, where the two cell types are physically separated but can communicate in shared media by paracrine signaling. The physical barrier can be a porous membrane, a solid wall, or a hydrogel divider.[48][49][50][51][52][53] If the physical barrier is removable (such as in PDMS or hydrogel), the assay can also be used to study cell invasion or cell migration.[49][52] Co-culture designs can be adapted to tri- or multi-culture, which are often more representative of in vivo conditions relative to co-culture.[49][50][54][55]

Closed channel multi-culture systems

The flexibility of microfluidic devices greatly contributes to the development of multi-culture studies by improved control over spatial patterns. Closed channel systems made by PDMS are most commonly used because PDMS has traditionally enabled rapid prototyping. For example, mixed co-culture can be achieved in droplet-based microfluidics easily by a co-encapsulation system to study paracrine and juxtacrine signaling.[56] Two types of cells are co-encapsulated in droplets by combining two streams of cell-laden agarose solutions. After gelation, the agarose microgels will serve as a 3D microenvironment for cell co-culture.[56] Segregated co-culture is also realized in microfluidic channels to study paracrine signaling. Human alveolar epithelial cells and microvascular endothelial cells can be co-cultured in compartmentalized PDMS channels, separated by a thin, porous, and stretchable PDMS membrane to mimic alveolar-capillary barrier.[51] Endothelial cells can also be co-cultured with cancer cells in a monolayer while separated by a 3D collagen scaffold to study endothelial cell migration and capillary growth.[57] When embedded in gels, salivary gland adenoid cystic carcinoma (ACC) cells can be co-cultured with carcinoma-associated fibroblast (CAF) in a 3D extracellular matrix to study stroma-regulated cancer invasion in the 3D environment.[58] If juxtacrine signaling is to be investigated solely without paracrine signaling, a single cell coupling co-culture microfluidic array can be designed based on a cellular valving principle.[59]

Open channel multi-culture systems

Although closed channel microfluidics (discussed in the section above) offers high customizability and biological complexity for multi-culture, the operation often requires handling expertise and specialized equipment, such as pumps and valves.[49][53] In addition, the use of PDMS is known to cause adverse effects to cell culture, including leaching of oligomers or absorption of small molecules, thus often doubted by biologists.[60] Therefore, open microfluidic devices made of polystyrene (PS), a well-established cell culture material, started to emerge.[60] The advantages of open multi-culture designs are direct pipette accessibility and easy fabrication (micro-milling, 3D printing, injection molding, or razor-printing – without the need for a subsequent bonding step or channel clearance techniques).[49][53][61][62][63] They can also be incorporated into traditional cultureware (well plate or petri dish) while remaining the complexity for multi-culture experiments.[49][53][62][63] For example, the ‘monorail device’ which patterns hydrogel walls along a rail via spontaneous capillary flow can be inserted into commercially available 24-well plates.[62] Flexible patterning geometries are achieved by merely changing 3D printed or milled inserts. The monorail device can also be adapted to study multikingdom soluble factor signaling, which is difficult in traditional shared media co-culture due to the different media and culture requirements for microbial and mammalian cells.[62] Another open multi-culture device fabricated by razor-printing is capable of integrating numerous culture modalities, including 2D, 3D, Transwell, and spheroid culture.[49] It also shows improved diffusion to promote soluble factor paracrine signaling.[49]

Controlling cell microenvironment

Microfluidic systems expand their ability to control the local cell microenvironment beyond what is possible with conventional culture systems. Being able to provide different environments in a steady, sustainable and precise manner has a significant impact on cell culture research and study. Those environmental factors include physical (shear stress), biochemical (cell-cell interactions, cell-molecule interactions, cell-substrate interactions), and physicochemical (pH, CO2, temperature, O2) factors.[64]

Oxygen concentration control

Oxygen plays an essential role in biological systems.[65] Oxygen concentration control is one of the key elements when designing the microfluidic systems, whether the aerobic species or when modulating cellular functions in vivo, such as baseline metabolism and function.[65] Multiple microfluidic systems have been designed to control the desired gas concentrations for cell culture. For example, generating oxygen gradients was achieved by single-thin-layer PDMS construction within channels (thicknesses less than 50 μm, diffusion coefficient of oxygen in native PDMS at 25 °C, D= 3.55x10−5 cm2 s−1) without utilizing gas cylinders or oxygen scavenging agents; thus the microfluidic cell culture device can be placed in incubators and be operated easily.[66] However, the PDMS may be problematic for the adsorption of small hydrophobic species.[67] Poly(methyl pentene) (PMP) may be an alternative material, because it has high oxygen permeability and biocompatibility like PDMS.[68][69] In addition to the challenges of controlling gas concentration, monitoring oxygen in the microfluidic system is another challenge to address. There are numerous different dye indicators that can be used as optical, luminescence-based oxygen sensing, which is based on the phenomenon of luminescence quenching by oxygen, without consuming oxygen in the system.[70] This technique makes monitoring oxygen in microscale environments feasible and can be applied in biological laboratories.[70]

Temperature control

Temperature can be sensed by cells and influences their behavior, such as biochemical reaction kinetics.[71] However, it is hard to control high-resolution temperature in traditional cell culture systems; whereas, microfluidic systems are proven to successfully reach the desired temperature under different temperature conditions through several techniques.[71] For example, the temperature gradient in the microfluidic system can be achieved by mixing two or more inputs at different temperatures and flow rates, and the temperature is measured in the outlet channels by embedding polymer-based aquarium thermocouples.[72] Also, by installing heaters and digital temperature sensors at the base of the microfluidic system, it has been demonstrated that a microfluidic cell culture system can continuously operate for at least 500 hours.[73] The circulating water channels in the microfluidic system are also used to precisely control temperatures of the cell culture channels and chambers.[39] Furthermore, putting the device inside a cell culture incubator can also easily control the cell culture temperature.[74]

See also

References
  1. Bhatia SN, Ingber DE (August 2014). "Microfluidic organs-on-chips". Nature Biotechnology. 32 (8): 760–72. doi:10.1038/nbt.2989. PMID 25093883. S2CID 988255.
  2. Young EW, Beebe DJ (March 2010). "Fundamentals of microfluidic cell culture in controlled microenvironments". Chemical Society Reviews. 39 (3): 1036–48. doi:10.1039/b909900j. PMC 2967183. PMID 20179823.
  3. Mehling M, Tay S (February 2014). "Microfluidic cell culture". Current Opinion in Biotechnology. 25: 95–102. doi:10.1016/j.copbio.2013.10.005. PMID 24484886.
  4. 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.
  5. Cho BS, Schuster TG, Zhu X, Chang D, Smith GD, Takayama S (April 2003). "Passively driven integrated microfluidic system for separation of motile sperm". Analytical Chemistry. 75 (7): 1671–5. doi:10.1021/ac020579e. PMID 12705601.
  6. Zimmermann M, Schmid H, Hunziker P, Delamarche E (January 2007). "Capillary pumps for autonomous capillary systems". Lab on a Chip. 7 (1): 119–25. doi:10.1039/b609813d. PMID 17180214. S2CID 5583380.
  7. Walker G, Beebe DJ (August 2002). "A passive pumping method for microfluidic devices". Lab on a Chip. 2 (3): 131–4. CiteSeerX 10.1.1.118.5648. doi:10.1039/b204381e. PMID 15100822.
  8. Kim L, Toh YC, Voldman J, Yu H (June 2007). "A practical guide to microfluidic perfusion culture of adherent mammalian cells". Lab on a Chip. 7 (6): 681–94. doi:10.1039/b704602b. PMID 17538709. S2CID 1453088.
  9. Regehr KJ, Domenech M, Koepsel JT, Carver KC, Ellison-Zelski SJ, Murphy WL, Schuler LA, Alarid ET, Beebe DJ (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.
  10. 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.
  11. Berthier E, Young EW, Beebe D (April 2012). "Engineers are from PDMS-land, Biologists are from Polystyrenia". Lab on a Chip. 12 (7): 1224–37. doi:10.1039/c2lc20982a. PMID 22318426.
  12. van Midwoud PM, Janse A, Merema MT, Groothuis GM, Verpoorte E (May 2012). "Comparison of biocompatibility and adsorption properties of different plastics for advanced microfluidic cell and tissue culture models". Analytical Chemistry. 84 (9): 3938–44. doi:10.1021/ac300771z. PMID 22444457.
  13. Rhee SW, Taylor AM, Tu CH, Cribbs DH, Cotman CW, Jeon NL (January 2005). "Patterned cell culture inside microfluidic devices". Lab on a Chip. 5 (1): 102–7. doi:10.1039/b403091e. hdl:10371/7982. PMID 15616747. S2CID 45351341.
  14. Folch A, Toner M (1998-01-01). "Cellular micropatterns on biocompatible materials". Biotechnology Progress. 14 (3): 388–92. doi:10.1021/bp980037b. PMID 9622519. S2CID 7780457.
  15. Hung PJ, Lee PJ, Sabounchi P, Lin R, Lee LP (January 2005). "Continuous perfusion microfluidic cell culture array for high-throughput cell-based assays". Biotechnology and Bioengineering. 89 (1): 1–8. doi:10.1002/bit.20289. PMID 15580587.
  16. Tourovskaia A, Figueroa-Masot X, Folch A (January 2005). "Differentiation-on-a-chip: a microfluidic platform for long-term cell culture studies". Lab on a Chip. 5 (1): 14–9. doi:10.1039/b405719h. PMID 15616734.
  17. Meyvantsson I, Beebe DJ (2008-06-13). "Cell culture models in microfluidic systems". Annual Review of Analytical Chemistry. 1 (1): 423–49. Bibcode:2008ARAC....1..423M. doi:10.1146/annurev.anchem.1.031207.113042. PMID 20636085. S2CID 10720180.
  18. Yu H, Alexander CM, Beebe DJ (June 2007). "Understanding microchannel culture: parameters involved in soluble factor signaling". Lab on a Chip. 7 (6): 726–30. doi:10.1039/b618793e. PMID 17538714. S2CID 31753568.
  19. Varma S, Voldman J (November 2018). "Caring for cells in microsystems: principles and practices of cell-safe device design and operation". Lab on a Chip. 18 (22): 3333–3352. doi:10.1039/C8LC00746B. PMC 6254237. PMID 30324208.
  20. Gómez-Sjöberg R, Leyrat AA, Pirone DM, Chen CS, Quake SR (November 2007). "Versatile, fully automated, microfluidic cell culture system". Analytical Chemistry. 79 (22): 8557–63. doi:10.1021/ac071311w. PMID 17953452.
  21. Cimetta E, Vunjak-Novakovic G (September 2014). "Microscale technologies for regulating human stem cell differentiation". Experimental Biology and Medicine. 239 (9): 1255–63. doi:10.1177/1535370214530369. PMC 4476254. PMID 24737735.
  22. Clark AJ, Menendez G, AlQatari M, Patel N, Arstad E, Schiavo G, Koltzenburg M (July 2018). "Functional imaging in microfluidic chambers reveals sensory neuron sensitivity is differentially regulated between neuronal regions". Pain. 159 (7): 1413–1425. doi:10.1097/j.pain.0000000000001145. PMID 29419650. S2CID 3441948.
  23. Keller GM (December 1995). "In vitro differentiation of embryonic stem cells". Current Opinion in Cell Biology. 7 (6): 862–9. doi:10.1016/0955-0674(95)80071-9. PMID 8608017.
  24. Kelm JM, Timmins NE, Brown CJ, Fussenegger M, Nielsen LK (July 2003). "Method for generation of homogeneous multicellular tumor spheroids applicable to a wide variety of cell types". Biotechnology and Bioengineering. 83 (2): 173–80. doi:10.1002/bit.10655. PMID 12768623.
  25. Duffy DC, McDonald JC, Schueller OJ, Whitesides GM (December 1998). "Rapid Prototyping of Microfluidic Systems in Poly(dimethylsiloxane)". Analytical Chemistry. 70 (23): 4974–84. doi:10.1021/ac980656z. PMID 21644679.
  26. Gupta N, Liu JR, Patel B, Solomon DE, Vaidya B, Gupta V (March 2016). "Microfluidics-based 3D cell culture models: Utility in novel drug discovery and delivery research". Bioengineering & Translational Medicine. 1 (1): 63–81. doi:10.1002/btm2.10013. PMC 5689508. PMID 29313007.
  27. 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.
  28. Ma YH, Middleton K, You L, Sun Y (2018-04-09). "A review of microfluidic approaches for investigating cancer extravasation during metastasis". Microsystems & Nanoengineering. 4: 17104. doi:10.1038/micronano.2017.104. ISSN 2055-7434.
  29. Ong SM, Zhang C, Toh YC, Kim SH, Foo HL, Tan CH, et al. (August 2008). "A gel-free 3D microfluidic cell culture system". Biomaterials. 29 (22): 3237–44. doi:10.1016/j.biomaterials.2008.04.022. PMID 18455231.
  30. Pampaloni F, Reynaud EG, Stelzer EH (October 2007). "The third dimension bridges the gap between cell culture and live tissue". Nature Reviews. Molecular Cell Biology. 8 (10): 839–45. doi:10.1038/nrm2236. PMID 17684528. S2CID 23837249.
  31. Huh D, Hamilton GA, Ingber DE (December 2011). "From 3D cell culture to organs-on-chips". Trends in Cell Biology. 21 (12): 745–54. doi:10.1016/j.tcb.2011.09.005. PMC 4386065. PMID 22033488.
  32. van Duinen V, Trietsch SJ, Joore J, Vulto P, Hankemeier T (December 2015). "Microfluidic 3D cell culture: from tools to tissue models". Current Opinion in Biotechnology. 35: 118–26. doi:10.1016/j.copbio.2015.05.002. PMID 26094109.
  33. Benam KH, Villenave R, Lucchesi C, Varone A, Hubeau C, Lee HH, et al. (February 2016). "Small airway-on-a-chip enables analysis of human lung inflammation and drug responses in vitro". Nature Methods. 13 (2): 151–7. doi:10.1038/nmeth.3697. PMID 26689262. S2CID 13239849.
  34. Soroush F, Zhang T, King DJ, Tang Y, Deosarkar S, Prabhakarpandian B, et al. (November 2016). "A novel microfluidic assay reveals a key role for protein kinase C δ in regulating human neutrophil-endothelium interaction". Journal of Leukocyte Biology. 100 (5): 1027–1035. doi:10.1189/jlb.3ma0216-087r. PMC 5069089. PMID 27190303.
  35. Tang Y, Soroush F, Deosarkar S, Wang B, Pandian P, Kiani MF (April 2016). "A Novel Synthetic Tumor Platform for Screening Drug Delivery systems". The FASEB Journal. doi:10.1096/fasebj.30.1_supplement.698.7 (inactive 1 August 2023).{{cite journal}}: CS1 maint: DOI inactive as of August 2023 (link)
  36. Patra B, Peng CC, Liao WH, Lee CH, Tung YC (February 2016). "Drug testing and flow cytometry analysis on a large number of uniform sized tumor spheroids using a microfluidic device". Scientific Reports. 6 (1): 21061. Bibcode:2016NatSR...621061P. doi:10.1038/srep21061. PMC 4753452. PMID 26877244.
  37. Barbulovic-Nad, Irena; Au, Sam H.; Wheeler, Aaron R. (2010-06-21). "A microfluidic platform for complete mammalian cell culture". Lab on a Chip. 10 (12): 1536–1542. doi:10.1039/c002147d. ISSN 1473-0197. PMID 20393662.
  38. Mishra, Shubhanvit; Liu, Yi-Ju; Chen, Chi-Shuo; Yao, Da-Jeng (January 2021). "An Easily Accessible Microfluidic Chip for High-Throughput Microalgae Screening for Biofuel Production". Energies. 14 (7): 1817. doi:10.3390/en14071817.
  39. Groisman, Alex; Lobo, Caroline; Cho, HoJung; Campbell, J. Kyle; Dufour, Yann S.; Stevens, Ann M.; Levchenko, Andre (September 2005). "A microfluidic chemostat for experiments with bacterial and yeast cells". Nature Methods. 2 (9): 685–689. doi:10.1038/nmeth784. ISSN 1548-7091. PMID 16118639. S2CID 6556619.
  40. Haidas, Dominik; Napiorkowska, Marta; Schmitt, Steven; Dittrich, Petra S. (2020-03-03). "Parallel Sampling of Nanoliter Droplet Arrays for Noninvasive Protein Analysis in Discrete Yeast Cultivations by MALDI-MS". Analytical Chemistry. 92 (5): 3810–3818. doi:10.1021/acs.analchem.9b05235. ISSN 0003-2700. PMID 31990188. S2CID 210935049.
  41. Cooper, Geoffrey M. (2000). "Signaling Molecules and Their Receptors". The Cell: A Molecular Approach. 2nd Edition.
  42. Wordinger RJ, Clark AF (2008). "Growth Factors and Neurotrophic Factors as Targets". Ocular Therapeutics. Elsevier. pp. 87–116. doi:10.1016/b978-012370585-3.50007-8. ISBN 978-0-12-370585-3.
  43. Torii KU (2004). "Leucine-Rich Repeat Receptor Kinases in Plants: Structure, Function, and Signal Transduction Pathways". International Review of Cytology. Vol. 234. Elsevier. pp. 1–46. doi:10.1016/s0074-7696(04)34001-5. ISBN 978-0-12-364638-5. PMID 15066372.
  44. Regier MC, Alarid ET, Beebe DJ (June 2016). "Progress towards understanding heterotypic interactions in multi-culture models of breast cancer". Integrative Biology. 8 (6): 684–92. doi:10.1039/C6IB00001K. PMC 4993016. PMID 27097801.
  45. Lyons RM, Keski-Oja J, Moses HL (May 1988). "Proteolytic activation of latent transforming growth factor-beta from fibroblast-conditioned medium". The Journal of Cell Biology. 106 (5): 1659–65. doi:10.1083/jcb.106.5.1659. PMC 2115066. PMID 2967299.
  46. Bogdanowicz DR, Lu HH (April 2013). "Studying cell-cell communication in co-culture". Biotechnology Journal. 8 (4): 395–6. doi:10.1002/biot.201300054. PMC 4230534. PMID 23554248.
  47. Gandolfi F, Moor RM (September 1987). "Stimulation of early embryonic development in the sheep by co-culture with oviduct epithelial cells". Journal of Reproduction and Fertility. 81 (1): 23–8. doi:10.1530/jrf.0.0810023. PMID 3668954.
  48. Benam KH, Villenave R, Lucchesi C, Varone A, Hubeau C, Lee HH, et al. (February 2016). "Small airway-on-a-chip enables analysis of human lung inflammation and drug responses in vitro". Nature Methods. 13 (2): 151–7. doi:10.1038/nmeth.3697. PMID 26689262. S2CID 13239849.
  49. Álvarez-García YR, Ramos-Cruz KP, Agostini-Infanzón RJ, Stallcop LE, Beebe DJ, Warrick JW, Domenech M (October 2018). "Open multi-culture platform for simple and flexible study of multi-cell type interactions". Lab on a Chip. 18 (20): 3184–3195. doi:10.1039/C8LC00560E. PMC 8815088. PMID 30204194.
  50. Hatherell K, Couraud PO, Romero IA, Weksler B, Pilkington GJ (August 2011). "Development of a three-dimensional, all-human in vitro model of the blood-brain barrier using mono-, co-, and tri-cultivation Transwell models". Journal of Neuroscience Methods. 199 (2): 223–9. doi:10.1016/j.jneumeth.2011.05.012. PMID 21609734. S2CID 6512165.
  51. Huh D, Matthews BD, Mammoto A, Montoya-Zavala M, Hsin HY, Ingber DE (June 2010). "Reconstituting organ-level lung functions on a chip". Science. 328 (5986): 1662–8. Bibcode:2010Sci...328.1662H. doi:10.1126/science.1188302. PMC 8335790. PMID 20576885. S2CID 11011310.
  52. Wang IE, Shan J, Choi R, Oh S, Kepler CK, Chen FH, Lu HH (December 2007). "Role of osteoblast-fibroblast interactions in the formation of the ligament-to-bone interface". Journal of Orthopaedic Research. 25 (12): 1609–20. doi:10.1002/jor.20475. PMID 17676622. S2CID 22463821.
  53. Zhang T, Lih D, Nagao RJ, Xue J, Berthier E, Himmelfarb J, et al. (May 2020). "Open microfluidic coculture reveals paracrine signaling from human kidney epithelial cells promotes kidney specificity of endothelial cells". American Journal of Physiology. Renal Physiology. 319 (1): F41–F51. doi:10.1152/ajprenal.00069.2020. PMC 7468832. PMID 32390509.
  54. Regier MC, Maccoux LJ, Weinberger EM, Regehr KJ, Berry SM, Beebe DJ, Alarid ET (August 2016). "Transitions from mono- to co- to tri-culture uniquely affect gene expression in breast cancer, stromal, and immune compartments". Biomedical Microdevices. 18 (4): 70. doi:10.1007/s10544-016-0083-x. PMC 5076020. PMID 27432323.
  55. Theberge AB, Yu J, Young EW, Ricke WA, Bushman W, Beebe DJ (March 2015). "Microfluidic multiculture assay to analyze biomolecular signaling in angiogenesis". Analytical Chemistry. 87 (6): 3239–46. doi:10.1021/ac503700f. PMC 4405103. PMID 25719435.
  56. Tumarkin E, Tzadu L, Csaszar E, Seo M, Zhang H, Lee A, et al. (June 2011). "High-throughput combinatorial cell co-culture using microfluidics". Integrative Biology. 3 (6): 653–62. doi:10.1039/c1ib00002k. PMID 21526262.
  57. Chung S, Sudo R, Mack PJ, Wan CR, Vickerman V, Kamm RD (January 2009). "Cell migration into scaffolds under co-culture conditions in a microfluidic platform". Lab on a Chip. 9 (2): 269–75. doi:10.1039/B807585A. PMID 19107284.
  58. Liu T, Lin B, Qin J (July 2010). "Carcinoma-associated fibroblasts promoted tumor spheroid invasion on a microfluidic 3D co-culture device". Lab on a Chip. 10 (13): 1671–7. doi:10.1039/c000022a. PMID 20414488.
  59. Frimat JP, Becker M, Chiang YY, Marggraf U, Janasek D, Hengstler JG, et al. (January 2011). "A microfluidic array with cellular valving for single cell co-culture". Lab on a Chip. 11 (2): 231–7. doi:10.1039/C0LC00172D. PMID 20978708.
  60. Berthier E, Young EW, Beebe D (April 2012). "Engineers are from PDMS-land, Biologists are from Polystyrenia". Lab on a Chip. 12 (7): 1224–37. doi:10.1039/c2lc20982a. PMID 22318426.
  61. Lee Y, Choi JW, Yu J, Park D, Ha J, Son K, et al. (August 2018). "Microfluidics within a well: an injection-molded plastic array 3D culture platform". Lab on a Chip. 18 (16): 2433–2440. doi:10.1039/C8LC00336J. PMID 29999064.
  62. Berry SB, Zhang T, Day JH, Su X, Wilson IZ, Berthier E, Theberge AB (December 2017). "Upgrading well plates using open microfluidic patterning". Lab on a Chip. 17 (24): 4253–4264. doi:10.1039/C7LC00878C. PMID 29164190.
  63. Day JH, Nicholson TM, Su X, van Neel TL, Clinton I, Kothandapani A, et al. (January 2020). "Injection molded open microfluidic well plate inserts for user-friendly coculture and microscopy". Lab on a Chip. 20 (1): 107–119. doi:10.1039/C9LC00706G. PMC 6917835. PMID 31712791.
  64. Coluccio, Maria Laura; Perozziello, Gerardo; Malara, Natalia; Parrotta, Elvira; Zhang, Peng; Gentile, Francesco; Limongi, Tania; Raj, Pushparani Michael; Cuda, Gianni; Candeloro, Patrizio; Di Fabrizio, Enzo (2019-03-01). "Microfluidic platforms for cell cultures and investigations". Microelectronic Engineering. 208: 14–28. doi:10.1016/j.mee.2019.01.004. ISSN 0167-9317. S2CID 139526196.
  65. Allen, Jared W.; Bhatia, Sangeeta N. (2003-05-05). "Formation of steady-state oxygen gradients in vitro: application to liver zonation". Biotechnology and Bioengineering. 82 (3): 253–262. doi:10.1002/bit.10569. ISSN 0006-3592. PMID 12599251.
  66. Chen, Yung-Ann; King, Andrew D.; Shih, Hsiu-Chen; Peng, Chien-Chung; Wu, Chueh-Yu; Liao, Wei-Hao; Tung, Yi-Chung (2011-11-07). "Generation of oxygen gradients in microfluidic devices for cell culture using spatially confined chemical reactions". Lab on a Chip. 11 (21): 3626–3633. doi:10.1039/c1lc20325h. ISSN 1473-0189. PMID 21915399.
  67. Toepke, Michael W.; Beebe, David J. (December 2006). "PDMS absorption of small molecules and consequences in microfluidic applications". Lab on a Chip. 6 (12): 1484–1486. doi:10.1039/b612140c. ISSN 1473-0197. PMID 17203151.
  68. Slepička, Petr; Trostová, Simona; Slepičková Kasálková, Nikola; Kolská, Zdeňka; Malinský, Petr; MacKová, Anna; Bačáková, Lucie; Švorčík, Václav (2012-07-01). "Nanostructuring of polymethylpentene by plasma and heat treatment for improved biocompatibility". Polymer Degradation and Stability. 97 (7): 1075–1082. doi:10.1016/j.polymdegradstab.2012.04.013. ISSN 0141-3910.
  69. Ochs, Christopher J.; Kasuya, Junichi; Pavesi, Andrea; Kamm, Roger D. (2013-12-23). "Oxygen levels in thermoplastic microfluidic devices during cell culture". Lab on a Chip. 14 (3): 459–462. doi:10.1039/C3LC51160J. ISSN 1473-0189. PMC 4305448. PMID 24302467.
  70. Grist, Samantha M.; Chrostowski, Lukas; Cheung, Karen C. (2010). "Optical oxygen sensors for applications in microfluidic cell culture". Sensors (Basel, Switzerland). 10 (10): 9286–9316. doi:10.3390/s101009286. ISSN 1424-8220. PMC 3230974. PMID 22163408.
  71. Meyvantsson, Ivar; Beebe, David J. (2008). "Cell culture models in microfluidic systems". Annual Review of Analytical Chemistry. 1: 423–449. Bibcode:2008ARAC....1..423M. doi:10.1146/annurev.anchem.1.031207.113042. ISSN 1936-1335. PMID 20636085.
  72. Pearce, Thomas M.; Wilson, J. Adam; Oakes, S. George; Chiu, Shing-Yan; Williams, Justin C. (January 2005). "Integrated microelectrode array and microfluidics for temperature clamp of sensory neurons in culture". Lab on a Chip. 5 (1): 97–101. doi:10.1039/b407871c. ISSN 1473-0197. PMID 15616746.
  73. Lee, Kevin S.; Boccazzi, Paolo; Sinskey, Anthony J.; Ram, Rajeev J. (2011-05-21). "Microfluidic chemostat and turbidostat with flow rate, oxygen, and temperature control for dynamic continuous culture". Lab on a Chip. 11 (10): 1730–1739. doi:10.1039/c1lc20019d. ISSN 1473-0189. PMID 21445442.
  74. Hung, Paul J.; Lee, Philip J.; Sabounchi, Poorya; Lin, Robert; Lee, Luke P. (2005-01-05). "Continuous perfusion microfluidic cell culture array for high-throughput cell-based assays". Biotechnology and Bioengineering. 89 (1): 1–8. doi:10.1002/bit.20289. ISSN 0006-3592. PMID 15580587.
This article is issued from Wikipedia. The text is licensed under Creative Commons - Attribution - Sharealike. Additional terms may apply for the media files.