Generation of dynamic temporal and spatial concentration gradients using microfluidic devices

Lin, Francis; Saadi, Wajeeh; Rhee, Seog Woo; Wang, Shur-Jen; Mittal, Sukant; Jeon, Noo Li

doi:10.1039/b313600k

Cited by 196 publications

(165 citation statements)

References 12 publications

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“…One important difference between our approach and existent microfluidic systems capable of producing nonlinear gradients is the flexibility in the shape of the output gradients starting from only two inlets. Using the system of dividers, any monotonic gradients can be produced, a significant improvement compared to the multiple inlets networks 17 and asymmetric irrigation of the symmetric microfluidic network that can only generate power series gradients 13 or the dilutor networks that can only produce dilution series gradients. 14 Nonetheless, a smaller footprint of the gradient generator compared to gradient network devices is achieved through the precise implementation based on calculations.…”

Section: Resultsmentioning

confidence: 99%

Universal Microfluidic Gradient Generator

2006

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The study of cellular responses to chemical gradients in vitro would greatly benefit from experimental systems that can generate precise and stable gradients comparable to chemical nonhomogeneities occurring in vivo. Recently, microfluidic devices have been demonstrated for linear gradient generation for biological applications with unmatched accuracy and stability. However, no systematic approach exists at this time for generating other gradients of target spatial configuration. Here we demonstrate experimentally and provide mathematical proof for a systematic approach to generating stable gradients of any profile by the controlled mixing of two starting solutions.Replication of complex chemical gradients is essential for many in vitro experimental studies in prokaryotic and eukaryotic cells. Investigation of fundamental processes such as the migration of prokaryotic cell toward sources of nutrients, 1 immune cells against intruders, 2,3 the growth or regeneration of axons toward their connection target, 4 and the differentiation of embryonic cells in response to morphogens 5 require precise duplication of the in vivo spatial distribution of various signaling molecules. Such distributions usually occur in nonhomogeneous mediums, under various production, transport, and degradation conditions, and gradients of nonlinear, more or less complex shapes are usually formed. 6,7 Although linear gradients represent a good first-order approximation for in vivo gradients, and are useful in gaining insights into the biology of cellular responses, growing evidence suggests that a lot of complexity arises and many cellular responses are specific to spatial gradients that are not linear. For example, in bacteria migrating in chemoattractant gradients, the interplay between sensory adaptation and concentration changes due to displacement can lead to variations in chemotactic responses. 8 Similarly, cancerous cells that typically do not respond to linear chemotactic gradients have been recently shown to migrate in response to nonlinear gradients. 9 As a result, it is critical for better understanding of cellular polarization, migration, growth, or division responses of cells to biochemical heterogeneities in their microenvironment to be able to consistently replicate chemical concentration profiles comparable to those experienced by cells in vivo. Still, most of the current experimental systems for generating chemical gradients, e.g., Boyden chambers, 10 Dunn chambers, 11 or microfluidic gradient generators, 12 only produce linear gradients of soluble biochemical factors, and few alternatives exist for producing gradients of other spatial profiles at scales comparable to cell size. While some gradients that are not linear have been generated using asymmetric flow in symmetric networks, 13 or serial dilutions schemes, 14,15

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Section: Resultsmentioning

confidence: 99%

Universal Microfluidic Gradient Generator

2006

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“…Previous attempts to gradient changes using microfluidic chemotaxis devices 13,14 also resulted in long switching times that limited their use to the generation of stable gradients only. 15 Micropipettes and photoactivated release of caged chemicals can generate new gradients in seconds, but these gradients can be easily perturbed by external factors and reproducibility of experimental conditions is generally a concern. 16,17 While the first group of techniques is generally used to study steady state cellular behavior, the second is usually employed in exploring fast cellular responses.…”

Section: Introductionmentioning

confidence: 99%

Microfluidic system for measuring neutrophil migratory responses to fast switches of chemical gradients

et al. 2006

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Experimental systems that provide temporal and spatial control of chemical gradients are required for probing into the complex mechanisms of eukaryotic cell chemotaxis. However, no current technique can simultaneously generate stable chemical gradients and allow fast gradient changes. We developed a microfluidic system with microstructured membranes for exposing neutrophils to fast and precise changes between stable, linear gradients of the known chemoattractant Interleukin-8 (IL-8). We observed that rapidly lowering the average concentration of IL-8 within a gradient, while preserving the direction of the gradient, resulted in temporary neutrophil depolarization. Fast reversal of the gradient direction while increasing or decreasing the average concentration also resulted in temporary depolarization. Neutrophils adapted and maintained their directional motility, only when the average gradient concentration was increased and the direction of the gradient preserved. Based on these observations we propose a two-component temporal sensing mechanism that uses variations of chemokine concentration averaged over the entire cell surface and localized at the leading edge, respectively, and directs neutrophil responses to changes in their chemical microenvironment.

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“…Simultaneous imaging of chemotaxis of multiple HL60 cells using cell mobility analysis device Based on the principle of microfluidics 16 , the manufacturer has provided simulated profiles of gradients: a gradient is generated within 1 min, stabilized within 5 min, and maintained over 2 hr. The highly predictable profiles of the stable gradients generated by microfluidics allow multiple chemotaxis assays to be carried out simultaneously.…”

Section: Representative Resultsmentioning

confidence: 99%

Imaging G Protein-coupled Receptor-mediated Chemotaxis and its Signaling Events in Neutrophil-like HL60 Cells

Wen

Jin

2016

JoVE

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Eukaryotic cells sense and move towards a chemoattractant gradient, a cellular process referred as chemotaxis. Chemotaxis plays critical roles in many physiological processes, such as embryogenesis, neuron patterning, metastasis of cancer cells, recruitment of neutrophils to sites of inflammation, and the development of the model organism Dictyostelium discoideum. Eukaryotic cells sense chemo-attractants using G proteincoupled receptors. Visual chemotaxis assays are essential for a better understanding of how eukaryotic cells control chemoattractant-mediated directional cell migration. Here, we describe detailed methods for: 1) real-time, high-resolution monitoring of multiple chemotaxis assays, and 2) simultaneously visualizing the chemoattractant gradient and the spatiotemporal dynamics of signaling events in neutrophil-like HL60 cells.

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Generation of dynamic temporal and spatial concentration gradients using microfluidic devices

Cited by 196 publications

References 12 publications

Universal Microfluidic Gradient Generator

Universal Microfluidic Gradient Generator

Microfluidic system for measuring neutrophil migratory responses to fast switches of chemical gradients

Imaging G Protein-coupled Receptor-mediated Chemotaxis and its Signaling Events in Neutrophil-like HL60 Cells

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