An electrically-controlled programmable microfluidic concentration waveform generator

Garrison, Joshua; Li, Zidong; Palanisamy, Barath; Wang, Ling; Şeker, Erkin

doi:10.1186/s13036-018-0126-3

Cited by 8 publications

(2 citation statements)

References 34 publications

(36 reference statements)

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“…These techniques are called ‘function generator’ or ‘digital-to-analogue converter’ of chemical concentrations named after its circuit analogy in electrical engineering. Some existing microfluidic digital-to-analogue converters (DACs) used gravity pumps [ 7 , 13 , 23 ], and pressure regulators [ 3 ] that modulate the flow rates or inlet pressures of multiple solutions to be mixed. Others adopted on-chip membrane valves [ 24 ] that can control the flow lines based on a series of well-defined valve operations to achieve higher precision of dynamic concentration control [ 25 , 26 ].…”

Section: Introductionmentioning

confidence: 99%

L-2L ladder digital-to-analogue converter for dynamics generation of chemical concentrations

et al. 2023

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Cellular response to dynamic chemical stimulation encodes rich information about the underlying reaction pathways and their kinetics. Microfluidic chemical stimulators play a key role in generating dynamic concentration waveforms by mixing several aqueous solutions. In this article, we propose a multi-layer microfluidic chemical stimulator capable of modulating chemical concentrations by a simple binary logic based on the electronic-hydraulic analogy of electronic R-2R ladder circuits. The proposed device, which we call L-2L ladder digital-to-analogue converter (DAC), allows us to systematically modulate 2 n levels of concentrations from single sources of solution and solvent by a single operation of 2 n membrane valves, which contrasts with existing devices that require complex channel geometry with multiple input sources and valve operations. We fabricated the L-2L ladder DAC with n = 3 bit resolution and verified the concept by comparing the generated waveforms with computational simulations. The response time of the proposed DAC was within the order of seconds because of its simple operation logic of membrane valves. Furthermore, detailed analysis of the waveforms revealed that the transient concentration can be systematically predicted by a simple addition of the transient waveforms of 2 n = 6 base patterns, enabling facile optimization of the channel geometry to fine-tune the output waveforms.

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Section: Introductionmentioning

confidence: 99%

L-2L ladder digital-to-analogue converter for dynamics generation of chemical concentrations

et al. 2023

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“…However, if the input can be modulated spatially—e.g., in the case of a cylindrical channels: radially (polar coordinates)—it attributes yet another degree of freedom to the versatility of the design. To achieve diverse modulated inputs, microfluidic techniques offer a vast toolbox for input generation, including, e.g., programmable sequences of composition and complex input waveforms, which enable co‐dispersing different particles—even different carrier fluids—in a composition‐ time‐, and position‐shared manner. Furthermore, the velocity of a laminar flow in a tapered channel would systematically increase/decrease (narrowing/widening channel radius), even if the driving pressure remains constant.…”

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confidence: 99%

Versatile Macroscale Concentration Gradients of Nanoparticles in Soft Nanocomposites

Taladriz‐Blanco

Rothen‐Rutishauser

Petri‐Fink

et al. 2020

Small

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exponential concentration gradients were generated when sedimentation and diffusion were in equilibrium at lower centrifugal forces. [13] This is a big step in the design of soft nanocomposites for it enables that such monotonic gradient profiles can be modeled quantitatively and designed precisely before processing-owing to the availability of a mathematical framework that is able to model faithfully the related phenomena. Following this concept, i.e., that 1) the creation and fixation of macroscale gradient profiles may be decoupled and 2) may be designed and tailored accurately by mathematical means, we present an approach dedicated to creating continuous and smooth long-range longitudinal concentration gradients of NPs in macroscopic 1D soft materials, such as fibers. The available design-space is rich, and includes either symmetric or asymmetric, monotonic or nonmonotonic, linear, or nonlinear profiles, with the possibility of, e.g., periodicity, having multiple local minima and maxima with either complementary or orthogonal functionalities.The physical phenomenon our approach is based on is called Taylor dispersion, which can be accurately described by the asymptotic solution of the convective-diffusion equation [14][15][16] corresponding to the geometry of the flow channels. [17] Taylor dispersion refers to the enhanced dispersion of particles in a steady Poiseuille flow, where the linear shear stress creates a quadratic flow-velocity profile, and induces a spontaneous net transport of particles via translational self-diffusion. The rate and overall extent of spread is a function of the unidirectional velocity profile and translational self-diffusion coefficient of the particles. Taylor dispersion is characteristic to laminar flows and scalable on a wide range of dimensions. In the case of NPs, the phenomenon can be easily realized in a microcapillary laminar flow, which also provides an outstanding experimental technique to characterize the hydrodynamic radius of organic and inorganic NPs. [18][19][20][21][22][23][24][25][26] Although from the theoretical point of view, its dimensionality is scalable, Taylor dispersion is essentially a microfluidic technique, and microfluidics offer an excellent platform to create a gradient, e.g., via electrospinning. [27] Indeed, Taylor dispersion was connected to the creation of simple concentration gradients more than ten years ago, [28][29][30] yet it was shown only recently that Taylor dispersion is de facto a casual linear timeinvariant system. [31] We show here that this mathematical property has important implications for the applicability of Taylor dispersion when creating macroscale gradient profiles of NPs, because the gradient profile of NPs can be designed accurately www.advancedsciencenews.com

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A continuous flow cell culture system for precision cell stimulation and time-resolved profiling of cell secretion

Erickson

Houwayek

Burr

et al. 2021

Analytical Biochemistry

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An electrically-controlled programmable microfluidic concentration waveform generator

Cited by 8 publications

References 34 publications

L-2L ladder digital-to-analogue converter for dynamics generation of chemical concentrations

L-2L ladder digital-to-analogue converter for dynamics generation of chemical concentrations

Versatile Macroscale Concentration Gradients of Nanoparticles in Soft Nanocomposites

A continuous flow cell culture system for precision cell stimulation and time-resolved profiling of cell secretion

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