Microfluidic chip with integrated microvalves based on temperature‐ and pH‐responsive hydrogel thin films

Bäcker, Matthias; Raue, M.; Schusser, Sebastian; Jeitner, C.; Breuer, Lars; Wagner, Patrick; Poghossian, Arshak; Förster, A.; Mang, Thomas S.; Schöning, Michael J.

doi:10.1002/pssa.201100763

Cited by 28 publications

(19 citation statements)

References 43 publications

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“…Either the PH structure is directly integrated into the microfluidic channel to achieve blocking and releasing functionality upon temperature change [122][123][124][125], or the PH actuator is separated from the fluid channel by an elastomer that squeezes the channel [126,127]. In [128], an analytical and numerical study of the inhomogeneous swelling behavior of the temperature-sensitive hydrogel PNIPAAm was presented and verified by experimental results, which is valuable for the design of hydrogel-based microvalves.…”

Section: Temperature-sensitive Phsmentioning

confidence: 99%

Stimulus-active polymer actuators for next-generation microfluidic devices

Hilber

2016

Appl. Phys. A

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Microfluidic devices have not yet evolved into commercial off-the-shelf products. Although highly integrated microfluidic structures, also known as lab-on-a-chip (LOC) and micrototal-analysis-system (lTAS) devices, have consistently been predicted to revolutionize biomedical assays and chemical synthesis, they have not entered the market as expected. Studies have identified a lack of standardization and integration as the main obstacles to commercial breakthrough. Soft microfluidics, the utilization of a broad spectrum of soft materials (i.e., polymers) for realization of microfluidic components, will make a significant contribution to the proclaimed growth of the LOC market. Recent advances in polymer science developing novel stimulus-active soft-matter materials may further increase the popularity and spreading of soft microfluidics. Stimulus-active polymers and composite materials change shape or exert mechanical force on surrounding fluids in response to electric, magnetic, light, thermal, or water/solvent stimuli. Specifically devised actuators based on these materials may have the potential to facilitate integration significantly and hence increase the operational advantage for the end-user while retaining costeffectiveness and ease of fabrication. This review gives an overview of available actuation concepts that are based on functional polymers and points out promising concepts and trends that may have the potential to promote the commercial success of microfluidics.

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Section: Temperature-sensitive Phsmentioning

confidence: 99%

Stimulus-active polymer actuators for next-generation microfluidic devices

Hilber

2016

Appl. Phys. A

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“…However, hydrogel-based actuation technology is still at the early stage of development. The first microfluidic actuators realized with these materials were reported at the turn of the century 17 ; since then, numerous devices have been fabricated: pumps (coupled to membranes) [18][19][20][21][22][23] , reconfigurable systems 24 , drug delivery devices 25 , self-regulating systems 26 , gel-based electroactive 27 or photoactive valves 28 , and MEMS-coupled active mixers 29 . Despite multiple laboratory projects and twenty years of research, several bottlenecks restrict the technology from developing: mediocre spatial resolution, limited miniaturization capabilities, long time responses (usually more than 10 s), complexity in the fabrication process and poor control of the physicochemistry 30,31 .…”

Section: Introductionmentioning

confidence: 99%

Microfluidic actuators based on temperature-responsive hydrogels

D'Eramo

Chollet

Leman³

et al. 2018

Microsyst Nanoeng

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The concept of using stimuli-responsive hydrogels to actuate fluids in microfluidic devices is particularly attractive, but limitations, in terms of spatial resolution, speed, reliability and integration, have hindered its development during the past two decades. By patterning and grafting poly(N-isopropylacrylamide) PNIPAM hydrogel films on plane substrates with a 2 μm horizontal resolution and closing the system afterward, we have succeeded in unblocking bottlenecks that thermo-sensitive hydrogel technology has been challenged with until now. In this paper, we demonstrate, for the first time with this technology, devices with up to 7800 actuated micro-cages that sequester and release solutes, along with valves actuated individually with closing and opening switching times of 0.6 ± 0.1 and 0.25 ± 0.15 s, respectively. Two applications of this technology are illustrated in the domain of single cell handling and the nuclear acid amplification test (NAAT) for the Human Synaptojanin 1 gene, which is suspected to be involved in several neurodegenerative diseases such as Parkinson's disease. The performance of the temperature-responsive hydrogels we demonstrate here suggests that in association with their moderate costs, hydrogels may represent an alternative to the actuation or handling techniques currently used in microfluidics, that are, pressure actuated polydimethylsiloxane (PDMS) valves and droplets.

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“…An outstanding class of polymeric compounds for electrode modifications is the class of stimuli‐responsive polymers . These organic macromolecular compounds undergo (mostly reversible) phase transitions in response to an external stimulus which can be of physical (temperature, irradiation) , chemical (pH, ionic strength) , or biological nature.…”

Section: Introductionmentioning

confidence: 99%

Electrochemical characterization of a responsive macromolecular interface on gold

Fandrich

Buller

Schäfer

et al. 2015

Physica Status Solidi (a)

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This study reports on the investigation of a thermoresponsive polymer as a thinfilm on electrodes and the influence of coupling a peptide and an antibody to thefilm. The utilized polymer from the class of poly(oligoethylene glycol)-methacrylate polymers (poly(OEGMA)) with carboxy functions containing side chains was synthesized and properly characterized in aqueous solutions. The dependence of the cloud point on the pH of the surrounding media is discussed. The responsive polymer was immobilized on gold electrodes as shown by electrochemical, quartz crystal microbalance (QCM), and atomic force microscopy (AFM) techniques. The temperature dependent behavior of the polymer covalently grafted to gold substrates is investigated using cyclic voltammetry (CV) in ferro-/ferricyanide solution. Significant changes in the slope of the temperature-dependence of the voltammetric peak current and the peak separation values clearly indicate the thermally induced conformational change on the surface. Finally, a biorecognition reaction between a short FLAG peptide (N-Asp-Tyr-Lys-Asp-Asp-Asp-Asp-LysC) covalently immobilized on the polymer interface and the corresponding IgG antibody was performed. The study shows that the responsiveness of the electrode is retained after peptide coupling and antibody binding, although the response is diminished

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Microfluidic chip with integrated microvalves based on temperature‐ and pH‐responsive hydrogel thin films

Cited by 28 publications

References 43 publications

Stimulus-active polymer actuators for next-generation microfluidic devices

Stimulus-active polymer actuators for next-generation microfluidic devices

Microfluidic actuators based on temperature-responsive hydrogels

Electrochemical characterization of a responsive macromolecular interface on gold

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