A microvalve for lab-on-a-chip applications based on electrochemically actuated SU8 cantilevers

Ezkerra, A.; Fernández, Luís; Mayora, Kepa; Ruano-Lopez, Jesus M.

doi:10.1016/j.snb.2010.12.054

Cited by 21 publications

(13 citation statements)

References 35 publications

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“…The valve features a compact actuator, negligible footprint, and mass-production capabilities. These characteristics make the valve particularly suited for lab-on-a-chip applications [37].…”

Section: Electrochemical Actuationmentioning

confidence: 99%

“…Unlike electrostatic microvalves, electrochemical microvalves use electrodes to electrolyze solution, such as NaCl solution, to produce hydrogen bubbles [38]. Figure 3 shows two types of schematic diagrams of the electrochemical actuated microvalve: one is the microvalve based on electrochemically actuated SU8 cantilevers [37], the other is a microfluidic valve based on electrochemical (ECM) actuated membrane [39]. The gas is produced by electrolysis to make the membrane deflect in the electrochemical microvalve.…”

Section: Electrochemical Actuationmentioning

confidence: 99%

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Actuation Mechanism of Microvalves: A Review

Qian

Hou

2020

Micromachines

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The microvalve is one of the most important components in microfluidics. With decades of development, the microvalve has been widely used in many industries such as life science, chemical engineering, chip, and so forth. This paper presents a comprehensive review of the progress made over the past years about microvalves based on different actuation mechanisms. According to driving sources, plenty of actuation mechanisms are developed and adopted in microvalves, including electricity, magnetism, gas, material and creature, surface acoustic wave, and so on. Although there are currently a variety of microvalves, problems such as leakage, low precision, poor reliability, high energy consumption, and high cost still exist. Problems deserving to be further addressed are suggested, aimed at materials, fabrication methods, controlling performances, flow characteristics, and applications.

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Section: Electrochemical Actuationmentioning

confidence: 99%

Section: Electrochemical Actuationmentioning

confidence: 99%

Actuation Mechanism of Microvalves: A Review

Qian

Hou

2020

Micromachines

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“…Because chitosan is positively charged, has active functional groups, and has excellent biodegradability and biocompatibility, research on chitosan can be seen in disease treatment and drug release [ 43 , 44 , 45 , 46 ]. There are many other applications, such as external dressing [ 47 ], protein separation [ 48 ], biosensor [ 49 ], tissue engineering [ 50 ], and biochips [ 51 , 52 , 53 , 54 , 55 , 56 , 57 , 58 ].…”

Section: Introductionmentioning

confidence: 99%

Preparation and Characterization of pH Sensitive Chitosan/3-Glycidyloxypropyl Trimethoxysilane (GPTMS) Hydrogels by Sol-Gel Method

Weng

Huang

2020

Polymers

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pH responsive chitosan and 3-Glycidyloxypropyl trimethoxysilane (GPTMS) hydrogels were synthesized by the sol-gel crosslinking reaction. GPTMS was introduced to influence several behaviors of the chitosan hydrogels, such as the swelling ratio, mechanical properties, swelling thermodynamics, kinetics, and expansion mechanism. The functional groups of Chitosan/GPTMS hybrid hydrogels were verified by FT-IR spectrometer. Differential scanning calorimetry (DSC) and the thermogravimetric analysis (TGA) were used to analyzed the thermal behavior of water molecules, the expansion of thermodynamics, and the content of water molecules in the hydrogel. The results show that hydrogel consists of 50 wt.% GPTMS (CG50) and has good mechanical properties and sensitivity to pH response characteristics in the acidic/alkaline buffer solution. The increase of GPTMS content leads to the increase of hydrophobic groups in the hydrogel and causes the decrease of the overall water content and the freezing bond water content. When the hydrogels were immersed in acid solution, the interaction force parameter was smaller than that of DI-water and alkaline. It means that the interaction forces between hydrogel and water molecules are relatively strong. The swelling kinetics of hybrid hydrogels were investigated to inspect the swelling mechanism. The result is consistent with the Fisk’s diffusion mechanism, meaning that the rate of water penetration is adjustable. The biodegradable hydrogel (CG50) in this study has good environmental sensitivity and mechanical properties. It is suitable to be applied in the fields of drug release or biomedical technology.

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“…Microcantilevers are one of the most important components of micro-electromechanical systems (MEMS), superparamagnetic particle embedded microprobe (SPEM) sensors, or lab-on chips devices [5][6][7][8]. Microcantilevers are also an important component of atomic force microscopes (AFM).…”

Section: Introductionmentioning

confidence: 99%

Design of V-shaped cantilevers for enhanced multifrequency AFM measurements

Damircheli

Eslami

2020

Beilstein J. Nanotechnol.

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As the application of atomic force microscopy (AFM) in soft matter characterization has expanded, the use of different types of cantilevers for these studies have also increased. One of the most common types of cantilevers used in soft matter imaging is V-shaped cantilevers due to their low normal spring constant. These types of cantilevers are also suitable for nanomanipulation due to their high lateral spring constants. The combination of low normal spring constant and high lateral spring constants makes V-shaped cantilevers promising candidates for imaging soft matter. Although these cantilevers are widely used in the field, there are no studies on the static and dynamic behavior of V-shaped cantilevers in multifrequency AFM due to their complex geometry. In this work, the static and dynamic properties of V-shaped cantilevers are studied while investigating their performance in multifrequency AFM (specifically bimodal AFM). By modeling the cantilevers based on Timoshenko beam theory, the geometrical dimensions such as length, base width, leg width and thickness are studied. By finding the static properties (mass, spring constants) and dynamic properties (resonance frequencies and quality factors) for different geometrical dimensions, the optimum V-shaped cantilever that can provide the maximum phase contrast in bimodal AFM between gold (Au) and polystyrene (PS) is found. Based on this study, it is found that as the length of the cantilever increases the 2nd eigenmode phase contrast decreases. However, the base width exhibits the opposite relationship. It is also found that the leg width does not have a monotone relationship similar to length and base width. The phase contrast increases for the range of 14 to 32 µm but decreases afterwards. The thickness of a V-shaped cantilever does not play a major role in defining the dynamics of the cantilever compared to other parameters. This work shows that in order to maximize the phase contrast, the ratio of second to first eigenmode frequencies should be minimized and be close to a whole number. Additionally, since V-shaped cantilevers are mostly used for soft matter imaging, lower frequency ratios dictate lower spring constant ratios, which can be advantageous due to lower forces applied to the surface by the tip given a sufficiently high first eigenmode frequency. Finally, two commercially available V-shaped cantilevers are theoretically and experimentally benchmarked with an optimum rectangular cantilever. Two sets of bimodal AFM experiments are carried out on Au-PS and PS-LDPE (polystyrene and low-density polyethylene) samples to verify the simulation results.

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A microvalve for lab-on-a-chip applications based on electrochemically actuated SU8 cantilevers

Cited by 21 publications

References 35 publications

Actuation Mechanism of Microvalves: A Review

Actuation Mechanism of Microvalves: A Review

Preparation and Characterization of pH Sensitive Chitosan/3-Glycidyloxypropyl Trimethoxysilane (GPTMS) Hydrogels by Sol-Gel Method

Design of V-shaped cantilevers for enhanced multifrequency AFM measurements

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