Paper Microfluidics in Bioanalysis

Gomez, Frank A.

doi:10.4155/bio.14.240

Cited by 23 publications

(13 citation statements)

References 21 publications

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“…One of the highest undercooling achieved so far is 0.7 T m for 3–15 nm gallium particles 10 . The literature on metal undercooling, however, is heavily skewed towards studies on understanding the solidification behavior and thermodynamics of metal systems 12 13 14 15 16 17 18 19 20 21 22 23 and, to the best of our knowledge, there is limited discussion on practical applications except for heat transfer 24 and production of metastable solids 11 . A major barrier limiting application could be challenges in preparing stable undercooled particles in high yields and across size scales, especially where large undercooling values are desired 1 2 5 6 .…”

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confidence: 99%

Mechanical Fracturing of Core-Shell Undercooled Metal Particles for Heat-Free Soldering

Çınar

Tevis

Chen

et al. 2016

Sci Rep

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Phase-change materials, such as meta-stable undercooled (supercooled) liquids, have been widely recognized as a suitable route for complex fabrication and engineering. Despite comprehensive studies on the undercooling phenomenon, little progress has been made in the use of undercooled metals, primarily due to low yields and poor stability. This paper reports the use of an extension of droplet emulsion technique (SLICE) to produce undercooled core-shell particles of structure; metal/oxide shell-acetate (‘/’ = physisorbed, ‘-’ = chemisorbed), from molten Field’s metal (Bi-In-Sn) and Bi-Sn alloys. These particles exhibit stability against solidification at ambient conditions. Besides synthesis, we report the use of these undercooled metal, liquid core-shell, particles for heat free joining and manufacturing at ambient conditions. Our approach incorporates gentle etching and/or fracturing of outer oxide-acetate layers through mechanical stressing or shearing, thus initiating a cascade entailing fluid flow with concomitant deformation, combination/alloying, shaping, and solidification. This simple and low cost technique for soldering and fabrication enables formation of complex shapes and joining at the meso- and micro-scale at ambient conditions without heat or electricity.

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confidence: 99%

Mechanical Fracturing of Core-Shell Undercooled Metal Particles for Heat-Free Soldering

Çınar

Tevis

Chen

et al. 2016

Sci Rep

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“…A current global challenge is the increasing cost of healthcare, putting populations at risk due to hospital care limitations. Microfluidic technologies have been successfully incorporated in point‐of‐care (POC) testing thereby reducing hospital visits and costs by bringing treatment directly to primary care clinics . POC diagnostic devices incorporating microfluidic platforms require only microliter volumes of fluid from a patient thereby increasing the gamut of tests available to a clinician.…”

Section: Introductionmentioning

confidence: 99%

3D Multilayered paper‐ and thread/paper‐based microfluidic devices for bioassays

et al. 2018

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In this paper we describe the fabrication of novel 3D microfluidic paper‐based analytical devices (3D‐μPADs) and a 3D microfluidic thread/paper‐based analytical device (3D‐μTPAD) to detect glucose and BSA through colorimetric assays. The 3D‐μPAD and 3D‐μTPAD consisted of three (wax, heat pressed wax‐printed paper, single‐sided tape) and four (hole‐punched single‐sided tape, blank chromatography circles, heat‐pressed wax‐printed paper, hole‐punched single‐sided tape containing trifurcated thread) layers, respectively. The saturation curves for each assay were generated for all platforms. For the glucose assay, a solution of glucose oxidase (GOx), horseradish peroxidase, and potassium iodide was flowed through each platform and, upon contact with glucose, generated a yellow‐brown color indicative of the oxidation of iodide to iodine. For the protein assay, BSA was flowed through each device and, upon contact with citrate buffer and tetrabromophenol blue, resulted in a color change from yellow to blue. The devices were dried, scanned, and analyzed yielding a correlation between either yellow intensity and glucose concentration or cyan intensity and BSA concentration. A similar glucose assay, using unknown concentrations of glucose in artificial urine, was conducted and, when compared to the saturation curve, showed good correlation between the theoretical and actual concentrations (percent differences <10%). The development of 3D‐μPADs and 3D‐μTPADs can further facilitate the use of these platforms for colorimetric bioassays.

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“…Microfluidics‐based technologies continue to gain traction as alternatives to traditional techniques and have great potential in resource‐limited settings where access to more expensive instrumentation is not always possible . These techniques offer a number of advantages, including small sample volume requirements, ease of fabrication, low‐cost, and compatibility with biological systems.…”

Section: Introductionmentioning

confidence: 99%

Thread‐based microfluidic chips as a platform to assess acetylcholinesterase activity

2017

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In this paper, a microfluidic thread-based analytical device (μTAD) to assess the activity of acetylcholinesterase (AChE) via colorimetric analylsis is described. Fabrication of the device consists of two platforms, both with a nylon thread trifurcated into three channels terminating at open analysis sites at the end of the thread. 5,5'-Dithiobis-(2-nitrobenzoic acid) (DTNB) was spotted and dried on the analysis sites. Acetylthiocholine iodide (ATC) (or cysteine, Cys) is transported through an inlet channel of the nylon thread by capillary action due to the hydrophilic nature of nylon. AChE is transported through the other inlet channel and mixes with the ATC (or Cys) as they travel up to the analysis sites. As the solution reaches the analysis sites, an intense yellow color change occurs indicating the reaction of the thiol with DTNB to produce the yellow anion TNB . The sites are then dried, scanned, yielding a linear range of inverse yellow mean intensity versus substrate concentration. An IC value (1.74 nM) with a known inhibitor, neostigmine bromide (NB), is obtained on the device. The multiplex design enables triplicate data collection in a device that is easy to use. μTADs have great potential to be employed in a myriad of tests including point-of-care diagnostic devices for resource-challenged settings.

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Paper Microfluidics in Bioanalysis

Cited by 23 publications

References 21 publications

Mechanical Fracturing of Core-Shell Undercooled Metal Particles for Heat-Free Soldering

Mechanical Fracturing of Core-Shell Undercooled Metal Particles for Heat-Free Soldering

3D Multilayered paper‐ and thread/paper‐based microfluidic devices for bioassays

Thread‐based microfluidic chips as a platform to assess acetylcholinesterase activity

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