scholarly journals Recreating mineralogical petrographic heterogeneity within microfluidic chips: assembly, examples, and applications

Lab on a Chip ◽  
2016 ◽  
Vol 16 (24) ◽  
pp. 4677-4681 ◽  
Author(s):  
Stephen A. Bowden ◽  
Yukie Tanino ◽  
Blessing Akamairo ◽  
Magali Christensen

We developed a technique for rapid, low-cost assembly of single-use, mineralogically heterogeneous microfluidic rock analogues.

2012 ◽  
Vol 548 ◽  
pp. 254-257 ◽  
Author(s):  
Yan He ◽  
Bai Ling Huang ◽  
Yong Lai Zhang ◽  
Li Gang Niu

In this paper, a simple and facile technique for manufacturing glass-based microfluidic chips was developed. Instead of using expensive dry etching technology, the standard UV lithography and wet chemical etching technique was used to fabricate microchannels on a K9 glass substrate. The fabrication process of microfluidic chip including vacuum evaporation, annealing, lithography, and BHF (HF-NH4F-H2O) wet etching were investigated. Through series experiments, we found that anneal was the critical factor for chip quality. As a representative example, a microfluidic channel with 20 m of depth, and 80 m of width was successfully prepared, and the channel surfaces are quite smooth. These results present a simple, low cost, flexible and easy way to fabricate glass-based microfluidic chips.


Author(s):  
Athira N. Surendran ◽  
Ran Zhou

Abstract Microfluidics has a lot of applications in fields ranging from pharmaceutical to energy, and one of the major applications is micromixers. A challenge faced by most micromixers is the difficulty in mixing within micro-size fluidic channels because of the domination of laminar flow in a small channel. Hence, magnetic field generated by permanent magnets and electromagnets have been widely used to mix ferrofluids with other sample fluids on a micro level. However, permanent magnets are bulky, and electromagnets produce harmful heat to biological samples; both properties are detrimental to a microfluidic chip’s performance. Taking these into consideration, this study proposes rapid mixing of ferrofluid using a two-layer microfluidic device with microfabricated magnet. Two microfluidic chips that consist of microchannels and micromagnets respectively are fabricated using a simple and low-cost soft lithography method. The custom-designed microscale magnet consists of an array of stripes and is bonded below the plane of the microchannel. The combination of the planar location and angle of the array of magnets allow the migration of ferrofluids, hence mixing it with buffer flow. Parametric studies are performed to ensure comprehensive understanding, including the angle of micro-scale magnets with respect to the fluidic channels, total flow rate and density of the array of magnets. The result from this study can be applied in chemical synthesis and pre-processing, sample dilution, or inducing reactions between samples and reagent.


Author(s):  
Byron L. Newberry

Resistive strain gauges are the most commonly used experimental devices for stress analysis. Their versatility stems from their ability to directly measure local strain on the surface of a structure, almost regardless of geometry. This strength can represent an educational limitation, however. Measurements made using strain gauges tend to provide results without students assessing or understanding the global structural response; limiting the insight gained and the instructional value of the experiment. Herein a low-cost device is presented that allows accurate measurement of local curvature in a beam. Once the local curvature is known, the elastic equations governing the beam may be used to calculate the local strain, stress, and deflection. The educational strength of the device is that students are forced to understand the interrelation of stress, strain, and deflection to post-process the experimental results. The device, though limited to beam geometries, has proven effective in helping students master engineering mechanics. It also allows investigation of the entire beam without added expense; as the device is not permanently affixed to one location. This is a significant advantage compared to strain gauges that provide only point data and are single-use. Details of the device itself, how it has been incorporated into the curriculum, and data assessing its effectiveness within a junior-level course are presented.


2007 ◽  
Vol 339 ◽  
pp. 246-251
Author(s):  
L.Q. Du ◽  
C. Liu ◽  
H.J. Liu ◽  
J. Qin ◽  
N. Li ◽  
...  

Micro hot embossing mold of microfluidic chip used in flow cytometry is designed and microfabricated. After some kinds of microfabrication processes are tried, this paper presents a novel microfabrication technology of micro hot embossing metal mold. Micro metal mold is fabricated by low-cost UV-LIGA surface micro fabrication process using negative thick photoresist, SU-8. Different from other micro hot embossing molds, the micro mold with vertical sidewalls is fabricated by micro nickel electroforming directly on Nickel base. Based on the micro Nickel mold and automation fabrication system, high precision and mass-producing microfluidic chips have been fabricated and they have been used in flow cytometry


Author(s):  
Benjamin R. Hubbard ◽  
Joshua M. Pearce

To assist firefighters and other first responders to use their existing equipment for respiration during the COVID-19 pandemic without using single-use, low-supply, masks, this study outlines an open source kit to convert a 3M-manufactured Scott Safety self-contained breathing apparatus (SCBA) into a powered air-purifying particulate respirator (PAPR). The open source PAPR can be fabricated with a low-cost 3-D printer and widely available components for less than $150, replacing commercial conversion kits saving 85% or full-fledged proprietary PAPRs saving over 90%. The parametric designs allow for adaptation to other core components and can be custom fit specifically to fire-fighter equipment, including their suspenders. The open source PAPR has controllable air flow and its design enables breathing even if the fan is disconnected or if the battery dies. The open source PAPR was tested for air flow as a function of battery life and was found to meet NIOSH air flow requirements for 4 hours, which is 300% over expected regular use.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Yushen Zhang ◽  
Tsun-Ming Tseng ◽  
Ulf Schlichtmann

AbstractState-of-the-art microfluidic systems rely on relatively expensive and bulky off-chip infrastructures. The core of a system—the microfluidic chip—requires a clean room and dedicated skills to be fabricated. Thus, state-of-the-art microfluidic systems are barely accessible, especially for the do-it-yourself (DIY) community or enthusiasts. Recent emerging technology—3D-printing—has shown promise to fabricate microfluidic chips more simply, but the resulting chip is mainly hardened and single-layered and can hardly replace the state-of-the-art Polydimethylsiloxane (PDMS) chip. There exists no convenient fluidic control mechanism yet suitable for the hardened single-layered chip, and particularly, the hardened single-layered chip cannot replicate the pneumatic valve—an essential actuator for automatically controlled microfluidics. Instead, 3D-printable non-pneumatic or manually actuated valve designs are reported, but their application is limited. Here, we present a low-cost accessible all-in-one portable microfluidic system, which uses an easy-to-print single-layered 3D-printed microfluidic chip along with a novel active control mechanism for fluids to enable more applications. This active control mechanism is based on air or gas interception and can, e.g., block, direct, and transport fluid. As a demonstration, we show the system can automatically control the fluid in microfluidic chips, which we designed and printed with a consumer-grade 3D-printer. The system is comparably compact and can automatically perform user-programmed experiments. All operations can be done directly on the system with no additional host device required. This work could support the spread of low budget accessible microfluidic systems as portable, usable on-the-go devices and increase the application field of 3D-printed microfluidic devices.


Micromachines ◽  
2019 ◽  
Vol 10 (9) ◽  
pp. 576 ◽  
Author(s):  
Edgar Jiménez-Díaz ◽  
Mariel Cano-Jorge ◽  
Diego Zamarrón-Hernández ◽  
Lucia Cabriales ◽  
Francisco Páez-Larios ◽  
...  

Microfluidics has become a very promising technology in recent years, due to its great potential to revolutionize life-science solutions. Generic microfabrication processes have been progressively made available to academic laboratories thanks to cost-effective soft-lithography techniques and enabled important progress in applications like lab-on-chip platforms using rapid- prototyping. However, micron-sized features are required in most designs, especially in biomimetic cell culture platforms, imposing elevated costs of production associated with lithography and limiting the use of such devices. In most cases, however, only a small portion of the structures require high-resolution and cost may be decreased. In this work, we present a replica-molding method separating the fabrication steps of low (macro) and high (micro) resolutions and then merging the two scales in a single chip. The method consists of fabricating the largest possible area in inexpensive macromolds using simple techniques such as plastics micromilling, laser microfabrication, or even by shrinking printed polystyrene sheets. The microfeatures were made on a separated mold or onto existing macromolds using photolithography or 2-photon lithography. By limiting the expensive area to the essential, the time and cost of fabrication can be reduced. Polydimethylsiloxane (PDMS) microfluidic chips were successfully fabricated from the constructed molds and tested to validate our micro–macro method.


Lab on a Chip ◽  
2019 ◽  
Vol 19 (17) ◽  
pp. 2915-2924 ◽  
Author(s):  
Han Sun ◽  
Chiu-Wing Chan ◽  
Yisu Wang ◽  
Xiao Yao ◽  
Xuan Mu ◽  
...  

Using an antimicrobial susceptibility test (AST) as an example, this work demonstrates a practical method to fabricate microfluidic chips entirely from polypropylene (PP) and the benefits for potential commercial use.


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