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Hua Gong, Adam T Woolley, Gregory P Nordin
In this paper, we demonstrate the ability to 3D print tightly integrated structures with active valves, pumps, and mixers, and we use our compact chip-to-chip interconnects [Gong et al. , Lab Chip 18 , 639-647 (2018)] to move bulky world-to-chip connections to separate interface chips for both post-print flushing and post-cure device operation. As example devices, we first examine 3D printed pumps, followed by two types of selectable ratio mixer pumps, a linear dilution mixer pump (LDMP) and a parallelized dilution mixer pump (PDMP), which occupy volumes of only <mml:math xmlns:mml="http://www...
January 2019: Biomicrofluidics
Tamer AbdelFatah, Mahsa Jalali, Sara Mahshid
We present a nanofilter based on pillar-assisted self-assembly microparticles for efficient capture of bacteria. Under an optimized condition, we simply fill the arrays of microscale pillars with submicron scale polystyrene particles to create a filter with nanoscale pore diameter in the range of 308 nm. The design parameters such as the pillar diameter and the inter-pillar spacing in the range of 5  μ m-40  μ m are optimized using a multi-physics finite element analysis and computational study based on bi-directionally coupled laminar flow and particle tracking solvers...
November 2018: Biomicrofluidics
Muhammad Omar Shaikh, Lung-Yu Chang, Cheng-Ho Chen, Ting-Feng Wu, Cheng-Hsin Chuang
In this study, we have developed a novel paper based immunoassay for the quantitative detection of immunoreactions using electrochemical impedance spectroscopy. Paper provides an attractive platform for fabrication of simple, low cost, and portable diagnostic devices as it allows passive liquid transport, is biocompatible, and has tunable properties such as hydrophilicity, flexibility, permeability, and reactivity. We have used screen-printing to fabricate interdigitated electrodes (finger width and gap of 200  μ m) on the paper substrate, while UV-lithography enables patterning of the paper into hydrophobic/hydrophilic regions...
November 2018: Biomicrofluidics
L M Lambert, I I Pipinos, B T Baxter, Y S Chatzizisis, S J Ryu, R I Leighton, T Wei
This paper presents micro-particle tracking velocimetry measurements over cultured bovine aortic endothelial cell monolayers in microchannels. The objective was to quantify fluid forces and cell morphology at the sub-cellular scale for monolayers subjected to steady shear rates of 5, 10, and 20 dyn/cm2 . The ultimate goal of this study was to develop an experimental methodology for in vitro detailed study of physiologically realistic healthy and diseased conditions. Cell topography, shear stress, and pressure distributions were calculated from sets of velocity fields made in planes parallel to the microchannel wall...
November 2018: Biomicrofluidics
Behrouz Behdani, Saman Monjezi, Mason J Carey, Curtis G Weldon, Jie Zhang, Cheng Wang, Joontaek Park
The production of particles with shape-specific properties is reliant upon the separation of micro-/nanoparticles of particular shapes from particle mixtures of similar volumes. However, compared to a large number of size-based particle separation methods, shape-based separation methods have not been adequately explored. We review various up-to-date approaches to shape-based separation of rigid micro-/nanoparticles in liquid phases including size exclusion chromatography, field flow fractionation, deterministic lateral displacement, inertial focusing, electrophoresis, magnetophoresis, self-assembly precipitation, and centrifugation...
September 2018: Biomicrofluidics
Grant M Landwehr, Andrew J Kristof, Sharif M Rahman, Jacob H Pettigrew, Rachael Coates, Joseph B Balhoff, Ursula L Triantafillu, Yonghyun Kim, Adam T Melvin
Even though the majority of breast cancers respond well to primary therapy, a large percentage of patients relapse with metastatic disease, for which there is no treatment. In metastasis, a tumor sheds a small number of cancerous cells, termed circulating tumor cells (CTCs), into the local vasculature, from where they spread throughout the body to form new tumors. As CTCs move through the circulatory system, they experience physiological forces not present in the initial tumor environment, namely, fluid shear stress (FSS)...
September 2018: Biomicrofluidics
Hossein Heidari, Hayden Taylor
With the accelerating pace of brain research in recent years and the growing appreciation of the complexity of the brain and several brain-associated neurological diseases, the demand for powerful tools to enhance drug screening, diagnosis, and fundamental research is greater than ever. Highly representative models of the central nervous system (CNS) can play a critical role in meeting these needs. Unfortunately, in vivo animal models lack controllability, are difficult to monitor, and do not model human-specific brain behavior accurately...
September 2018: Biomicrofluidics
Lien-Yu Hung, Chien-Yu Fu, Chih-Hung Wang, Yuan-Jhe Chuang, Yi-Cheng Tsai, Yi-Ling Lo, Pang-Hung Hsu, Hwan-You Chang, Shu-Chu Shiesh, Keng-Fu Hsu, Gwo-Bin Lee
Cancer is the most serious disease worldwide, and ovarian cancer (OvCa) is the second most common type of gynecological cancer. There is consequently an urgent need for early-stage detection of OvCa, which requires affinity reagent biomarkers for OvCa. Systematic evolution of ligands by exponential enrichment (SELEX) and phage display technology are two powerful technologies for identifying affinity reagent biomarkers. However, the benchtop protocols for both screening technologies are relatively lengthy and require well-trained personnel...
September 2018: Biomicrofluidics
Daniel J Berard, Sabrina R Leslie
Convex Lens-induced Confinement (CLiC) is a single-molecule imaging technique that uses a deformable glass flow cell to gently trap, manipulate, and visualize single molecules within micro- and nano-structures, to enable a wide range of applications. Here, we miniaturize the CLiC flow cell, from <mml:math xmlns:mml=""> <mml:mn>25</mml:mn> <mml:mo>×</mml:mo> <mml:mn>25</mml:mn> </mml:math> to <mml:math xmlns:mml="http://www...
September 2018: Biomicrofluidics
Christopher Rahimi, Benjamin Rahimi, Dominic Padova, Seyed A Rooholghodos, Diane R Bienek, Xiaolong Luo, Gili Kaufman, Christopher B Raub
The human oral mucosa hosts a diverse microbiome and is exposed to potentially toxic biomaterials from dental restoratives. Mucosal health is partly determined by cell and tissue responses to challenges such as dental materials and pathogenic bacteria. An in vitro model to rapidly determine potential layer-specific responses would lead to a better understanding of mucosal homeostasis and pathology. Therefore, this study aimed to develop a co-cultured microfluidic mucosal model on-a-chip to rapidly assess mucosal remodeling and the responses of epithelial and subepithelial layers to challenges typically found in the oral environment...
September 2018: Biomicrofluidics
H Lee, Y H Roh, H U Kim, K W Bong
Flow lithography (FL) is a microfluidic technique distinguished for its ability to produce hydrogel microparticles of various geometrical and chemical designs. While FL is typically performed in room temperature, this paper reports a new technique called low temperature flow lithography that uses low synthesis temperature to increase the degree of polymerization of microparticles without compromising other aspects of flow lithography. We suggest that decreased oxygen diffusivity in low temperature is responsible for the increase in polymerization...
September 2018: Biomicrofluidics
Do-Hyun Lee, Xuan Li, Alan Jiang, Abraham P Lee
Reliable separation and isolation of target single cells from bodily fluids with high purity is of great significance for an accurate and quantitative understanding of the cellular heterogeneity. Here, we describe a fully integrated single-blood-cell analysis platform capable of size-selective cell separation from a population containing a wide distribution of sizes such as diluted blood sample and highly efficient entrapment of single monocytes. The spiked single U937 cells (human monocyte cell line) are separated in sequence by two different-sized microfilters for removing large cell clumps, white blood cells, and red blood cells and then discriminated by dielectrophoretic force and isolated individually by downstream single-cell trapping arrays...
September 2018: Biomicrofluidics
Francisco Pimenta, Renato G Sousa, Manuel A Alves
We present a methodology for the shape optimization of flow-focusing devices with the purpose of creating a wide region of homogeneous extensional flow, characterized by a uniform strain-rate along the centerline of the devices. The numerical routines employed include an optimizer, a finite-volume solver, and a mesh generator operating on geometries with the walls parameterized by Bézier curves. The optimizations are carried out for devices with different geometric characteristics (channel aspect ratio and length)...
September 2018: Biomicrofluidics
Xiao Xiao, Yuan Zhou, Yuqiong Sun, Qing Wang, Jianbo Liu, Jin Huang, Xiaobei Zhu, Xiaohai Yang, Kemin Wang
Recombinant proteins have shown several benefits compared with their non-recombinant counterparts in protein therapeutics. However, there are still some problems with the storage and distribution of recombinant proteins, owing to their temperature sensitivity. Microfluidic chips can integrate different functional modules into a single device because of the advantages of integration and miniaturization, which have the special potential to synthesize drugs when and where they are needed most. Here, we integrated cell-free protein synthesis and purification into a microfluidic chip for the production of recombinant protein...
September 2018: Biomicrofluidics
Ho-Chin Wu, Yen-Hao Chen, Chih-Hsin Shih
A cost-effective way to carry out multiple enzyme-linked immunosorbent assays (ELISAs) on a centrifugal platform using the liquid-aliquoting and siphoning-evacuation (LASE) technique was developed in this paper. Instead of preloading all the reagents in the reservoirs before testing, each reagent was loaded only one time during testing. The reagent was distributed into equal aliquots and delivered into reaction chambers by the aliquoting fluidic function. In addition, a siphoning-evacuation technique was developed to improve the washing efficiency and simplify the assay protocol...
September 2018: Biomicrofluidics
Dong Jun Lee, John Mai, Tony Jun Huang
The search for next-generation biomarkers has enabled cell-based diagnostics in a number of disciplines ranging from oncology to pharmacogenetics. However, cell-based diagnostics are still far from clinical reality due to the complex assays and associated protocols which typically require cell isolation, lysis, DNA extraction, amplification, and detection steps. Leveraging recent advances in microfluidics, many biochemical assays have been translated onto microfluidic platforms. We have compared and summarized recent advances in modular approaches toward the realization of fully-integrated, cell-based molecular diagnostics for clinical and point-of-care applications...
September 2018: Biomicrofluidics
Q L Pham, N A N Tong, A Mathew, S Basuray, R S Voronov
A custom-built mask aligner (CBMA), which fundamentally covers all the key features of a commercial mask aligner, while being low cost and light weight and having low power consumption and high accuracy, is constructed. The CBMA is composed of a custom high fidelity light emitting diode light source, a vacuum chuck, a mask holder, high-precision translation and rotation stages, and high resolution digital microscopes. The total cost of the system is under $7500, which is over ten times cheaper than a comparable commercial system...
July 2018: Biomicrofluidics
Maciej Urbaniak, Dennis Holzinger, Arno Ehresmann, Feliks Stobiecki
Colloidal magnetophoretic lensing of water suspended micrometer-sized superparamagnetic beads (SPBs) above a topographically patterned magnetic thin film system with perpendicular magnetic anisotropy is demonstrated. The magnetic pattern consisting of concentric annuli of micron-sized widths has been superimposed with a rotating external magnetic field, and it is shown that the trajectories of the SPBs above this structure are similar to light rays in an optical focusing lens. SPB trajectories converge towards the central region and have divergent trajectories while passing the center...
July 2018: Biomicrofluidics
Ishita Biswas, Mohtada Sadrzadeh, Aloke Kumar
We investigate the effect of biofouling in a microfluidic filtration system. The microfluidic platform consists of cylindrical microposts with a pore-spacing of 2  μ m, which act as the filtration section of the device. One of our key findings is that there exists a critical pressure difference above which pronounced streamer formation is observed, which eventually leads to rapid clogging of the device with an accompanying exponential decrease in permeate flow. Moreover, when streamers do form, de-clogging of pores also occurs intermittently, which leads to small time scale fluctuations [O(101  s)] superimposed upon the large time scale [O(102  min)] clogging of the system...
July 2018: Biomicrofluidics
Ngan Nguyen, Peter Thurgood, Jiu Yang Zhu, Elena Pirogova, Sara Baratchi, Khashayar Khoshmanesh
Here, we describe a novel method for fabrication of microfluidic structures in classroom environments. This method is based on replica moulding of pasta structures in polydimethylsiloxane. Placing pasta structures on a petroleum jelly base layer enables templating round-shaped structures with controllable cross-sectional profiles. The pasta structures can be easily deformed and combined to create more complex 3D microfluidic structures. Proof-of-concept experiments indicate the capability of this method for studying the mixing of neighbouring flows, generation of droplets, lateral migration of particles, as well as culturing, shear stress stimulation, and imaging of cells...
July 2018: Biomicrofluidics
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