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Jiheum Park, Gi-Hun Lee, Joong Yull Park, Jung Chan Lee, Hee Chan Kim
In living tissue, cells exist in three-dimensional (3D) microenvironments with intricate cell-cell interactions. To model these cellular environments, numerous techniques for generating cell spheroids have been proposed and improved. However, previously reported methods still have limitations in uniformity, reproducibility, scalability, through-put, etc. Here, we present a centrifugal microfluidic-based spheroid (CMS) formation method for generating both co-culture and mono-culture 3D spheroids in a highly controlled manner...
October 18, 2017: Biofabrication
Siyang Xiao, Yongchao Zeng, Eric D Vavra, Peng He, Maura C Puerto, George J Hirasaki, Sibani Lisa Biswal
Foam flooding in porous media is of increasing interest due to its numerous applications such as enhanced oil recovery, aquifer remediation, and hydraulic fracturing. However, the mechanisms of oil-foam interactions have yet to be fully understood at the pore level. Here, we present three characteristic zones identified in experiments involving the displacement of crude oil from model porous media via surfactant-stabilized foam, and we describe a series of pore-level dynamics in these zones which were not observed in experiments involving paraffin oil...
October 18, 2017: Langmuir: the ACS Journal of Surfaces and Colloids
Brian R Branchford, Timothy J Stalker, Luke Law, Gilbert Acevedo, Susan Sather, Christine Brzezinski, Katina M Wilson, Katherine Minson, Alisa B Lee-Sherick, Pavel Davizon-Castillo, Christopher Ng, Weihe Zhang, Keith B Neeves, Steven R Lentz, Xiaodong Wang, Stephen V Frye, H Shelton Earp, Deborah DeRyckere, Lawrence F Brass, Douglas K Graham, Jorge A Di Paola
BACKGROUND: Gas6 signals through the TAM (TYRO-3, AXL, MERTK) receptor family mediating platelet activation and thrombus formation via activation of the aggregate-stabilizing αIIb β3 integrin. OBJECTIVE: Here we describe anti-thrombotic effects mediated by UNC2025, a small molecule MERTK tyrosine kinase inhibitor. METHODS: MERTK phosphorylation and downstream signaling were assessed by immunoblot. Light transmission aggregometry, flow cytometry, and microfluidic analysis were used to evaluate the impact of MERTK inhibition on platelet activation and stability of aggregate formation in vitro...
October 17, 2017: Journal of Thrombosis and Haemostasis: JTH
Yankai Jia, Yukun Ren, Likai Hou, Weiyu Liu, Xiaokang Deng, Hongyuan Jiang
Advances in microfluidic emulsification have enabled the generation of exquisite multiple-core droplets, which are promising structures to accommodate microreactions. An essential requirement for conducting reactions is the sequential coalescence of the multiple cores encapsulated within these droplets, therefore, mixing the reagents together in a controlled sequence. Here, a microfluidic approach is reported for the conduction of two-step microreactions by electrically fusing three cores inside double-emulsion droplets...
October 16, 2017: Small
Daud H Khan, Steven A Roberts, John Robert Cressman, Nitin Agrawal
Hypoxic regions exist within most solid tumors and often lead to altered cellular metabolism, metastasis, and drug resistance. Reliable generation and detection of biomimetic gaseous gradients in vitro is challenging due to low spatiotemporal resolution and poor longevity of gradients utilizing microfluidic techniques. Here, we present a novel and simplistic approach for producing gradients of dissolved oxygen (DO) within a lab-on-a-chip platform. Linear and stable DO gradients with high spatial resolution are established by introducing pre-gassed media into the gradient generating network...
October 18, 2017: Scientific Reports
Gregor W Schmidt, Olivier Frey, Fabian Rudolf
Time-lapse fluorescence imaging of yeast cells allows the study of multiple fluorescent targets in single cells, but is often hampered by the tedious cultivation using agar pads or glass bottom wells. Here, we describe the fabrication and operation of a microfluidic device for long-term imaging of yeast cells under constant or changing media conditions. The device allows acquisition of high quality images as cells are fixed in a two-dimensional imaging plane. Four yeast strains can be analyzed simultaneously over several days while up to four different media can be flushed through the chip...
2018: Methods in Molecular Biology
Jessica F Liu, Sagar Yadavali, Andrew Tsourkas, David Issadore
Diafiltration is a membrane filtration technique that rapidly removes permeable molecules from a solution by controlling the tangential and orthogonal flows over a membrane and by replenishing the permeate with an equivalent amount of replacement buffer. However, its application to the purification of many key biomaterials and nanomaterials has been limited by the large dead volume (>10 mL) that is required to automate the process. To address this challenge, we have developed a diafiltration-on-a-chip device that can process low-volume samples (50 μL)...
October 18, 2017: Lab on a Chip
Sascha Lutz, Eloisa Lopez-Calle, Pamela Espindola, Christoph Boehm, Thorsten Brueckner, Juergen Spinke, Moritz Marcinowski, Thomas Keller, Armin Tgetgel, Nicolas Herbert, Thomas Fischer, Erik Beiersdorf
We present a novel fully integrated centrifugal microfluidic platform for highly sensitive immunoassays in point-of-care settings. The platform consists of a disposable cartridge containing structures for assay processing, a porous membrane and all dried reagents required for the analysis. Additionally, a blister containing a washing buffer is connected to a new aliquoting structure enabling the serial aliquoting of washing buffer for repetitive bound-free separation steps. The proof-of-concept for two immunoassays is shown in the cartridge with each requiring only 30 μL of whole blood or plasma as the sample material...
October 18, 2017: Analyst
F Weyer, A Duchesne, N Vandewalle
Lately, curious structures have been erected in arid regions: they are large nets able to catch water from fog. Tiny droplets condense on the mesh and are collected on the bottom of it. This innovative technology is crucial to obtain drinkable water in these inhospitable areas. Many studies aim to understand the behavior of droplets trapped on this entanglement of fibers. However, the motion of a droplet sliding on a network of inclined fibers and encountering several crossings when going down remains an open question...
October 17, 2017: Scientific Reports
Ran Drori, Miranda Holmes-Cerfon, Bart Kahr, Robert V Kohn, Michael D Ward
The growth dynamics of D2O ice in liquid H2O in a microfluidic device were investigated between the melting points of D2O ice (3.8 °C) and H2O ice (0 °C). As the temperature was decreased at rates between 0.002 °C/s and 0.1 °C/s, the ice front advanced but retreated immediately upon cessation of cooling, regardless of the temperature. This is a consequence of the competition between diffusion of H2O into the D2O ice, which favors melting of the interface, and the driving force for growth supplied by cooling...
October 17, 2017: Proceedings of the National Academy of Sciences of the United States of America
Kunjian Cao, Yi Liu, Shiliang Qu
An optical breakdown-driven micro-pump was reported to deliver the quantitative liquid to the fiber microstructure efficiently. The amount of the pumped liquid can be controlled by adjusting the irradiation time of the femtosecond laser pulses. Such a method of microfluidic delivery has potential for the fabrication of fiber functional devices and the rapid injection of analytes into a lab-in-fiber for chemical and biological analysis. As a demonstration, a fiber spirit level based on a mobile microbubble was achieved by pumping nanoliter scale liquid into a fiber micro-cavity with this method...
October 2, 2017: Optics Express
R Thomas, A Harrison, D Barrow, P M Smowton
Chip based particle sensing using 3D capillary fill microfluidics integrated with monolithically integrated lasers and photodetectors is used to demonstrate the feasibility of true chip scale photonic measurements of fluids. The approach is scalable and manufactured using industry standard compound semiconductor fabrication tools. The need for fluid speed regulation via external pumps is removed by measuring local particle velocity at the point of interrogation and particle position within the fluid flow is derived from multiple time resolved forward scattered light signals...
October 2, 2017: Optics Express
Yao-Xiong Huang, Chun-Lan He, Ping Wang, Yan-Ting Pan, Wei-Wei Tuo, Cheng-Can Yao
We report here a versatile on-stage microfluidic cell culture and assay system which is compatible with different microscopes and sensors, can simultaneously perform steps of long term cell culture, high throughput time lapse cell assays/imaging, and cell micromanipulations. With the system, we cultured a variety of cells for different periods of time and monitored their cell morphology, migration and division. We also performed a series non-invasive real time in situ time lapse assays and micromanipulations on different cells...
October 4, 2017: Biosensors & Bioelectronics
Monirosadat Sadati, Ye Zhou, Drew Melchert, Ashley Guo, Jose A Martinez-Gonzalez, Tyler F Roberts, Rui Zhang, Juan J de Pablo
Liquid crystal shells have attracted considerable attention in recent years. In such systems, a combination of confinement and curvature generates topological defect structures that do not exist in the bulk. Past studies, however, have largely focused on perfectly spherical shells, and little attention has been devoted to the impact of core geometry on the configuration and arrangement of topological defects. In this work, a microfluidic glass capillary device is used to encapsulate spherical and prolate ellipsoidal particles in nematic liquid crystal (LC) droplets dispersed in aqueous media...
October 17, 2017: Soft Matter
Prateek Sehgal, Brian J Kirby
Separation of particles on the order of 100 nm with acoustophoresis has been challenging to date because of the competing natures of acoustic radiation force and acoustic streaming on the particles. In this work, we present a surface acoustic wave (SAW)-based device that integrates a Fabry-Perot type acoustic resonator into a microfluidic channel to separate submicron particles. This configuration enhances the overall acoustic radiation force on the particles and thereby offers controlled manipulation of particles as small as 300 nm...
October 17, 2017: Analytical Chemistry
H Eslami Amirabadi, S SahebAli, J P Frimat, R Luttge, J M J den Toonder
A major challenge in studying tumor cell invasion into its surrounding tissue is to identify the contribution of individual factors in the tumor microenvironment (TME) to the process. One of the important elements of the TME is the fibrous extracellular matrix (ECM) which is known to influence cancer cell invasion, but exactly how remains unclear. Therefore, there is a need for new models to unravel mechanisms behind the tumor-ECM interaction. In this article, we present a new microfabrication method, called selective curing, to integrate ECM-mimicking layers between two microfluidic channels...
October 17, 2017: Biomedical Microdevices
Samira Musah, Akiko Mammoto, Thomas C Ferrante, Sauveur S F Jeanty, Mariko Hirano-Kobayashi, Tadanori Mammoto, Kristen Roberts, Seyoon Chung, Richard Novak, Miles Ingram, Tohid Fatanat-Didar, Sandeep Koshy, James C Weaver, George M Church, Donald E Ingber
An in vitro model of the human kidney glomerulus - the major site of blood filtration - could facilitate drug discovery and illuminate kidney-disease mechanisms. Microfluidic organ-on-a-chip technology has been used to model the human proximal tubule, yet a kidney-glomerulus-on-a-chip has not been possible because of the lack of functional human podocytes - the cells that regulate selective permeability in the glomerulus. Here, we demonstrate an efficient (> 90%) and chemically defined method for directing the differentiation of human induced pluripotent stem (hiPS) cells into podocytes that express markers of the mature phenotype (nephrin+, WT1+, podocin+, Pax2-) and that exhibit primary and secondary foot processes...
2017: Nature biomedical engineering
Chih-Hao Chiu, Kin Fong Lei, Wen-Ling Yeh, Poyu Chen, Yi-Sheng Chan, Kuo-Yao Hsu, Alvin Chao-Yu Chen
BACKGROUND: Local injections of anesthetics, NSAIDs, and corticosteroids for tendinopathies are empirically used. They are believed to have some cytotoxicity toward tenocytes. The maximal efficacy dosages of local injections should be determined. A commercial 2D microfluidic xCELLigence system had been developed to detect real-time cellular proliferation and their responses to different stimuli and had been used in several biomedical applications. The purpose of this study is to determine if human tenocytes can successfully proliferate inside xCELLigence system and the result has high correlation with conventional cell culture methods in the same condition...
October 16, 2017: Journal of Orthopaedic Surgery and Research
Mohammad F Khanfar, Wisam Al-Faqheri, Ala'aldeen Al-Halhouli
The diagnostics of health status and the quality of drinking water are among the most important United Nations sustainable development goals. However, in certain areas, wars and instability have left millions of people setting in refugee camps and dangerous regions where infrastructures are lacking and rapid diagnostics of water quality and medical status are critical. In this work, microfluidic testing chips and photometric setups are developed in cheap and portable way to detect nitrate concentrations in water...
October 14, 2017: Sensors
Michał Chudy, Katarzyna Tokarska, Elżbieta Jastrzębska, Magdalena Bułka, Sławomir Drozdek, Łukasz Lamch, Kazimiera A Wilk, Zbigniew Brzózka
In recent years photodynamic therapy (PDT) has received widespread attention in cancer treatment due to its smaller surgical trauma, better selectivity towards tumor cells, reduced side effects and possibility of repeatable treatment. Since cancer is the second cause of death worldwide, scientists constantly seek for new potential therapeutic agents including nanotechnology-based photosensitizers used in PDT. The new-designed nanostructures must be carefully studied and well characterized what require analytically useful and powerful tools that enable real progress in nanoscience development...
October 7, 2017: Biosensors & Bioelectronics
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