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José I Padovani, Stefanie S Jeffrey, Roger T Howe
Droplet actuation is an essential mechanism for droplet-based microfluidic systems. On-demand electromagnetic actuation is used in a ferrofluid-based microfluidic system for water droplet displacement. Electropermanent magnets (EPMs) are used to induce 50 mT magnetic fields in a ferrofluid filled microchannel with gradients up to 6.4 × 10(4) kA/m(2). Short 50 µs current pulses activate the electropermanent magnets and generate negative magnetophoretic forces that range from 10 to 70 nN on 40 to 80 µm water-in-ferrofluid droplets...
June 2016: Technology
Y Alapan, Y Matsuyama, J A Little, U A Gurkan
In sickle cell disease (SCD), hemoglobin molecules polymerize intracellularly and lead to a cascade of events resulting in decreased deformability and increased adhesion of red blood cells (RBCs). Decreased deformability and increased adhesion of sickle RBCs lead to blood vessel occlusion (vaso-occlusion) in SCD patients. Here, we present a microfluidic approach integrated with a cell dimensioning algorithm to analyze dynamic deformability of adhered RBC at the single-cell level in controlled microphysiological flow...
June 2016: Technology
Daniel Vocelle, Olivia M Chesniak, Amanda P Malefyt, Georgina Comiskey, Kwasi Adu-Berchie, Milton R Smith, Christina Chan, S Patrick Walton
Understanding the endocytosis and intracellular trafficking of short interfering RNA (siRNA) delivery vehicle complexes remains a critical bottleneck in designing siRNA delivery vehicles for highly active RNA interference (RNAi)-based therapeutics. In this study, we show that dextran functionalization of silica nanoparticles enhanced uptake and intracellular delivery of siRNAs in cultured cells. Using pharmacological inhibitors for endocytotic pathways, we determined that our complexes are endocytosed via a previously unreported mechanism for siRNA delivery in which dextran initiates scavenger receptor-mediated endocytosis through a clathrin/caveolin-independent process...
March 2016: Technology
Justin R Klesmith, Timothy A Whitehead
A central challenge in the field of metabolic engineering is the efficient identification of a metabolic pathway genotype that maximizes specific productivity over a robust range of process conditions. Here we review current methods for optimizing specific productivity of metabolic pathways in living cells. New tools for library generation, computational analysis of pathway sequence-flux space, and high-throughput screening and selection techniques are discussed.
March 2016: Technology
Tim C Chang, Weiliang Tang, William Jen Hoe Koh, Alexander J E Rettie, Mary J Emond, Raymond J Monnat, Albert Folch
We developed micromolded microwell arrays to study the proliferation and senescence of single cells. Microwell arrays were designed to be compatible with conventional cell culture protocols to simplify cell loading, cell culture, and imaging. We demonstrated the utility of these arrays by measuring the proliferation and senescence of isogenic cells which expressed or had been depleted of the human Werner syndrome protein. Our results allowed us to reveal cell-to-cell heterogeneity in proliferation in WRN+ and WRN-depleted fibroblasts during clonal growth...
December 2015: Technology
Shyam Sundhar Bale, Gautham Vivek Sridharan, Inna Golberg, Ljupcho Prodanov, William J McCarty, Osman Berk Usta, Rohit Jindal, Martin L Yarmush
To evaluate drug and metabolite efficacy on a target organ, it is essential to include metabolic function of hepatocytes, and to evaluate metabolite influence on both hepatocytes and the target of interest. Herein, we have developed a two-chamber microfabricated device separated by a membrane enabling communication between hepatocytes and cancer cells. The microscale environment created enables cell co-culture in a low media-to-cell ratio leading to higher metabolite formation and rapid accumulation, which is lost in traditional plate cultures or other interconnected models due to higher culture volumes...
December 2015: Technology
U Hassan, B Reddy, G Damhorst, O Sonoiki, T Ghonge, C Yang, R Bashir
Complete blood cell counts (CBCs) are one of the most commonly ordered and informative blood tests in hospitals. The results from a CBC, which typically include white blood cell (WBC) counts with differentials, red blood cell (RBC) counts, platelet counts and hemoglobin measurements, can have implications for the diagnosis and screening of hundreds of diseases and treatments. Bulky and expensive hematology analyzers are currently used as a gold standard for acquiring CBCs. For nearly all CBCs performed today, the patient must travel to either a hospital with a large laboratory or to a centralized lab testing facility...
December 2015: Technology
Mohammed Arif I Mahmood, Mohammad Raziul Hasan, Umair J M Khan, Peter B Allen, Young-Tae Kim, Andrew D Ellington, Samir M Iqbal
In this paper, we report a one-step tumor cell detection approach based on the dynamic morphological behavior tracking of cancer cells on a ligand modified surface. Every cell on the surface was tracked in real time for several minutes immediately after seeding until these were finally attached. Cancer cells were found to be very active in the aptamer microenvironment, changing their shapes rapidly from spherical to semi-elliptical, with much flatter spread and extending pseudopods at regular intervals. When incubated on a functionalized surface, the balancing forces between cell surface molecules and the surface-bound aptamers, together with the flexibility of the membranes, caused cells to show these distinct dynamic activities and variations in their morphologies...
December 2015: Technology
Jungwoo Lee, Nathaniel Kohl, Sachin Shanbhang, Biju Parekkadan
Microfluidic technologies have substantially advanced cancer research by enabling the isolation of rare circulating tumor cells (CTCs) for diagnostic and prognostic purposes. The characterization of isolated CTCs has been limited due to the difficulty in recovering and growing isolated cells with high fidelity. Here, we present a strategy that uses a 3D scaffold, integrated into a microfludic device, as a transferable substrate that can be readily isolated after device operation for serial use in vivo as a transplanted tissue bed...
December 2015: Technology
Young Shik Shin, Jungwoo Kim, Dazy Johnson, Alex A Dooraghi, Wilson X Mai, Lisa Ta, Arion F Chatziioannou, Michael E Phelps, David A Nathanson, James R Heath
The most common positron emission tomography (PET) radio-labeled probe for molecular diagnostics in patient care and research is the glucose analog, 2-deoxy-2-[F-18]fluoro-D-glucose ((18)F-FDG). We report on an integrated microfluidics-chip/beta particle imaging system for in vitro (18)F-FDG radioassays of glycolysis with single cell resolution. We investigated the kinetic responses of single glioblastoma cancer cells to targeted inhibitors of receptor tyrosine kinase signaling. Further, we find a weak positive correlation between cell size and rate of glycolysis...
June 2015: Technology
O B Usta, W J McCarty, S Bale, M Hegde, R Jindal, A Bhushan, I Golberg, M L Yarmush
The liver performs many key functions, the most prominent of which is serving as the metabolic hub of the body. For this reason, the liver is the focal point of many investigations aimed at understanding an organism's toxicological response to endogenous and exogenous challenges. Because so many drug failures have involved direct liver toxicity or other organ toxicity from liver generated metabolites, the pharmaceutical industry has constantly sought superior, predictive in-vitro models that can more quickly and efficiently identify problematic drug candidates before they incur major development costs, and certainly before they are released to the public...
March 2015: Technology
Chia-Hsien Hsu, Chihchen Chen, Daniel Irimia, Mehmet Toner
The isolation of CD4 positive T lymphocyte (CD4+) from peripheral blood is important for monitoring patients after HIV infection. Here, we demonstrate a fast isolation strategy for CD4+ cells that involves mixing blood and glass microbubbles. After the specific binding of target cells to the microbubbles carrying specific antibodies on their surface, target cells will spontaneously float to the top of the blood vial and can be quickly separated. Using this strategy, we demonstrate that the isolation of CD4+ cells in less than 5 minutes and with better than 90% efficiency...
March 2015: Technology
David Mayerich, Michael J Walsh, Andre Kadjacsy-Balla, Partha S Ray, Stephen M Hewitt, Rohit Bhargava
Dyes such as hematoxylin and eosin (H&E) and immunohistochemical stains have been increasingly used to visualize tissue composition in research and clinical practice. We present an alternative approach to obtain the same information using stain-free chemical imaging. Relying on Fourier transform infrared (FT-IR) spectroscopic imaging and computation, stainless computed histopathology can enable a rapid, digital, quantitative and non-perturbing visualization of morphology and multiple molecular epitopes simultaneously in a variety of research and clinical pathology applications...
March 2015: Technology
Yun Seok Heo, Sunitha Nagrath, Alessandra L Moore, Mahnaz Zeinali, Daniel Irimia, Shannon L Stott, Thomas L Toth, Mehmet Toner
Long-term preservation of live cells is critical for a broad range of clinical and research applications. With the increasing diversity of cells that need to be preserved (e.g. oocytes, stem and other primary cells, genetically modified cells), careful optimization of preservation protocols becomes tedious and poses significant limitations for all but the most expert users. To address the challenge of long-term storage of critical, heterogeneous cell types, we propose a universal protocol for cell vitrification that is independent of cell phenotype and uses only low concentrations of cryoprotectant (1...
March 2015: Technology
Kaitlin Cassady, Albert You, Alex Doud, Bin He
Brain-computer interface (BCI) systems allow users to interact with their environment by bypassing muscular control to tap directly into the users' thoughts. In the present study, we investigate the role of prior experience with yoga and meditation, examples of formalized mind-body awareness training (MBAT), in learning to use a one-dimensional sensorimotor rhythm based BCI. Thirty-six human subjects volunteered to participate in two different cohorts based on past experience with MBAT - experienced MBAT practitioners and controls...
September 2014: Technology
Jun Yan, Daniel Irimia
We combined microfluidic tools and molecular probes to monitor the migration speed of successive generations of cancer cells. We found that the migratory speed of individual cells changes stochastically from parent cells to their descendants, while the average speed of successive generations of cells remains constant. Further studies of the interrelations between cell migration and division processes may help identify the molecular determinants of cell speed and lead to new therapies to slow the invasion of cancer cells and delay metastases...
September 2014: Technology
Michael L Etheridge, Katie R Hurley, Jinjin Zhang, Seongho Jeon, Hattie L Ring, Christopher Hogan, Christy L Haynes, Michael Garwood, John C Bischof
Aggregation is a known consequence of nanoparticle use in biology and medicine; however, nanoparticle characterization is typically performed under the pretext of well-dispersed, aqueous conditions. Here, we systematically characterize the effects of aggregation on the alternating magnetic field induced heating and magnetic resonance (MR) imaging performance of iron oxide nanoparticles (IONPs) in non-ideal biological systems. Specifically, the behavior of IONP aggregates composed of ~10 nm primary particles, but with aggregate hydrodynamic sizes ranging from 50 nm to 700 nm, was characterized in phosphate buffered saline and fetal bovine serum suspensions, as well as in gels and cells...
September 2014: Technology
Jean-Pierre Dollé, Barclay Morrison, Rene S Schloss, Martin L Yarmush
Diffuse axonal injury (DAI) is a devastating consequence of traumatic brain injury, resulting in significant axon and neuronal degeneration. Currently, therapeutic options are limited. Using our brain-on-a-chip device, we evaluated axonal responses to DAI. We observed that axonal diameter plays a significant role in response to strain injury, which correlated to delayed elasticity and inversely correlated to axonal beading and axonal degeneration. When changes in mitochondrial membrane potential (MMP) were monitored an applied strain injury threshold was noted, below which delayed hyperpolarization was observed and above which immediate depolarization occurred...
June 2014: Technology
Alexander Golberg, G Felix Broelsch, Daniela Vecchio, Saiqa Khan, Michael R Hamblin, William G Austen, Robert L Sheridan, Martin L Yarmush
Emerging bacterial resistance to multiple drugs is an increasing problem in burn wound management. New non-pharmacologic interventions are needed for burn wound disinfection. Here we report on a novel physical method for disinfection: antiseptic pulsed electric field (PEF) applied externally to the infected burns. In a mice model, we show that PEF can reduce the load of multidrug resistant Acinetobacter baumannii present in a full thickness burn wound by more than four orders of magnitude, as detected by bioluminescence imaging...
June 1, 2014: Technology
Arlyne B Simon, John P Frampton, Nien-Tsu Huang, Katsuo Kurabayashi, Sophie Paczesny, Shuichi Takayama
Quantitative measurement of protein biomarkers is critical for biomarker validation and early disease detection. Current multiplex immunoassays are time consuming costly and can suffer from low accuracy. For example, multiplex ELISAs require multiple, tedious, washing and blocking steps. Moreover, they suffer from nonspecific antibody cross-reactions, leading to high background and false-positive signals. Here, we show that co-localizing antibody-bead pairs in an aqueous two-phase system (ATPS) enables multiplexing of sensitive, no-wash, homogeneous assays, while preventing nonspecific antibody cross-reactions...
June 2014: Technology
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