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https://www.readbyqxmd.com/read/28332813/competitive-adsorption-of-polyelectrolytes-onto-and-into-pellicle-coated-hydroxyapatite-investigated-by-qcm-d-and-force-spectroscopy
#1
Hyun-Su Lee, Carl Myers, Lynette Zaidel, Prathima Chandra Nalam, Matthew Alexander Caporizzo, Carlo Daep, David M Eckmann, James G Masters, Russell J Composto
A current effort in preventive dentistry is to inhibit surface attachment of bacteria using antibacterial polymer coatings on the tooth surface. For the antibacterial coatings, the physisorption of anionic and cationic polymers directly onto hydroxyapatite (HA) and saliva treated HA surfaces was studied using quartz crystal microbalance, force spectroscopy and atomic force microscopy. First, single species adsorption is shown to be stronger on HA surfaces than on silicon oxide surfaces for all polymers (i.e...
March 23, 2017: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/28332631/integrated-dna-and-rna-extraction-using-magnetic-beads-from-viral-pathogens-causing-acute-respiratory-infections
#2
Hui He, Rongqun Li, Yi Chen, Ping Pan, Wenjuan Tong, Xueyan Dong, Yueming Chen, Daojun Yu
Current extraction methods often extract DNA and RNA separately, and few methods are capable of co-extracting DNA and RNA from sputum. We established a nucleic acid co-extraction method from sputum based on magnetic beads and optimized the method by evaluating influencing factors, such as the guanidinium thiocyanate (GTC) and dithiothreitol (DTT) concentrations, magnetic bead amount, incubation temperature, lysis buffer pH and RNA carrier type. The feasibility of the simultaneous nucleic acid co-extraction method was evaluated by amplifying DNA and RNA viruses from a single clinical specimen with a multiplex RT-qPCR method...
March 23, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28331957/digital-triplex-dna-assay-based-on-plasmonic-nanocrystals
#3
Guohua Li, Liang Zhu, Yonghong He, Hui Tan, Shuqing Sun
A new analytical method has been developed to detect three kinds of DNA simultaneously based on magnetic beads and color-encoded plasmonic nanocrystals. Magnetic beads modified with capture DNA are employed to collect the specific target DNA, and color-encoded plasmonic nanocrystals are applied to signal the target through DNA hybridization. As a proof of concept, three types of representative metal nanocrystals of gold nanoparticle (AuNP), gold nanorod (AuNR), and gold/silver nanoparticle (Au/AgNP) were employed to signal three dissimilar virus-related protective antigen genes, Ebola virus (EV), Variola virus (VV), and Bacillus anthracis (BA), respectively...
March 22, 2017: Analytical and Bioanalytical Chemistry
https://www.readbyqxmd.com/read/28328943/structurally-detailed-coarse-grained-model-for-sec-facilitated-co-translational-protein-translocation-and-membrane-integration
#4
Michiel J M Niesen, Connie Y Wang, Reid C Van Lehn, Thomas F Miller
We present a coarse-grained simulation model that is capable of simulating the minute-timescale dynamics of protein translocation and membrane integration via the Sec translocon, while retaining sufficient chemical and structural detail to capture many of the sequence-specific interactions that drive these processes. The model includes accurate geometric representations of the ribosome and Sec translocon, obtained directly from experimental structures, and interactions parameterized from nearly 200 μs of residue-based coarse-grained molecular dynamics simulations...
March 22, 2017: PLoS Computational Biology
https://www.readbyqxmd.com/read/28319896/a-dynamic-sandwich-assay-on-magnetic-beads-for-selective-detection-of-single-nucleotide-mutations-at-room-temperature
#5
Junxiu Wang, Guoliang Xiong, Liang Ma, Shihui Wang, Xu Zhou, Lei Wang, Lehui Xiao, Xin Su, Changyuan Yu
Single-nucleotide mutation (SNM) has proven to be associated with a variety of human diseases. Development of reliable methods for the detection of SNM is crucial for molecular diagnosis and personalized medicine. The sandwich assays are widely used tools for detecting nucleic acid biomarkers due to their low cost and rapid signaling. However, the poor hybridization specificity of signal probe at room temperature hampers the discrimination of mutant and wild type. Here, we demonstrate a dynamic sandwich assay on magnetic beads for SNM detection based on the transient binding between signal probe and target...
March 12, 2017: Biosensors & Bioelectronics
https://www.readbyqxmd.com/read/28314140/an-investigation-of-the-immunotoxicity-of-oil-sands-processed-water-and-leachates-in-trout-leukocytes
#6
F Gagné, A Bruneau, P Turcotte, C Gagnon, E Lacaze
Increased oil sands (OS) mining activity has raised concerns about impacts on aquatic organisms. This study sought to examine the effects of single representative compounds from OS (benzo(a)pyrene, naphthalene), a mixture of naphthenic acids (NAs), OS-processed water (OSPW) and OS leachate (OSL) extracts on rainbow trout leukocytes. Primary cultures of trout leukocytes were exposed to increasing concentrations of benzo(a)pyrene, naphthalene, NAs, OSPW and OSL for 48h at 18°C. Immunocompetence was followed by measuring changes in lymphocyte and macrophage viability and phagocytosis...
March 14, 2017: Ecotoxicology and Environmental Safety
https://www.readbyqxmd.com/read/28303796/rapid-structural-analysis-of-nanomaterials-in-aqueous-solutions
#7
Sou Ryuzaki, Makusu Tsutsui, Yuhui He, Kazumichi Yokota, Akihide Arima, Takanori Morikawa, Masateru Taniguchi, Tomoji Kawai
Rapid structural analysis of nanoscale matter in a liquid environment represents innovative technologies that reveal the identities and functions of biologically important molecules. However, there is currently no method with high spatio-temporal resolution that can scan individual particles in solutions to gain structural information. Here we report the development of a nanopore platform realizing quantitative structural analysis for suspended nanomaterials in solutions with a high z-axis and xy-plane spatial resolution of 35...
April 18, 2017: Nanotechnology
https://www.readbyqxmd.com/read/28301748/single-molecule-arrays-for-protein-and-nucleic-acid-analysis
#8
Limor Cohen, David R Walt
The last few years have seen breakthroughs that will transform our ability to measure important analytes. Miniaturization of reaction volumes and confinement of analytes of interest into ultrasmall containers have greatly enhanced the sensitivity and throughput of many detection methods. Fabrication of microwell arrays and implementation of bead-based assays have been instrumental in the development of methods for measuring relevant biomolecules, with applications to both diagnostics and fundamental biological studies...
March 15, 2017: Annual Review of Analytical Chemistry
https://www.readbyqxmd.com/read/28297643/effects-of-polymer-length-and-salt-concentration-on-the-transport-of-ssdna-in-nanofluidic-channels
#9
Weixin Qian, Kentaro Doi, Satoyuki Kawano
Electrokinetic phenomena in micro/nanofluidic channels have attracted considerable attention because precise control of molecular transport in liquids is required to optically and electrically capture the behavior of single molecules. However, the detailed mechanisms of polymer transport influenced by electroosmotic flows and electric fields in micro/nanofluidic channels have not yet been elucidated. In this study, a Langevin dynamics simulation was used to investigate the electrokinetic transport of single-stranded DNA (ssDNA) in a cylindrical nanochannel, employing a coarse-grained bead-spring model that quantitatively reproduced the radius of gyration, diffusion coefficient, and electrophoretic mobility of the polymer...
March 14, 2017: Biophysical Journal
https://www.readbyqxmd.com/read/28297344/improvement-in-ct-image-resolution-due-to-the-use-of-focal-spot-deflection-and-increased-sampling
#10
Nicholas Rubert, Timothy Szczykutowicz, Frank Ranallo
When patient anatomy is positioned away from a CT scanner's isocenter, scans of limited diagnostic value may result. Yet in some cases, positioning of patient anatomy far from isocenter is unavoidable. This study examines the effect of position and reconstruction algorithm on image resolution achieved by a CT scanner operating in a high resolution (HR) scan mode which incorporates focal spot deflection and acquires an increased number of projections per rotation. Images of a metal bead contained in a phantom were acquired on a GE CT750 HD scanner with multiple reconstruction algorithms, in the normal and HR scan mode, and at two positions, scanner isocenter and 15 cm directly above isocenter...
May 2016: Journal of Applied Clinical Medical Physics
https://www.readbyqxmd.com/read/28289288/3d-structures-of-individual-mammalian-genomes-studied-by-single-cell-hi-c
#11
Tim J Stevens, David Lando, Srinjan Basu, Liam P Atkinson, Yang Cao, Steven F Lee, Martin Leeb, Kai J Wohlfahrt, Wayne Boucher, Aoife O'Shaughnessy-Kirwan, Julie Cramard, Andre J Faure, Meryem Ralser, Enrique Blanco, Lluis Morey, Miriam Sansó, Matthieu G S Palayret, Ben Lehner, Luciano Di Croce, Anton Wutz, Brian Hendrich, Dave Klenerman, Ernest D Laue
The folding of genomic DNA from the beads-on-a-string-like structure of nucleosomes into higher-order assemblies is crucially linked to nuclear processes. Here we calculate 3D structures of entire mammalian genomes using data from a new chromosome conformation capture procedure that allows us to first image and then process single cells. The technique enables genome folding to be examined at a scale of less than 100 kb, and chromosome structures to be validated. The structures of individual topological-associated domains and loops vary substantially from cell to cell...
March 13, 2017: Nature
https://www.readbyqxmd.com/read/28267878/quantification-of-substrate-and-cellular-strains-in-stretchable-3d-cell-cultures-an-experimental-and-computational-framework
#12
P González-Avalos, M Mürnseer, J Deeg, A Bachmann, J Spatz, S Dooley, R Eils, E Gladilin
The mechanical cell environment is a key regulator of biological processes . In living tissues, cells are embedded into the 3D extracellular matrix and permanently exposed to mechanical forces. Quantification of the cellular strain state in a 3D matrix is therefore the first step towards understanding how physical cues determine single cell and multicellular behaviour. The majority of cell assays are, however, based on 2D cell cultures that lack many essential features of the in vivo cellular environment. Furthermore, nondestructive measurement of substrate and cellular mechanics requires appropriate computational tools for microscopic image analysis and interpretation...
March 7, 2017: Journal of Microscopy
https://www.readbyqxmd.com/read/28266828/single-step-imprinting-of-femtoliter-microwell-arrays-allows-digital-bioassays-with-attomolar-limit-of-detection
#13
Deborah Decrop, Gaspard Pardon, Luigi Brancato, Dries Kil, Reza Zandi Shafagh, Tadej Kokalj, Tommy Haraldsson, Robert Puers, Wouter van der Wijngaart, Jeroen Lammertyn
Bead-based microwell array technology is growing as an ultrasensitive analysis tool as exemplified by the successful commercial applications from Illumina and Quanterix for nucleic acid analysis and ultrasensitive protein measurements, respectively. High-efficiency seeding of magnetic beads is key for these applications and is enhanced by hydrophilic-in-hydrophobic microwell arrays, which are unfortunately often expensive or labor-intensive to manufacture. Here, we demonstrate a new single-step manufacturing approach for imprinting cheap and disposable hydrophilic-in-hydrophobic microwell arrays suitable for digital bioassays...
March 15, 2017: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/28266562/applying-torque-to-the-escherichia-coli-flagellar-motor-using-magnetic-tweezers
#14
Maarten M van Oene, Laura E Dickinson, Bronwen Cross, Francesco Pedaci, Jan Lipfert, Nynke H Dekker
The bacterial flagellar motor of Escherichia coli is a nanoscale rotary engine essential for bacterial propulsion. Studies on the power output of single motors rely on the measurement of motor torque and rotation under external load. Here, we investigate the use of magnetic tweezers, which in principle allow the application and active control of a calibrated load torque, to study single flagellar motors in Escherichia coli. We manipulate the external load on the motor by adjusting the magnetic field experienced by a magnetic bead linked to the motor, and we probe the motor's response...
March 7, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28257884/development-of-advanced-biantibiotic-loaded-bone-cement-spacers-for-arthroplasty-associated-infections
#15
F J Parra-Ruíz, A González-Gómez, M Fernández-Gutiérrez, J Parra, J García-García, G Azuara, B De la Torre, J Buján, B Ibarra, L Duocastella-Codina, M Molina-Crisol, B Vázquez-Lasa, J San Román
The incidence increase of infections in patients with hip or knee implants with resistant pathogens (mainly some S. coagulase-negative and gram positive bacteria) demands advanced antibiotic loaded formulations. In this paper, we report the design of new biantibiotic acrylic bone cements for in situ delivery. They include a last generation antibiotic (daptomycin or linezolid) in combination with vancomycin and are performed based on a novel modification of the Palacos R(®) acrylic bone cement, which is based on two components, a liquid (methyl methacrylate) and a solid (polymeric phase)...
February 28, 2017: International Journal of Pharmaceutics
https://www.readbyqxmd.com/read/28249423/efficient-shapes-for-microswimming-from-three-body-swimmers-to-helical-flagella
#16
Bram Bet, Gijs Boosten, Marjolein Dijkstra, René van Roij
We combine a general formulation of microswimmer equations of motion with a numerical bead-shell model to calculate the hydrodynamic interactions with the fluid, from which the swimming speed, power, and efficiency are extracted. From this framework, a generalized Scallop theorem emerges. The applicability to arbitrary shapes allows for the optimization of the efficiency with respect to the swimmer geometry. We apply this scheme to "three-body swimmers" of various shapes and find that the efficiency is characterized by the single-body friction coefficient in the long-arm regime, while in the short-arm regime the minimal approachable distance becomes the determining factor...
February 28, 2017: Journal of Chemical Physics
https://www.readbyqxmd.com/read/28237901/detection-of-bisphenol-a-using-palm-size-nanoaptamer-analyzer
#17
Hyun Jeong Lim, Beelee Chua, Ahjeong Son
We have demonstrated a palm-size NanoAptamer analyzer capable of detecting bisphenol A (BPA) at environmentally relevant concentrations (<1ng/mL or ppb). It is designed for performing reaction and fluorescence measurement on single cuvette sample. Modified NanoGene assay was used as the sensing mechanism where signaling DNA and QD655 was tethered to QD565 and magnetic bead via the aptamer. Aptamer affinity with BPA resulted in the release of the signaling DNA and QD655 from the complex and hence corresponding decrease in QD655 fluorescence measurement signal...
February 21, 2017: Biosensors & Bioelectronics
https://www.readbyqxmd.com/read/28225104/coplanar-electrode-microfluidic-chip-enabling-accurate-sheathless-impedance-cytometry
#18
Adele De Ninno, Vito Errico, Francesca Romana Bertani, Luca Businaro, Paolo Bisegna, Federica Caselli
Microfluidic impedance cytometry offers a simple non-invasive method for single-cell analysis. Coplanar electrode chips are especially attractive due to ease of fabrication, yielding miniaturized, reproducible, and ultimately low-cost devices. However, their accuracy is challenged by the dependence of the measured signal on particle trajectory within the interrogation volume, that manifests itself as an error in the estimated particle size, unless any kind of focusing system is used. In this paper, we present an original five-electrode coplanar chip enabling accurate particle sizing without the need for focusing...
March 14, 2017: Lab on a Chip
https://www.readbyqxmd.com/read/28224137/hmgb1-anti-hmgb1-antibodies-define-a-molecular-signature-of-early-stages-of-hiv-associated-neurocognitive-isorders-hand
#19
Marie-Lise Gougeon, Béatrice Poirier-Beaudouin, Jacques Durant, Christine Lebrun-Frenay, Héla Saïdi, Valérie Seffer, Michel Ticchioni, Stephane Chanalet, Helene Carsenti, Alexandra Harvey-Langton, Muriel Laffon, Jacqueline Cottalorda, Christian Pradier, Pierre Dellamonica, Matteo Vassallo
BACKGROUND: HIV-associated neurocognitive disorders (HAND) persist in the post-HAART era, characterized by asymptomatic neurocognitive impairment (ANI) and mild neurocognitive disorders (MND). High mobility group box 1 (HMGB1) is a non-histone chromosomal protein widely expressed in the nucleus of all eukaryotic cells, including brain cells, which acts as a potent proinflammatory cytokine when actively secreted from immune cells. Recent reports suggested that HMGB1 acts on microglial cells to promote neuroinflammation...
February 2017: Heliyon
https://www.readbyqxmd.com/read/28223693/single-cd28-stimulation-induces-stable-and-polyclonal-expansion-of-human-regulatory-t-cells
#20
Xuehui He, Ruben L Smeets, Esther van Rijssen, Annemieke M H Boots, Irma Joosten, Hans J P M Koenen
CD4+FOXP3+ Treg are essential for immune tolerance. Phase-1 clinical trials of Treg-therapy to treat graft-versus-host-disease reported safety and potential therapeutic efficacy. Treg-based trials have started in organ-transplant patients. However, efficient ex vivo expansion of a stable Treg population remains a challenge and exploring novel ways for Treg expansion is a pre-requisite for successful immunotherapy. Based on the recent finding that CD28-signaling is crucial for survival and proliferation of mouse Treg, we studied single-CD28 stimulation of human Treg, without T cell receptor stimulation...
February 22, 2017: Scientific Reports
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