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paper based assay

D Mackey, E Kelly, R Nooney
One of the primary considerations in immunoassay design is optimizing the concentration of capture antibody in order to achieve maximal antigen binding and, subsequently, improved sensitivity and limit of detection. Many immunoassay technologies involve immobilization of the antibody to solid surfaces. Antibodies are large molecules in which the position and accessibility of the antigen-binding site depend on their orientation and packing density. In this paper we propose a simple mathematical model, based on the theory known as random sequential adsorption (RSA), in order to calculate how the concentration of correctly oriented antibodies (active site exposed for subsequent reactions) evolves during the deposition process...
December 1, 2016: Mathematical Biosciences and Engineering: MBE
Erin A Henslee, Ruth M Torcal Serrano, Fatima H Labeed, Rita I Jabr, Christopher H Fry, Michael P Hughes, Kai F Hoettges
A loss of ability of cells to undergo apoptosis (programmed cell death, whereby the cell ceases to function and destroys itself) is commonly associated with cancer, and many anti-cancer interventions aim to restart the process. Consequently, the accurate quantification of apoptosis is essential in understanding the function and performance of new anti-cancer drugs. Dielectrophoresis has previously been demonstrated to detect apoptosis more rapidly than other methods, and is low-cost, label-free and rapid, but has previously been unable to accurately quantify cells through the apoptotic process because cells in late apoptosis disintegrate, making cell tracking impossible...
October 24, 2016: Analyst
Chao Jiang, Yuan Yuan, Guang Yang, Yan Jin, Libing Liu, Yuyang Zhao, Luqi Huang
Inaccurate labeling of materials used in herbal products may compromise the therapeutic efficacy and may pose a threat to medicinal safety. In this paper, a rapid (within 3 h), sensitive and visual colorimetric method for identifying substitutions in terminal market products was developed using cationic conjugated polymer-based fluorescence resonance energy transfer (CCP-based FRET). Chinese medicinal materials with similar morphology and chemical composition were clearly distinguished by the single-nucleotide polymorphism (SNP) genotyping method...
October 21, 2016: Scientific Reports
Nurkhalida Kamal, Christina V Viegelmann, Carol J Clements, RuAngelie Edrada-Ebel
Fungal endophytes offer diverse and unique secondary metabolites, making these organisms potential sources of promising drug leads. The application of high-resolution-liquid chromatography mass spectrometry and nuclear magnetic resonance-based metabolomics to fungal endophytes is practical in terms of dereplication studies and the mining of bioactive compounds. In this paper, we report the application of metabolomics in parallel with anti-trypanosomal assays to determine the ideal conditions for the medium-scale fermentation of the endophyte Lasiodiplodia theobromae...
October 19, 2016: Planta Medica
Jing-Min Liu, Yao-Yao Liu, Dong-Dong Zhang, Guozhen Fang, Shuo Wang
The rise of multimodal nanoprobes has promoted the development of new methods to explore multiple molecular targets simultaneously, or to combine various bioimaging tools in one assay to more clearly delineate localization and expression of bio-markers. Persistent luminescence nanophosphors (PLNPs) have been qualified as the promising contrast agent for in vivo imaging. The easy surface modification and proper nanostructure design strategy would favor the fabrication of PLNPs based multi-functional nanoprobes for biological application...
October 19, 2016: ACS Applied Materials & Interfaces
Yohei Kurosaki, Sayaka Okada, Sayuri Nakamae, Jiro Yasuda
Bovine papular stomatitis virus (BPSV) causes pustular cutaneous disease in cattle worldwide. This paper describes the development of a specific loop-mediated isothermal amplification (LAMP) assay to detect BPSV which did not cross-react with other parapoxviruses. To assess analytical sensitivity of this LAMP assay, DNA was extracted from serially diluted BPSV from which the infectious titer was determined by a novel assay based on calf kidney epithelial cells. The LAMP assay had equivalent analytical sensitivity to quantitative PCR, and could detect as few as 86 copies of viral DNA per reaction...
October 14, 2016: Journal of Virological Methods
Jaclyn A Adkins, Eka Noviana, Charles S Henry
An electrochemical paper-based analytical device (ePAD) was developed for quasi-steady flow detection at microwire electrodes, for the first time. The device implements a fan shaped geometry connected to an analysis channel whereby solution is pulled from an inlet, through a channel, and into the steadily increasing capillary network of the fan. The network counteracts the decrease in solution flow rate associated with increasing viscosity within the channel, generating quasi-steady flow within the analysis channel...
October 17, 2016: Analytical Chemistry
Arne Biesiekierski, Jixing Lin, Yuncang Li, Dehai Ping, Yoko Yamabe-Mitarai, Cuie Wen
: In this paper, we present further work on the influence of minor additions of Ru to the Ti-20Nb alloy system, with a primary focus on mechanical properties of the as-cast material, along with microstructural response to elevated temperatures. Findings include high as-cast strengths and admissible strain values, up to 920MPa and 1.5% respectively, along with moduli down to approximately 65GPa in the as-cast state. Together with a significant increase in cell proliferation under MTS assay relative to controls, this indicates the chosen alloy system has significant promise for application in porous orthopaedic biomaterials, in particular those alloys with 0...
October 14, 2016: Acta Biomaterialia
Cecilia Rossetti, Maren C S Levernæs, Léon Reubsaet, Trine G Halvorsen
Mass spectrometric assays are now of great relevance for trace compound analysis in complex matrices such as serum and plasma samples. Especially in the quantification of low abundant protein-biomarkers, the choice of the sample preparation is crucial. In the present paper immunocapture and Molecular Imprinted Polymers (MIPs) have been applied in the determination of pro-gastrin-releasing peptide, a Small Cell Lung Cancer marker. These affinity-based techniques were compared in terms of matrix effect, limits of detection, repeatability and extraction specificity...
October 1, 2016: Journal of Chromatography. A
Natalija Topić Popović, Snježana P Kazazić, Ivančica Strunjak-Perović, Rozelindra Čož-Rakovac
Identification of bacteria in aquatic and environmental applications, for monitoring purposes and research, for health assessments and therapy considerations of farmed and free-living aquatic organisms, still relies on conventional phenotypic and biochemical protocols. Although molecular techniques based on DNA amplification and sequencing are finding ways into diagnostic laboratories, they are time-consuming, costly and difficult in the case of multiplex assays. Matrix-assisted laser desorption/ionization time of flight mass spectrometry (MALDI-TOF MS) is a rapid and accurate proteomic method reliable for identification of unknown bacteria to the genus and species level...
October 11, 2016: Environmental Research
Paul Leonard, Stephen Hearty, Hui Ma, Richard O'Kennedy
The use of optical biosensors for studying macromolecular interactions is gaining increasing popularity. In one study, 1514 papers that involved the application of biosensor data were identified for the year 2009 alone (Rich and Myszka, J Mol Recognit 24:892-914, 2011), the sheer volume and variety of which present a daunting task for the burgeoning biosensor user to accumulate and decipher. This chapter is designed to provide the reader with the tools necessary to prepare, design, and efficiently execute a kinetic experiment on Biacore...
2017: Methods in Molecular Biology
Min-Yen Hsu, Yu-Chien Hung, De-Kuang Hwang, Shang-Chi Lin, Keng-Hung Lin, Chun-Yuan Wang, Hin-Yeung Choi, Yu-Ping Wang, Chao-Min Cheng
Intraocular vascular endothelial growth factor (VEGF) levels play an important role in the pathogenesis of blindness-related diseases, such as age-related macular degeneration (AMD). Here, we aimed to develop a paper-based enzyme-linked immunosorbent assay (P-ELISA) to analyze the suppression of aqueous VEGF concentrations following intravitreal injection (IVI) of anti-VEGF antibody (bevacizumab or ranibizumab). A total of 25 eyes with wet AMD, one with myopic neovascularization, and one with polypoidal choroidal vasculopathy were enrolled in this study...
October 11, 2016: Scientific Reports
Elizabeth A Phillips, Rui Shen, Siyu Zhao, Jacqueline C Linnes
The complexity of current paper-fluidic diagnostic devices is limited by their imperfect control of reagent incubation and delivery. Valves providing complete fluid obstruction and multiple actuation steps within a single paper-fluidic diagnostic would increase the range of diagnostic bioassays in these porous membranes. Here, we report the rapid fabrication of tunable wax-ink valves that are thermally actuated within porous membranes. Varying width bands of wax-ink were printed onto strips of nitrocellulose and cellulose membranes and characterized by their triggered obstruction and release of fluid wicking through the membranes...
October 18, 2016: Lab on a Chip
Katalin Jemnitz, Attila Bátai-Konczos, Mónika Szabó, Enikő Ioja, Orsolya Kolacsek, Tamás I Orbán, György Török, László Homolya, Eszter Kovács, István Jablonkai, Zsuzsa Veres
Increasing number of papers demonstrate that Kupffer cells (KCs) play a role in the development of drug induced liver injury (DILI). Furthermore, elevated intracellular Ca(2+) level of hepatocytes is considered as a common marker of DILI. Here we applied an in vitro model based on hepatocyte mono- and hepatocyte/KC co-cultures (H/KC) isolated from transgenic rats stably expressing the GCaMP2 fluorescent Ca(2+) sensor protein to investigate the effects of polycationic (G5), polyanionic (G4.5) and polyethylene-glycol coated neutral (G5 Peg) dendrimers known to accumulate in the liver, primarily in KCs...
October 4, 2016: Toxicology in Vitro: An International Journal Published in Association with BIBRA
Jason C Harper, Jenna M Andrews, Candice Ben, Andrew C Hunt, Jaclyn K Murton, Bryan D Carson, George D Bachand, Julie A Lovchik, William D Arndt, Melissa R Finley, Thayne L Edwards
Since the introduction of micro total analytical systems (μTASs), significant advances have been made toward development of lab-on-a-chip platforms capable of performing complex biological assays that can revolutionize public health, among other applications. However, use of these platforms in low-resource environments (e.g. developing countries) has yet to be realized as the majority of technologies used to control microfluidic flow rely on off-device hardware with non-negligible size, cost, power requirements and skill/training to operate...
October 18, 2016: Lab on a Chip
Lu Yang, Takatoki Yamamoto
Viruses have drawn much attention in recent years due to increased recognition of their important roles in virology, immunology, clinical diagnosis, and therapy. Because the biological and physical properties of viruses significantly impact their applications, quantitative detection of individual virus particles has become a critical issue. However, due to various inherent limitations of conventional enumeration techniques such as infectious titer assays, immunological assays, and electron microscopic observation, this issue remains challenging...
2016: Frontiers in Microbiology
Ashok Agarwal, Shubhadeep Roychoudhury, Kimberly B Bjugstad, Chak-Lam Cho
The diagnosis of male infertility relies largely on conventional semen analysis, and its interpretation has a profound influence on subsequent management of patients. Despite poor correlation between conventional semen parameters and male fertility potential, inclusion of advanced semen quality tests to routine male infertility workup algorithms has not been widely accepted. Oxidative stress is one of the major mediators in various etiologies of male infertility; it has deleterious effects on spermatozoa, including DNA damage...
October 2016: Therapeutic Advances in Urology
Julia Schückel, Stjepan Krešimir Kračun, William G T Willats
Carbohydrates active enzymes (CAZymes) have multiple roles in vivo and are widely used for industrial processing in the biofuel, textile, detergent, paper and food industries. A deeper understanding of CAZymes is important from both fundamental biology and industrial standpoints. Vast numbers of CAZymes exist in nature (especially in microorganisms) and hundreds of thousands have been cataloged and described in the carbohydrate active enzyme database (CAZy). However, the rate of discovery of putative enzymes has outstripped our ability to biochemically characterize their activities...
2016: Journal of Visualized Experiments: JoVE
Ming Zhou, Sudeep Kundu
Non-inferiority trials aim to demonstrate whether an experimental therapy is not unacceptably worse than an active reference therapy already in use. When applicable, a three-arm non-inferiority trial, including an experiment therapy, an active reference therapy, and a placebo, is often recommended to assess assay sensitivity and internal validity of a trial. In this paper, we share some practical considerations based on our experience from a phase III three-arm non-inferiority trial. First, we discuss the determination of the total sample size and its optimal allocation based on the overall power of the non-inferiority testing procedure and provide ready-to-use R code for implementation...
September 29, 2016: Pharmaceutical Statistics
Ezio Di Costanzo, Vincenzo Ingangi, Claudia Angelini, Maria Francesca Carfora, Maria Vincenza Carriero, Roberto Natalini
Experiments of cell migration and chemotaxis assays have been classically performed in the so-called Boyden Chambers. A recent technology, xCELLigence Real Time Cell Analysis, is now allowing to monitor the cell migration in real time. This technology measures impedance changes caused by the gradual increase of electrode surface occupation by cells during the course of time and provide a Cell Index which is proportional to cellular morphology, spreading, ruffling and adhesion quality as well as cell number...
2016: PloS One
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