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https://www.readbyqxmd.com/read/29152135/evaluation-of-pre-analytical-conditions-and-comparison-of-the-performance-of-several-digital-pcr-assays-for-the-detection-of-major-egfr-mutations-in-circulating-dna-from-non-small-cell-lung-cancers-the-circan_0-study
#1
Jessica Garcia, Eric Dusserre, Valérie Cheynet, Pierre Paul Bringuier, Karen Brengle-Pesce, Anne-Sophie Wozny, Claire Rodriguez-Lafrasse, Gilles Freyer, Marie Brevet, Léa Payen, Sébastien Couraud
Non invasive somatic detection assays are suitable for repetitive tumor characterization or for detecting the appearance of somatic resistance during lung cancer. Molecular diagnosis based on circulating free DNA (cfDNA) offers the opportunity to track the genomic evolution of the tumor, and was chosen to assess the molecular profile of several EGFR alterations, including deletions in exon 19 (delEX19), the L858R substitution on exon 21 and the EGFR resistance mutation T790M on exon 20. Our study aimed at determining optimal pre-analytical conditions and EGFR mutation detection assays for analyzing cfDNA using the picoliter-droplet digital polymerase chain reaction (ddPCR) assay...
October 20, 2017: Oncotarget
https://www.readbyqxmd.com/read/29138790/high-efficiency-single-cell-encapsulation-and-size-selective-capture-of-cells-in-picoliter-droplets-based-on-hydrodynamic-micro-vortices
#2
Gopakumar Kamalakshakurup, Abraham P Lee
Single cell analysis has emerged as a paradigm shift in cell biology to understand the heterogeneity of individual cells in a clone for pathological interrogation. Microfluidic droplet technology is a compelling platform to perform single cell analysis by encapsulating single cells inside picoliter-nanoliter (pL-nL) volume droplets. However, one of the primary challenges for droplet based single cell assays is single cell encapsulation in droplets, currently achieved either randomly, dictated by Poisson statistics, or by hydrodynamic techniques...
November 15, 2017: Lab on a Chip
https://www.readbyqxmd.com/read/29120603/a-high-sensitivity-integrated-absorbance-and-fluorescence-detection-scheme-for-probing-picoliter-volume-droplets-in-segmented-flows
#3
Tianjin Yang, Stavros Stavrakis, Andrew deMello
Droplet-based microfluidic systems that incorporate flowing streams of pL-volume droplets surrounded by a continuous and immiscible carrier phase have attracted significant recent attention due to their utility in complex chemical and biological experimentation. Analysis of pL droplets, generated at kHz frequencies and moving at high linear velocities, is almost exclusively achieved using fluorescence-based detection schemes. To extend the applicability of such optical detection schemes, we herein report the development of a simple and cost-effective optofluidic platform, integrating liquid-core PDMS waveguides, that allows the accurate measurement of absorbance within individual pL-volume droplets moving within segmented flows...
November 17, 2017: Analytical Chemistry
https://www.readbyqxmd.com/read/29067441/multiplex-picoliter-droplet-digital-pcr-for-quantitative-assessment-of-egfr-mutations-in-circulating-cell-free-dna-derived-from-advanced-non-small-cell-lung-cancer-patients
#4
Qian Yu, Fei Huang, Meilin Zhang, Haiying Ji, Shenchao Wu, Ying Zhao, Chunyan Zhang, Jiong Wu, Beili Wang, Baisheng Pan, Xin Zhang, Wei Guo
To explore the possible diagnostic value of liquid biopsy, two multiplex panels using picoliter-droplet digital polymerase chain reaction (ddPCR) were established to quantitatively assess the epidermal growth factor receptor (EGFR) mutations in cell‑free DNA (cfDNA) extracted from the plasma of advanced non‑small cell lung cancer (NSCLC) patients. Plasma samples derived from 22 patients with stage IIIB/IV NSCLC harboring EGFR mutations in matched tumor tissues confirmed by amplification refractory mutation system (ARMS) analysis were subjected to two multiplex ddPCR panels to assess the abundance of tyrosine kinase inhibitor (TKI) ‑sensitive (19DEL, L858R) and TKI‑resistant (T790 M) mutations...
August 2017: Molecular Medicine Reports
https://www.readbyqxmd.com/read/28982006/single-cell-neurometabolomics
#5
Meng Qi, Marina C Philip, Ning Yang, Jonathan V Sweedler
Metabolomics, the characterization of metabolites and their changes within biological systems, has seen great technological and methodological progress over the past decade. Most metabolomic experiments involve the characterization of the small-molecule content of fluids or tissue homogenates. While these microliter and larger volume metabolomic measurements can characterize hundreds to thousands of compounds, the coverage of molecular content decreases as sample sizes are reduced to the nanoliter and even to the picoliter volume range...
October 19, 2017: ACS Chemical Neuroscience
https://www.readbyqxmd.com/read/28972786/absolute-quantification-of-amyloid-propagons-by-digital-microfluidics
#6
Manuela Pfammatter, Maria Andreasen, Georg Meisl, Christopher G Taylor, Jozef Adamcik, Sreenath Bolisetty, Antoni Sánchez-Ferrer, David Klenerman, Christopher M Dobson, Raffaele Mezzenga, Tuomas P J Knowles, Adriano Aguzzi, Simone Hornemann
The self-replicating properties of proteins into amyloid fibrils is a common phenomenon and underlies a variety of neurodegenerative diseases. Because propagation-active fibrils are chemically indistinguishable from innocuous aggregates and monomeric precursors, their detection requires measurements of their replicative capacity. Here we present a digital amyloid quantitative assay (d-AQuA) with insulin as model protein for the absolute quantification of single replicative units, propagons. D-AQuA is a microfluidics-based technology that performs miniaturized simultaneous propagon-induced amplification chain reactions within hundreds to thousands of picoliter-sized droplets...
November 1, 2017: Analytical Chemistry
https://www.readbyqxmd.com/read/28967022/differential-detection-photothermal-spectroscopy-towards-ultra-fast-and-sensitive-label-free-detection-in-picoliter-femtoliter-droplets
#7
Richard M Maceiczyk, David Hess, Flora W Y Chiu, Stavros Stavrakis, Andrew J deMello
Despite the growing importance of droplet-based microfluidics in high-throughput experimentation, few current methods allow the sensitive measurement of absorbance within rapidly moving droplets. To address this significant limitation, we herein present the application of differential detection photothermal interferometry (DDPI) for single-point absorbance quantification in pL- and fL-volume droplets. To assess the efficacy of our approach, we initially measure absorbance in 100 pL droplets at frequencies in excess of 1 kHz and determine a detection limit of 1...
October 25, 2017: Lab on a Chip
https://www.readbyqxmd.com/read/28858351/controlled-droplet-microfluidic-systems-for-multistep-chemical-and-biological-assays
#8
T S Kaminski, P Garstecki
Droplet microfluidics is a relatively new and rapidly evolving field of science focused on studying the hydrodynamics and properties of biphasic flows at the microscale, and on the development of systems for practical applications in chemistry, biology and materials science. Microdroplets present several unique characteristics of interest to a broader research community. The main distinguishing features include (i) large numbers of isolated compartments of tiny volumes that are ideal for single cell or single molecule assays, (ii) rapid mixing and negligible thermal inertia that all provide excellent control over reaction conditions, and (iii) the presence of two immiscible liquids and the interface between them that enables new or exotic processes (the synthesis of new functional materials and structures that are otherwise difficult to obtain, studies of the functions and properties of lipid and polymer membranes and execution of reactions at liquid-liquid interfaces)...
October 16, 2017: Chemical Society Reviews
https://www.readbyqxmd.com/read/28794817/rapid-chemical-free-breaking-of-microfluidic-emulsions-with-a-hand-held-antistatic-gun
#9
Mohsen Karbaschi, Payam Shahi, Adam R Abate
Droplet microfluidics can form and process millions of picoliter droplets with speed and ease, allowing the execution of huge numbers of biological reactions for high-throughput studies. However, at the conclusion of most experiments, the emulsions must be broken to recover and analyze their contents. This is usually achieved with demulsifiers, like perfluorooctanol and chloroform, which can interfere with downstream reactions and harm cells. Here, we describe a simple approach to rapidly and efficiently break microfluidic emulsions, which requires no chemicals...
July 2017: Biomicrofluidics
https://www.readbyqxmd.com/read/28775280/solution-nuclear-magnetic-resonance-spectroscopy-on-a-nanostructured-diamond-chip
#10
P Kehayias, A Jarmola, N Mosavian, I Fescenko, F M Benito, A Laraoui, J Smits, L Bougas, D Budker, A Neumann, S R J Brueck, V M Acosta
Sensors using nitrogen-vacancy centers in diamond are a promising tool for small-volume nuclear magnetic resonance (NMR) spectroscopy, but the limited sensitivity remains a challenge. Here we show nearly two orders of magnitude improvement in concentration sensitivity over previous nitrogen-vacancy and picoliter NMR studies. We demonstrate NMR spectroscopy of picoliter-volume solutions using a nanostructured diamond chip with dense, high-aspect-ratio nanogratings, enhancing the surface area by 15 times. The nanograting sidewalls are doped with nitrogen-vacancies located a few nanometers from the diamond surface to detect the NMR spectrum of roughly 1 pl of fluid lying within adjacent nanograting grooves...
August 4, 2017: Nature Communications
https://www.readbyqxmd.com/read/28760972/printed-droplet-microfluidics-for-on-demand-dispensing-of-picoliter-droplets-and-cells
#11
Russell H Cole, Shi-Yang Tang, Christian A Siltanen, Payam Shahi, Jesse Q Zhang, Sean Poust, Zev J Gartner, Adam R Abate
Although the elementary unit of biology is the cell, high-throughput methods for the microscale manipulation of cells and reagents are limited. The existing options either are slow, lack single-cell specificity, or use fluid volumes out of scale with those of cells. Here we present printed droplet microfluidics, a technology to dispense picoliter droplets and cells with deterministic control. The core technology is a fluorescence-activated droplet sorter coupled to a specialized substrate that together act as a picoliter droplet and single-cell printer, enabling high-throughput generation of intricate arrays of droplets, cells, and microparticles...
August 15, 2017: Proceedings of the National Academy of Sciences of the United States of America
https://www.readbyqxmd.com/read/28715388/measuring-the-densities-of-aqueous-glasses-at-cryogenic-temperatures
#12
Chen Shen, Ethan F Julius, Timothy J Tyree, Ritwik Dan, David W Moreau, Robert Thorne
We demonstrate a method for determining the vitreous phase cryogenic temperature densities of aqueous mixtures, and other samples that require rapid cooling, to prepare the desired cryogenic temperature phase. Microliter to picoliter size drops are cooled by projection into a liquid nitrogen-argon (N2-Ar) mixture. The cryogenic temperature phase of the drop is evaluated using a visual assay that correlates with X-ray diffraction measurements. The density of the liquid N2-Ar mixture is adjusted by adding N2 or Ar until the drop becomes neutrally buoyant...
June 28, 2017: Journal of Visualized Experiments: JoVE
https://www.readbyqxmd.com/read/28701744/massively-parallel-whole-genome-amplification-for-single-cell-sequencing-using-droplet-microfluidics
#13
Masahito Hosokawa, Yohei Nishikawa, Masato Kogawa, Haruko Takeyama
Massively parallel single-cell genome sequencing is required to further understand genetic diversities in complex biological systems. Whole genome amplification (WGA) is the first step for single-cell sequencing, but its throughput and accuracy are insufficient in conventional reaction platforms. Here, we introduce single droplet multiple displacement amplification (sd-MDA), a method that enables massively parallel amplification of single cell genomes while maintaining sequence accuracy and specificity. Tens of thousands of single cells are compartmentalized in millions of picoliter droplets and then subjected to lysis and WGA by passive droplet fusion in microfluidic channels...
July 12, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28701267/development-of-capillary-liquid-chromatography-a-personal-perspective
#14
REVIEW
Milos V Novotny
This is a historical account on the development of capillary LC from its beginning to the present day. The first investigations into the viability of capillary LC date back to the late 1970s, a decade after the pioneering efforts in HPLC. The drastically reduced column dimensions were required to counter the slow solute diffusion in liquids. There were numerous instrumental difficulties with sample introduction and detection in the picoliter or even femtoliter volumes. High-efficiency separations were needed in the analysis of complex biological mixtures...
November 10, 2017: Journal of Chromatography. A
https://www.readbyqxmd.com/read/28667971/controllable-picoliter-pipetting-using-hydrophobic-microfluidic-valves
#15
M Zhang, J Huang, X Qian, S Mi, X Wang
A picoliter pipetting technique using the microfluidic method is presented. Utilizing the hydrophobic self-assembled monolayer films patterned in microchannels as pressure-controlled valves, a small volume of liquid can be separated by a designed channel trap and then ejected from the channel end at a higher pressure. The liquid trap section is composed of a T-shaped channel junction and a hydrophobic patch. The liquid volume can be precisely controlled by varying the distance of the hydrophobic patch from the T-junction...
June 2017: Review of Scientific Instruments
https://www.readbyqxmd.com/read/28609716/accelerating-bacterial-growth-detection-and-antimicrobial-susceptibility-assessment-in-integrated-picoliter-droplet-platform
#16
Aniruddha M Kaushik, Kuangwen Hsieh, Liben Chen, Dong Jin Shin, Joseph C Liao, Tza-Huei Wang
There remains an urgent need for rapid diagnostic methods that can evaluate antibiotic resistance for pathogenic bacteria in order to deliver targeted antibiotic treatments. Toward this end, we present a rapid and integrated single-cell biosensing platform, termed dropFAST, for bacterial growth detection and antimicrobial susceptibility assessment. DropFAST utilizes a rapid resazurin-based fluorescent growth assay coupled with stochastic confinement of bacteria in 20 pL droplets to detect signal from growing bacteria after 1h incubation, equivalent to 2-3 bacterial replications...
November 15, 2017: Biosensors & Bioelectronics
https://www.readbyqxmd.com/read/28604851/analysis-of-ribonuclease-activity-in-sub-nanoliter-droplets-by-label-free-fluorescence-measurements
#17
Jae-Won Choi, Bala Murali Krishna Vasamsetti, Kyu-Wan Kim, Seung Hwan Seo, Dong-Hun Lee, Soo-Ik Chang, Jaebum Choo, Hak Yong Kim
We report the results of a label-free analysis of ribonuclease activity using droplet-based microfluidics. The ribonucleolytic activity of ribonucleases (RNases) plays a critical role in cellular functions such as development, survival, growth and differentiation. Altered ribonucleolytic activity and/or the expression level of the RNase A family are known to be associated with pancreatic, bladder, ovarian and thyroid cancers among others. For this reason, the RNase A family is a meaningful protein biomarker that can be used in the diagnosis of cancer and as a target for new drug screening...
July 10, 2017: Analyst
https://www.readbyqxmd.com/read/28569852/micro-sized-tunable-liquid-crystal-optical-filters
#18
Caleb Stoltzfus, Russell Barbour, David Atherton, Zeb Barber
Liquid crystal arrayed microcavities (LCAM) is a new technology for ultra-narrow optical filtering (FWHM ∼0.1  nm) that uses picoliter volume Fabry-Perot-type optical cavities filled with liquid crystal for tuning. LCAMs are sub-nm spectral resolution filters, which utilize well-established laser writing, thin film deposition, and wafer manufacturing techniques. These filters are compact, robust, and inexpensive. Compact, high-resolution optical filters have applications, including biomedical imaging, chemical detection, and environmental monitoring...
June 1, 2017: Optics Letters
https://www.readbyqxmd.com/read/28532147/development-of-a-bacterial-biosensor-for-rapid-screening-of-yeast-p-coumaric-acid-production
#19
Solvej Siedler, Narendar K Khatri, Andrea Zsohár, Inge Kjærbølling, Michael Vogt, Petter Hammar, Christian F Nielsen, Jan Marienhagen, Morten O A Sommer, Haakan N Joensson
Transcription factor-based biosensors are used to identify producer strains, a critical bottleneck in cell factory engineering. Here, we address two challenges with this methodology: transplantation of heterologous transcriptional regulators into new hosts to generate functional biosensors and biosensing of the extracellular product concentration that accurately reflects the effective cell factory production capacity. We describe the effects of different translation initiation rates on the dynamic range of a p-coumaric acid biosensor based on the Bacillus subtilis transcriptional repressor PadR by varying its ribosomal binding site...
June 21, 2017: ACS Synthetic Biology
https://www.readbyqxmd.com/read/28527094/circulating-tumor-dna-measurement-by-picoliter-droplet-based-digital-pcr-and-vemurafenib-plasma-concentrations-in-patients-with-advanced-braf-mutated-melanoma
#20
Fanny Garlan, Benoit Blanchet, Nora Kramkimel, Alicja Puszkiel, Jean-Louis Golmard, Gaelle Noe, Nicolas Dupin, Pierre Laurent-Puig, Michel Vidal, Valerie Taly, Audrey Thomas-Schoemann
BACKGROUND: Circulating tumor DNA (ctDNA) has been reported as a prognostic marker in melanoma. In BRAF V600-mutant melanoma, a plasma under-exposure to vemurafenib could favor emerging resistance but no biological data are available to support this hypothesis. OBJECTIVE: We aimed to investigate the relationship between vemurafenib plasma concentrations and the ctDNA plasma concentration during follow-up of BRAF-mutated melanoma patients. PATIENTS AND METHODS: Eleven patients treated with single-agent vemurafenib for advanced BRAF V600-mutant melanoma were analyzed in an exploratory monocentric study...
June 2017: Targeted Oncology
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