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Yanzhen Zhang, Gunther Wittstock
Small droplets can be manipulated based on controlling the adhesion work to a hydrophobic wire. The wire can be used to pick up, transport, and lay down droplets with volumes between picoliters to microliters avoiding the sliding of droplets over chip surfaces. Handling of droplets on surfaces with large steps such as engraved wells or channels is possible.
November 14, 2016: Small
G Arrabito, F Cavaleri, V Montalbano, V Vetri, M Leone, B Pignataro
The assembly of scalable liquid compartments for binding assays in array formats constitutes a topic of fundamental importance in life sciences. This challenge can be addressed by mimicking the structure of cellular compartments with biological native conditions. Here, inkjet printing is employed to develop up to hundreds of picoliter aqueous droplet arrays stabilized by oil-confinement with mild surfactants (Tween-20). The aqueous environments constitute specialized compartments in which biomolecules may exploit their function and a wide range of molecular interactions can be quantitatively investigated...
November 4, 2016: Lab on a Chip
Yusi Fu, He Chen, Lu Liu, Yanyi Huang
Prevalent single cell RNA amplification and sequencing chemistries mainly focus on polyadenylated RNAs in eukaryotic cells by using oligo(dT) primers for reverse transcription. We develop a new RNA amplification method, "easier-seq", to reverse transcribe and amplify the total RNAs, both with and without polyadenylate tails, from a single cell for transcriptome sequencing with high efficiency, reproducibility, and accuracy. By distributing the reverse transcribed cDNA molecules into 1.5x10(5) aqueous droplets in oil, the cDNAs are isothermally amplified using random primers in each of these 65-picoliter reactors separately...
October 26, 2016: Analytical Chemistry
Jodi L Connell, Eric T Ritschdorff, Jason B Shear
Advances in microscopic three-dimensional (µ3D) printing provide a means to microfabricate an almost limitless range of arbitrary geometries, offering new opportunities to rapidly prototype complex architectures for microfluidic and cellular applications. Such 3D lithographic capabilities present the tantalizing prospect for engineering micromechanical components - for example, pumps and valves - for cellular environments comprised of smart materials whose size, shape, permeability, stiffness, and other attributes might be modified in real time to precisely manipulate ultra-low-volume samples...
October 26, 2016: Analytical Chemistry
Zitian Chen, Yusi Fu, Fangli Zhang, Lu Liu, Naiqing Zhang, Dong Zhou, Junrui Yang, Yuhong Pang, Yanyi Huang
Many on-chip approaches that use flow-focusing to pinch the continuous aqueous phase into droplets have become the most popular methods that provide monodisperse emulsion droplets. However, not every lab can easily adapt a microfluidic workflow into their familiar protocols. We develop an off-chip approach, spinning micro-pipette liquid emulsion (SiMPLE) generator, to produce highly stable monodisperse water-in-oil emulsions using a moving micropipette to disperse the aqueous phase in an oil-filled microcentrifuge tube...
October 24, 2016: Lab on a Chip
Xianming Kong, Yuting Xi, Paul LeDuff, Erwen Li, Ye Liu, Li-Jing Cheng, Gregory L Rorrer, Hua Tan, Alan X Wang
Novel transducers for detecting an ultra-small volume of an analyte solution play pivotal roles in many applications such as chemical analysis, environmental protection and biomedical diagnosis. Recent advances in optofluidics offer tremendous opportunities for analyzing miniature amounts of samples with high detection sensitivity. In this work, we demonstrate enormous enhancement factors (10(6)-10(7)) of the detection limit for optofluidic analysis from inkjet-printed droplets by evaporation-induced spontaneous flow on photonic crystal biosilica when compared with conventional surface-enhanced Raman scattering (SERS) sensing using the pipette dispensing technology...
October 6, 2016: Nanoscale
Roshni J Best, Jan J Lyczakowski, Sara Abalde-Cela, Ziyi Yu, Chris Abell, Alison G Smith
Microalgae and cyanobacteria are promising organisms for sustainable biofuel production, but several challenges remain to make this economically viable, including identification of optimized strains with high biomass productivity. Here we report on a novel methodology for the label-free screening and sorting of cyanobacteria and microalgae in a microdroplet platform. We show for the first time that chlorophyll fluorescence can be used to measure differences in biomass between populations of picoliter microdroplets containing different species of cyanobacteria, Synechocystis PCC 6803 and Synechococcus PCC 7002, which exhibit different growth dynamics in bulk culture...
October 21, 2016: Analytical Chemistry
J Riba, T Gleichmann, S Zimmermann, R Zengerle, P Koltay
The isolation and analysis of single prokaryotic cells down to 1 μm and less in size poses a special challenge and requires micro-engineered devices to handle volumes in the picoliter to nanoliter range. Here, an advanced Single-Cell Printer (SCP) was applied for automated and label-free isolation and deposition of bacterial cells encapsulated in 35 pl droplets by inkjet-like printing. To achieve this, dispenser chips to generate micro droplets have been fabricated with nozzles 20 μm in size. Further, the magnification of the optical system used for cell detection was increased...
2016: Scientific Reports
Lindong Weng, Shannon N Tessier, Kyle Smith, Jon F Edd, Shannon L Stott, Mehmet Toner
Ice nucleation is of fundamental significance in many areas, including atmospheric science, food technology, and cryobiology. In this study, we investigated the ice-nucleation characteristics of picoliter-sized drops consisting of different D2O and H2O mixtures with and without the ice-nucleating bacteria Pseudomonas syringae. We also studied the effects of commonly used cryoprotectants such as ethylene glycol, propylene glycol, and trehalose on the nucleation characteristics of D2O and H2O mixtures. The results show that the median freezing temperature of the suspension containing 1 mg/mL of a lyophilized preparation of P...
September 13, 2016: Langmuir: the ACS Journal of Surfaces and Colloids
Xiaoyun Shawn Yang, Soojeong Shin, Woon Seob Lee, Jong Wook Hong
We have demonstrated fine control of droplet volumes on a chip using pneumatically actuated micro valve systems resulting in confined nanoliter or picoliter reagent generation. Using the micro valves, we are able to align multi-inlet droplet generating chips for systematic generation of combinatorial mixtures of chemical constituents. By following the change of chemical conditions such as pH we converted musical note information into sequential droplets representing musical scores of 'Twinkle little star.' It would just one of the interesting application of micro-droplet generation systems based on accurate droplet generation, mixing, and incubation...
June 2016: Journal of Nanoscience and Nanotechnology
Orane Guillaume-Gentil, Rashel V Grindberg, Romain Kooger, Livie Dorwling-Carter, Vincent Martinez, Dario Ossola, Martin Pilhofer, Tomaso Zambelli, Julia A Vorholt
Because of cellular heterogeneity, the analysis of endogenous molecules from single cells is of significant interest and has major implications. While micromanipulation or cell sorting followed by cell lysis is already used for subsequent molecular examinations, approaches to directly extract the content of living cells remain a challenging but promising alternative to achieving non-destructive sampling and cell-context preservation. Here, we demonstrate the quantitative extraction from single cells with spatiotemporal control using fluidic force microscopy...
July 14, 2016: Cell
Eleonora Zonta, Fanny Garlan, Nicolas Pécuchet, Karla Perez-Toralla, Ouriel Caen, Coren Milbury, Audrey Didelot, Elizabeth Fabre, Hélène Blons, Pierre Laurent-Puig, Valérie Taly
In cancer research, the accuracy of the technology used for biomarkers detection is remarkably important. In this context, digital PCR represents a highly sensitive and reproducible method that could serve as an appropriate tool for tumor mutational status analysis. In particular, droplet-based digital PCR approaches have been developed for detection of tumor-specific mutated alleles within plasmatic circulating DNA. Such an approach calls for the development and validation of a very significant quantity of assays, which can be extremely costly and time consuming...
2016: PloS One
Xiao-Xia Fang, Pan Fang, Jian-Zhang Pan, Qun Fang
Here, a compact high-speed CE bioanalyzer based on a short capillary has been developed. Multiple modules of picoliter scale sample injection, high-speed CE separation, sample changing, LIF detection, as well as a custom designed tablet computer for data processing, instrument controlling, and result displaying were integrated in the bioanalyzer with a total size of 23 × 17 × 19 cm (length × width × height). The high-speed CE bioanalyzer is capable of performing automated sample injection and separation for multiple samples and has been successfully applied in fast separations of amino acids, chiral amino acids, proteins and DNA fragments...
September 2016: Electrophoresis
Bingzhao Xia, Kaspars Krutkramelis, John Oakey
Encapsulating cells within biocompatible materials is a widely used strategy for cell delivery and tissue engineering. While cells are commonly suspended within bulk hydrogel-forming solutions during gelation, substantial interest in the microfluidic fabrication of miniaturized cell encapsulation vehicles has more recently emerged. Here, we utilize multiphase microfluidics to encapsulate cells within photopolymerized picoliter-volume water-in-oil droplets at high production rates. The photoinitiated polymerization of polyethylene glycol diacrylate (PEGDA) is used to continuously produce solid particles from aqueous liquid drops containing cells and hydrogel forming solution...
July 11, 2016: Biomacromolecules
C Wyatt Shields, Korine A Ohiri, Lizzy M Szott, Gabriel P López
Advances in microfluidic cell sorting have revolutionized the ways in which cell-containing fluids are processed, now providing performances comparable to, or exceeding, traditional systems, but in a vastly miniaturized format. These technologies exploit a wide variety of physical phenomena to manipulate cells and fluid flow, such as magnetic traps, sound waves and flow-altering micropatterns, and they can evaluate single cells by immobilizing them onto surfaces for chemotherapeutic assessment, encapsulate cells into picoliter droplets for toxicity screenings and examine the interactions between pairs of cells in response to new, experimental drugs...
June 10, 2016: Cytometry. Part B, Clinical Cytometry
Fabio Del Ben, Matteo Turetta, Giorgia Celetti, Aigars Piruska, Michela Bulfoni, Daniela Cesselli, Wilhelm T S Huck, Giacinto Scoles
The number of circulating tumor cells (CTCs) in blood is strongly correlated with the progress of metastatic cancer. Current methods to detect CTCs are based on immunostaining or discrimination of physical properties. Herein, a label-free method is presented exploiting the abnormal metabolic behavior of cancer cells. A single-cell analysis technique is used to measure the secretion of acid from individual living tumor cells compartmentalized in microfluidically prepared, monodisperse, picoliter (pL) droplets...
July 18, 2016: Angewandte Chemie
Gia Chuong Phan-Quang, Hiang Kwee Lee, Xing Yi Ling
Miniaturized liquid-liquid interfacial reactors offer enhanced surface area and rapid confinement of compounds of opposite solubility, yet they are unable to provide in situ reaction monitoring at a molecular level at the interface. A picoreactor operative at the liquid-liquid interface is described, comprising plasmonic colloidosomes containing Ag octahedra strategically assembled at the water-in-decane emulsion interface. The plasmonic colloidosomes isolate ultrasmall amounts of solutions (<200 pL), allowing parallel monitoring of multiple reactions simultaneously...
July 11, 2016: Angewandte Chemie
Q Li, Y Zhu, N-Q Zhang, Q Fang
In this paper, we developed a novel approach for interfacing a microfluidic two-dimensional droplet array to a high-speed capillary electrophoresis (HSCE) system. Picoliter-scale sample injection (ca. 200 pL) from a nanoliter-scale droplet array covered by nonvolatile oil was automatically achieved using the spontaneous injection mode, without the interference from the cover oil and the need of special droplet extraction interface as in previously reported systems. The system was applied in consecutive separations of 25 different samples of amino acids with a whole separation time less than 15 min, as well as on-line monitoring of in-droplet derivatizing reaction of amino acids by fluorescein isothiocyanate (FITC) over 3 hours...
2016: Scientific Reports
Joseph P Patterson, Lucas R Parent, Joshua Cantlon, Holger Eickhoff, Guido Bared, James E Evans, Nathan C Gianneschi
Liquid cell transmission electron microscopy (LCTEM) provides a unique insight into the dynamics of nanomaterials in solution. Controlling the addition of multiple solutions to the liquid cell remains a key hurdle in our ability to increase throughput and to study processes dependent on solution mixing including chemical reactions. Here, we report that a piezo dispensing technique allows for mixing of multiple solutions directly within the viewing area. This technique permits deposition of 50 pL droplets of various aqueous solutions onto the liquid cell window, before assembly of the cell in a fully controlled manner...
June 2016: Microscopy and Microanalysis
Rui Hu, Pian Liu, Pu Chen, Liang Wu, Yao Wang, Xiaojun Feng, Bi-Feng Liu
Random compartmentalization of cells by common droplet formation methods, i.e., T-junction and flow-focusing, results in low occupancy of droplets by single cells. To resolve this issue, a fluorescence-activated droplet formation method was developed for the on-command generation of droplets and encapsulation of single cells. In this method, droplets containing one cell were generated by switching on/off a two-phase hydrodynamic gating valve upon optical detection of single cells. To evaluate the developed method, flow visualization experiments were conducted with fluorescein...
June 1, 2016: Talanta
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