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Lab on a Chip

D H Yoon, K Kobayashi, D Tanaka, T Sekiguchi, S Shoji
This paper presents the formation of complex cross-sectional microfibers using three-dimensional microfluidic devices. The compartments and shapes of core and shell layers in the microfibers were independently controlled via three-dimensional fluidic channels fabricated by the combination of sheath units. The number of layers is easily expanded by the stacking of these units. Therefore, the highly heterogeneous microfibers of alginate hydrogel are obtained in polydimethylsiloxane structures. This widely expandable method has great potential for the development of functional and complex fiber-shaped materials...
March 16, 2017: Lab on a Chip
Collin B Eaker, Ishan D Joshipura, Logan R Maxwell, Jason Heikenfeld, Michael D Dickey
Correction for 'Electrowetting without external voltage using paint-on electrodes' by Collin B. Eaker et al., Lab Chip, 2017, DOI: .
March 16, 2017: Lab on a Chip
Despina Moschou, Angeliki Tserepi
Commercialization of lab-on-a-chip devices is currently the "holy grail" within the μTAS research community. While a wide variety of highly sophisticated chips which could potentially revolutionize healthcare, biology, chemistry and all related disciplines are increasingly being demonstrated, very few chips are or can be adopted by the market and reach the end-users. The major inhibition factor lies in the lack of an established commercial manufacturing technology. The lab-on-printed circuit board (lab-on-PCB) approach, while suggested many years ago, only recently has re-emerged as a very strong candidate, owing to its inherent upscaling potential: the PCB industry is well established all around the world, with standardized fabrication facilities and processes, but commercially exploited currently only for electronics...
March 15, 2017: Lab on a Chip
Rhonda Jack, Khadijah Hussain, Danika Rodrigues, Mina Zeinali, Ebrahim Azizi, Max Wicha, Diane M Simeone, Sunitha Nagrath
The extent of inter- and intra-tumor cell heterogeneity observed in patient tumors appears to be directly associated with patient prognosis. Moreover, studies indicate that targeting distinct subpopulations of tumor cells may be more relevant to successfully managing cancer metastasis. The ability to distinguish and characterize unique tumor cell subpopulations within a given sample is thus exigent. Existing platforms separate cells binarily, based on some threshold level of phenotypic characteristics without consideration of the continuum levels of biomarker expression and the associated implications...
March 15, 2017: Lab on a Chip
Wonjin Yun, Cynthia M Ross, Sophie Roman, Anthony R Kovscek
Silicon-based microfluidic devices, so-called micromodels in this application, are particularly useful laboratory tools for the direct visualization of fluid flow revealing pore-scale mechanisms controlling flow and transport phenomena in natural porous media. Current microfluidic devices with uniform etched depths, however, are limited when representing complex geometries such as the multiple-scale pore sizes common in carbonate rocks. In this study, we successfully developed optimized sequential photolithography to etch micropores (1...
March 15, 2017: Lab on a Chip
Esther Amstad, Frans Spaepen, Michael P Brenner, David A Weitz
Many powders employed in the food and pharmaceutical industries are produced through spray drying because it is a cost efficient process that offers control over the particle size. However, most commercially available spray-driers cannot produce drops with diameters below 1 μm, limiting the size of spray-dried particles to values above 300 nm. We recently developed a microfluidic spray-drier that can form much smaller drops than commercially available spray-driers. This is achieved through a two-step process: first, the microfluidic spray-drier operates in the dripping regime to form 100 μm diameter primary drops in air and, second, subjects them to high shear stresses due to supersonic flow of air to break them into many much smaller secondary drops...
March 15, 2017: Lab on a Chip
Yao Lu, Liu Yang, Wei Wei, Qihui Shi
Cellular heterogeneity has been widely recognized but only recently have single cell tools become available that allow characterizing heterogeneity at the genomic and proteomic levels. We review the technological advances in microchip-based toolkits for single-cell functional proteomics. Each of these tools has distinct advantages and limitations, and a few have advanced toward being applied to address biological or clinical problems that traditional population-based methods fail to address. High-throughput single-cell proteomic assays generate high-dimensional data sets that contain new information and thus require developing new analytical frameworks to extract new biology...
March 10, 2017: Lab on a Chip
L D'Amico, N J Ajami, J A Adachi, P R C Gascoyne, J F Petrosino
A microfluidic system that combines membraneless microfluidic dialysis and dielectrophoresis to achieve label-free isolation and concentration of bacteria from whole blood is presented. Target bacteria and undesired blood cells are discriminated on the basis of their differential susceptibility to permeabilizing agents that alter the dielectrophoretic behavior of blood cells but not bacteria. The combined membraneless microdialysis and dielectrophoresis system isolated 79 ± 3% of Escherichia coli and 78 ± 2% of Staphylococcus aureus spiked into whole blood at a processing rate of 0...
March 9, 2017: Lab on a Chip
Ata Dolatmoradi, Elnaz Mirtaheri, Bilal El-Zahab
Biomechanical properties of cells such as cellular stiffness have been increasingly considered as biomarkers for diseases. For instance, stiffness of cancer cells has been correlated to the malignant potential in certain cell lines. In cells, the cholesterol content plays a crucial role in determining stiffness. Changes in the cholesterol content in cellular membranes can be an indication of pathological disorders. Acoustophoresis as a separation and diagnostic tool is well positioned to help in the separation and diagnosis of cells taking advantage of its unique separation criteria of density and compressibility...
March 8, 2017: Lab on a Chip
W Postek, T S Kaminski, P Garstecki
We present a novel geometry of microfluidic channels that allows us to passively generate monodisperse emulsions of hundreds of droplets smaller than 1 nL from collections of larger (ca. 0.4 μL) mother droplets. We introduce a new microfluidic module for the generation of droplets via passive break-up at a step. The module alleviates a common problem in step emulsification with efficient removal of the droplets from the vicinity of the step. In our solution, the droplets are pushed away from the step by a continuous liquid that bypasses the mother droplets via specially engineered bypasses that lead to the step around the main channel...
March 8, 2017: Lab on a Chip
Ruihua Tang, Hui Yang, Yan Gong, MinLi You, Zhi Liu, Jane Ru Choi, Ting Wen, Zhiguo Qu, Qibing Mei, Feng Xu
Nucleic acid testing (NAT) has been widely used for disease diagnosis, food safety control and environmental monitoring. At present, NAT mainly involves nucleic acid extraction, amplification and detection steps that heavily rely on large equipment and skilled workers, making the test expensive, time-consuming, and thus less suitable for point-of-care (POC) applications. With advances in paper-based microfluidic technologies, various integrated paper-based devices have recently been developed for NAT, which however require off-chip reagent storage, complex operation steps and equipment-dependent nucleic acid amplification, restricting their use for POC testing...
March 8, 2017: Lab on a Chip
H L Liu, Y Shi, L Liang, L Li, S S Guo, L Yin, Y Yang
A gradient refractive index (GRIN) lens has a great potential for on-chip imaging and detection systems because of its flat surface with reduced defects. This paper reports a liquid thermal GRIN lens prepared using heat conduction between only one liquid, and uses it as a tunable optical tweezer for single living cell trapping in a flowing environment. This liquid GRIN lens consists of a trapezoidal region in the upper layer which is used to establish a GRIN profile by the heat conduction between three streams of benzyl alcohol with different temperatures, and subsequently a rhombus region in the lower layer with compensation liquids to form a steady square-law parabolic refractive index profile only in transverse direction...
March 8, 2017: Lab on a Chip
H Wang, N Sobahi, A Han
An impedance spectroscopy-based cell/particle position detection method in microfluidic systems is presented. A single pair of non-parallel surface microelectrodes was utilized to detect the transverse positions of particles/cells flowing in a microchannel without the need for a multi-electrode multi-channel impedance detection. This method can be a simple solution for high-throughput and low-cost position detection in microfluidic sorting and separation applications.
March 7, 2017: Lab on a Chip
Eugene Kim, Martin D Baaske, Frank Vollmer
Whispering gallery mode biosensors have been widely exploited over the past decade to study molecular interactions by virtue of their high sensitivity and applicability in real-time kinetic analysis without the requirement to label. There have been immense research efforts made for advancing the instrumentation as well as the design of detection assays, with the common goal of progressing towards real-world sensing applications. We therefore review a set of recent developments made in this field and discuss the requirements that whispering gallery mode label-free sensors need to fulfill for making a real world impact outside of the laboratory...
March 7, 2017: Lab on a Chip
Koen de Wijs, Chengxun Liu, Alexandra Dusa, Dries Vercruysse, Bivragh Majeed, Deniz Sabuncuoglu Tezcan, Kamil Blaszkiewicz, Josine Loo, Liesbet Lagae
Safe, high-rate and cost-effective cell sorting is important for clinical cell isolation. However, commercial fluorescence-activated cell sorters (FACS) are expensive and prone to aerosol-induced sample contamination. Here we report a microfluidic cell sorter allowing high rate and fully enclosed cell sorting. The sorter chip consists of an array of micro heating hotspots. Pulsed resistive heating in the hotspots produces numerous micro vapor bubbles with short duration, which gives rise to a rapid jet flow for cell sorting...
March 2, 2017: Lab on a Chip
Thomas F Scherr, Sparsh Gupta, David W Wright, Frederick R Haselton
Many countries are shifting their efforts from malaria control to disease elimination. New technologies will be necessary to meet the more stringent demands of elimination campaigns, including improved quality control of malaria diagnostic tests, as well as an improved means for communicating test results among field healthcare workers, test manufacturers, and national ministries of health. In this report, we describe and evaluate an embedded barcode within standard rapid diagnostic tests as one potential solution...
March 2, 2017: Lab on a Chip
Kentaro Yamada, Hiroyuki Shibata, Koji Suzuki, Daniel Citterio
Microfluidic paper-based analytical devices (μPADs) have emerged as a promising diagnostic platform a decade ago. In contrast to highly active academic developments, their entry into real-life applications is still very limited. This discrepancy is attributed to the gap between research developments and their practical utility, particularly in the aspects of operational simplicity, long-term stability of devices, and associated equipment. On the basis of these backgrounds, this review attempts to: 1) identify the reasons for success of paper-based devices already in the market, 2) describe the current status and remaining issues of μPADs in terms of operational complexity, signal interpretation approaches, and storage stability, and 3) discuss the possibility of mass production based on established manufacturing technologies...
March 2, 2017: Lab on a Chip
Zhimin Zhai, Fengqiu Zhang, Xiangyu Chen, Jie Zhong, Gang Liu, Yangchao Tian, Qing Huang
This paper reports on the synthesis and application of biocompatible and sensitive SERS nanoparticles for the study of uptake of nanoparticles into living cells in a microfluidic chip through surface-enhanced Raman spectroscopy (SERS). The nanoparticles were fabricated as beta-cyclodextrin-coated silver nanoparticles (Ag@CD NPs) modified with para-aminothiophenol (p-ATP) and folic acid (FA) on the surface. The p-ATP molecules act as the Raman reporter while the FA tags have high affinity for folate receptors (FR) that are over-expressed on the surface cancerous cells, so that the nanoparticles can enter the cells and be monitored by the Raman reporter...
March 1, 2017: Lab on a Chip
Gang Zhao, Zhiguo Zhang, Yuntian Zhang, Zhongrong Chen, Dan Niu, Yunxia Cao, Xiaoming He
Accurate characterization of the cell membrane transport properties of human oocytes is of great significance to reproductive pharmacology, fertility preservation, and assisted reproduction. However, the commonly used manual method for quantifying the transport properties is associated with uncontrolled operator-to-operator and run-to-run variability. Here, we report a novel sandwich structured microfluidic device that can be readily fabricated for characterizing oocyte membrane transport properties. Owing to its capacity for excellent control of both solution replacement and temperature in the microchannel, the temperature-dependent permeability of the oocyte membrane can be precisely characterized...
February 28, 2017: Lab on a Chip
Kristian Torbensen, Federico Rossi, Sandra Ristori, Ali Abou-Hassan
Chemical communication leading to synchronization and collective behaviour of dynamic elements, such as cell colonies, is a widespread phenomenon with biological, physical and chemical importance. Such synchronization between elements proceeds via chemical communication by emmision, interdiffusion and reception of specific messenger molecules. On a lab scale, these phenomena can be modeled by encapsulating an oscillating chemical reaction, which serves as a signal (information) sender/receiver element, inside microcompartments such as droplet emulsions, liposomes and polymersomes...
February 27, 2017: Lab on a Chip
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