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Lab on a Chip

Crispin Szydzik, Rose J Brazilek, Khashayar Khoshmanesh, Farzan Akbaridoust, Markus Knoerzer, Peter Thurgood, Ineke Muir, Ivan Marusic, Harshal Nandurkar, Arnan Mitchell, Warwick S Nesbitt
This paper reports on the parameters that determine the haemocompatibility of elastomeric microvalves for blood handling in microfluidic systems. Using a comprehensive investigation of blood function, we describe a hierarchy of haemocompatibility as a function of microvalve geometry and identify a "normally-closed" v-gate pneumatic microvalve design that minimally affects blood plasma fibrinogen and von Willebrand factor composition, minimises effects on erythrocyte structure and function, and limits effects on platelet activation and aggregation, while facilitating rapid switching control for blood sample delivery...
May 23, 2018: Lab on a Chip
H Antypas, M Veses-Garcia, E Weibull, H Andersson-Svahn, A Richter-Dahlfors
The Petri dish and microtiter plate are the golden standard for selection and screening of bacteria in microbiological research. To improve on the limited resolution and throughput of these methods, we developed a universal, user-friendly platform for selection and high-resolution phenotypic screening based on the nanowell slide. This miniaturized platform has an optimal ratio between throughput and assay complexity, holding 672 nanowells of 500 nl each. As monoclonality is essential in bacterial genetics, we used FACS to inoculate each nanowell with a single bacterium in 15 min...
May 21, 2018: Lab on a Chip
Xin-Yu Cao, Fan-Zhi Kong, Qiang Zhang, Wei-Wen Liu, Xiao-Ping Liu, Guo-Qing Li, Ran Zhong, Liu-Yin Fan, Hua Xiao, Cheng-Xi Cao
As a vital enzyme, alkaline phosphatase (ALP) has great clinical significance in diagnoses of bone or liver cancer, bone metastases, rickets, and extrahepatic biliary obstruction. However, there is still no really portable chip for the ALP assay in blood. Herein, a simple electrophoresis titration (ET) model was developed for ALP detection via a moving reaction boundary (MRB). In the model, ALP catalyzed the dephosphorylation of a 4-methylumbelliferyl phosphate disodium salt (4-MUP) substrate in the cathode well to 4-methylumbelliferone ([4-MU]-) with a negative charge and blue fluorescence under UV excitation...
May 21, 2018: Lab on a Chip
Qingfu Zhu, Mikala Heon, Zheng Zhao, Mei He
Study of extracellular vesicles (EVs), particularly exosomes, holds significant promise; however, it is technically challenging to define these small and molecularly diverse nanovesicles. With intrinsic molecular payload and biodegradability, molecular engineering of exosomes opens new avenues for mediating cellular responses and developing novel nano-delivery systems in precision therapeutics. Microfluidic lab-on-chip technology is playing pivotal roles in this emerging field. In this review, we have examined scientific advancements of microfluidic technology for engineering exosomes and assessed future applications and perspectives in developing precision therapeutics; this can serve the community via identification of potential new research areas or technologies that are urgently needed in precision therapeutics...
May 21, 2018: Lab on a Chip
C Pin, J-B Jager, M Tardif, E Picard, E Hadji, F de Fornel, B Cluzel
Fourteen years ago, optical lattices and holographic tweezers were considered as a revolution, allowing for trapping and manipulating multiple particles at the same time using laser light. Since then, near-field optical forces have aroused tremendous interest as they enable efficient trapping of a wide range of objects, from living cells to atoms, in integrated devices. Yet, handling at will multiple objects using a guided light beam remains a challenging task for current on-chip optical trapping techniques...
May 18, 2018: Lab on a Chip
Anne M Benneker, Burcu Gumuscu, Ernest G H Derckx, Rob G H Lammertink, Jan C T Eijkel, Jeffery A Wood
A microfluidic platform containing charged hydrogels is used to investigate the effect of geometry on charge transport in electrodialysis applications. The influence of heterogeneity on ion transport is determined by electrical characterization and fluorescence microscopy of three different hydrogel geometries. We found that electroosmotic transport of ions towards the hydrogel is enhanced in heterogeneous geometries, as a result of the inhomogeneous electric field in these systems. This yields higher ionic currents for equal applied potentials when compared to homogeneous geometries...
May 17, 2018: Lab on a Chip
Roger Krenger, Thomas Lehnert, Martin A M Gijs
Basal heat production is a key phenotype for assessing the metabolic activity of small living organisms. Here, we present a new nanocalorimetric system, based on thin film thermopile sensors combined with microfluidic chips for measuring metabolic heat signals generated by Caenorhabditis elegans larval populations (60 to 220 organisms). In addition to versatile on-chip fluidic manipulation, our microfluidic approach allows confining worm populations close to the sensor surface, thus increasing the sensitivity of the assays...
May 17, 2018: Lab on a Chip
Jae Jung Kim, Eduardo Reátegui, Alex Hopke, Fatemeh Jalali, Maedeh Roushan, Patrick S Doyle, Daniel Irimia
Neutrophils are the first white blood cells to respond to microbes and to limit their invasion of the body. However, the growth of the microbes into colonies often challenges the neutrophils ability to contain them. To study the interactions between neutrophils and microbial colonies, we designed an assay for arranging microbes in clusters of controlled size (i.e. living colloids). The patterned microbes in the living colloid are mechanically trapped inside the wells and fully accessible to neutrophils. Using the assay, we studied the interactions between human neutrophils and Candida albicans and Staphylococcus aureus, two common human pathogens...
May 17, 2018: Lab on a Chip
Nianbing Zhong, Ming Chen, Zhengkun Wang, Xin Xin, Bingxin Li
We demonstrate that a lab-on-a-chip device (hereafter termed a photochemical phenol sensor) that integrates a photocatalytic long-period fiber grating (PLPFG), fiber Bragg grating (FBG), polymer membrane, ultraviolet (UV) visible light, and microchannels can be exploited to selectively detect phenol in aqueous solutions. The novel PLPFG consisted of a thinned long-period fiber grating (LPFG) and a UV-visible-light-driven Er3+:YAlO3/SiO2/TiO2 (EYST) coating. The polymer membrane with high phenol permselectivity was synthesized using PEBA2533 doped with β-cyclodextrin and was wrapped around the EYST surface, thus forming a microchannel between the membrane and PLPFG to enable the injection and outflow of standard analytes...
May 16, 2018: Lab on a Chip
Jia-Han Wu, Chih-Hung Wang, Yu-Dong Ma, Gwo-Bin Lee
Bacteria such as Acinetobacter baumannii (AB) can cause serious infections, resulting in high mortality if not diagnosed early and treated properly; there is consequently a need for rapid and accurate detection of this bacterial species. Therefore, we developed a new, nitrocellulose-based microfluidic system featuring AB-specific aptamers capable of automating the bacterial detection process via the activity of microfluidic devices composed of magnetic-composite membranes. Electromagnets were used to actuate these microfluidic devices such that the entire diagnostic process could be conducted in the integrated microfluidic system within 40 minutes with a limit of detection as low as 450 CFU per reaction for AB...
May 16, 2018: Lab on a Chip
Emily S Park, Justin P Yan, Richard A Ang, Jeong Hyun Lee, Xiaoyan Deng, Simon P Duffy, Kevin Beja, Matti Annala, Peter C Black, Kim N Chi, Alexander W Wyatt, Hongshen Ma
Circulating tumor cells (CTCs) are malignant cells released into the bloodstream with the potential to form metastases in secondary sites. These cells, acquired non-invasively, represent a sample of highly relevant tumor tissue that is an alternative to difficult and low-yield tumor biopsies. In recent years, there has been growing interest in genomic profiling of CTCs to enable longitudinal monitoring of the tumor's adaptive response to therapy. However, due to their extreme rarity, genotyping CTCs has proved challenging...
May 15, 2018: Lab on a Chip
Nicole C A van Engeland, Andreas M A O Pollet, Jaap M J den Toonder, Carlijn V C Bouten, Oscar M J A Stassen, Cecilia M Sahlgren
Cell signalling and mechanics influence vascular pathophysiology and there is an increasing demand for in vitro model systems that enable examination of signalling between vascular cells under hemodynamic conditions. Current 3D vessel wall constructs do not recapitulate the mechanical conditions of the native tissue nor do they allow examination of cell-cell interactions under relevant hemodynamic conditions. Here, we describe a 3D microfluidic chip model of arterial endothelial and smooth muscle cells where cellular organization, composition and interactions, as well as the mechanical environment of the arterial wall are mimicked...
May 14, 2018: Lab on a Chip
Chanyong Park, Yong Duk Han, Han Vit Kim, Jinkee Lee, Hyun C Yoon, Sungsu Park
Recently, much effort has been focused on developing three-dimensional, paper-based microfluidic analytical devices (3D-μPADs) targeting in vitro diagnostics. However, 3D-μPAD fabrication typically requires tedious assembly that hinders mass production. Here, we report on a fabrication method for 3D-μPADs made of plastics without the need for additional assembly. Both sides of the paper were printed via liquid resin photopolymerization using a digital light processing (DLP) printer. The sample reservoir and detection zones are located on the top of the 3D-μPADs, and three microchannels are located on the bottom...
May 11, 2018: Lab on a Chip
Jenifer Gómez-Pastora, Cristina González-Fernández, Eusebio Real, Alexander Iles, Eugenio Bringas, Edward P Furlani, Inmaculada Ortiz
Magnetic beads can be functionalized to capture and separate target pathogens from blood for extracorporeal detoxification. The beads can be magnetically separated from a blood stream and collected into a coflowing buffer solution using a two-phase liquid-liquid continuous-flow microfluidic device in the presence of an external field. However, device design and process optimization, i.e. high bead recovery with minimum blood loss or dilution remain a substantial technological challenge. We introduce a CFD-based Eulerian-Lagrangian computational model that enables the rational design and optimization of such systems...
May 11, 2018: Lab on a Chip
Jacob Chamoun, Ashish Pattekar, Farzaneh Afshinmanesh, Joerg Martini, Michael I Recht
A novel microfluidic calorimeter that measures the enthalpy change of reactions occurring in 100 μm diameter aqueous droplets in fluoropolymer oil has been developed. The aqueous reactants flow into a microfluidic droplet generation chip in separate fluidic channels, limiting contact between the streams until immediately before they form the droplet. The diffusion-driven mixing of reactants is predominantly restricted to within the droplet. The temperature change in droplets due to the heat of reaction is measured optically by recording the reflectance spectra of encapsulated thermochromic liquid crystals (TLC) that are added to one of the reactant streams...
May 10, 2018: Lab on a Chip
Devasier Bennet, Zachary Estlack, Ted Reid, Jungkyu Kim
Animals are commonly used for pharmacokinetic studies which are the most frequent events tested during ocular drug development and preclinical evaluation. Inaccuracy, cost, and ethical criticism in these tests have created a need to construct an in vitro model for studying corneal constraints. In this work, a porous membrane embedded microfluidic platform is fabricated that separates a chip into an apical and basal side. After functionalizing the membrane surface with fibronectin, the membrane's mechanical and surface properties are measured to ensure correct modeling of in vivo characteristics...
May 8, 2018: Lab on a Chip
Ruben R G Soares, Denis R Santos, Inês F Pinto, Ana M Azevedo, M Raquel Aires-Barros, Virginia Chu, João P Conde
Portable, rapid, cost effective and simple analytical tools are in increasing demand to facilitate the routine monitoring of target chemical/biological compounds at the point-of-need. Such devices are highly relevant within the context of food safety, particularly concerning the screening of highly toxic and strictly regulated mycotoxins. To achieve ultrarapid detection of mycotoxins, namely aflatoxin B1, ochratoxin A and deoxynivalenol, at the point-of-need, a novel multiplexed bead-based microfluidic competitive immunosensor, coupled with an array of a-Si:H thin-film photodiodes for integrated fluorescence signal acquisition, is reported...
May 8, 2018: Lab on a Chip
Si Kuan Thio, Dongyue Jiang, Sung-Yong Park
Optofluidics is an emerging research field that combines the two disciplines of microfluidics and optics. By using microfluidic technologies for light control, optofluidic devices can offer several advantages over solid-type optical components, including optical-grade smoothness at the fluidic interface and a high degree of optical tunability without bulky and complex mechanical moving parts. These features have made optofluidic devices more versatile and reconfigurable to improve their optical performances...
May 4, 2018: Lab on a Chip
Tao Luo, Lei Fan, Yixiao Zeng, Ya Liu, Shuxun Chen, Qiulin Tan, Raymond H W Lam, Dong Sun
Prefocusing of the cell mixture is necessary for achieving a high-efficiency and continuous dielectrophoretic (DEP) cell separation. However, prefocusing through sheath flow requires a complex and tedious peripheral system for multi-channel fluid control, hindering the integration of DEP separation systems with other microfluidic functionalities for comprehensive clinical and biological tasks. This paper presented a simplified sheathless cell separation approach that combines gravitational-sedimentation-based sheathless prefocusing and DEP separation methods...
May 4, 2018: Lab on a Chip
Sankha Shuvra Das, Shantimoy Kar, Tarique Anwar, Partha Saha, Suman Chakraborty
We exploit the combinatorial advantage of electrokinetics and tortuosity of a cellulose-based paper network on laboratory grade filter paper for the development of a simple, inexpensive, yet extremely robust (shows constant performance for 12 days) 'paper-and-pencil'-based device for energy harvesting applications. We successfully achieve harvesting of a maximum output power of ∼640 pW in a single channel, while the same is significantly improved (by ∼100 times) with the use of a multichannel microfluidic array (maximum of up to 20 channels)...
May 3, 2018: Lab on a Chip
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