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Lab on a Chip

Xiaonan Xu, Ruyuan Song, Minghao He, Chuan Peng, Miao Yu, Youmin Hou, Huihe Qiu, Ruhai Zou, Shuhuai Yao
Liquid perfluorocarbon (PFC) nanodroplets may have a better chance to extravasate through inter-endothelial gaps (400-800 nm) into tumor interstitium for extravascular imaging, which holds promise as an innovative strategy for imaging-guided drug delivery, early diagnosis of cancer and minimally invasive treatment of cancer. Currently available emulsion technologies still face challenges in reducing droplet sizes from the microscale to the nanoscale. To control size and ensure monodispersity of PFC nanodroplets, we developed a flame-shaped glass capillary and polydimethylsiloxane (PDMS) hybrid device that creates a concentric flow of the dispersed phase enclosed by the focusing continuous phase at the cross-junction...
September 21, 2017: Lab on a Chip
Xiaocheng Jiang, Keith H K Wong, Aimal H Khankhel, Mahnaz Zeinali, Eduardo Reategui, Matthew J Phillips, Xi Luo, Nicola Aceto, Fabio Fachin, Anh N Hoang, Wooseok Kim, Annie E Jensen, Lecia V Sequist, Shyamala Maheswaran, Daniel A Haber, Shannon L Stott, Mehmet Toner
The interplay between platelets and tumor cells is known to play important roles in metastasis by enhancing tumor cell survival, tumor-vascular interactions, and escape from immune surveillance. However, platelet-covered circulating tumor cells (CTC) are extremely difficult to isolate due to masking or downregulation of surface epitopes. Here we describe a microfluidic platform that takes advantage of the satellite platelets on the surface of these "stealth" CTCs as a ubiquitous surface marker for isolation...
September 21, 2017: Lab on a Chip
Jia Wei Ng, Citsabehsan Devendran, Adrian Neild
Surface acoustic waves offer a versatile and biocompatible method of manipulating the location of suspended particles or cells within microfluidic systems. The most common approach uses the interference of identical frequency, counter propagating travelling waves to generate a standing surface acoustic wave, in which particles migrate a distance less than half the acoustic wavelength to their nearest pressure node. The result is the formation of a periodic pattern of particles. Subsequent displacement of this pattern, the prerequisite for tweezing, can be achieved by translation of the standing wave, and with it the pressure nodes; this requires changing either the frequency of the pair of waves, or their relative phase...
September 20, 2017: Lab on a Chip
Yong Liu, Xingyu Jiang
The intrinsic limitations of conventional batch synthesis have hindered its applications in both solving classical problems and exploiting new frontiers. Microfluidic technology offers a new platform for chemical synthesis toward either molecules or materials, which has promoted the progress of diverse fields such as organic chemistry, materials science, and biomedicine. In this review, we focus on the improved performance of microreactors in handling various situations, and outline the trend of microfluidic synthesis (microsynthesis, μSyn) from simple microreactors to integrated microsystems...
September 15, 2017: Lab on a Chip
Thomas M Valentin, Susan E Leggett, Po-Yen Chen, Jaskiranjeet K Sodhi, Lauren H Stephens, Hayley D McClintock, Jea Yun Sim, Ian Y Wong
3D printed biomaterials with spatial and temporal functionality could enable interfacial manipulation of fluid flows and motile cells. However, such dynamic biomaterials are challenging to implement since they must be responsive to multiple, biocompatible stimuli. Here, we show stereolithographic printing of hydrogels using noncovalent (ionic) crosslinking, which enables reversible patterning with controlled degradation. We demonstrate this approach using sodium alginate, photoacid generators and various combinations of divalent cation salts, which can be used to tune the hydrogel degradation kinetics, pattern fidelity, and mechanical properties...
September 14, 2017: Lab on a Chip
Mikkel Schou Andersen, Emily Howard, Shulin Lu, Matthew Richard, Mark Gregory, Gordon Ogembo, Ofer Mazor, Pavel Gorelik, Nathan I Shapiro, Anish V Sharda, Ionita Ghiran
Magnetic levitation is a technique for measuring the density and the magnetic properties of objects suspended in a paramagnetic field. We describe a novel magnetic levitation-based method that can specifically detect cell membrane-bound and soluble antigens by measurable changes in levitation height that result from the formation of antibody-coated bead and antigen complex. We demonstrate our method's ability to sensitively detect an array of membrane-bound and soluble antigens found in blood, including T-cell antigen CD3, eosinophil antigen Siglec-8, red blood cell antigens CD35 and RhD, red blood cell-bound Epstein-Barr viral particles, and soluble IL-6, and validate the results by flow cytometry and immunofluorescence microscopy performed in parallel...
September 14, 2017: Lab on a Chip
Chaoyang Gong, Yuan Gong, Qiushu Chen, Yun-Jiang Rao, Gang-Ding Peng, Xudong Fan
Disposable sensors are widely used in biomedical detection due to their inherent safety, ease of use and low cost. An optofluidic laser is a sensitive bioassay platform; however, demonstrating its fabrication cheaply and reproducibly enough for disposable use has been challenging. Here, we report a low-cost, reproducible fiber optofluidic laser (FOFL) using a microstructured optical fiber (MOF). The MOF not only supports the whispering gallery modes for lasing but also serves as a microfluidic channel for sampling the liquid gain medium via capillary force...
September 6, 2017: Lab on a Chip
Gaurav Agrawal, Aereas Aung, Shyni Varghese
Engineered skeletal muscle tissues can be used for in vitro studies that require physiologically relevant models of native tissues. Herein, we describe the development of a three-dimensional (3D) skeletal muscle tissue that recapitulates the architectural and structural complexities of muscle within a microfluidic device. Using a 3D photo-patterning approach, we spatially confined a cell-laden gelatin network around two bio-inert hydrogel pillars, which induce uniaxial alignment of the cells and serve as anchoring sites for the encapsulated cells and muscle tissues as they form and mature...
September 5, 2017: Lab on a Chip
Philippe Q N Vo, Mathieu C Husser, Fatemeh Ahmadi, Hugo Sinha, Steve C C Shih
Digital microfluidics (DMF) is a technology that provides a means of manipulating nL-μL volumes of liquids on an array of electrodes. By applying an electric potential to an electrode, these discrete droplets can be controlled in parallel which can be transported, mixed, reacted, and analyzed. Typically, an automation system is interfaced with a DMF device that uses a standard set of basic instructions written by the user to execute droplet operations. Here, we present the first feedback method for DMF that relies on imaging techniques that will allow online detection of droplets without the need to reactivate all destination electrodes...
September 5, 2017: Lab on a Chip
Zichen Zhao, Yuanye Bao, Lok Ting Chu, John Kin Lim Ho, Ching-Chang Chieng, Ting-Hsuan Chen
We demonstrate a microfluidic bead trap capable of forming a dipstick-type bar visible to the naked eye for simple and quantitative detection of oligonucleotides. We use magnetic microparticles (MMPs) and polystyrene microparticles (PMPs) that are connected and form MMPs-targets-PMPs when target oligonucleotides are present, leaving free PMPs with a number inversely proportional to the amount of targets. Using a capillary flow-driven microfluidic circuitry consisting of a magnetic separator to remove the MMPs-targets-PMPs, the free PMPs can be trapped at the narrowing nozzle downstream, forming a visual bar quantifiable based on the length of PMP accumulation...
September 4, 2017: Lab on a Chip
Zidong Li, Erkin Seker
Advanced biomedical device coatings have shown significant promise in delivery of therapeutics (e.g., small-molecule drugs, proteins) for a wide range of medical interventions ranging from targeted cancer therapy to management of atherosclerosis. In order to accelerate the development of such coatings, there is a need for tools to investigate the loading capacity and release kinetics with high temporal resolution and in a variety of physiological conditions. To address this need, we report a microfluidic platform, where the coating on a substrate can be mounted onto the microchannel and the device can be configured in two physiologically-relevant modes: (i) flow-mode allows for monitoring the release from the coating in contact with a liquid flowing at a specific rate, modeling the case of a drug-eluting stent...
September 4, 2017: Lab on a Chip
Yongha Hwang, Rob N Candler
This review examines the state of the art for manufacturing non-planar miniature channels and actuators from PDMS, where non-planar structures are defined here as those beyond simple extrusions of 2D designs, either with rounded or variable cross sections or with an emergence of the channel trajectory out-of-plane. The motivation for 3D PDMS structures and advances in their fabrication are described, focusing on geometries that were previously unachievable through conventional microfabrication. The motivation for non-planar microfluidic channels and actuators is first discussed and the existing literature is grouped into general fabrication themes and described...
September 1, 2017: Lab on a Chip
Rohan Vernekar, Timm Krüger, Kevin Loutherback, Keith Morton, David W Inglis
We uncover anisotropic permeability in microfluidic deterministic lateral displacement (DLD) arrays. A DLD array can achieve high-resolution bimodal size-based separation of microparticles, including bioparticles, such as cells. For an application with a given separation size, correct device operation requires that the flow remains at a fixed angle to the obstacle array. We demonstrate via experiments and lattice-Boltzmann simulations that subtle array design features cause anisotropic permeability. Anisotropic permeability indicates the microfluidic array's intrinsic tendency to induce an undesired lateral pressure gradient...
September 1, 2017: Lab on a Chip
Chunmei Zhou, Pingan Zhu, Ye Tian, Xin Tang, Rui Shi, Liqiu Wang
Existing approaches for droplet generation with an ultra-low interfacial tension using aqueous two-phase systems, ATPS, are either constricted by a narrow range of flow conditions using passive methods or subjected to complex chip fabrication with the integration of external components using active actuation. To address these issues, we present a simple approach to produce uniform ATPS droplets facilitated by oil-droplet choppers in microfluidics. Our solution counts on the synchronized formation of high-interfacial-tension oil-in-water and low-interfacial-tension water-in-water droplets, where the ATPS interface is distorted by oil droplets and decays into water-in-water droplets...
September 1, 2017: Lab on a Chip
David Caballero, Sophie M Blackburn, Mar de Pablo, Josep Samitier, Lorenzo Albertazzi
Nanocarriers for drug delivery have great potential to revolutionize cancer treatment, due to their enhanced selectivity and efficacy. Despite this great promise, researchers have had limited success in the clinical translation of this approach. One of the main causes of these difficulties is that standard in vitro models, typically used to understand nanocarriers' behaviour and screen their efficiency, do not provide the complexity typically encountered in living systems. In contrast, in vivo models, despite being highly physiological, display serious bottlenecks which threaten the relevancy of the obtained data...
September 1, 2017: Lab on a Chip
Guangyong Li, Dong-Weon Lee
This paper presents a novel stretchable pulse sensor fabricated by a selective liquid-metal plating process (SLMP), which can conveniently attach to the human skin and monitor the patient's heartbeat. The liquid metal-based stretchable pulse sensor consists of polydimethylsiloxane (PDMS) thin films and liquid metal functional circuits with electronic elements that are embedded into the PDMS substrate. In order to verify the utility of the fabrication process, various complex liquid-metal patterns are achieved by using the selective wetting behavior of the reduced liquid metal on the Cu patterns of the PDMS substrate...
August 29, 2017: Lab on a Chip
Xiaolong Qiu, Trisha M Westerhof, Amrith A Karunaratne, Erik M Werner, Pedram P Pourfard, Edward L Nelson, Elliot E Hui, Jered B Haun
The ability to harvest single cells from tissues is currently a bottleneck for cell-based diagnostic technologies, and remains crucial in the fields of tissue engineering and regenerative medicine. Tissues are typically broken down using proteolytic digestion and various mechanical treatments, but success has been limited due to long processing times, low yield, and high manual labor burden. Here, we present a novel microfluidic device that utilizes precision fluid flows to improve the speed and efficiency of tissue digestion...
August 29, 2017: Lab on a Chip
Kevin M Koo, Eugene J H Wee, Yuling Wang, Matt Trau
The concept of personalised diagnostics is to direct accurate clinical decisions based on an individual's unique disease molecular profile. Lab-on-a-chip (LOC) systems are prime personalised diagnostics examples which seek to perform an entire sample-to-outcome detection of disease nucleic acid (NA) biomarkers on a single miniaturised platform with minimal user handling. Despite the great potential of LOC devices in providing rapid, portable, and inexpensive personalised diagnosis at the point-of-care (POC), the translation of this technology into widespread use has still been hampered by the need for sophisticated and complex engineering...
August 29, 2017: Lab on a Chip
Wentao Shi, Shunqiang Wang, Ahmad Maarouf, Christopher G Uhl, Ran He, Doruk Yunus, Yaling Liu
A wavy-herringbone (wavy-HB) structured microfluidic device was used to effectively and selectively capture and release circulating tumor cells (CTCs) by using immunoaffinity and magnetic force. This device was designed to create passive turbulence and increase the possibility of tumor cells colliding with the device wall. Under an external magnetic field, magnetic particles (MPs) coated with anti-EpCAM against a tumor cell surface protein (EpCAM) were immobilized over the wavy-HB surface to capture tumor cells...
August 25, 2017: Lab on a Chip
Matteo Cornaglia, Thomas Lehnert, Martin A M Gijs
In a typical high-throughput drug screening (HTS) process, up to millions of chemical compounds are applied to cells cultured in well plates, aiming to find molecules that exhibit a robust dose-response, as evidenced for example by a fluorescence signal. In high-content screening (HCS), one goes a step further by linking the tested compounds to phenotypic information, obtained, for instance, from microscopic cell images, thereby creating richer data sets that also require more advanced analysis methods. The nematode Caenorhabditis elegans came into the screening picture due to the wide availability of its mutants and human disease models, its relatively easy culture and short life cycle...
August 25, 2017: Lab on a Chip
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