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Norikane Y, Ohnuma M, Kwaria D, Kikkawa Y, Ohzono T, Mizokuro T, Abe K, Manabe K, Saito K. Photo-controllable azobenzene microdroplets on an open surface and their application as transporters. MATERIALS HORIZONS 2024; 11:1495-1501. [PMID: 38226904 DOI: 10.1039/d3mh01774e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/17/2024]
Abstract
The control of droplet motion is a significant challenge, as there has been no simple method for effective manipulation. Utilizing light for the control of droplets offers a promising solution due to its non-contact nature and high degree of controllability. In this study, we present our findings on the translational motion of pre-photomelted droplets composed of azobenzene derivatives on a glass surface when exposed to UV and visible light sources from different directions. These droplets exhibited directional and continuous motion upon light irradiation and this motion was size-dependent. Only droplets with diameters less than 10 μm moved with a maximum velocity of 300 μm min-1. In addition, the direction of the movement was controllable by the direction of the light. The motion is driven by a change in contact angle, where UV or visible light switched the contact angle to approximately 50° or 35°, respectively. In addition, these droplets were also found to be capable carriers for fluorescent quantum dots. As such, droplets composed of photoresponsive molecules offer unique opportunities for designing novel light-driven open-surface microfluidic systems.
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Affiliation(s)
- Yasuo Norikane
- Research Institute for Advanced Electronics and Photonics, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Ibaraki, 305-8565, Japan.
- Faculty of Pure and Applied Sciences, University of Tsukuba, Ibaraki, 305-8571, Japan
| | - Mio Ohnuma
- Research Institute for Advanced Electronics and Photonics, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Ibaraki, 305-8565, Japan.
| | - Dennis Kwaria
- Research Institute for Advanced Electronics and Photonics, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Ibaraki, 305-8565, Japan.
| | - Yoshihiro Kikkawa
- Research Institute for Advanced Electronics and Photonics, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Ibaraki, 305-8565, Japan.
| | - Takuya Ohzono
- Research Institute for Advanced Electronics and Photonics, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Ibaraki, 305-8565, Japan.
| | - Toshiko Mizokuro
- Research Institute for Advanced Electronics and Photonics, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Ibaraki, 305-8565, Japan.
| | - Koji Abe
- Research Institute for Advanced Electronics and Photonics, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Ibaraki, 305-8565, Japan.
| | - Kengo Manabe
- Research Institute for Advanced Electronics and Photonics, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Ibaraki, 305-8565, Japan.
| | - Koichiro Saito
- Research Institute for Advanced Electronics and Photonics, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Ibaraki, 305-8565, Japan.
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Lucaci AG, Zehr JD, Enard D, Thornton JW, Kosakovsky Pond SL. Evolutionary Shortcuts via Multinucleotide Substitutions and Their Impact on Natural Selection Analyses. Mol Biol Evol 2023; 40:msad150. [PMID: 37395787 PMCID: PMC10336034 DOI: 10.1093/molbev/msad150] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2023] [Revised: 06/15/2023] [Accepted: 06/26/2023] [Indexed: 07/04/2023] Open
Abstract
Inference and interpretation of evolutionary processes, in particular of the types and targets of natural selection affecting coding sequences, are critically influenced by the assumptions built into statistical models and tests. If certain aspects of the substitution process (even when they are not of direct interest) are presumed absent or are modeled with too crude of a simplification, estimates of key model parameters can become biased, often systematically, and lead to poor statistical performance. Previous work established that failing to accommodate multinucleotide (or multihit, MH) substitutions strongly biases dN/dS-based inference towards false-positive inferences of diversifying episodic selection, as does failing to model variation in the rate of synonymous substitution (SRV) among sites. Here, we develop an integrated analytical framework and software tools to simultaneously incorporate these sources of evolutionary complexity into selection analyses. We found that both MH and SRV are ubiquitous in empirical alignments, and incorporating them has a strong effect on whether or not positive selection is detected (1.4-fold reduction) and on the distributions of inferred evolutionary rates. With simulation studies, we show that this effect is not attributable to reduced statistical power caused by using a more complex model. After a detailed examination of 21 benchmark alignments and a new high-resolution analysis showing which parts of the alignment provide support for positive selection, we show that MH substitutions occurring along shorter branches in the tree explain a significant fraction of discrepant results in selection detection. Our results add to the growing body of literature which examines decades-old modeling assumptions (including MH) and finds them to be problematic for comparative genomic data analysis. Because multinucleotide substitutions have a significant impact on natural selection detection even at the level of an entire gene, we recommend that selection analyses of this type consider their inclusion as a matter of routine. To facilitate this procedure, we developed, implemented, and benchmarked a simple and well-performing model testing selection detection framework able to screen an alignment for positive selection with two biologically important confounding processes: site-to-site synonymous rate variation, and multinucleotide instantaneous substitutions.
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Affiliation(s)
- Alexander G Lucaci
- Institute for Genomics and Evolutionary Medicine, Temple University, Philadelphia, PA, USA
| | - Jordan D Zehr
- Institute for Genomics and Evolutionary Medicine, Temple University, Philadelphia, PA, USA
| | - David Enard
- Department of Ecology and Evolutionary Biology, University of Arizona, Tucson, Arizona
| | - Joseph W Thornton
- Department of Human Genetics, University of Chicago, Chicago, Illinois
- Department of Ecology & Evolution, University of Chicago, Chicago, Illinois
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Chen F, Zhao Y, Zhang S, Wei S, Ming A, Mao C. Hydrophobic Wafer-Scale High-Reproducibility SERS Sensor Based on Silicon Nanorods Arrays Decorated with Au Nanoparticles for Pesticide Residue Detection. BIOSENSORS 2022; 12:bios12050273. [PMID: 35624574 PMCID: PMC9138717 DOI: 10.3390/bios12050273] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/25/2022] [Revised: 04/21/2022] [Accepted: 04/24/2022] [Indexed: 05/09/2023]
Abstract
High sensitivity and reproducibility are highly desirable to a SERS sensor in diverse detection applications. Moreover, it is a great challenge to determine how to promote the target molecules to be more concentrated on the hotspots of the SERS substrate by engineering a surface with switching interfacial wettability. Along these lines, wafer-scale uniformly hydrophobic silicon nanorods arrays (SiNRs) decorated with Au nanoparticles were designed as the SERS substrate. Typically, the SERS substrate was fabricated by enforcing the polystyrene (PS) sphere self-assembly, as well as the plasma etching and the magnetron sputtering techniques. Consequently, the SERS substrate was treated by soaking within a n-dodecyl mercaptan (NDM) solution at different times in order to obtain adjustable wettabilities. By leveraging the electromagnetic enhancement resulted from the Au nanostructures and enrichment effect induced by the hydrophobicity, the SERS substrate is endowed with efficient SERS capabilities. During the detection of malachite green (MG), an ultralow relative standard deviation (RSD) 4.04-6.14% is achieved and the characteristic signal of 1172 cm-1 can be detected as low as 1 ng/mL. The proposed SiNRs' structure presents outstanding SERS activity with sensitivity and reproducibility rendering thus an ideal candidate for potential application in analytical detection fields.
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Affiliation(s)
- Fanhong Chen
- State Key Laboratory of Advanced Materials for Smart Sensing, GRINM Group Corporation Limited, Beijing 100088, China; (F.C.); (S.Z.)
- Department of Advanced Electronic Materials, GRIMAT Engineering Institute Co., Ltd., Beijing 101407, China;
| | - Yupeng Zhao
- Department of Advanced Electronic Materials, GRIMAT Engineering Institute Co., Ltd., Beijing 101407, China;
- School of Information Science and Technology, North China University of Technology, Beijing 100144, China;
| | - Shaoxun Zhang
- State Key Laboratory of Advanced Materials for Smart Sensing, GRINM Group Corporation Limited, Beijing 100088, China; (F.C.); (S.Z.)
- Department of Advanced Electronic Materials, GRIMAT Engineering Institute Co., Ltd., Beijing 101407, China;
| | - Shuhua Wei
- School of Information Science and Technology, North China University of Technology, Beijing 100144, China;
| | - Anjie Ming
- State Key Laboratory of Advanced Materials for Smart Sensing, GRINM Group Corporation Limited, Beijing 100088, China; (F.C.); (S.Z.)
- Department of Advanced Electronic Materials, GRIMAT Engineering Institute Co., Ltd., Beijing 101407, China;
- Correspondence: (A.M.); (C.M.)
| | - Changhui Mao
- State Key Laboratory of Advanced Materials for Smart Sensing, GRINM Group Corporation Limited, Beijing 100088, China; (F.C.); (S.Z.)
- Department of Advanced Electronic Materials, GRIMAT Engineering Institute Co., Ltd., Beijing 101407, China;
- Correspondence: (A.M.); (C.M.)
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Zhang Y, Li J, Xiang L, Wang J, Wu T, Jiao Y, Jiang S, Li C, Fan S, Zhang J, Wu H, Zhang Y, Bian Y, Zhao K, Peng Y, Zhu W, Li J, Hu Y, Wu D, Chu J, Wang Z. A Biocompatible Vibration-Actuated Omni-Droplets Rectifier with Large Volume Range Fabricated by Femtosecond Laser. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2022; 34:e2108567. [PMID: 34865264 DOI: 10.1002/adma.202108567] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/25/2021] [Revised: 11/15/2021] [Indexed: 06/13/2023]
Abstract
High-performance droplet transport is crucial for diverse applications including biomedical detection, chemical micro-reaction, and droplet microfluidics. Despite extensive progress, traditional passive and active strategies are restricted to limited liquid types, small droplet volume ranges, and poor biocompatibilities. Moreover, more challenges occur for biological fluids due to large viscosity and low surface tension. Here, a vibration-actuated omni-droplets rectifier (VAODR) consisting of slippery ratchet arrays fabricated by femtosecond laser and vibration platforms is reported. Through the relative competition between the asymmetric adhesive resistance originating from the lubricant meniscus on the VAODR and the periodic inertial driving force originating from isotropic vibration, the fast (up to ≈60 mm s-1 ), programmable, and robust transport of droplets is achieved for a large volume range (0.05-2000 µL, Vmax /Vmin ≈ 40 000) and in various transport modes including transport of liquid slugs in tubes, programmable and sequential transport, and bidirectional transport. This VAODR is general to a high diversity of biological and medical fluids, and thus can be used for biomedical detection including ABO blood-group tests and anticancer drugs screening. These strategies provide a complementary and promising platform for maneuvering omni-droplets that are fundamental to biomedical applications and other high-throughput omni-droplet operation fields.
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Affiliation(s)
- Yiyuan Zhang
- CAS Key Laboratory of Mechanical Behavior and Design of Materials, Key Laboratory of Precision Scientific Instrumentation of Anhui Higher Education Institutes, Department of Precision Machinery and Precision Instrumentation, University of Science and Technology of China, Hefei, 230027, China
| | - Jing Li
- Department of Mechanical Engineering, City University of Hong Kong, Hong Kong, China
| | - Le Xiang
- School of Instrument Science and Opto-electronics Engineering, Hefei University of Technology, Hefei, 230009, P. R. China
| | - Jinxing Wang
- CAS Key Laboratory of Mechanical Behavior and Design of Materials, Key Laboratory of Precision Scientific Instrumentation of Anhui Higher Education Institutes, Department of Precision Machinery and Precision Instrumentation, University of Science and Technology of China, Hefei, 230027, China
| | - Tao Wu
- Department of Modern Mechanics, University of Science and Technology of China, Hefei, 230027, China
| | - Yunlong Jiao
- Institute of Tribology, Hefei University of Technology, Hefei, 230009, P. R. China
| | - Shaojun Jiang
- CAS Key Laboratory of Mechanical Behavior and Design of Materials, Key Laboratory of Precision Scientific Instrumentation of Anhui Higher Education Institutes, Department of Precision Machinery and Precision Instrumentation, University of Science and Technology of China, Hefei, 230027, China
| | - Chuanzong Li
- School of Instrument Science and Opto-electronics Engineering, Hefei University of Technology, Hefei, 230009, P. R. China
| | - Shengying Fan
- Center for Biomedical Engineering Department of Electronic Science and Technology, University of Science and Technology of China, Hefei, 230026, China
| | - Juan Zhang
- Department of Clinical Laboratory, The First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, Anhui, 230001, China
| | - Hao Wu
- CAS Key Laboratory of Mechanical Behavior and Design of Materials, Key Laboratory of Precision Scientific Instrumentation of Anhui Higher Education Institutes, Department of Precision Machinery and Precision Instrumentation, University of Science and Technology of China, Hefei, 230027, China
| | - Yuxuan Zhang
- CAS Key Laboratory of Mechanical Behavior and Design of Materials, Key Laboratory of Precision Scientific Instrumentation of Anhui Higher Education Institutes, Department of Precision Machinery and Precision Instrumentation, University of Science and Technology of China, Hefei, 230027, China
| | - Yucheng Bian
- CAS Key Laboratory of Mechanical Behavior and Design of Materials, Key Laboratory of Precision Scientific Instrumentation of Anhui Higher Education Institutes, Department of Precision Machinery and Precision Instrumentation, University of Science and Technology of China, Hefei, 230027, China
| | - Kun Zhao
- Information Materials and Intelligent Sensing Laboratory of Anhui Province, School of Electronics and Information Engineering, Anhui University, Hefei, 230039, China
| | - Yubin Peng
- CAS Key Laboratory of Mechanical Behavior and Design of Materials, Key Laboratory of Precision Scientific Instrumentation of Anhui Higher Education Institutes, Department of Precision Machinery and Precision Instrumentation, University of Science and Technology of China, Hefei, 230027, China
| | - Wulin Zhu
- CAS Key Laboratory of Mechanical Behavior and Design of Materials, Key Laboratory of Precision Scientific Instrumentation of Anhui Higher Education Institutes, Department of Precision Machinery and Precision Instrumentation, University of Science and Technology of China, Hefei, 230027, China
| | - Jiawen Li
- CAS Key Laboratory of Mechanical Behavior and Design of Materials, Key Laboratory of Precision Scientific Instrumentation of Anhui Higher Education Institutes, Department of Precision Machinery and Precision Instrumentation, University of Science and Technology of China, Hefei, 230027, China
| | - Yanlei Hu
- CAS Key Laboratory of Mechanical Behavior and Design of Materials, Key Laboratory of Precision Scientific Instrumentation of Anhui Higher Education Institutes, Department of Precision Machinery and Precision Instrumentation, University of Science and Technology of China, Hefei, 230027, China
| | - Dong Wu
- CAS Key Laboratory of Mechanical Behavior and Design of Materials, Key Laboratory of Precision Scientific Instrumentation of Anhui Higher Education Institutes, Department of Precision Machinery and Precision Instrumentation, University of Science and Technology of China, Hefei, 230027, China
| | - Jiaru Chu
- CAS Key Laboratory of Mechanical Behavior and Design of Materials, Key Laboratory of Precision Scientific Instrumentation of Anhui Higher Education Institutes, Department of Precision Machinery and Precision Instrumentation, University of Science and Technology of China, Hefei, 230027, China
| | - Zuankai Wang
- Department of Mechanical Engineering, City University of Hong Kong, Hong Kong, China
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5
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Remote, selective, and in situ manipulation of liquid droplets on a femtosecond laser-structured superhydrophobic shape-memory polymer by near-infrared light. Sci China Chem 2021. [DOI: 10.1007/s11426-020-9940-6] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
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6
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Jiang T, Jia Y, Sun H, Deng X, Tang D, Ren Y. Dielectrophoresis Response of Water-in-Oil-in-Water Double Emulsion Droplets with Singular or Dual Cores. MICROMACHINES 2020; 11:mi11121121. [PMID: 33348930 PMCID: PMC7766960 DOI: 10.3390/mi11121121] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/26/2020] [Revised: 12/09/2020] [Accepted: 12/09/2020] [Indexed: 11/16/2022]
Abstract
Microfluidic technologies have enabled generation of exquisite multiple emulsion droplets, which have been used in many fields, including single-cell assays, micro-sized chemical reactions, and material syntheses. Electrical controlling is an important technique for droplet manipulation in microfluidic systems, but the dielectrophoretic behaviors of multiple emulsion droplets in electrical fields are rarely studied. Here, we report on the dielectrophoresis response of double emulsion droplets in AC electric fields in microfluidic channel. A core-shell model is utilized for analyzing the polarization of droplet interfaces and the overall dielectrophoresis (DEP) force. The water-in-oil-in-water droplets, generated by glass capillary devices, experience negative DEP at low field frequency. At high frequency, however, the polarity of DEP is tunable by adjusting droplet shell thickness or core conductivity. Then, the behavior of droplets with two inner cores is investigated, where the droplets undergo rotation before being repelled or attracted by the strong field area. This work should benefit a wide range of applications that require manipulation of double emulsion droplets by electric fields.
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Affiliation(s)
- Tianyi Jiang
- School of Mechatronics Engineering, Harbin Institute of Technology, Harbin 150001, Heilongjiang, China; (T.J.); (Y.J.); (H.S.); (X.D.); (D.T.)
| | - Yankai Jia
- School of Mechatronics Engineering, Harbin Institute of Technology, Harbin 150001, Heilongjiang, China; (T.J.); (Y.J.); (H.S.); (X.D.); (D.T.)
| | - Haizhen Sun
- School of Mechatronics Engineering, Harbin Institute of Technology, Harbin 150001, Heilongjiang, China; (T.J.); (Y.J.); (H.S.); (X.D.); (D.T.)
| | - Xiaokang Deng
- School of Mechatronics Engineering, Harbin Institute of Technology, Harbin 150001, Heilongjiang, China; (T.J.); (Y.J.); (H.S.); (X.D.); (D.T.)
| | - Dewei Tang
- School of Mechatronics Engineering, Harbin Institute of Technology, Harbin 150001, Heilongjiang, China; (T.J.); (Y.J.); (H.S.); (X.D.); (D.T.)
| | - Yukun Ren
- School of Mechatronics Engineering, Harbin Institute of Technology, Harbin 150001, Heilongjiang, China; (T.J.); (Y.J.); (H.S.); (X.D.); (D.T.)
- State Key Laboratory of Robotics and System, Harbin Institute of Technology, West Da-Zhi Street 92, Harbin 150001, Heilongjiang, China
- Correspondence: ; Tel.: +86-0451-86418028; Fax: +86-0451-86402658
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Wang Y, Lai H, Cheng Z, Zhang H, Zhang E, Lv T, Liu Y, Jiang L. Gecko toe pads inspired in situ switchable superhydrophobic shape memory adhesive film. NANOSCALE 2019; 11:8984-8993. [PMID: 31017157 DOI: 10.1039/c9nr00154a] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Recently, smart adhesive superhydrophobic surfaces have attracted much attention. However, it is still a challenge to obtain a superhydrophobic surface with shape memory adhesive performance. Herein, inspired by the special back-scrolling/unfolding ability of gecko toe pads and corresponding tunable adhesion, we report such a film produced by sticking a layer of superhydrophobic pillar structured polyurethane (s-PU) onto a shape memory polyurethane-cellulose nanofiber (PU-CNF) substrate to mimic the hair-like skin structure and underlying muscle of the gecko toe pads, respectively. Similar to the muscle of the gecko toe pads, the excellent shape memory effect of the PU-CNF substrate can help the obtained film to memorize and repeatedly display different shapes and solid/water contact models. Thus reversible switching between multiple states from the low-adhesive rolling performance to the high-adhesive pinning performance can be realized. Meanwhile, based on its smart wetting performance, not only the traditional in situ capture/release of one microdroplet, but also the step-by-step release of different droplets can be realized on our film. This work reports a new superhydrophobic shape memory adhesive film, which offers a novel strategy for surface adhesion control and meanwhile opens a new road for applications in controlled droplet manipulation.
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Affiliation(s)
- Yongzhen Wang
- MIIT Key Laboratory of Critical Materials Technology for New Energy Conversion and Storage, School of Chemistry and Chemical Engineering, Harbin Institute of Technology, Harbin 150001, P. R. China.
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8
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Qi L, Niu Y, Ruck C, Zhao Y. Mechanical-activated digital microfluidics with gradient surface wettability. LAB ON A CHIP 2019; 19:223-232. [PMID: 30539191 DOI: 10.1039/c8lc00976g] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
This paper reports a simple yet effective droplet manipulation approach that can displace aqueous droplets over a long distance within the working plane. Repeated patterns with surface gradient wettability were created on a super-hydrophobic surface by laser irradiation. Aqueous droplets as small as 2 μL are moved on the patterns over a long distance under in-plane symmetric cyclic vibration. Typical droplet manipulation actions including droplet movement along a pre-determined trajectory, droplet mixing, and selective movement of multiple droplets were successfully demonstrated. Biochemical detection using this approach was demonstrated via a bicinchoninic acid (BCA) assay. This approach allows for long-distance droplet movement and simultaneous manipulation of multiple droplets without sacrificing the manipulation efficiency or increasing the cross-contamination risk. The device can be fabricated outside cleanrooms and operated without special equipment. It provides a solid technical basis for developing the next generation of affordable open channel microfluidic devices for various applications.
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Affiliation(s)
- Lin Qi
- Department of Biomedical Engineering, The Ohio State University, Columbus, OH 43210, USA.
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9
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Kaushik AM, Hsieh K, Wang TH. Droplet microfluidics for high-sensitivity and high-throughput detection and screening of disease biomarkers. WILEY INTERDISCIPLINARY REVIEWS. NANOMEDICINE AND NANOBIOTECHNOLOGY 2018; 10:e1522. [PMID: 29797414 PMCID: PMC6185786 DOI: 10.1002/wnan.1522] [Citation(s) in RCA: 44] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/15/2017] [Revised: 03/02/2018] [Accepted: 03/10/2018] [Indexed: 12/17/2022]
Abstract
Biomarkers are nucleic acids, proteins, single cells, or small molecules in human tissues or biological fluids whose reliable detection can be used to confirm or predict disease and disease states. Sensitive detection of biomarkers is therefore critical in a variety of applications including disease diagnostics, therapeutics, and drug screening. Unfortunately for many diseases, low abundance of biomarkers in human samples and low sample volumes render standard benchtop platforms like 96-well plates ineffective for reliable detection and screening. Discretization of bulk samples into a large number of small volumes (fL-nL) via droplet microfluidic technology offers a promising solution for high-sensitivity and high-throughput detection and screening of biomarkers. Several microfluidic strategies exist for high-throughput biomarker digitization into droplets, and these strategies have been utilized by numerous droplet platforms for nucleic acid, protein, and single-cell detection and screening. While the potential of droplet-based platforms has led to burgeoning interest in droplets, seamless integration of sample preparation technologies and automation of platforms from biological sample to answer remain critical components that can render these platforms useful in the clinical setting in the near future. This article is categorized under: Diagnostic Tools > Biosensing Diagnostic Tools > Diagnostic Nanodevices Therapeutic Approaches and Drug Discovery > Emerging Technologies Therapeutic Approaches and Drug Discovery > Nanomedicine for Infectious Disease.
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Affiliation(s)
| | - Kuangwen Hsieh
- Department of Mechanical Engineering, Johns Hopkins University
| | - Tza-Huei Wang
- Department of Mechanical Engineering, Department of Biomedical Engineering, Johns Hopkins University
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10
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A novel magnet-actuated droplet manipulation platform using a floating ferrofluid film. Sci Rep 2017; 7:15705. [PMID: 29146931 PMCID: PMC5691075 DOI: 10.1038/s41598-017-15964-8] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2017] [Accepted: 11/03/2017] [Indexed: 01/05/2023] Open
Abstract
In this paper, we propose a novel but versatile magnet-actuated platform for droplet manipulation, which uses a ferrofluid film floating on a liquid surface as magnetic actuator. In contrast to the traditional magnetic droplet manipulation, this platform can handle droplets without magnetically functionalizing them. Due to the immiscibility of the oil-based ferrofluid and water, the droplets desired to be manipulated can stably rest on the surface of the floating ferrofluid film (FFF) under the action of surface tension, thereby offering possibilities for magnetically-driven droplet manipulations. Such a floating, magnetically responsive liquid film not only offers an open surface for active 2D droplet manipulation, but also enables complex droplet manipulations in 3D space. Using FFF, we demonstrate a “full-space” droplet manipulation, including droplet transport/coalescence above FFF (i.e. in air), droplet transport/coalescence on FFF and droplet encapsulation/release under FFF (i.e. in liquid). Furthermore, we investigated the effects of the magnetic field intensity, the ferrofluid concentration, the droplet volume, and the FFF thickness on droplet kinematics. By finely tuning these operating conditions, the FFF strategy can enjoy more operational latitude than traditional droplet systems, thus allowing more versatile liquid handling.
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11
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Park JK, Kim S. Droplet manipulation on a structured shape memory polymer surface. LAB ON A CHIP 2017; 17:1793-1801. [PMID: 28426055 DOI: 10.1039/c6lc01354f] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
While methods for dynamic tuning of surface wettability to manipulate water droplets have been widely explored for many applications including digital microfluidics, those based on dynamically changeable surface morphology have remained challenging to achieve. In this work, we present a structured shape memory polymer (SMP) surface which shows dynamically tunable surface wettability through changeable surface morphology in order to manipulate water droplets. The structured SMP surface involves a SMP pillar array consisting of nanotextured small and large pillars which can change its morphology between permanent and temporary shapes upon thermomechanical loading. Specifically, the structured SMP surface dynamically creates a surface morphological gradient and changes its surface wettability during thermally induced shape recovery of the SMP pillar array. Different wetting characteristics of the structured SMP surface between permanent and temporary shapes are theoretically predicted and experimentally verified. Based on these measured wetting characteristics, the structured SMP surface is designed to demonstrate that the morphological difference between two shapes under a water droplet overcomes contact angle hysteresis, resulting in driving a water droplet, when combined with the thermal Marangoni effect.
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Affiliation(s)
- Jun Kyu Park
- Department of Mechanical Science and Engineering, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA.
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12
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Zhang Y, Wittstock G. A Platform for Electric Field Aided and Wire-Guided Droplet Manipulation. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2017; 13:1601691. [PMID: 27860309 DOI: 10.1002/smll.201601691] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/19/2016] [Revised: 09/30/2016] [Indexed: 06/06/2023]
Abstract
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.
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Affiliation(s)
- Yanzhen Zhang
- Carl von Ossietzky University of Oldenburg, Faculty of Mathematics and Science, Center of Interface Sciences, Institute of Chemistry, D-26111, Oldenburg, Germany
| | - Gunther Wittstock
- Carl von Ossietzky University of Oldenburg, Faculty of Mathematics and Science, Center of Interface Sciences, Institute of Chemistry, D-26111, Oldenburg, Germany
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13
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Yeh SI, Fang WF, Huang CJ, Wang TM, Yang JT. The Visual Colorimetric Detection of Multi-nucleotide Polymorphisms on a Pneumatic Droplet Manipulation Platform. J Vis Exp 2016. [PMID: 27768033 DOI: 10.3791/54424] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022] Open
Abstract
A simple and visual method to detect multi-nucleotide polymorphism (MNP) was performed on a pneumatic droplet manipulation platform on an open surface. This approach to colorimetric DNA detection was based on the hybridization-mediated growth of gold nanoparticle probes (AuNP probes). The growth size and configuration of the AuNP are dominated by the number of DNA samples hybridized with the probes. Based on the specific size- and shape-dependent optical properties of the nanoparticles, the number of mismatches in a sample DNA fragment to the probes is able to be discriminated. The tests were conducted via droplets containing reagents and DNA samples respectively, and were transported and mixed on the pneumatic platform with the controlled pneumatic suction of the flexible PDMS-based superhydrophobic membrane. Droplets can be delivered simultaneously and precisely on an open-surface on the proposed pneumatic platform that is highly biocompatible with no side effect of DNA samples inside the droplets. Combining the two proposed methods, the multi-nucleotide polymorphism can be detected at sight on the pneumatic droplet manipulation platform; no additional instrument is required. The procedure from installing the droplets on the platform to the final result takes less than 5 min, much less than with existing methods. Moreover, this combined MNP detection approach requires a sample volume of only 10 µl in each operation, which is remarkably less than that of a macro system.
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Affiliation(s)
- Szu-I Yeh
- Department of Mechanical Engineering, National Taiwan University
| | - Wei-Feng Fang
- Department of Mechanical Engineering, National Taiwan University
| | - Chao-Jyun Huang
- Department of Mechanical Engineering, National Taiwan University
| | - Tzu-Ming Wang
- Department of Mechanical Engineering, National Taiwan University
| | - Jing-Tang Yang
- Department of Mechanical Engineering, National Taiwan University;
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14
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Yeh SI, Huang YC, Cheng CH, Cheng CM, Yang JT. Development of a millimetrically scaled biodiesel transesterification device that relies on droplet-based co-axial fluidics. Sci Rep 2016; 6:29288. [PMID: 27426677 PMCID: PMC4947928 DOI: 10.1038/srep29288] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2015] [Accepted: 06/17/2016] [Indexed: 11/09/2022] Open
Abstract
In this study, we investigated a fluidic system that adheres to new concepts of energy production. To improve efficiency, cost, and ease of manufacture, a millimetrically scaled device that employs a droplet-based co-axial fluidic system was devised to complete alkali-catalyzed transesterification for biodiesel production. The large surface-to-volume ratio of the droplet-based system, and the internal circulation induced inside the moving droplets, significantly enhanced the reaction rate of immiscible liquids used here – soybean oil and methanol. This device also decreased the molar ratio between methanol and oil to near the stoichiometric coefficients of a balanced chemical equation, which enhanced the total biodiesel volume produced, and decreased the costs of purification and recovery of excess methanol. In this work, the droplet-based co-axial fluidic system performed better than other methods of continuous-flow production. We achieved an efficiency that is much greater than that of reported systems. This study demonstrated the high potential of droplet-based fluidic chips for energy production. The small energy consumption and low cost of the highly purified biodiesel transesterification system described conforms to the requirements of distributed energy (inexpensive production on a moderate scale) in the world.
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Affiliation(s)
- S I Yeh
- Department of Mechanical Engineering, National Taiwan University, No. 1, Sec. 4, Roosevelt Road, Taipei, Taiwan
| | - Y C Huang
- Department of Mechanical Engineering, National Taiwan University, No. 1, Sec. 4, Roosevelt Road, Taipei, Taiwan
| | - C H Cheng
- Department of Mechanical Engineering, National Taiwan University, No. 1, Sec. 4, Roosevelt Road, Taipei, Taiwan
| | - C M Cheng
- Institute of Biomedical Engineering, National Tsing Hua University, No.101, Sec. 2, Guangfu Road, Hsinchu, Taiwan
| | - J T Yang
- Department of Mechanical Engineering, National Taiwan University, No. 1, Sec. 4, Roosevelt Road, Taipei, Taiwan
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15
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Kong T, Brien R, Njus Z, Kalwa U, Pandey S. Motorized actuation system to perform droplet operations on printed plastic sheets. LAB ON A CHIP 2016; 16:1861-72. [PMID: 27080172 DOI: 10.1039/c6lc00176a] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
We developed an open microfluidic system to dispense and manipulate discrete droplets on planar plastic sheets. Here, a superhydrophobic material is spray-coated on commercially-available plastic sheets followed by the printing of hydrophilic symbols using an inkjet printer. The patterned plastic sheets are taped to a two-axis tilting platform, powered by stepper motors, that provides mechanical agitation for droplet transport. We demonstrate the following droplet operations: transport of droplets of different sizes, parallel transport of multiple droplets, merging and mixing of multiple droplets, dispensing of smaller droplets from a large droplet or a fluid reservoir, and one-directional transport of droplets. As a proof-of-concept, a colorimetric assay is implemented to measure the glucose concentration in sheep serum. Compared to silicon-based digital microfluidic devices, we believe that the presented system is appealing for various biological experiments because of the ease of altering design layouts of hydrophilic symbols, relatively faster turnaround time in printing plastic sheets, larger area to accommodate more tests, and lower operational costs by using off-the-shelf products.
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Affiliation(s)
- Taejoon Kong
- Department of Electrical and Computer Engineering, Iowa State University, 1050 Coover Hall, Ames, IA 50011, USA.
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16
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Gaddam A, Agrawal A, Joshi SS, Thompson MC. Utilization of Cavity Vortex To Delay the Wetting Transition in One-Dimensional Structured Microchannels. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2015; 31:13373-13384. [PMID: 26598001 DOI: 10.1021/acs.langmuir.5b03666] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Frictional resistance across rough surfaces depends on the existence of slip on the liquid-gas interface; therefore, prolonging the existence of liquid-gas interface becomes relevant. In this work, we explore manipulation of the cavity shape in order to delay the wetting transition. We propose that liquid-driven vortices generated in the air cavity dissipate sufficient energy to delay the Cassie-Wenzel transition. Toward this, we fabricated cavities on the side walls of a polydimethylsiloxane-based microchannel for easy visualization and analysis of the dynamics of the liquid-gas interface. Two distinct flow regimes are identified in the experimental envelope. In the first regime, the liquid-gas interface is found to be protruding into the flow field, thus increasing the pressure drop at low Reynolds number. In the second regime, flow rate and geometry-based wetting transitions are established at moderate to high Reynolds numbers. We then investigate the effect of different cavity shapes (square, trapezoidal, and U-shape) in delaying the wetting transition by manipulating liquid-driven vortices. Out of the shapes considered in this study, trapezoidal cavities perform better than cavities with vertical walls in delaying the wetting transition due to geometrical squeezing of vortices toward the liquid-gas interface. Numerical simulations corroborate the experimental findings in that cavities with inclined walls exert more force on the liquid-gas interface, thus delaying their wetting transition. The proposed method being passive in nature appears more attractive than previous active methods.
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Affiliation(s)
- Anvesh Gaddam
- Department of Mechanical Engineering, Indian Institute of Technology Bombay , Powai, Mumbai 400076, India
| | - Amit Agrawal
- Department of Mechanical Engineering, Indian Institute of Technology Bombay , Powai, Mumbai 400076, India
| | - Suhas S Joshi
- Department of Mechanical Engineering, Indian Institute of Technology Bombay , Powai, Mumbai 400076, India
| | - M C Thompson
- Fluids Laboratory for Aeronautical and Industrial Research (FLAIR), Department of Mechanical and Aerospace Engineering, Monash University , Clayton 3800, Australia
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18
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Song D, Song B, Hu H, Du X, Zhou F. Selectively splitting a droplet using superhydrophobic stripes on hydrophilic surfaces. Phys Chem Chem Phys 2015; 17:13800-3. [DOI: 10.1039/c5cp01530h] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The droplet can be split by impinging on the hybrid hydrophobic–hydrophilic surface at a high velocity.
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Affiliation(s)
- Dong Song
- School of Marine Science and Technology
- Northwestern Polytechnical University
- Xi'an
- P. R. China
| | - Baowei Song
- School of Marine Science and Technology
- Northwestern Polytechnical University
- Xi'an
- P. R. China
| | - Haibao Hu
- School of Marine Science and Technology
- Northwestern Polytechnical University
- Xi'an
- P. R. China
| | - Xiaosong Du
- Microproducts Breakthrough Institute
- Corvallis
- USA
| | - Feng Zhou
- State Key Laboratory of Solid Lubrication
- Lanzhou Institute of Chemical Physics
- Chinese Academy of Sciences
- Lanzhou
- P. R. China
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19
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Yu IF, Yu YH, Chen LY, Fan SK, Chou HYE, Yang JT. A portable microfluidic device for the rapid diagnosis of cancer metastatic potential which is programmable for temperature and CO2. LAB ON A CHIP 2014; 14:3621-3628. [PMID: 25075570 DOI: 10.1039/c4lc00502c] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
If metastasis of lung cancer can be found and treated early, a victim might have an improved chance to prevail over it, but routine examinations such as chest radiography, computed tomography and biopsy cannot characterize the metastatic potential of lung cancer cells; critical diagnoses to define optimal therapeutic strategies are thus lost. We designed a portable microfluidic device for the rapid diagnosis of cancer metastatic potential. Featuring a micro system to control temperature and a bicarbonate buffered environment, our device discriminates a rate of surface detachment as an index of the migratory ability of cells cultured on pH-responsive chitosan. We labeled metastatic subpopulations of lung cancer cell lines, and verified that our device is capable of separating cells according to their metastatic ability. As only few cells are needed, a patient's specimen from biopsies, e.g. from fine-needle aspiration, can be processed on site to offer immediate information to physicians. We expect that our design will provide valuable information in pre-operative evaluations to assist the definition of therapeutic plans for lung cancer, as well as for metastatic tumors of other types.
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Affiliation(s)
- I F Yu
- Department of Mechanical Engineering, College of Engineering, National Taiwan University, Taipei 106, Taiwan.
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20
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Zec H, Shin DJ, Wang TH. Novel droplet platforms for the detection of disease biomarkers. Expert Rev Mol Diagn 2014; 14:787-801. [PMID: 25109704 DOI: 10.1586/14737159.2014.945437] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Personalized medicine - healthcare based on individual genetic variation - has the potential to transform the way healthcare is delivered to patients. The promise of personalized medicine has been predicated on the predictive and diagnostic power of genomic and proteomic biomarkers. Biomarker screening may help improve health outcomes, for example, by identifying individuals' susceptibility to diseases and predicting how patients will respond to drugs. Microfluidic droplet technology offers an exciting opportunity to revolutionize the accessibility of personalized medicine. A framework for the role of droplet microfluidics in biomarker detection can be based on two main themes. Emulsion-based microdroplet platforms can provide new ways to measure and detect biomolecules. In addition, microdroplet platforms facilitate high-throughput screening of biomarkers. Meanwhile, surface-based droplet platforms provide an opportunity to develop miniaturized diagnostic systems. These platforms may function as portable benchtop environments that dramatically shorten the transition of a benchtop assay into a point-of-care format.
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Affiliation(s)
- Helena Zec
- Department of Biomedical Engineering, Johns Hopkins University, Baltimore MD 21218, USA
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