1
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Luo G, Zhang Y, Wang S, Lv X, Yang T, Wang J. Establishment and Validation of an Integrated Microfluidic Step Emulsification Chip Supporting Droplet Digital Nucleic Acid Analysis. BIOSENSORS 2023; 13:888. [PMID: 37754123 PMCID: PMC10527055 DOI: 10.3390/bios13090888] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/19/2023] [Revised: 08/31/2023] [Accepted: 09/11/2023] [Indexed: 09/28/2023]
Abstract
Uniform and stable droplet generation is critical for accurate and efficient digital nucleic acid analysis (dNAA). In this study, an integrated microfluidic step emulsification device with wide-range droplet generation capability, small device dimensions, convenient fabrication strategy, low contamination and high robustness was developed. A tree-shaped droplet generation nozzle distribution design was proposed to increase the uniformity of droplet generation by equating flow rates, and the flow field in the design was numerically simulated. Theoretical analysis and comparative experiments on droplet size were performed regarding the influences of nozzle dimensions and surface properties. With incubation and hydrophobic reagent treatment, droplets as small as 73.1 μm were generated with multiplex nozzles of 18 μm (h) × 80 μm (w). The droplets were then collected into a standard PCR tube and an on-chip monolayer droplet collection chamber, without manual transfer and sample contamination. The oil-to-sample volume ratio in the PCR tube was recorded during collection. In the end, the droplets generated and collected using the microfluidic device proved to be stable and uniform for nucleic acid amplification and detection. This study provides reliable characteristic information for the design and fabrication of a micro-droplet generation device, and represents a promising approach for the realization of a three-in-one dNAA device under a step emulsification method.
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Affiliation(s)
- Gangyin Luo
- Suzhou Institute of Biomedical Engineering and Technology, Chinese Academy of Sciences, Suzhou 215163, China; (G.L.); (S.W.)
- School of Biomedical Engineering (Suzhou), Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei 230026, China
| | | | - Shun Wang
- Suzhou Institute of Biomedical Engineering and Technology, Chinese Academy of Sciences, Suzhou 215163, China; (G.L.); (S.W.)
| | - Xinbei Lv
- Qingdao Innovation and Development Base, Harbin Engineering University, Qingdao 266000, China;
| | - Tianhang Yang
- Suzhou Institute of Biomedical Engineering and Technology, Chinese Academy of Sciences, Suzhou 215163, China; (G.L.); (S.W.)
| | - Jinxian Wang
- Suzhou Institute of Biomedical Engineering and Technology, Chinese Academy of Sciences, Suzhou 215163, China; (G.L.); (S.W.)
- School of Biomedical Engineering (Suzhou), Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei 230026, China
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2
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Lai YK, Opalski AS, Garstecki P, Derzsi L, Guzowski J. A double-step emulsification device for direct generation of double emulsions. SOFT MATTER 2022; 18:6157-6166. [PMID: 35770691 DOI: 10.1039/d2sm00327a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
In microfluidic step emulsification, the size of droplets generated in the dripping regime is predominantly determined by the nozzle's height and only weakly depends on the applied flow rates or liquid properties. While the generation of monodisperse emulsions at high throughput using step emulsifiers has been well established, the generation of double emulsions, i.e., liquid core-shell structures, is still challenging. Here, we demonstrate a novel double-step emulsification method for the direct generation of multi-core double-emulsions and provide a predictive model for the number of cores. While the mechanism of the formation of the core droplets or empty shell droplets follows the well-established scenario of simple step emulsification, the formation of double-emulsion droplets is strongly affected by the presence of the cores. Passing of the cores through the narrowing neck of the shell postpones shell pinch-off. In particular, we demonstrate that our system can be used for the generation of arbitrary large, tightly packed droplet clusters consisting of a controllable number of droplets. Finally, we discuss the options of upscaling the system for high-throughput generation of tailored double emulsions.
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Affiliation(s)
- Yu-Kai Lai
- Institute of Physical Chemistry, Polish Academy of Sciences, Warsaw, Poland.
- Laboratory for MEMS Applications, IMTEK - Department of Microsystems Engineering, University of Freiburg, Georges-Koehler-Allee 103, 79110 Freiburg, Germany
| | - Adam S Opalski
- Institute of Physical Chemistry, Polish Academy of Sciences, Warsaw, Poland.
| | - Piotr Garstecki
- Institute of Physical Chemistry, Polish Academy of Sciences, Warsaw, Poland.
| | - Ladislav Derzsi
- Institute of Physical Chemistry, Polish Academy of Sciences, Warsaw, Poland.
| | - Jan Guzowski
- Institute of Physical Chemistry, Polish Academy of Sciences, Warsaw, Poland.
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3
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Zhang Z, Ekanem EE, Nakajima M, Bolognesi G, Vladisavljević GT. Monodispersed Sirolimus-Loaded PLGA Microspheres with a Controlled Degree of Drug–Polymer Phase Separation for Drug-Coated Implantable Medical Devices and Subcutaneous Injection. ACS APPLIED BIO MATERIALS 2022; 5:3766-3777. [PMID: 35848106 PMCID: PMC9382632 DOI: 10.1021/acsabm.2c00319] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
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Monodispersed sirolimus (SRL)-loaded poly(lactic-co-glycolic acid) microspheres with a diameter of 1.8, 3.8,
and 8.5
μm were produced by high-throughput microfluidic step emulsification—solvent
evaporation using single crystal silicon chips consisted of 540–1710
terraced microchannels with a depth of 2, 4, or 5 μm arranged
in 10 parallel arrays. Uniform sized droplets were generated over
25 h across all channels. Nearly 15% of the total drug was released
by the initial burst release during an accelerated drug release testing
performed at 37 °C using a hydrotropic solution containing 5.8
M N,N-diethylnicotinamide. After
24 h, 71% of the drug was still entrapped in the particles. The internal
morphology of microspheres was investigated by fluorescence microscopy
using Nile red as a selective fluorescent stain with higher binding
affinity toward SRL. By increasing the drug loading from 33 to 50
wt %, the particle morphology evolved from homogeneous microspheres,
in which the drug and polymer were perfectly mixed, to patchy particles,
with amorphous drug patches embedded within a polymer matrix to anisotropic
patchy Janus particles. Janus particles with fully segregated drug
and polymer regions were achieved by pre-saturating the aqueous phase
with the organic solvent, which decreased the rate of solvent evaporation
and allowed enough time for complete phase separation. This approach
to manufacturing drug-loaded monodisperse microparticles can enable
the development of more effective implantable drug-delivery devices
and improved methods for subcutaneous drug administration, which can
lead to better therapeutic treatments.
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Affiliation(s)
- Zilin Zhang
- Department of Chemical Engineering, Loughborough University, Loughborough LE11 3TU, U.K
- Guangxi Key Laboratory of Green Chemical Materials and Safety Technology, Beibu Gulf University, Qinzhou 535011, China
| | - Ekanem E. Ekanem
- Department of Chemical Engineering, Loughborough University, Loughborough LE11 3TU, U.K
- Department of Chemical Engineering, University of Bath, Bath BA2 7AY, U.K
| | - Mitsutoshi Nakajima
- Faculty of Life and Environmental Sciences, University of Tsukuba, 1-1-1 Tennoudai, Tsukuba, Ibaraki 305-8572, Japan
| | - Guido Bolognesi
- Department of Chemical Engineering, Loughborough University, Loughborough LE11 3TU, U.K
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4
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Bubble formation in high-viscosity liquids in step-emulsification microdevices. J IND ENG CHEM 2022. [DOI: 10.1016/j.jiec.2022.07.012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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5
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Wei C, Yu C, Li S, Li T, Meng J, Li J. Easy-to-Operate Co-Flow Step Emulsification Device for High-Throughput Three-Dimensional Cell Culture. BIOSENSORS 2022; 12:bios12050350. [PMID: 35624651 PMCID: PMC9138713 DOI: 10.3390/bios12050350] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/26/2022] [Revised: 05/12/2022] [Accepted: 05/16/2022] [Indexed: 11/16/2022]
Abstract
Cell culture plays an essential role in tissue engineering and high-throughput drug screening. Compared with two-dimensional (2D) in vitro culture, three-dimensional (3D) in vitro culture can mimic cells in vivo more accurately, including complex cellular organizations, heterogeneity, and cell–extracellular matrix (ECM) interactions. This article presents a droplet-based microfluidic chip that integrates cell distribution, 3D in vitro cell culture, and in situ cell monitoring in a single device. Using the microfluidic “co-flow step emulsification” approach, we have successfully prepared close-packed droplet arrays with an ultra-high-volume fraction (72%) which can prevent cells from adhering to the chip surface so as to achieve a 3D cell culture and make scalable and high-throughput cell culture possible. The proposed device could produce droplets from 55.29 ± 1.52 to 95.64 ± 3.35 μm, enabling the diverse encapsulation of cells of different sizes and quantities. Furthermore, the cost for each microfluidic CFSE chip is approximately USD 3, making it a low-cost approach for 3D cell culture. The proposed device is successfully applied in the 3D culture of saccharomyces cerevisiae cells with an occurrence rate for proliferation of 80.34 ± 3.77%. With low-cost, easy-to-operate, high-throughput, and miniaturization characteristics, the proposed device meets the requirements for 3D in vitro cell culture and is expected to be applied in biological fields such as drug toxicology and pharmacokinetics.
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Affiliation(s)
- Chunyang Wei
- Hebei Key Laboratory of Robotic Sensing and Human-Robot Interactions, School of Mechanical Engineering, Hebei University of Technology, Tianjin 300132, China; (C.W.); (S.L.)
| | - Chengzhuang Yu
- State Key Laboratory of Reliability and Intelligence of Electrical Equipment, Hebei University of Technology, Tianjin 300130, China; (C.Y.); (J.M.)
| | - Shanshan Li
- Hebei Key Laboratory of Robotic Sensing and Human-Robot Interactions, School of Mechanical Engineering, Hebei University of Technology, Tianjin 300132, China; (C.W.); (S.L.)
- State Key Laboratory of Reliability and Intelligence of Electrical Equipment, Hebei University of Technology, Tianjin 300130, China; (C.Y.); (J.M.)
- Jiangsu Key Laboratory of Advanced Food Manufacturing Equipment and Technology, Jiangnan University, Wuxi 214122, China
| | - Tiejun Li
- Hebei Key Laboratory of Robotic Sensing and Human-Robot Interactions, School of Mechanical Engineering, Hebei University of Technology, Tianjin 300132, China; (C.W.); (S.L.)
- Correspondence: (T.L.); (J.L.); Tel.: +86-22-60202605 (T.L.); +86-22-60201070 (J.L.)
| | - Jiyu Meng
- State Key Laboratory of Reliability and Intelligence of Electrical Equipment, Hebei University of Technology, Tianjin 300130, China; (C.Y.); (J.M.)
| | - Junwei Li
- Institute of Biophysics, School of Health Sciences and Biomedical Engineering, Hebei University of Technology, Tianjin 300401, China
- Department of Computer Science and Electrical Engineering, Hebei University of Technology, Langfang 065000, China
- Correspondence: (T.L.); (J.L.); Tel.: +86-22-60202605 (T.L.); +86-22-60201070 (J.L.)
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6
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Mathekga BSP, Nxumalo Z, Thimiri Govinda Raj DB. Micro and nanofluidics for high throughput drug screening. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2022; 187:93-120. [PMID: 35094783 DOI: 10.1016/bs.pmbts.2021.07.020] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
In this book chapter, we elaborate on the state-of-the-art technology developments in high throughput screening, microfluidics and nanofluidics. This book chapter further elaborated on the application of microfluidics and nanofluidics for high throughput drug screening with respect to communicable diseases and non-communicable diseases such as cancer. As a future perspective, there is tremendous potential for microfluidics and nanofluidics to be applied in high throughput drug screening which could be applied for various biotechnology applications such as in cancer precision medicine, point-of-care diagnostics and imaging. With the integration of Fourth industrial revolution (4IR) technologies with micro and nanofluidics technologies, it envisioned that such integration along with digital health would enable next generation technology development in medical field.
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Affiliation(s)
| | - Zandile Nxumalo
- Synthetic Nanobiotechnology and Biomachines Group, Synthetic Biology and Precision Medicine Centre, CSIR, Pretoria, South Africa
| | - Deepak B Thimiri Govinda Raj
- Synthetic Nanobiotechnology and Biomachines Group, Synthetic Biology and Precision Medicine Centre, CSIR, Pretoria, South Africa.
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7
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Low Cost, Easily-Assembled Centrifugal Buoyancy-Based Emulsification and Digital PCR. MICROMACHINES 2022; 13:mi13020171. [PMID: 35208296 PMCID: PMC8924881 DOI: 10.3390/mi13020171] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/22/2021] [Revised: 01/18/2022] [Accepted: 01/20/2022] [Indexed: 11/29/2022]
Abstract
Microfluidic-based droplet generation approaches require the design of microfluidic chips and a precise lithography process, which require skilled technicians and a long manufacturing time. Here we developed a centrifugal buoyancy-based emulsification (CBbE) method for producing droplets with high efficiency and minimal fabrication time. Our approach is to fabricate a droplet generation module that can be easily assembled using syringe needles and PCR tubes. With this module and a common centrifuge, high-throughput droplet generation with controllable droplet size could be realized in a few minutes. Experiments showed that the droplet diameter depended mainly on centrifugal speed, and droplets with controllable diameter from 206 to 158 μm could be generated under a centrifugal acceleration range from 14 to 171.9 g. Excellent droplet uniformity was achieved (CV < 3%) when centrifugal acceleration was greater than 108 g. We performed digital PCR tests through the CBbE approach and demonstrated that this cost-effective method not only eliminates the usage of complex microfluidic devices and control systems but also greatly suppresses the loss of materials and cross-contamination. CBbE-enabled droplet generation combines both easiness and robustness, and breaks the technical challenges by using conventional lab equipment and supplies.
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8
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Wu J, Yadavali S, Lee D, Issadore DA. Scaling up the throughput of microfluidic droplet-based materials synthesis: A review of recent progress and outlook. APPLIED PHYSICS REVIEWS 2021; 8:031304. [PMID: 34484549 PMCID: PMC8293697 DOI: 10.1063/5.0049897] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/10/2021] [Accepted: 06/07/2021] [Indexed: 05/14/2023]
Abstract
The last two decades have witnessed tremendous progress in the development of microfluidic chips that generate micrometer- and nanometer-scale materials. These chips allow precise control over composition, structure, and particle uniformity not achievable using conventional methods. These microfluidic-generated materials have demonstrated enormous potential for applications in medicine, agriculture, food processing, acoustic, and optical meta-materials, and more. However, because the basis of these chips' performance is their precise control of fluid flows at the micrometer scale, their operation is limited to the inherently low throughputs dictated by the physics of multiphasic flows in micro-channels. This limitation on throughput results in material production rates that are too low for most practical applications. In recent years, however, significant progress has been made to tackle this challenge by designing microchip architectures that incorporate multiple microfluidic devices onto single chips. These devices can be operated in parallel to increase throughput while retaining the benefits of microfluidic particle generation. In this review, we will highlight recent work in this area and share our perspective on the key unsolved challenges and opportunities in this field.
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Affiliation(s)
- Jingyu Wu
- Department of Chemical and Biomolecular Engineering, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
| | | | - Daeyeon Lee
- Department of Chemical and Biomolecular Engineering, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
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9
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Ge X, Rubinstein BY, He Y, Bruce FNO, Li L, Leshansky AM, Li Z. Double emulsions with ultrathin shell by microfluidic step-emulsification. LAB ON A CHIP 2021; 21:1613-1622. [PMID: 33683225 DOI: 10.1039/d0lc01044h] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Double emulsions with ultrathin shells are important in some biomedical applications, such as controlled drug release. However, the existing production techniques require two or more manipulation steps, or more complicated channel geometry, to form thin-shell double emulsions. This work presents a novel microfluidic tri-phasic step-emulsification device, with an easily fabricated double-layer PDMS channel, for production of oil-in-oil-in-water and water-in-water-in-oil double emulsions in a single step. The shell thickness is controlled by the flow rates and can reach 1.4% of the μm-size droplet diameter. Four distinct emulsification regimes are observed depending on the experimental conditions. A theoretical model for the tri-phasic step-emulsification is proposed to predict the boundaries separating the four regimes of emulsification in plane of two dimensionless capillary numbers, Ca. The theory yields two coupled nonlinear differential equations that can be solved numerically to find the approximate shape of the free interfaces in the shallow (Hele-Shaw) microfluidic channel. This approximation is then used as the initial guess for the more accurate finite element method solution, showing very good agreement with the experimental findings. This study demonstrates the feasibility of co-flow step-emulsification as a promising method to production of double (and multiple) emulsions and micro-capsules with ultrathin shells of controllable thickness.
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Affiliation(s)
- Xinjin Ge
- School of Aerospace Engineering, Beijing Institute of Technology, ZhongGuanCunNan Street #5, 100081, Beijing, China.
| | | | - Yifeng He
- School of Aerospace Engineering, Beijing Institute of Technology, ZhongGuanCunNan Street #5, 100081, Beijing, China.
| | - Frederick N O Bruce
- School of Aerospace Engineering, Beijing Institute of Technology, ZhongGuanCunNan Street #5, 100081, Beijing, China.
| | - Liaonan Li
- School of Aerospace Engineering, Beijing Institute of Technology, ZhongGuanCunNan Street #5, 100081, Beijing, China.
| | - Alexander M Leshansky
- Department of Chemical Engineering, Technion - Israel Institute of Technology, Haifa 32000, Israel.
| | - Zhenzhen Li
- School of Aerospace Engineering, Beijing Institute of Technology, ZhongGuanCunNan Street #5, 100081, Beijing, China.
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10
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Liu Z, Duan C, Jiang S, Zhu C, Ma Y, Fu T. Microfluidic step emulsification techniques based on spontaneous transformation mechanism: A review. J IND ENG CHEM 2020. [DOI: 10.1016/j.jiec.2020.08.025] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
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11
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Huang X, He B, Xu Z, Pei H, Ruan YJ. Electro-coalescence in step emulsification: dynamics and applications. LAB ON A CHIP 2020; 20:592-600. [PMID: 31903468 DOI: 10.1039/c9lc01115c] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Step emulsification is a low-shear method to produce monodispersed microdroplets by spontaneous breakup of dispersed fluid at a spatial "step". As a semi-open microfluidic system, controllable coalescence of multiple components in step emulsification has not been achieved. Here, we use a low voltage to control the coalescence position of flow tips in the terrace. By investigating the interaction between the coalescence behavior and the hydrodynamics of the drop formation, we numerically predict the shape evolution of the flow tips and give a semi-empirical model to calculate the sizes of droplets by the flow rates and the voltage. Furthermore, we explore the capabilities of the electro-coalescer based on step emulsification. To trigger the coalescence in the wide reservoir, the clogging problem in precipitate-producing reactions is avoided. Besides, the low-shear nature of step emulsification also facilitates the production of multilayered droplets.
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Affiliation(s)
- Xing Huang
- Institute of Process Equipment, Department of Energy Engineering, Zhejiang University, Hangzhou, 310027, China. and John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138, USA
| | - Binbin He
- Institute of Process Equipment, Department of Energy Engineering, Zhejiang University, Hangzhou, 310027, China.
| | - Zhongbin Xu
- Institute of Process Equipment, Department of Energy Engineering, Zhejiang University, Hangzhou, 310027, China.
| | - Hao Pei
- John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138, USA
| | - Yun Jie Ruan
- Institute of Agricultural Bio-Environmental Engineering, College of Bio-systems Engineering and Food Science, Zhejiang University, Hangzhou 310058, China. and Institute of New Countryside Development, Zhejiang University, Hangzhou 310058, China
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12
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Shi Z, Lai X, Sun C, Zhang X, Zhang L, Pu Z, Wang R, Yu H, Li D. Step emulsification in microfluidic droplet generation: mechanisms and structures. Chem Commun (Camb) 2020; 56:9056-9066. [DOI: 10.1039/d0cc03628e] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Step emulsification for micro- and nano-droplet generation is reviewed in brief, including the emulsion mechanisms and microfluidic devices.
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Affiliation(s)
- Zhi Shi
- State Key Laboratory of Precision Measuring Technology and Instruments
- Tianjin University
- Tianjin
- China
| | - Xiaochen Lai
- State Key Laboratory of Precision Measuring Technology and Instruments
- Tianjin University
- Tianjin
- China
| | - Chengtao Sun
- State Key Laboratory of Precision Measuring Technology and Instruments
- Tianjin University
- Tianjin
- China
| | - Xingguo Zhang
- State Key Laboratory of Precision Measuring Technology and Instruments
- Tianjin University
- Tianjin
- China
| | - Lei Zhang
- State Key Laboratory of Precision Measuring Technology and Instruments
- Tianjin University
- Tianjin
- China
| | - Zhihua Pu
- State Key Laboratory of Precision Measuring Technology and Instruments
- Tianjin University
- Tianjin
- China
| | - Ridong Wang
- State Key Laboratory of Precision Measuring Technology and Instruments
- Tianjin University
- Tianjin
- China
| | - Haixia Yu
- Tianjin Key Laboratory of Biomedical Detecting Techniques and Instruments
- Tianjin University
- Tianjin
- China
| | - Dachao Li
- State Key Laboratory of Precision Measuring Technology and Instruments
- Tianjin University
- Tianjin
- China
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13
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Opalski AS, Makuch K, Derzsi L, Garstecki P. Split or slip – passive generation of monodisperse double emulsions with cores of varying viscosity in microfluidic tandem step emulsification system. RSC Adv 2020; 10:23058-23065. [PMID: 35520343 PMCID: PMC9054724 DOI: 10.1039/d0ra03007d] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2020] [Accepted: 06/02/2020] [Indexed: 12/22/2022] Open
Abstract
We investigate the role of viscosities on the formation of double emulsion in a microfluidic step emulsification system. Aqueous droplets of various viscosities and sizes were engulfed in fluorocarbon oil and subsequently transformed into double droplets in the microfluidic step emulsifying device. We identify two distinct regimes of double droplet formation: (i) core droplets split into multiple smaller droplets, or (ii) cores slip whole into the forming oil shell. We show that the viscosity ratio of the core and shell phases plays a crucial role in determining the mode of formation of the double emulsions. Finally, we demonstrate that high viscosity of the core droplet allows for generation of double emulsions with constant shell thickness for cores of various sizes. We investigate the role of fluid viscosities on formation of double emulsion in a microfluidic step emulsification system. The ratio of fluid viscosities controls double droplet formation, leading to splitting of the core for low core-to-shell viscosity ratio.![]()
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Affiliation(s)
- Adam S. Opalski
- Institute of Physical Chemistry of Polish Academy of Sciences
- 01-224 Warsaw
- Poland
| | - Karol Makuch
- Institute of Physical Chemistry of Polish Academy of Sciences
- 01-224 Warsaw
- Poland
| | - Ladislav Derzsi
- Institute of Physical Chemistry of Polish Academy of Sciences
- 01-224 Warsaw
- Poland
| | - Piotr Garstecki
- Institute of Physical Chemistry of Polish Academy of Sciences
- 01-224 Warsaw
- Poland
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14
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Deng B, de Ruiter J, Schroën K. Application of Microfluidics in the Production and Analysis of Food Foams. Foods 2019; 8:E476. [PMID: 31614474 PMCID: PMC6835574 DOI: 10.3390/foods8100476] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2019] [Revised: 10/07/2019] [Accepted: 10/09/2019] [Indexed: 12/13/2022] Open
Abstract
Emulsifiers play a key role in the stabilization of foam bubbles. In food foams, biopolymers such as proteins are contributing to long-term stability through several effects such as increasing bulk viscosity and the formation of viscoelastic interfaces. Recent studies have identified promising new stabilizers for (food) foams and emulsions, for instance biological particles derived from water-soluble or water-insoluble proteins, (modified) starch as well as chitin. Microfluidic platforms could provide a valuable tool to study foam formation on the single-bubble level, yielding mechanistic insights into the formation and stabilization (as well as destabilization) of foams stabilized by these new stabilizers. Yet, the recent developments in microfluidic technology have mainly focused on emulsions rather than foams. Microfluidic devices have been up-scaled (to some extent) for large-scale emulsion production, and also designed as investigative tools to monitor interfaces at the (sub)millisecond time scale. In this review, we summarize the current state of the art in droplet microfluidics (and, where available, bubble microfluidics), and provide a perspective on the applications for (food) foams. Microfluidic investigations into foam formation and stability are expected to aid in optimization of stabilizer selection and production conditions for food foams, as well as provide a platform for (large-scale) production of monodisperse foams.
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Affiliation(s)
- Boxin Deng
- Food Process Engineering Group, Wageningen University, Bornse Weilanden 9, 6708 WG Wageningen, The Netherlands.
| | - Jolet de Ruiter
- Food Process Engineering Group, Wageningen University, Bornse Weilanden 9, 6708 WG Wageningen, The Netherlands.
| | - Karin Schroën
- Food Process Engineering Group, Wageningen University, Bornse Weilanden 9, 6708 WG Wageningen, The Netherlands.
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15
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Schulz M, von Stetten F, Zengerle R, Paust N. Centrifugal Step Emulsification: How Buoyancy Enables High Generation Rates of Monodisperse Droplets. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2019; 35:9809-9815. [PMID: 31283246 DOI: 10.1021/acs.langmuir.9b01165] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
We demonstrate that buoyancy in centrifugal step emulsification enables substantially higher generation rates of monodisperse droplets compared to pressure driven set-ups. Step emulsification in general can produce droplets in comparatively simple systems (only one moving liquid) with a low CV of <5% in droplet diameter and with a minimum dead volume. If operated below a critical capillary number, the droplet diameter is defined by geometry and surface forces only. Above that critical capillary number, however, jetting occurs, leading to an increased droplet diameter and CV. Consequently, generation rates of monodisperse droplets are limited in pressure-driven systems. In this paper, we show that centrifugal step emulsification can overcome this limitation by applying sufficient buoyancy to the system. The buoyancy, induced by the centrifugal field and a density difference of the continuous and disperse phase, supports droplet necking by pulling the forming droplet away from the nozzle. The influence of buoyancy is studied using specific microfluidic designs that allow for supplying different buoyancies to the same droplet generation rates. For a droplet diameter of 100 μm, droplet generation at rates above 2.8k droplets per second and nozzle were reached, which is an increase of more than a factor of 8 in comparison to pressure-driven systems.
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Affiliation(s)
- Martin Schulz
- Hahn-Schickard , Georges-Koehler-Allee 103 , 79110 Freiburg , Germany
| | - Felix von Stetten
- Hahn-Schickard , Georges-Koehler-Allee 103 , 79110 Freiburg , Germany
- Laboratory for MEMS Applications, IMTEK - Department of Microsystems Engineering , University of Freiburg , Georges-Koehler-Allee 103 , 79110 Freiburg , Germany
| | - Roland Zengerle
- Hahn-Schickard , Georges-Koehler-Allee 103 , 79110 Freiburg , Germany
- Laboratory for MEMS Applications, IMTEK - Department of Microsystems Engineering , University of Freiburg , Georges-Koehler-Allee 103 , 79110 Freiburg , Germany
| | - Nils Paust
- Hahn-Schickard , Georges-Koehler-Allee 103 , 79110 Freiburg , Germany
- Laboratory for MEMS Applications, IMTEK - Department of Microsystems Engineering , University of Freiburg , Georges-Koehler-Allee 103 , 79110 Freiburg , Germany
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