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Xiang N, Ni Z. Inertial microfluidics: current status, challenges, and future opportunities. LAB ON A CHIP 2022; 22:4792-4804. [PMID: 36263793 DOI: 10.1039/d2lc00722c] [Citation(s) in RCA: 20] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
Inertial microfluidics uses the hydrodynamic effects induced at finite Reynolds numbers to achieve passive manipulation of particles, cells, or fluids and offers the advantages of high-throughput processing, simple channel geometry, and label-free and external field-free operation. Since its proposal in 2007, inertial microfluidics has attracted increasing interest and is currently widely employed as an important sample preparation protocol for single-cell detection and analysis. Although great success has been achieved in the inertial microfluidics field, its performance and outcome can be further improved. From this perspective, herein, we reviewed the current status, challenges, and opportunities of inertial microfluidics concerning the underlying physical mechanisms, available simulation tools, channel innovation, multistage, multiplexing, or multifunction integration, rapid prototyping, and commercial instrument development. With an improved understanding of the physical mechanisms and the development of novel channels, integration strategies, and commercial instruments, improved inertial microfluidic platforms may represent a new foundation for advancing biomedical research and disease diagnosis.
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Affiliation(s)
- Nan Xiang
- School of Mechanical Engineering, and Jiangsu Key Laboratory for Design and Manufacture of Micro-Nano Biomedical Instruments, Southeast University, Nanjing, 211189, China.
| | - Zhonghua Ni
- School of Mechanical Engineering, and Jiangsu Key Laboratory for Design and Manufacture of Micro-Nano Biomedical Instruments, Southeast University, Nanjing, 211189, China.
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Tang H, Niu J, Jin H, Lin S, Cui D. Geometric structure design of passive label-free microfluidic systems for biological micro-object separation. MICROSYSTEMS & NANOENGINEERING 2022; 8:62. [PMID: 35685963 PMCID: PMC9170746 DOI: 10.1038/s41378-022-00386-y] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/09/2021] [Revised: 02/27/2022] [Accepted: 03/18/2022] [Indexed: 05/05/2023]
Abstract
Passive and label-free microfluidic devices have no complex external accessories or detection-interfering label particles. These devices are now widely used in medical and bioresearch applications, including cell focusing and cell separation. Geometric structure plays the most essential role when designing a passive and label-free microfluidic chip. An exquisitely designed geometric structure can change particle trajectories and improve chip performance. However, the geometric design principles of passive and label-free microfluidics have not been comprehensively acknowledged. Here, we review the geometric innovations of several microfluidic schemes, including deterministic lateral displacement (DLD), inertial microfluidics (IMF), and viscoelastic microfluidics (VEM), and summarize the most creative innovations and design principles of passive and label-free microfluidics. We aim to provide a guideline for researchers who have an interest in geometric innovations of passive label-free microfluidics.
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Affiliation(s)
- Hao Tang
- Institute of Nano Biomedicine and Engineering, Shanghai Engineering Research Center for Intelligent Diagnosis and Treatment Instrument, Department of Instrument Science and Engineering, School of Electronic Information and Electrical Engineering, Shanghai Jiao Tong University, 800 Dongchuan RD, Shanghai, 200240 China
| | - Jiaqi Niu
- Institute of Nano Biomedicine and Engineering, Shanghai Engineering Research Center for Intelligent Diagnosis and Treatment Instrument, Department of Instrument Science and Engineering, School of Electronic Information and Electrical Engineering, Shanghai Jiao Tong University, 800 Dongchuan RD, Shanghai, 200240 China
| | - Han Jin
- Institute of Nano Biomedicine and Engineering, Shanghai Engineering Research Center for Intelligent Diagnosis and Treatment Instrument, Department of Instrument Science and Engineering, School of Electronic Information and Electrical Engineering, Shanghai Jiao Tong University, 800 Dongchuan RD, Shanghai, 200240 China
- National Engineering Research Center for Nanotechnology, Shanghai Jiao Tong University, 28 Jiangchuan Easternroad, Shanghai, 200241 China
| | - Shujing Lin
- Institute of Nano Biomedicine and Engineering, Shanghai Engineering Research Center for Intelligent Diagnosis and Treatment Instrument, Department of Instrument Science and Engineering, School of Electronic Information and Electrical Engineering, Shanghai Jiao Tong University, 800 Dongchuan RD, Shanghai, 200240 China
- National Engineering Research Center for Nanotechnology, Shanghai Jiao Tong University, 28 Jiangchuan Easternroad, Shanghai, 200241 China
| | - Daxiang Cui
- Institute of Nano Biomedicine and Engineering, Shanghai Engineering Research Center for Intelligent Diagnosis and Treatment Instrument, Department of Instrument Science and Engineering, School of Electronic Information and Electrical Engineering, Shanghai Jiao Tong University, 800 Dongchuan RD, Shanghai, 200240 China
- National Engineering Research Center for Nanotechnology, Shanghai Jiao Tong University, 28 Jiangchuan Easternroad, Shanghai, 200241 China
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Antognoli M, Stoecklein D, Galletti C, Brunazzi E, Di Carlo D. Optimized design of obstacle sequences for microfluidic mixing in an inertial regime. LAB ON A CHIP 2021; 21:3910-3923. [PMID: 34636817 DOI: 10.1039/d1lc00483b] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Mixing is a basic but challenging step to achieve in high throughput microfluidic applications such as organic synthesis or production of particles. A common approach to improve micromixer performance is to devise a single component that enhances mixing through optimal convection, and then sequence multiple such units back-to-back to enhance overall mixing at the end of the sequence. However, the mixing units are often optimized only for the initial non-mixed fluid composition, which is no longer the input condition for each subsequent unit. Thus, there is no guarantee that simply repeating a single mixing unit will achieve optimally mixed fluid flow at the end of the sequence. In this work, we analyzed sequences of 20 cylindrical obstacles, or pillars, to optimize the mixing in the inertial regime (where mixing is more difficult due to higher Péclet number) by managing their interdependent convection operations on the composition of the fluid. Exploiting a software for microfluidic design optimization called FlowSculpt, we predicted and optimized the interfacial stretching of two co-flowing fluids, neglecting diffusive effects. We were able to quickly design three different optimal pillar sequences through a space of 3220 possible combinations of pillars. As proof of concept, we tested the new passive mixer designs using confocal microscopy and full 3D CFD simulations for high Péclet numbers (Pe ≈ O(105-6)), observing fluid flow shape and mixing index at several cross-sections, reaching mixing efficiencies around 80%. Furthermore, we investigated the effect of the inter-pillar spacing on the most optimal design, quantifying the tradeoff between mixing performance and hydraulic resistance. These micromixer designs and the framework for the design in inertial regimes can be used for various applications, such as lipid nanoparticle fabrication which has been of great importance in vaccine scale up during the pandemic.
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Affiliation(s)
- Matteo Antognoli
- Dipartimento di Ingegneria Civile e Industriale, University of Pisa, Pisa 56122, Italy
| | - Daniel Stoecklein
- Department of Mechanical Engineering, Rose-Hulman Institute of Technology, Terre Haute, IN, 47803, USA
| | - Chiara Galletti
- Dipartimento di Ingegneria Civile e Industriale, University of Pisa, Pisa 56122, Italy
| | - Elisabetta Brunazzi
- Dipartimento di Ingegneria Civile e Industriale, University of Pisa, Pisa 56122, Italy
| | - Dino Di Carlo
- Department of Bioengineering, University of California, Los Angeles, CA, 90055, USA.
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Chizari S, Udani S, Farzaneh A, Stoecklein D, Carlo DD, Hopkins JB. Scanning two-photon continuous flow lithography for the fabrication of multi-functional microparticles. OPTICS EXPRESS 2020; 28:40088-40098. [PMID: 33379542 DOI: 10.1364/oe.410090] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/16/2020] [Accepted: 11/17/2020] [Indexed: 06/12/2023]
Abstract
In this work, we demonstrate the high-throughput fabrication of 3D microparticles using a scanning two-photon continuous flow lithography (STP-CFL) technique in which microparticles are shaped by scanning the laser beam at the interface of laminar co-flows. The results demonstrate the ability of STP-CFL to manufacture high-resolution complex geometries of cell carriers that possess distinct regions with different functionalities. A new approach is presented for printing out-of-plane features on the microparticles. The approach eliminates the use of axial scanning stages, which are not favorable since they induce fluctuations in the flowing polymer media and their scanning speed is slower than the speed of galvanometer mirror scanners.
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Wu CY, Ouyang M, Wang B, de Rutte J, Joo A, Jacobs M, Ha K, Bertozzi AL, Di Carlo D. Monodisperse drops templated by 3D-structured microparticles. SCIENCE ADVANCES 2020; 6:eabb9023. [PMID: 33148643 PMCID: PMC7673687 DOI: 10.1126/sciadv.abb9023] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/26/2020] [Accepted: 09/21/2020] [Indexed: 05/27/2023]
Abstract
The ability to create uniform subnanoliter compartments using microfluidic control has enabled new approaches for analysis of single cells and molecules. However, specialized instruments or expertise has been required, slowing the adoption of these cutting-edge applications. Here, we show that three dimensional-structured microparticles with sculpted surface chemistries template uniformly sized aqueous drops when simply mixed with two immiscible fluid phases. In contrast to traditional emulsions, particle-templated drops of a controlled volume occupy a minimum in the interfacial energy of the system, such that a stable monodisperse state results with simple and reproducible formation conditions. We describe techniques to manufacture microscale drop-carrier particles and show that emulsions created with these particles prevent molecular exchange, concentrating reactions within the drops, laying a foundation for sensitive compartmentalized molecular and cell-based assays with minimal instrumentation.
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Affiliation(s)
- Chueh-Yu Wu
- Department of Bioengineering, University of California, Los Angeles, CA 90095, USA
| | - Mengxing Ouyang
- Department of Bioengineering, University of California, Los Angeles, CA 90095, USA
| | - Bao Wang
- Department of Mathematics, University of California, Los Angeles, CA 90095, USA
| | - Joseph de Rutte
- Department of Bioengineering, University of California, Los Angeles, CA 90095, USA
| | - Alexis Joo
- Department of Bioengineering, University of California, Los Angeles, CA 90095, USA
| | - Matthew Jacobs
- Department of Mathematics, University of California, Los Angeles, CA 90095, USA
| | - Kyung Ha
- Department of Mathematics, University of California, Los Angeles, CA 90095, USA
| | - Andrea L Bertozzi
- Department of Mathematics, University of California, Los Angeles, CA 90095, USA
- Department of Mechanical and Aerospace Engineering, University of California, Los Angeles, CA 90095, USA
- California NanoSystems Institute, University of California, Los Angeles, CA 90095, USA
| | - Dino Di Carlo
- Department of Bioengineering, University of California, Los Angeles, CA 90095, USA.
- Department of Mechanical and Aerospace Engineering, University of California, Los Angeles, CA 90095, USA
- California NanoSystems Institute, University of California, Los Angeles, CA 90095, USA
- Jonsson Comprehensive Cancer Center, University of California, Los Angeles, CA 90095, USA
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Tang W, Zhu S, Jiang D, Zhu L, Yang J, Xiang N. Channel innovations for inertial microfluidics. LAB ON A CHIP 2020; 20:3485-3502. [PMID: 32910129 DOI: 10.1039/d0lc00714e] [Citation(s) in RCA: 76] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Inertial microfluidics has gained significant attention since first being proposed in 2007 owing to the advantages of simplicity, high throughput, precise manipulation, and freedom from an external field. Superior performance in particle focusing, filtering, concentrating, and separating has been demonstrated. As a passive technology, inertial microfluidics technology relies on the unconventional use of fluid inertia in an intermediate Reynolds number range to induce inertial migration and secondary flow, which depend directly on the channel structure, leading to particle migration to the lateral equilibrium position or trapping in a specific cavity. With the advances in micromachining technology, many channel structures have been designed and fabricated in the past decade to explore the fundamentals and applications of inertial microfluidics. However, the channel innovations for inertial microfluidics have not been discussed comprehensively. In this review, the inertial particle manipulations and underlying physics in conventional channels, including straight, spiral, sinusoidal, and expansion-contraction channels, are briefly described. Then, recent innovations in channel structure for inertial microfluidics, especially channel pattern modification and unconventional cross-sectional shape, are reviewed. Finally, the prospects for future channel innovations in inertial microfluidic chips are also discussed. The purpose of this review is to provide guidance for the continued study of innovative channel designs to improve further the accuracy and throughput of inertial microfluidics.
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Affiliation(s)
- Wenlai Tang
- School of Electrical and Automation Engineering, Jiangsu Key Laboratory of 3D Printing Equipment and Manufacturing, Nanjing Normal University, Nanjing, 210023, China.
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