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Lee KCM, Chung BMF, Siu DMD, Ho SCK, Ng DKH, Tsia KK. Dispersion-free inertial focusing (DIF) for high-yield polydisperse micro-particle filtration and analysis. LAB ON A CHIP 2024. [PMID: 39101363 DOI: 10.1039/d4lc00275j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/06/2024]
Abstract
Inertial focusing excels at the precise spatial ordering and separation of microparticles by size within fluid flows. However, this advantage, resulting from its inherent size-dependent dispersion, could turn into a drawback that challenges applications requiring consistent and uniform positioning of polydisperse particles, such as microfiltration and flow cytometry. To overcome this fundamental challenge, we introduce Dispersion-Free Inertial Focusing (DIF). This new method minimizes particle size-dependent dispersion while maintaining the high throughput and precision of standard inertial focusing, even in a highly polydisperse scenario. We demonstrate a rule-of-thumb principle to reinvent an inertial focusing system and achieve an efficient focusing of particles ranging from 6 to 30 μm in diameter onto a single plane with less than 3 μm variance and over 95% focusing efficiency at highly scalable throughput (2.4-30 mL h-1) - a stark contrast to existing technologies that struggle with polydispersity. We demonstrated that DIF could be applied in a broad range of applications, particularly enabling high-yield continuous microparticle filtration and large-scale high-resolution single-cell morphological analysis of heterogeneous cell populations. This new technique is also readily compatible with the existing inertial microfluidic design and thus could unleash more diverse systems and applications.
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Affiliation(s)
- Kelvin C M Lee
- The University of Hong Kong, Pokfulam Road, Hong Kong, Hong Kong.
- Advanced Biomedical Instrumentation Centre, Hong Kong Science Park, Shatin, New Territories, Hong Kong
| | - Bob M F Chung
- The University of Hong Kong, Pokfulam Road, Hong Kong, Hong Kong.
- Advanced Biomedical Instrumentation Centre, Hong Kong Science Park, Shatin, New Territories, Hong Kong
| | - Dickson M D Siu
- The University of Hong Kong, Pokfulam Road, Hong Kong, Hong Kong.
- Advanced Biomedical Instrumentation Centre, Hong Kong Science Park, Shatin, New Territories, Hong Kong
| | - Sam C K Ho
- The University of Hong Kong, Pokfulam Road, Hong Kong, Hong Kong.
| | - Daniel K H Ng
- The University of Hong Kong, Pokfulam Road, Hong Kong, Hong Kong.
| | - Kevin K Tsia
- The University of Hong Kong, Pokfulam Road, Hong Kong, Hong Kong.
- Advanced Biomedical Instrumentation Centre, Hong Kong Science Park, Shatin, New Territories, Hong Kong
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Akbari Z, Raoufi MA, Mirjalali S, Aghajanloo B. A review on inertial microfluidic fabrication methods. BIOMICROFLUIDICS 2023; 17:051504. [PMID: 37869745 PMCID: PMC10589053 DOI: 10.1063/5.0163970] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/20/2023] [Accepted: 10/02/2023] [Indexed: 10/24/2023]
Abstract
In recent decades, there has been significant interest in inertial microfluidics due to its high throughput, ease of fabrication, and no need for external forces. The focusing efficiency of inertial microfluidic systems relies entirely on the geometrical features of microchannels because hydrodynamic forces (inertial lift forces and Dean drag forces) are the main driving forces in inertial microfluidic devices. In the past few years, novel microchannel structures have been propounded to improve particle manipulation efficiency. However, the fabrication of these unconventional structures has remained a serious challenge. Although researchers have pushed forward the frontiers of microfabrication technologies, the fabrication techniques employed for inertial microfluidics have not been discussed comprehensively. This review introduces the microfabrication approaches used for creating inertial microchannels, including photolithography, xurography, laser cutting, micromachining, microwire technique, etching, hot embossing, 3D printing, and injection molding. The advantages and disadvantages of these methods have also been discussed. Then, the techniques are reviewed regarding resolution, structures, cost, and materials. This review provides a thorough insight into the manufacturing methods of inertial microchannels, which could be helpful for future studies to improve the harvesting yield and resolution by choosing a proper fabrication technique.
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Affiliation(s)
- Zohreh Akbari
- Department of Mechanical Engineering, Ferdowsi University of Mashhad, Mashhad, Iran
| | | | - Sheyda Mirjalali
- School of Engineering, Macquarie University, Sydney, New South Wales, Australia
| | - Behrouz Aghajanloo
- School of Engineering, Macquarie University, Sydney, New South Wales, Australia
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Li BW, Wei K, Liu QQ, Sun XG, Su N, Li WM, Shang MY, Li JM, Liao D, Li J, Lu WP, Deng SL, Huang Q. Enhanced Separation Efficiency and Purity of Circulating Tumor Cells Based on the Combined Effects of Double Sheath Fluids and Inertial Focusing. Front Bioeng Biotechnol 2021; 9:750444. [PMID: 34778227 PMCID: PMC8578950 DOI: 10.3389/fbioe.2021.750444] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2021] [Accepted: 09/15/2021] [Indexed: 12/25/2022] Open
Abstract
Circulating tumor cells (CTCs) play a crucial role in solid tumor metastasis, but obtaining high purity and viability CTCs is a challenging task due to their rarity. Although various works using spiral microchannels to isolate CTCs have been reported, the sorting purity of CTCs has not been significantly improved. Herein, we developed a novel double spiral microchannel for efficient separation and enrichment of intact and high-purity CTCs based on the combined effects of two-stage inertial focusing and particle deflection. Particle deflection relies on the second sheath to produce a deflection of the focused sample flow segment at the end of the first-stage microchannel, allowing larger particles to remain focused and entered the second-stage microchannel while smaller particles moved into the first waste channel. The deflection of the focused sample flow segment was visualized. Testing by a binary mixture of 10.4 and 16.5 μm fluorescent microspheres, it showed 16.5 μm with separation efficiency of 98% and purity of 90% under the second sheath flow rate of 700 μl min−1. In biological experiments, the average purity of spiked CTCs was 74% at a high throughput of 1.5 × 108 cells min−1, and the recovery was more than 91%. Compared to the control group, the viability of separated cells was 99%. Finally, we validated the performance of the double spiral microchannel using clinical cancer blood samples. CTCs with a concentration of 2–28 counts ml−1 were separated from all 12 patients’ peripheral blood. Thus, our device could be a robust and label-free liquid biopsy platform in inertial microfluidics for successful application in clinical trials.
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Affiliation(s)
- Bo-Wen Li
- Department of Laboratory Medicine, Daping Hospital, Army Medical University, Chongqing, China
| | - Kun Wei
- Department of Laboratory Medicine, Daping Hospital, Army Medical University, Chongqing, China
| | - Qi-Qi Liu
- Department of Nursing, Children's Hospital of Chongqing Medical University, Chongqing, China
| | - Xian-Ge Sun
- Department of Laboratory Medicine, Daping Hospital, Army Medical University, Chongqing, China
| | - Ning Su
- Department of Laboratory Medicine, Daping Hospital, Army Medical University, Chongqing, China
| | - Wen-Man Li
- Department of Laboratory Medicine, Daping Hospital, Army Medical University, Chongqing, China
| | - Mei-Yun Shang
- Department of Laboratory Medicine, Daping Hospital, Army Medical University, Chongqing, China
| | - Jin-Mi Li
- Department of Laboratory Medicine, Daping Hospital, Army Medical University, Chongqing, China
| | - Dan Liao
- Department of Laboratory Medicine, Daping Hospital, Army Medical University, Chongqing, China
| | - Jin Li
- Department of Laboratory Medicine, Daping Hospital, Army Medical University, Chongqing, China
| | - Wei-Ping Lu
- Department of Laboratory Medicine, Daping Hospital, Army Medical University, Chongqing, China
| | - Shao-Li Deng
- Department of Laboratory Medicine, Daping Hospital, Army Medical University, Chongqing, China
| | - Qing Huang
- Department of Laboratory Medicine, Daping Hospital, Army Medical University, Chongqing, China
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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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Mihandoust A, Maleki-Jirsaraei N, Rouhani S, Safi S, Alizadeh M. Improvement of size-based particle separation throughput in slanted spiral microchannel by modifying outlet geometry. Electrophoresis 2020; 41:353-359. [PMID: 32012295 DOI: 10.1002/elps.201900436] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2019] [Revised: 01/26/2020] [Accepted: 01/28/2020] [Indexed: 12/15/2022]
Abstract
The inertial microfluidic technique, as a powerful new tool for accurate cell/particle separation based on the hydrodynamic phenomenon, has drawn considerable interest in recent years. Despite numerous microfluidic techniques of particle separation, there are few articles in the literature on separation techniques addressing external outlet geometry to increase the throughput efficiency and purity. In this work, we report on a spiral inertial microfluidic device with high efficiency (>98%). Herein, we demonstrate how changing the outlet geometry can improve the particle separation throughput. We present a complete separation of 4 and 6 μm from 10 μm particles potentially applicable to separate microalgae (Tetraselmis suecica from Phaeodactylum tricornutum). Two spiral microchannels with the same cross section dimension but different outlet geometry were considered and tested to investigate the particle focusing behavior and separation efficiency. As compared with particle focusing observed in channels with a simple outlet, the particle focusing in a modified outlet geometry appears in a more successful focusing manner with complete separation. This simple approach of particle separation makes it attractive for lab-on-a-chip devices for continuous extraction and filtration of a wide range of cell/particle sizes.
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Affiliation(s)
- Asma Mihandoust
- Complex Systems Laboratory, School of Physics-Chemistry, Alzahra University, Tehran, Iran
| | - Nahid Maleki-Jirsaraei
- Complex Systems Laboratory, School of Physics-Chemistry, Alzahra University, Tehran, Iran
| | - Shahin Rouhani
- School of Physics, Sharif University of Technology, Tehran, Iran
| | - Shahabeddin Safi
- School of Pathobiology, Faculty of Specialized Veterinary Sciences, Science and Research Branch, Islamic Azad University, Tehran, Iran
| | - Majid Alizadeh
- School of Radiology, Hamadan University of Medical Science, Hamadan, Iran
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Rafeie M, Hosseinzadeh S, Taylor RA, Warkiani ME. New insights into the physics of inertial microfluidics in curved microchannels. I. Relaxing the fixed inflection point assumption. BIOMICROFLUIDICS 2019; 13:034117. [PMID: 31431813 PMCID: PMC6697030 DOI: 10.1063/1.5109004] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/05/2019] [Accepted: 06/12/2019] [Indexed: 05/08/2023]
Abstract
Inertial microfluidics represents a powerful new tool for accurately positioning cells and microparticles within fluids for a variety of biomedical, clinical, and industrial applications. In spite of enormous advancements in the science and design of these devices, particularly in curved microfluidic channels, contradictory experimental results have confounded researchers and limited progress. Thus, at present, a complete theory which describes the underlying physics is lacking. We propose that this bottleneck is due to one simple mistaken assumption-the locations of inflection points of the Dean velocity profile in curved microchannels are not fixed, but can actually shift with the flow rate. Herein, we propose that the dynamic distance (δ) between the real equilibrium positions and their nearest inflection points can clearly explain several (previously) unexplained phenomena in inertial microfluidic systems. More interestingly, we found that this parameter, δ, is a function of several geometric and operational parameters, all of which are investigated (in detail) here with a series of experiments and simulations of different spiral microchannels. This key piece of understanding is expected to open the door for researchers to develop new and more effective inertial microfluidic designs.
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Affiliation(s)
- Mehdi Rafeie
- School of Mechanical and Manufacturing Engineering, University of New South Wales, Sydney, New South Wales 2052, Australia
| | - Shahin Hosseinzadeh
- School of Mechanical and Manufacturing Engineering, University of New South Wales, Sydney, New South Wales 2052, Australia
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