Article
Nanoscience & Nanotechnology
Sagar N. Agnihotri, Mohammad Reza Raveshi, Rajneesh Bhardwaj, Adrian Neild
Summary: This paper demonstrates a selective multisite splitting and merging system using single-layer microfluidic valves, offering simplicity, biocompatibility, and high-speed operation. These valves control the generation of droplets and splitting locations, as well as allow for merging different types of droplets.
MICROFLUIDICS AND NANOFLUIDICS
(2021)
Article
Chemistry, Multidisciplinary
Taeyung Kim, Jaewook Kim, Jeon Woong Kang, Sun Beom Kwon, Jiwoo Hong
Summary: This study presents a compact and low-cost 3D digital microfluidics (DMF) platform constructed using 3D printing technology, which can be used for various biological, chemical, and medicinal research. The platform allows for basic 3D droplet manipulation and has been validated for chemical reaction-based analysis and synthesis. The proposed 3D DMF platform offers ease of manufacturing and flexibility for programmable 3D droplet manipulation in biochemical and medical applications.
Article
Computer Science, Information Systems
Rauno Joemaa, Nafisat Gyimah, Kanwal Ashraf, Kaiser Parnamets, Alexander Zaft, Ott Scheler, Toomas Rang, Tamas Pardy
Summary: Droplet microfluidics allows for the study of large cell populations in chemical isolation at a single-cell resolution. However, current systems rely on manual tuning and customization, limiting reproducibility. In this study, we propose an integrated, modular system for automated droplet generation with high monodispersity, providing dynamic feedback control and wireless communication. Experimental evaluations demonstrate the system's improved performance and reliability compared to existing methods.
Article
Biochemical Research Methods
Kunpeng Cai, Shruti Mankar, Taiga Ajiri, Kentaro Shirai, Tasuku Yotoriyama
Summary: The study introduces a fully integrated high-throughput microfluidic circulatory fluorescence-activated cell sorting system capable of significantly increasing the purity of rare cells in a short period of time and effectively enriching different types of cells. Through a sequential sorting process and efficient contamination-free design, effective enrichment of clinical rare cells has been achieved.
Article
Chemistry, Analytical
Jaewook Kim, Taeyung Kim, Inseo Ji, Jiwoo Hong
Summary: Contact charge electrophoresis (CCEP) is a technique for manipulating conductive droplets and particles using charging and discharging. This article presents a CCEP-based digital microfluidics platform that allows efficient mixing through droplet reciprocating motions. It also analyzes the mixing performance and visualizes the mixing flow patterns within shaking droplets.
Article
Biochemical Research Methods
Alina Peethan, M. Aravind, Santhosh Chidangil, Sajan D. George
Summary: Droplet splitting using tailored surface wettability is an important technique for creating ultralow volumes of samples, which have various applications in bioassays, tissue engineering, and material synthesis. In this work, a non-adhesive contrast quartz substrate is fabricated for the trapping and analysis of single biological cells using Raman spectroscopy. The substrate allows the splitting of microliter droplets into smaller daughter droplets, enabling high throughput screening and analysis of single cells.
Article
Nanoscience & Nanotechnology
Siying Lin, Lingjing Mao, Jiaxu Ying, Nicolas Berthet, Jia Zhou, Antoine Riaud
Summary: This paper presents a simple, convenient, and user-friendly method for converting single emulsions into double emulsions using vortex mixers. The authors studied the effects of vortex speed, vortex duration, and the number of vortex/flick cycles on the properties of the double emulsions. Interesting phenomena, such as droplet breakup and the production of inverted double emulsion droplets, were observed.
MICROFLUIDICS AND NANOFLUIDICS
(2022)
Article
Chemistry, Analytical
Gangyin Luo, Ying Zhang, Shun Wang, Xinbei Lv, Tianhang Yang, Jinxian Wang
Summary: This study developed an integrated microfluidic step emulsification device with wide-range droplet generation capability, small device dimensions, convenient fabrication strategy, low contamination, and high robustness. The uniformity of droplet generation was increased by proposing a tree-shaped droplet generation nozzle distribution design and numerically simulating the flow field. The experimental results showed that incubation and hydrophobic reagent treatment allowed for the generation of stable and uniform droplets using multiplex nozzles.
Article
Chemistry, Multidisciplinary
Jingyu Wu, Yoon-Ho Hwang, Sagar Yadavali, Daeyeon Lee, David A. Issadore
Summary: A method is developed to lithographically define micrometer-scale resolution patterns of wettability on all channel surfaces in silicon and glass microfluidic devices with complex 3D geometry. This approach demonstrates versatility by patterning wettability to generate uniform water-oil-water and oil-water-oil double emulsions.
ADVANCED FUNCTIONAL MATERIALS
(2023)
Article
Chemistry, Analytical
Shuhao Zhao, Zengming Zhang, Fei Hu, Junjun Wu, Niancai Peng
Summary: The study introduces a compact SE device integrating a smart SE chip into a reaction tube for preparing large-scale water-in-fluorinated-oil droplets for ddPCR analysis. This device allows for efficient, cost-effective, and flexible droplet preparation to meet the needs of ddPCR analysis.
Article
Chemistry, Analytical
Amith Mudugamuwa, Samith Hettiarachchi, Gehan Melroy, Shanuka Dodampegama, Menaka Konara, Uditha Roshan, Ranjith Amarasinghe, Dumith Jayathilaka, Peihong Wang
Summary: This paper discusses an active droplet generation system that successfully generates droplets using two fluid phases. The system is able to control, sense, and analyse the droplet generation, and the droplet morphology is analysed using vision sensing and digital image processing. The proposed system includes a droplet generator, camera module with image pre-processing and identification algorithm, and a controller and control algorithm with a workstation computer. The average droplet diameter varies with the droplet generation time in a second-order polynomial relationship.
Article
Chemistry, Analytical
Margaux Duchamp, Marion Arnaud, Sara Bobisse, George Coukos, Alexandre Harari, Philippe Renaud
Summary: Droplet microfluidics involve manipulating discrete volumes of solutions using immiscible phases. This study presents a novel device to efficiently co-encapsulate two different aqueous phases in micro-droplets by combining existing microfluidic modules. The device uses a filtering mechanism to pair and merge droplets containing different aqueous phases, achieving high efficiency.
Article
Engineering, Chemical
Ziwei Liu, Xiyang Liu, Shaokun Jiang, Chunying Zhu, Youguang Ma, Taotao Fu
Summary: This study investigated the application of Y step emulsification technology in microfluidic devices, focusing on the influences of microdevice structures and fluid physical properties on droplet generation. Important factors affecting emulsion flux were identified, and a prediction equation for droplet size was proposed based on inertial and viscous forces of the dispersed phase.
CHEMICAL ENGINEERING SCIENCE
(2021)
Review
Chemistry, Analytical
Shuang Ding, Haijun Zhang, Xuemei Wang
Summary: Lung diseases pose serious threats to human health worldwide, and traditional models are unable to accurately simulate lung conditions. Human organ-on-a-chip platforms and biosensors can better mimic lung characteristics, providing new methods for studying disease development and drug efficacy.
Article
Chemistry, Analytical
Yang Zhou, Zhibin Yu, Man Wu, Yuwei Lan, Chunping Jia, Jianlong Zhao
Summary: Single-cell analysis and sorting is an important technique in scientific research and industry. This study developed a microfluidic chip that integrates single-cell droplet generation, incubation, and sorting functions using a pneumatic micro-valve. Numerical simulations were used to optimize the design of the valve. Experimental results demonstrated that the integrated chip improved the purity of target droplets and reduced cell loss and labor. This design has various applications such as single-cell sequencing and antibody screening.
Article
Biochemical Research Methods
Matthew Courtney, Tomasz Glawdel, Carolyn L. Ren
Summary: Free-flow electrophoresis (FFE) is a useful tool for separation and collection of charged solutes in biological applications, and a free-flow counterflow gradient focusing (FF-CGF) mechanism has been proposed to improve resolution and versatility. A theoretical model was developed to study factors influencing solute dispersion, revealing asymmetric solute distribution over a wide range of parameters. FF-CGF shows potential for high-resolution separations and high-throughput protein purification, providing guidance for optimizing experimental conditions and a strong framework for further development.
Review
Engineering, Electrical & Electronic
Marie Hebert, Jan Huissoon, Carolyn L. Ren
Summary: Microfluidics has made significant progress as a field, but its independent use by end-users is still limited. This review aims to explore the potential of microfluidics as a tool for application-focused research and proposes a modular automated platform to lower the knowledge barrier for end-users. The analysis focuses on active microfluidics and its potential for end-users to conduct independent research in areas such as cell assays, biochemistry, materials, and environmental factors monitoring.
JOURNAL OF MICROMECHANICS AND MICROENGINEERING
(2022)
Article
Biochemical Research Methods
Run Ze Gao, Vivian Ngoc Tram Mai, Nicholas Levinski, Jacqueline Mary Kormylo, Robin Ward Murdock, Clark R. Dickerson, Carolyn L. Ren
Summary: This paper presents a proof of concept for a novel air microfluidics-enabled soft robotic sleeve, which aims to improve the treatment of lymphedema. The sleeve utilizes light, small, and inexpensive air microfluidic chips to provide sequential inflation and uniform deflation, generating intentional gradient compression for improved lymph fluid circulation. It offers improved wearability, reduced noise, and energy consumption compared to traditional compression sleeves. The system's cost, simplicity, and scalability are also detailed.
Article
Engineering, Electrical & Electronic
Weijia Cui, Zahra Abbasi, Carolyn L. Ren
Summary: This study investigates the crosstalk between two adjacent resonators with the aim of providing guidance for multiplexing resonators in a typical microfluidic device. The results suggest an optimal distance between the resonators and provide recommendations for resonator size and heating power for simultaneous sensing and heating of individual droplets.
JOURNAL OF MICROMECHANICS AND MICROENGINEERING
(2022)
Review
Engineering, Electrical & Electronic
Weijia Cui, Zhe Ren, Yongxin Song, Carolyn L. Ren
Summary: Heavy metal pollution is a global issue that poses serious risks to human health and sustainability. Current point-of-care detection methods for heavy metals are limited, but microfluidics show great potential for accurate and affordable detection. This review focuses on microfluidic-based devices for heavy metal sensing and discusses the integration of microwave sensing for accurate detection.
SENSORS AND ACTUATORS A-PHYSICAL
(2022)
Article
Biochemical Research Methods
Matthew Courtney, Tomasz Glawdel, Carolyn L. Ren
Summary: Free-flow electrophoresis (FFE) is used to continuously separate charged solutes from complex biological mixtures. A free-flow counterflow gradient focusing mechanism has been introduced to improve resolution and versatility. This work models the impact of electroosmotic flow on solute dispersion and presents preliminary experimental results for validation.
Article
Engineering, Electrical & Electronic
Marie Hebert, Jan P. Huissoon, Carolyn L. Ren
Summary: Inaccurate prediction of droplet hydrodynamic resistance impacts droplet chip performance and design process. Previous passive methods lack consensus due to varying conditions. This study verifies a novel active approach using system identification to determine droplet resistance, which has potential for a wide range of conditions and non-Newtonian fluids.
JOURNAL OF MICROMECHANICS AND MICROENGINEERING
(2023)
Article
Engineering, Electrical & Electronic
Megala Ramasamy, Brandon Ho, Chau-Minh Phan, Ning Qin, Carolyn L. Ren, Lyndon Jones
Summary: PDMS elastomers are widely used in microfluidic devices, but the fabrication process requires specialized facilities and materials. To address this limitation, we developed a simple and inexpensive method for fabricating PDMS microfluidic devices using readily available reagents and 3D printers.
JOURNAL OF MICROMECHANICS AND MICROENGINEERING
(2023)
Article
Engineering, Electrical & Electronic
Yiqi Zhang, Maziar Shafiei, John Z. Z. Wen, Zahra Abbasi, Carolyn R. L. Ren
Summary: Wearable technology and soft robotics have seen significant growth, necessitating the development of flexible and highly sensitive pressure and bending sensors. However, the challenge lies in creating a single sensor that can measure both pressure and bending with high sensitivity, and wirelessly transmit data. This article introduces a new wireless microwave sensor that achieves these requirements through a resonator-based design, offering selective sensing and easy fabrication, with the results displayed on a cost-effective handheld device. With a sensitivity of 3.39 MHz kPa(-1), this wireless sensor design presents a promising solution for wearable devices and soft robots due to its flexibility, compact size, and low cost.
IEEE TRANSACTIONS ON INSTRUMENTATION AND MEASUREMENT
(2023)
Proceedings Paper
Engineering, Electrical & Electronic
Maziar Shafiei, Zahra Abbasi, Carolyn L. Ren
Summary: This paper introduces a method for non-contact microplastic concentration monitoring using a sensitivity-enhanced planar microwave sensor. The sensor platform consists of a dual-resonator tag and a passive microwave reader, allowing for real-time monitoring of microplastic deposition in liquid.
2022 IEEE/MTT-S INTERNATIONAL MICROWAVE SYMPOSIUM (IMS 2022)
(2022)
Article
Biochemical Research Methods
Peter S. Lee, Run Ze Gao, Alyson Colpitts, Robin W. Murdock, Doug Dittmer, Andreas Schirm, James Y. Tung, Carolyn L. Ren
Summary: Residual limb volume fluctuations and contact pressures are key factors leading to skin ulcerations, pain, and decreased quality of life for transtibial amputees. A novel transtibial prosthetic socket liner with a small air microfluidic chip has been introduced, allowing for dynamic adjustment of the fit between the limb and socket. Proof-of-concept testing has shown that the pressures can be varied and redistributed as desired.
Article
Engineering, Electrical & Electronic
Marie Hebert, Jan Huissoon, Carolyn L. Ren
Summary: Polydimethylsiloxane (PDMS) is a widely used material for microfluidic devices due to its low cost, superior optical properties and fast iterative design process. However, its softness creates challenges for device design and operation, leading to low accuracy in active microfluidic that actuates flow frequently. Therefore, understanding the dynamic behavior of microfluidic devices due to material compliance is of fundamental and practical importance.
JOURNAL OF MICROMECHANICS AND MICROENGINEERING
(2022)
Article
Biochemical Research Methods
Weijia Cui, Pei Zhao, Jin Wang, Ning Qin, Emmanuel A. Ho, Carolyn L. Ren
Summary: This study presents a microfluidic microwave sensing method for point-of-care (POC) diagnosis of SARS-CoV-2 virus. The method captures and concentrates the virus using antibodies immobilized on a microwave sensor, and detects the resonance frequency shift caused by the change in permittivity of the sample. The method shows good sensitivity and linear relationship, and can distinguish other viruses.
Article
Physics, Fluids & Plasmas
Merve Marcali, Xiaoming Chen, Marc G. Aucoin, Carolyn L. Ren
Summary: This study investigates the formation dynamics of non-Newtonian fluid droplets in a microfluidic system. The results show that the formation of droplets in non-Newtonian fluids depends not only on geometry but also on the flow rate ratio and viscosity of the fluids. Through experimental observations and data analysis, the study reveals that the formation cycle of blood droplets consists of lag, filling, and necking stages, without a stretching stage.
Article
Physics, Fluids & Plasmas
Merve Marcali, Xiaoming Chen, Marc G. Aucoin, Carolyn L. Ren
Summary: This study investigates the dynamics of droplet formation using red blood cell solutions in a T-junction microfluidic system, presenting a model to predict the droplet volume. Experimental validation shows that the model can aid in the design of microfluidic systems.
