APPLIED PHYSICS LETTERS
·
2016
·Vol. 109
·期 10
·
IF 3.142
Zang Duyang,Zhai Zhicong,Li Lin,Lin Kejun,Li Xiaoguang,Geng Xingguo
We have studied the levitation and oscillation dynamics of complex drops containing two immiscible liquids. Two types of drops, core-shell drop and abnormal-shaped drop, have been obtained depending on the levitation procedures. The oscillation dynamics of the drops have been studied using a high speed camera. It has been found that the oscillation of the abnormal-shaped drop has a longer oscillation period and decays much faster than that of the core-shell drop, which cannot be accounted for by the air resistance itself. The acoustic streaming induced by ultrasound may bring an additional force against the motion of the drop due to the Bernoulli effect. This is responsible for the enhanced damping during the oscillation in acoustic levitation.
研究领域:
物理学
·
流体力学
✓ 已验证
产品关联
DOI
高影响因子
ANALYTICAL AND BIOANALYTICAL CHEMISTRY
·
2023
·
IF 4.3
Zhang Yiwei,Lin Yiwei,Hong Xianzhe,Di Chao,Xin Yuelai,Wang Xinru,Qi Shuhong,Liu Bi-Feng,Zhang Zhihong,Du Wei
Droplet microfluidics is a rapidly advancing area of microfluidic technology, which offers numerous advantages for cell analysis, such as isolation and accumulation of signals, by confining cells within droplets. However, controlling cell numbers in droplets is challenging due to the uncertainty of random encapsulation which result in many empty droplets. Therefore, more precise control techniques are needed to achieve efficient encapsulation of cells within droplets. Here, an innovative microfluidic droplet manipulation platform had been developed, which employed positive pressure as a stable and controllable driving force for manipulating fluid within chips. The air cylinder, electro-pneumatics proportional valve, and the microfluidic chip were connected through a capillary, which enabled the formation of a fluid wall by creating a difference in hydrodynamic resistance between two fluid streams at the channel junction. Lowering the pressure of the driving oil phase eliminates hydrodynamic resistance and breaks the fluid wall. Regulating the duration of the fluid wall breakage controls the volume of the introduced fluid. Several important droplet microfluidic manipulations were demonstrated on this microfluidic platform, such as sorting of cells/droplets, sorting of droplets co-encapsulated cells and hydrogels, and active generation of droplets encapsulated with cells in a responsive manner. The simple, on-demand microfluidic platform was featured with high stability, good controllability, and compatibility with other droplet microfluidic technologies. Graphical abstract
研究领域:
微流控
·
细胞分析
·
生物技术
·
芯片实验室
✓ 已验证
产品关联
DOI
PubMed
高影响因子
EXPERIMENTS IN FLUIDS
·
2020
·Vol. 61
·期 3
·1-12
·
IF 2.335
Wang Dongbao,Wang Junfeng,Yongphet Piyaphong,Wang Xiaoying,Zuo Ziwen,Li Bin,Zhang Wei
Electrical manipulation technique to produce qualified size of droplets has received substantial attention due to its wide applications in biology, medicine and chemistry, where the droplet behaviors could be controlled by adjusting external parameters. Characterization of charged droplet generation and breakup processes is crucial for understanding the basic mechanism of droplet manipulation. In this paper, the formation and breakup processes for charged droplets in dielectric immiscible oil were investigated experimentally at micro-scale by utilizing high-speed photography. The droplet behaviors at the ambient of needle orifice were visualized and captured at various electric field strengths and flow rates while its generation and motion characteristics were analyzed. Novel formation process of micro-droplets emitted from arrayed jets was found and depicted in detail when violent liquid breakup occurred at high voltage. Furthermore, the relationships of electric field and flow rate with characteristics of charged droplet behavior were quantitatively discussed. By consideration of electric field and flow rate, a scaling law to predict droplet size distributions was derived. Besides, a dimensionless model to predict charged droplet positions was given, which showed a linear increasing trend with electric field and time.
Graphic abstract
研究领域:
生物医学工程
·
微流控技术
·
软物质物理
·
应用电化学
·
界面科学
✓ 已验证
DOI
高影响因子
APPLIED ACOUSTICS
·
2024
·
IF 3.4
Jing Cao,Honghui Xue,Yinuo Zheng,Ling Wang,Litao Sun
Acoustic cavitation serves various therapeutic purposes, with both microbubbles and phase-transit droplets serving as potential cavitation nuclei. This project focused on investigating the intricate interaction between microbubbles and droplets and the resultant impact on acoustic cavitation. To facilitate this investigation, microbubbles with a negative potential of −51.58 mV were prepared, while droplets were endowed with a positive potential of +4.22 mV, facilitating the formation of microbubble-droplet clusters. Microscopic analysis was employed to observe the morphology of these clusters, revealing an initial mean size of 4.85 µm before ultrasound activation and subsequent transformation into larger bubbles with a mean size of 12.54 µm after ultrasound activation. The experimental approach involved the use of varying driven voltages to generate ultrasound waves with different intensities. A passive cavitation detector (PCD) was then employed to capture cavitation signals. Results demonstrated that, when maintaining a microbubble ratio of 50% and varying droplet ratios from 0% to 50%, the driven voltage at which the cavitation peak appeared decreased from 180 mV to 140 mV. Additionally, the mean cavitation intensity exhibited an initial increase from 0.58 to 0.78, followed by a subsequent decrease from 0.78 to 0.63 after normalization. This study provided valuable insights into the dynamic interactions between microbubbles and droplets. Specifically, it showed that microbubble cavitation transferred energy to droplets, leading to the generation of larger bubbles and higher cavitation intensity. Nevertheless, the observed cavitation intensity and threshold were contingent upon the ratios of microbubbles and droplets. Notably, to achieve an ideal cavitation intensity, the energy generated by microbubble cavitation must be substantial enough to activate all droplets, inducing acoustic droplet vaporization (ADV) and cavitation.
研究领域:
医学超声
·
生物医学工程
✓ 已验证
DOI
高影响因子
NANO LETTERS
·
2020
·
IF 11.238
Rui Feng,Qixiang Wang,Yiming Qiao,Runheng Yang,Shun An,Fanchen Meng,Shengtao Yu,Wei Hao,Benwei Fu,Peng Tao,Kehang Cui,Chengyi Song,Wen Shang,Tao Deng
A simple, fast, and contactless alternative for the generation of nanodroplets in solution is to apply light to stimulate their formation at a surface. In this work, a light-driven mechanism for the generation of nanodroplets is demonstrated by using a porous membrane. The membrane is placed at the interface between oil and water during the nanodroplet generation process. As light illuminates the membrane a photothermal conversion process induces the growth and release of water vapor bubbles into the aqueous phase. This release leads to the fluctuation of local pressure around the pores and enables the generation of oil nanodroplets. A computational simulation of the fluid dynamics provides insight into the underlying mechanism and the extent to which it is possible to increase nanodroplet concentrations. The ability to form nanodroplets in solutions without the need for mechanical moving parts is significant for the diverse biomedical and chemical applications of these materials.
研究领域:
材料科学
·
生物医学工程
·
流体力学
✓ 已验证
DOI
高影响因子
Nano Select
·
2020
·Vol. 2
·期 2
·338-345
·
IF 0
Dege Li,Bingfang Huang,Yi Cao,Molong Han,Xinlei Wu,Qiang Sun,Chi Ma,Lilong Zhao,Peng Liu,Chao Zheng,Hang Dong,Xiaolong Wang,Yonghong Liu,Yanzhen Zhang
The precise and effective generation and manipulation of micron-sized droplets is crucial for chemical and biological research and applications. Normally, droplets generation and manipulation are achieved by two separate devices/systems with their respective operation strategies. Pipette, inkjet nozzle, and microfluidic channels equipped with programed syringes are commonly used for droplets generation whereas the subsequent manipulation is normally achieved by leveraging of forces originating either from optical, electric, magnetic or acoustic field and the corresponding complicated devices. Here we report a new paradigm that can realize simultaneous droplets generation and manipulation in an immiscible liquid environment using only the confined interface vibration generated by the ordinary inkjet nozzle. Droplets, ranging from femtoliter to picoliter, can be generated and manipulated without interruption since they are actuated by the same nozzle. Our strategy provides a platform for precise generation and manipulating the micro-sized droplets that may be valuable for applications requiring simple setups and seamless connection between droplets generation and droplets manipulation.
研究领域:
生物医学工程
·
微流体技术
·
化学工程
✓ 已验证
DOI
LAB ON A CHIP
·
2023
·Vol. 23
·期 19
·4287-4301
·
IF 6.1
Wei Li,Dongliang Li,Xun Zhu,Dingding Ye,Yang Yang,Hong Wang,Rong Chen,Qiang Liao
Flexible and precise manipulation of droplet transport is of significance for scientific and engineering applications, but real-time and on-demand droplet manipulation remains a challenge. Herein, we report a strategy using light for the outstanding manipulation of binary droplet motion on a high-energy surface and reveal the underlying mechanism. Upon irradiation to a substrate by a focused light beam, the substrate can provide a localized heating source via photothermal conversion, and a binary droplet can be flexibly transported on a high-energy surface with free contact-line pinning, exhibiting light-propelled droplet transport. We theoretically showed that the surface tension gradient across the droplet interface resulting from the localized photothermal effect is responsible for actuating droplet transport. Remarkably, the high reconfigurability and flexibility of light allowed for binary droplet transport with dynamically tunable velocity and direction as well as arbitrary trajectory assisted by 2D channels on a high-energy surface. Complex droplet transportation, controllable droplet coalescence, and anti-gravity motion were realized. The promising applicability of this light-fueled droplet platform was also demonstrated by directional transport of biosample droplets containing DNA molecules and cells, as well as successional microreactions.
研究领域:
材料科学
·
流体力学
·
生物工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Droplet
·
2024
·Vol. 3
·期 2
·e118
·
IF 0
Chuchen Yue,Qingwen Dai,Xiaolong Yang,Carsten Gachot,Wei Huang,Xiaolei Wang
Preventing the accretion of droplets on surfaces is vital and slippery liquid-infused porous surfaces (SLIPS) have promising application prospects, such as surface self-cleaning and droplet transportation. In this work, controllable self-transport of bouncing droplets on ultraslippery surfaces with wedge-shaped grooves is reported. The impact behaviors of droplets on SLIPS under various impact velocities and diameters are explored, which can be classified as hover, total bounce, partial bounce, Worthington jet, and crush. SLIPS with wedge-shaped grooves were designed to transport accreted droplets. An energy and transport model is established to explain the impact and self-transport mechanism, where the Laplace pressure and moving resistance between droplets play a key role. Finally, SLIPS with branched wedge-shaped grooves were designed for droplet self-transport and demonstrated advantages. This work provides a general reference for spontaneous motion control of sessile droplets, droplets with initial impacting velocity, or even liquid films.
研究领域:
表面工程
·
流体力学
·
材料科学
✓ 已验证
DOI
LANGMUIR
·
2021
·
IF 3.882
Dege Li,Yi Cao,Bingfang Huang,Molong Han,Xinlei Wu,Qiang Sun,Chao Zheng,Lilong Zhao,Chi Ma,Hui Jin,Xiaolong Wang,Yonghong Liu,Yanzhen Zhang
The precise and effective generation of micron-sized droplets is one of the most common and important issues for droplet-based microfluidics. Active droplet generation makes use of additional energy input in promoting interfacial instabilities for droplet generation. Here, we report a new technique for the active generation of femtoliter droplets in microfluidic systems using confined interfacial vibration (CIV). The CIV is formed at the orifice of a traditional inkjet nozzle first by pushing the liquid out and then pulling it back. Droplets are pinched off during the withdrawal process, and this is different from the current active droplet generation techniques, which only monodirectionally push the liquid out. Droplets with radius ranging from ca. 1 to 28 μm can be actively generated by CIV at an orifice with radius 30 μm, distinguishing from conventional active generation techniques in which the droplets are always comparable or slightly bigger than the orifice. Experimental results showed that the droplet volume can be customized by controlling the intensity of the CIV. The inherent digital nature of the inkjet technique enables easy and precise regulating of the droplet volume, making it seamlessly compatible with the digital microfluidic systems.
研究领域:
生物工程
·
化学工程
·
物理学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
CHEMICAL ENGINEERING SCIENCE
·
2018
·
IF 3.306
Xin Sun,Chunying Zhu,Taotao Fu,Youguang Ma,Huai Z. Li
Dynamics for droplet breakup with tunnels and formation of satellite droplets in a symmetric microfluidic T-junction are investigated using a high-speed digital camera. The breakup process of droplet could be divided into four sequential stages: squeezing, transition, pinch-off, and thread rupture stages. Effects of the viscosity ratio of both phases λ , the capillary number of the continuous phase Ca c , and the dimensionless droplet length l 0 / w c on the breakup process of droplet are analyzed. In the squeezing stage controlled by squeezing pressure, the variation of the minimum width of the droplet neck with time could be scaled as a power-law relationship with exponent related to λ and l 0 / w c . The transition stage is dominated by the velocity of the fluid, and the pinch-off stage is mainly driven by the capillary force. For these two stages, the evolution of the minimum width of the droplet neck with the remaining time could be described as other power-law relationship with exponent related to λ . In the thread rupture stage controlled by viscous stresses of both phases and the surface tension, the minimum width of droplet neck decreases linearly with time, and the coefficient of the linear function depends on λ . Additionally, for the formation of satellite droplets, the size of satellite droplet increases with the increase of superficial velocity of the fluid and droplet viscosity. Furthermore, a critical capillary number 0.03 is observed in low viscosity of the droplet, which divides the variation of the size of the main satellite droplet with the capillary number into constant area and growth zone.
研究领域:
流体力学
·
生物工程
✓ 已验证
产品关联
DOI
高影响因子
Microsystems & Nanoengineering
·
2020
·Vol. 6
·期 1
·1-10
·
IF 5.048
Nan Lang,Cao Yang,Yuan Shuai,Shum Ho Cheung
Aqueous two-phase system (ATPS) droplets have demonstrated superior compatibility over conventional water-in-oil droplets for various biological assays. However, the ultralow interfacial tension hampers efficient and stable droplet generation, limiting further development and more extensive use of such approaches. Here, we present a simple strategy to employ oil as a transient medium for ATPS droplet generation. Two methods based on passive flow focusing and active pico-injection are demonstrated to generate water-water-oil double emulsions, achieving a high generation frequency of ~2.4 kHz. Through evaporation of the oil to break the double emulsions, the aqueous core can be released to form uniform-sized water-in-water droplets. Moreover, this technique can be used to fabricate aqueous microgels, and the introduction of the oil medium enables integration of droplet sorting to produce single-cell-laden hydrogels with a harvest rate of over 90%. We believe that the demonstrated high-throughput generation and sorting of ATPS droplets represent an important tool to advance droplet-based tissue engineering and single-cell analyses.
研究领域:
微流控技术
·
生物技术
·
组织工程
·
单细胞分析
✓ 已验证
DOI
PubMed
高影响因子
CHEMICAL ENGINEERING SCIENCE
·
2024
·
IF 4.1
Yanpeng Dong,Xingyu Xiang,Zhongdong Wang,Chunying Zhu,Wenyuan Fan,Youguang Ma,Taotao Fu
The breakup of filament is often accompanied by the formation of satellite droplet, which affects the uniformity of droplets, and inertial microfluidic technology is usually used to separate droplets of different sizes. In this study, different filament breakup modes are observed, and the variation of satellite droplet size with operating conditions are analyzed. Based on the experimental results, predictive model for the satellite droplet size is proposed. To better control the separation of particles with different sizes, the focusing and separation process of main and satellite droplets in microdevices are investigated by numerical simulation. It is found that increasing the fluid flow rate, the width of microchannel and rear cavity, and reducing the satellite droplet size are all beneficial for the separation of droplets of different sizes. At last, models for predicting the focusing positions of main and satellite droplets in rear cavity are established, and an integrated microfluidic device is proposed.
研究领域:
微流体力学
·
生物医学工程
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）