Preparation of Monodisperse PEG Microspheres by a T-Junction Microfluidic Chip

2012 ◽  
Vol 465 ◽  
pp. 178-181 ◽  
Author(s):  
Yu Min Ren ◽  
Bing Yu ◽  
Hai Lin Cong ◽  
Yu Rong Ma ◽  
Zhen Zhen Ma ◽  
...  
Keyword(s):  
Polyethylene Glycol ◽  
Flow Rate ◽  
Microfluidic Chip ◽  
Uv Exposure ◽  
Microfluidic Channels ◽  
Microfluidic Chips ◽  
Silicon Oil ◽  
Sample Flow Rate ◽  
Rate Ratios

Monodisperse polyethylene glycol (PEG) microspheres were prepared using microfluidic chips coupled with photopolymerization technique. Based on sheath effect in T-junction microfluidic channels, dispersions of uniform PEG prepolymer droplets in silicon oil are formed. The diameters of the formed PEG prepolymer droplets in the dispersions were controlled very well by altering the relative sheath/sample flow rate ratios. After photopolymerization under UV exposure, the uniform PEG prepolymer droplets isolated by silicon oil underwent photocrosslinking and became monodisperse PEG microspheres.

scholarly journals Formation of Polyethylene Glycol Particles Using a Low-Temperature Supercritical Assisted Atomization Process

Molecules ◽  
2019 ◽  
Vol 24 (12) ◽  
pp. 2235
Author(s):  
Hsien-Tsung Wu ◽  
Hong-Ming Tsai ◽  
Tsung-Hsuan Li
Keyword(s):  
Carbon Dioxide ◽  
Molecular Weight ◽  
Polyethylene Glycol ◽  
Low Temperature ◽  
Flow Rate ◽  
Fine Particles ◽  
Volumetric Flow Rate ◽  
Degree Of Crystallinity ◽  
Scanning Calorimetry ◽  
Rate Ratios

Polyethylene glycol (PEG) particles were prepared using low-temperature supercritical assisted atomization (LTSAA) with carbon dioxide as the spraying medium or the co-solute and acetone as the solvent. The effects of several key factors on the particle size were investigated. These factors included the concentration of the PEG solution, precipitator temperature, saturator temperature, ratio of the volumetric flow rate of carbon dioxide to the PEG solution, and the molecular weight of PEG. Spherical and non-aggregated PEG particles, with a mean size of 1.7–3.2 µm, were obtained in this study. The optimal conditions to produce fine particles were found to be a low concentration of the PEG solution, a low precipitator temperature, and low molecular weight of the PEG. The phase behavior of the solution mixture in the saturator presented a qualitative relationship. At the optimized volumetric flow rate ratios, the composition of CO2 in the feed streams was near the bubble points of the saturator temperatures. X-ray and differential scanning calorimetry analyses indicated that LTSAA-treated PEG had a reduced degree of crystallinity, which could be modulated via the precipitator temperature. PEG microparticles prepared by a LTSAA process would be promising carriers for drug-controlled formulations of PEG-drug composite particles.

Particle Separation in Microfluidic Channels Using Flow Rate Control

2004 ◽  
Author(s):  
Sung Yang ◽  
Jeffrey D. Zahn
Keyword(s):  
Flow Rate ◽  
Flow Resistance ◽  
Melanoma Cells ◽  
Microfluidic Channels ◽  
Cell Recovery ◽  
Fluorescent Particles ◽  
Green Fluorescent ◽  
Rate Ratios ◽  
Pdms Replica ◽  
Flow Rate Control

Microfluidic devices for particle recovery are successfully developed by controlling flow rate ratios of two daughter channels. Devices are prepared by using conventional Polydimethylsiloxane (PDMS) replica molding technique. The flow rate ratios of two daughter channels are controlled by changing the flow resistance through changing the geometry of the downstream channels. The particle recovery studies are conducted using 16 μm-diameter green fluorescent particles and using 8–10 μm-diameter human C8161 melanoma cells. For the fluorescent particles, the particle recovery efficiencies are 87.2%, 95.7%, 100%, and 100% for 2.5:1, 4:1, 6:1, and 8:1 flow rate ratios, respectively. Also, for the human C8161 melanoma cells, the cell recovery efficiencies are 88.7%, 98.9%, 100%, and 100% for 2.5:1, 4:1, 6:1, and 8:1 flow rate ratios, respectively.

Optical micro/nanofibre embedded soft film enables multifunctional flow sensing in microfluidic chips

Lab on a Chip ◽  
2020 ◽  
Vol 20 (14) ◽  
pp. 2572-2579
Author(s):  
Zhang Zhang ◽  
Jing Pan ◽  
Yao Tang ◽  
Yue Xu ◽  
Lei Zhang ◽  
...  
Keyword(s):  
Flow Rate ◽  
Microfluidic Chip ◽  
Microfluidic Chips ◽  
Flow Sensing

A smart microfluidic chip enabled by optical micro/nanofibres embedded soft film can detect flow rate, count droplets, and predict the morphology of droplets.

scholarly journals Design and Analysis of a Laminar Diffusion-Based Micromixer with Microfluidic Chip

2021 ◽  
Vol 2021 ◽  
pp. 1-10
Author(s):  
Osman Ulkir ◽  
Oguz Girit ◽  
Ishak Ertugrul
Keyword(s):  
Diffusion Coefficient ◽  
Flow Rate ◽  
Microfluidic Chip ◽  
Input Parameter ◽  
Diffusion Control ◽  
Microfluidic Channels ◽  
Inlet Flow ◽  
Inlet Flow Rate ◽  
Fuzzy Logic Method ◽  
Velocity Pressure

This study aims to perform optimizatione to achieve the best diffusion control between the channels by designing and analysing a microfluidic-based micromixer. The design and analysis of the micromixer were made with the COMSOL Multiphysics program. Some input and output parameters must be defined for diffusion control of the micromixer. Among these parameters, inputs are the diffusion coefficient and inlet flow rate, while outputs are velocity, pressure, and concentration. Each input parameter in the microfluidic chip affects the output of the system. To make the diffusion control in the most optimum way, the data were obtained by making much analysis. The data obtained from this program was also provided with the Fuzzy Logic method to optimize the microfluidic chip. The diffusion coefficient value (5E-11 m2/s) should be given to the channels to achieve the optimum diffusion between the micromixer channels, if the inlet flow rate value (15E-15 m3/s) is the output value of the system, the velocity is 0.09 mm/s. The pressure is 2 Pa, and the concentration is 0.45 mol/m3. These values are the optimum values obtained from the analysis without damaging the liquid’s microfluidic channels supplied to the micromixer’s inlet.

scholarly journals Design and Fabrication of a Microfluidic Chip for Particle Size-Exclusion and Enrichment

Micromachines ◽  
2021 ◽  
Vol 12 (10) ◽  
pp. 1218
Author(s):  
Luxia Yang ◽  
Tian Ye ◽  
Xiufeng Zhao ◽  
Taotao Hu ◽  
Yanlong Wei
Keyword(s):  
Flow Rate ◽  
Microfluidic Chip ◽  
Electromagnetic Force ◽  
Three Dimensional ◽  
Deionized Water ◽  
Sample Solution ◽  
Microfluidic Channels ◽  
Pdms Substrate ◽  
Polyethylene Particles ◽  
Micropillar Array

Based on the size of particles, a microfluidic chip integrating micro particles capture, controlled release and counting analysis was designed and fabricated in this paper. The chip is composed of a polydimethylsiloxane (PDMS) cover sheet and a PDMS substrate. The PDMS substrate is made of a sample inlet, microfluidic channels, a micropillar array, a three-dimensional (3D) focusing channel, and a sample outlet. The chip was fabricated by the multistep SU-8 lithography and PDMS molding method in this study. The micropillar array and channels in the chip can be molded in one step and can be replicated multiple times, which reduces the production cost and increases the practicability of the chip. Using a homemade electromagnetic drive device, the detection function of the chip was tested using a deionized water solution containing 22 μm polyethylene particles. The results showed that under the action of electromagnetic force, the chip enriched polyethylene particles; when the electromagnetic force disappeared, the enriched polyethylene particles were released by injecting buffer solution, and it was looked at as new sample solution. The flow rate of the sample solution and the sheath flow solution (deionized water) was injected into the three-dimensional focusing channel at a flow rate ratio of 1:4, and the polyethylene particles sample solution was focused, which could be used for the counting and analysis of polyethylene particles. The work of this paper can provide a reference for the subsequent detection of circulating tumor cells (CTCs).

scholarly journals Programmable hydraulic resistor for microfluidic chips using electrogate arrays

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Marie L. Salva ◽  
Yuksel Temiz ◽  
Marco Rocca ◽  
Yulieth C. Arango ◽  
Christof M. Niemeyer ◽  
...  
Keyword(s):  
Flow Rate ◽  
Microfluidic Chip ◽  
Rate Control ◽  
Flow Resistance ◽  
Smartphone Application ◽  
Microfluidic Chips ◽  
Specific Flow ◽  
Flow Rates ◽  
Peripheral Device ◽  
Flow Rate Control

AbstractFlow rates play an important role in microfluidic devices because they affect the transport of chemicals and determine where and when (bio)chemical reactions occur in these devices. Flow rates can conveniently be determined using external peripherals in active microfluidics. However, setting specific flow rates in passive microfluidics is a significant challenge because they are encoded on a design and fabrication level, leaving little freedom to users for adjusting flow rates for specific applications. Here, we present a programmable hydraulic resistor where an array of “electrogates” routes an incoming liquid through a set of resistors to modulate flow rates in microfluidic chips post-fabrication. This approach combines a battery-powered peripheral device with passive capillary-driven microfluidic chips for advanced flow rate control and measurement. We specifically show a programmable hydraulic resistor composed of 7 parallel resistors and 14 electrogates. A peripheral and smartphone application allow a user to activate selected electrogates and resistors, providing 127 (27-1) flow resistance combinations with values spanning on a 500 fold range. The electrogates feature a capillary pinning site (i.e. trench across the flow path) to stop a solution and an electrode, which can be activated in a few ms using a 3 V bias to resume flow based on electrowetting. The hydraulic resistor and microfluidic chip shown here enable flow rates from ~0.09 nL.s−1 up to ~5.66 nL.s−1 with the resistor occupying a footprint of only 15.8 mm2 on a 1 × 2 cm2 microfluidic chip fabricated in silicon. We illustrate how a programmable hydraulic resistor can be used to set flow rate conditions for laminar co-flow of 2 liquids and the enzymatic conversion of a substrate by stationary enzymes (alkaline phosphatase) downstream of the programmable hydraulic resistor.

Study on the Manufacture of Microfluidic Chip with Coated Glass

2012 ◽  
Vol 548 ◽  
pp. 254-257 ◽  
Author(s):  
Yan He ◽  
Bai Ling Huang ◽  
Yong Lai Zhang ◽  
Li Gang Niu
Keyword(s):  
Microfluidic Chip ◽  
Low Cost ◽  
Microfluidic Channel ◽  
Critical Factor ◽  
Wet Etching ◽  
Microfluidic Chips ◽  
Etching Technique ◽  
Chip Quality ◽  
Wet Chemical ◽  
Wet Chemical Etching

In this paper, a simple and facile technique for manufacturing glass-based microfluidic chips was developed. Instead of using expensive dry etching technology, the standard UV lithography and wet chemical etching technique was used to fabricate microchannels on a K9 glass substrate. The fabrication process of microfluidic chip including vacuum evaporation, annealing, lithography, and BHF (HF-NH4F-H2O) wet etching were investigated. Through series experiments, we found that anneal was the critical factor for chip quality. As a representative example, a microfluidic channel with 20 m of depth, and 80 m of width was successfully prepared, and the channel surfaces are quite smooth. These results present a simple, low cost, flexible and easy way to fabricate glass-based microfluidic chips.

Magnetofluidic control of the breakup of ferrofluid droplets in a microfluidic Y-junction

RSC Advances ◽  
2016 ◽  
Vol 6 (1) ◽  
pp. 778-785 ◽  
Author(s):  
Huajun Li ◽  
Yining Wu ◽  
Xiaoda Wang ◽  
Chunying Zhu ◽  
Taotao Fu ◽  
...  
Keyword(s):  
Flow Rate ◽  
Rate Ratios

Breakup of the ferrofluid droplets at the Y-junction divergence under various flow rate ratios.

scholarly journals Multistage Digital-to-Analogue Chip Based on a Weighted Flow Resistance Network for Soft Actuators

Micromachines ◽  
2021 ◽  
Vol 12 (9) ◽  
pp. 1016
Author(s):  
Zhou Zhou ◽  
Manman Xu ◽  
Chenlin Zhu ◽  
Gonghan He ◽  
Kunpeng Zhang ◽  
...  
Keyword(s):  
Flow Rate ◽  
Microfluidic Chip ◽  
Flow Resistance ◽  
Design Method ◽  
Control Unit ◽  
Digital Signal ◽  
Technical Problems ◽  
Pressure Signal ◽  
Resistance Network ◽  
Flow Adjustment

A control chip with a multistage flow-rate regulation function based on the correlation between the flow resistance and flow rate has been developed in this article. Compared with the traditional proportional solenoid valve, this kind of flow valve based on microfluidic technology has the characteristics of being light-weight and having no electric drive. It solves such technical problems as how the current digital microfluidic chip can only adjust the flow switch, and the adjustment of the flow rate is difficult. To linearize the output signal, we propose a design method of weighted resistance. The output flow is controlled by a 4-bit binary pressure signal. According to the binary value of the 4-bit pressure signal at the input, the output can achieve 16-stage flow adjustment. Furthermore, we integrate the three-dimensional flow resistance network, multilayer structure microvalve, and parallel fluid network into a single chip by using 3D printing to obtain a modular flow control unit. This structure enables the microflow control signal to be converted from a digital signal to an analogue signal (DA conversion), and is suitable for microflow driving components, such as in microfluidic chip sampling systems and proportional mixing systems. In the future, we expect this device to even be used in the automatic control system of a miniature pneumatic soft actuator.

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