scholarly journals Using a Digital Microfluidic System to Evaluate the Stretch Length of a Droplet with a L-DEP and Varied Parameters

Inventions ◽  
2020 ◽  
Vol 5 (2) ◽  
pp. 21
Author(s):  
Hsiang-Ting Lee ◽  
Ying-Jhen Ciou ◽  
Da-Jeng Yao
Keyword(s):  
Digital Microfluidics ◽  
Microfluidic System ◽  
Experimental Results ◽  
Force Balance ◽  
Electrode Spacing ◽  
Total Width ◽  
Precise Control ◽  
Liquid Dielectrophoresis ◽  
Droplet Liquid ◽  
Digital Microfluidic

Digital microfluidics has become intensively explored as an effective method for liquid handling in lab-on-a-chip (LOC) systems. Liquid dielectrophoresis (L-DEP) has many advantages and exciting prospects in driving droplets. To fully realize the potential benefits of this technique, one must know the droplet volume accurately for its distribution and manipulation. Here we present an investigation of the tensile length of a droplet subjected to a L-DEP force with varied parameters to achieve precise control of the volume of a droplet. Liquid propylene carbonate served as a driving liquid in the L-DEP experiment. The chip was divided into two parts: an electrode of width fixed at 0.1 mm and a total width fixed at 1 mm. Each had a variation of six electrode spacings. The experimental results showed that the stretching length decreased with decreasing electrode width, but the stretching length did not vary with an increased spacing of the electrode. When the two electrodes were activated, the length decreased because of an increase in electrode spacing. The theory was based on the force balance on a droplet that involved the force generated by the electric field, friction force, and capillary force. The theory was improved according to the experimental results. To verify the theoretical improvement through the results, we designed a three-electrode chip for experiments. The results proved that the theory is consistent with the results of the experiments, so that the length of a droplet stretched with L-DEP and its volume can be calculated.

Voltage Phase Control for Enhanced Addressability in Highly-Parallel Digital Microfluidic Architectures

2011 ◽  
Author(s):  
Christopher M. Collier ◽  
Brandon Born ◽  
Jonathan F. Holzman
Keyword(s):  
Digital Microfluidics ◽  
Fluid Motion ◽  
Microfluidic System ◽  
Dual Phase ◽  
Two Dimensional ◽  
End User ◽  
Electrode Structure ◽  
Voltage Transformer ◽  
Precise Control ◽  
Digital Microfluidic

Digital microfluidic architectures have been a source of great enthusiasm for on-chip fluid applications requiring precise control and reconfigurability. Droplet-based systems operating with exceedingly small volumes (pL) can make use of digital microfluidic control systems to direct fluid motion using voltages on cascaded electrode structures. The voltage on these electrodes can be adapted via software, thus the generalized templates offered by digital microfluidic systems can be tailored for numerous end-user applications. The work presented here addresses the two major challenges for implementing these digital microfluidics systems for end-user applications: parallel addressability and reduced input voltages. The challenges are overcome through dual-phase AC voltage routing in a 16×16 digital microfluidic multiplexer using low (10 Vrms) input voltages. The first challenge, related to parallel addressability, comes about because of the generalized template for digital microfluidics, with underlying square-grid electrodes forming a two-dimensional, M×N, plane. Such a structure cannot be readily scaled up for use in single-layered highly-parallel architectures as external address lines cannot be effectively contacted to internal square electrodes lying within a 2-dimensional. With this in mind, the work here introduces multiplexing with a cross-referenced architecture having only M+N input lines. Microdroplets lie between orthogonal overlying row electrodes and underlying column electrodes, and nonlinear threshold-voltage localization is used to initiate motion of the desired microdroplet in the two-dimensional plane. Microdroplet interference (motion of undesired microdroplets) along the activated row and column is avoided, as the applied voltage initiates motion only at the overlapped electrode region (where the voltage is doubled and above-threshold). A dual-phase AC voltage control system is used to address the above bi-layered cross-referenced electrode structure and simultaneously provides a natural solution to the second, reduced voltage, challenge of practical digital microfluidic architectures. Reduced input voltages can be achieved in the digital microfluidic system through an integrated centre-tap AC transformer (a dielectric layer in the digital microfluidic multiplexer limits the current and power consumption, allowing for step-up voltage transformation). The dual-phase outputs from this voltage transformer are 180° out-of-phase, and the AC signals from these outputs are routed to the appropriate row and column electrodes to bring about above-threshold motion. Controlled switching is demonstrated in this work for input voltages below 10 Vrms. Structural and electrical design issues for this dual-phase AC digital microfluidic integrated chip are addressed in this work, and results are presented for an integrated digital microfluidic multiplexer prototype.

scholarly journals Conquering the Tyranny of Number With Digital Microfluidics

2021 ◽  
Vol 9 ◽  
Author(s):  
Ya-Tang Yang ◽  
Tsung-Yi Ho
Keyword(s):  
Soft Lithography ◽  
Large Scale ◽  
Digital Microfluidics ◽  
Microfluidic System ◽  
Electrical Signal ◽  
Fundamental Physics ◽  
Large Scale Integration ◽  
Control Electronics ◽  
Digital Microfluidic ◽  
Scale Integration

The development of large-scale integration based on soft lithography has ushered a new revolution in microfluidics. This technology, however, relies inherently on pneumatic control of micromechanical valves that require air pressure to operate, while digital microfluidics uses a purely electrical signal on an electrode for droplet manipulation. In this article, we discuss the prospect and current challenges of digital microfluidics to solve the problem of the tyranny of numbers in arbitrary fluidic manipulation. We distill the fundamental physics governing electrowetting and their implications for specifications of the control electronics. We survey existing control electronics in digital microfluidics and detail the improvements needed to realize a low-power, programmable digital microfluidic system. Such an instrument would attract wide interest in both professional and non-professional (hobbyist) communities.

An integrated droplet-digital microfluidic system for on-demand droplet creation, mixing, incubation, and sorting

Lab on a Chip ◽  
2019 ◽  
Vol 19 (3) ◽  
pp. 524-535 ◽  
Author(s):  
Fatemeh Ahmadi ◽  
Kenza Samlali ◽  
Philippe Q. N. Vo ◽  
Steve C. C. Shih
Keyword(s):  
Ionic Liquid ◽  
Digital Microfluidics ◽  
Microfluidic System ◽  
Yeast Mutant ◽  
Microfluidic Platform ◽  
On Demand ◽  
Digital Microfluidic ◽  
Mutant Cells

A new microfluidic platform that integrates droplet and digital microfluidics to automate a variety of fluidic operations. The platform was applied to culturing and to selecting yeast mutant cells in ionic liquid.

scholarly journals Machine vision-based driving and feedback scheme for digital microfluidics system

2021 ◽  
Vol 19 (1) ◽  
pp. 665-677
Author(s):  
Zhijie Luo ◽  
Bangrui Huang ◽  
Jiazhi Xu ◽  
Lu Wang ◽  
Zitao Huang ◽  
...  
Keyword(s):  
Machine Vision ◽  
New Technology ◽  
Digital Microfluidics ◽  
Microfluidic System ◽  
Position Information ◽  
Electrowetting On Dielectric ◽  
System A ◽  
Feedback Scheme ◽  
Voltage Signal ◽  
Digital Microfluidic

Abstract A digital microfluidic system based on electrowetting-on-dielectric is a new technology for controlling microliter-sized droplets on a plane. By applying a voltage signal to an electrode, the droplets can be controlled to move, merge, and split. Due to device design, fabrication, and runtime uncertainties, feedback control schemes are necessary to ensure the reliability and accuracy of a digital microfluidic system for practical application. The premise of feedback is to obtain accurate droplet position information. Therefore, there is a strong need to develop a digital microfluidics system integrated with driving, position, and feedback functions for different areas of study. In this article, we propose a driving and feedback scheme based on machine vision for the digital microfluidics system. A series of experiments including droplet motion, merging, status detection, and self-adaption are performed to evaluate the feasibility and the reliability of the proposed scheme. The experimental results show that the proposed scheme can accurately locate multiple droplets and improve the success rate of different applications. Furthermore, the proposed scheme provides an experimental platform for scientists who focused on the digital microfluidics system.

scholarly journals Machine Learning Model of Dimensionless Numbers to Predict Flow Patterns and Droplet Characteristics for Two-Phase Digital Flows

2021 ◽  
Vol 11 (9) ◽  
pp. 4251
Author(s):  
Jinsong Zhang ◽  
Shuai Zhang ◽  
Jianhua Zhang ◽  
Zhiliang Wang
Keyword(s):  
Machine Learning ◽  
Learning Algorithms ◽  
Digital Microfluidics ◽  
Flow Patterns ◽  
Machine Learning Algorithms ◽  
Dimensionless Numbers ◽  
Two Phase ◽  
The Difference ◽  
Input Variables ◽  
Digital Microfluidic

In the digital microfluidic experiments, the droplet characteristics and flow patterns are generally identified and predicted by the empirical methods, which are difficult to process a large amount of data mining. In addition, due to the existence of inevitable human invention, the inconsistent judgment standards make the comparison between different experiments cumbersome and almost impossible. In this paper, we tried to use machine learning to build algorithms that could automatically identify, judge, and predict flow patterns and droplet characteristics, so that the empirical judgment was transferred to be an intelligent process. The difference on the usual machine learning algorithms, a generalized variable system was introduced to describe the different geometry configurations of the digital microfluidics. Specifically, Buckingham’s theorem had been adopted to obtain multiple groups of dimensionless numbers as the input variables of machine learning algorithms. Through the verification of the algorithms, the SVM and BPNN algorithms had classified and predicted the different flow patterns and droplet characteristics (the length and frequency) successfully. By comparing with the primitive parameters system, the dimensionless numbers system was superior in the predictive capability. The traditional dimensionless numbers selected for the machine learning algorithms should have physical meanings strongly rather than mathematical meanings. The machine learning algorithms applying the dimensionless numbers had declined the dimensionality of the system and the amount of computation and not lose the information of primitive parameters.

scholarly journals Microfluidic patterning using a digital microfluidic system

AIP Advances ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 125115
Author(s):  
Ying-Jhen Ciou ◽  
Hsiang-Ting Lee ◽  
Yi-Wei Lin ◽  
Da-Jeng Yao
Keyword(s):  
Microfluidic System ◽  
Digital Microfluidic ◽  
Microfluidic Patterning

scholarly journals Ultra-Portable Smartphone Controlled Integrated Digital Microfluidic System in a 3D-Printed Modular Assembly

Micromachines ◽  
2015 ◽  
Vol 6 (9) ◽  
pp. 1289-1305 ◽  
Author(s):  
Mohamed Yafia ◽  
Ali Ahmadi ◽  
Mina Hoorfar ◽  
Homayoun Najjaran
Keyword(s):  
Microfluidic System ◽  
Modular Assembly ◽  
3D Printed ◽  
Digital Microfluidic

A Framework for Validation of Synthesized MicroElectrode Dot Array Actuations for Digital Microfluidic Biochips

2021 ◽  
Vol 26 (6) ◽  
pp. 1-36
Author(s):  
Pushpita Roy ◽  
Ansuman Banerjee
Keyword(s):  
Formal Analysis ◽  
Digital Microfluidics ◽  
Analysis Method ◽  
Correctness Proofs ◽  
Synthesis Tool ◽  
Laboratory Procedures ◽  
Automated Tools ◽  
Digital Microfluidic ◽  
High Level ◽  
Smooth Transformation

Digital Microfluidics is an emerging technology for automating laboratory procedures in biochemistry. With more and more complex biochemical protocols getting mapped to biochip devices and microfluidics receiving a wide adoption, it is becoming indispensable to develop automated tools and synthesis platforms that can enable a smooth transformation from complex cumbersome benchtop laboratory procedures to biochip execution. Given an informal/semi-formal assay description and a target microfluidic grid architecture on which the assay has to be implemented, a synthesis tool typically translates the high-level assay operations to low-level actuation sequences that can drive the assay realization on the grid. With more and more complex biochemical assay protocols being taken up for synthesis and biochips supporting a wider variety of operations (e.g., MicroElectrode Dot Arrays (MEDAs)), the task of assay synthesis is getting intricately complex. Errors in the synthesized assay descriptions may have undesirable consequences in assay operations, leading to unacceptable outcomes after execution on the biochips. In this work, we focus on the challenge of examining the correctness of synthesized protocol descriptions, before they are taken up for realization on a microfluidic biochip. In particular, we take up a protocol description synthesized for a MEDA biochip and adopt a formal analysis method to derive correctness proofs or a violation thereof, pointing to the exact operation in the erroneous translation. We present experimental results on a few bioassay protocols and show the utility of our framework for verifiable protocol synthesis.

Numerical Investigation of the Combined Effects of Biomolecular Adsorption and Microdroplet Evaporation on the Performance of the Electrocapillary-Based Digital Microfluidic Systems

2011 ◽  
Author(s):  
Ali Ahmadi ◽  
Mina Hoorfar
Keyword(s):  
Mass Loss ◽  
Protein Concentration ◽  
Adsorption Rate ◽  
Force Balance ◽  
Combined Effects ◽  
Microfluidic Systems ◽  
Gibbs Equation ◽  
Rate Effects ◽  
Digital Microfluidic ◽  
Force Balance Equation

In this article, microdroplet motion in the electrocapillary-based digital microfluidic systems is modeled accurately, and the combined effects of the biomolecular adsorption and micro-droplet evaporation on the performance of the device are investigated. An electrohydrodynamic approach is used to model the driving and resisting forces, and Fick’s law and Gibbs equation are used to calculate the microdroplet evaporation and adsorption rate. Effects of the adsorption and evaporation rates are then implemented into the microdroplet dynamics by adding new terms into the force balance equation. It is shown that mass loss due to the evaporation tends to increase the protein concentration, and on the other hand, the increased concentration due to the mass loss increases the biomolecular adsorption rate which has a reverse effect on the concentration. The modeling results indicate that evaporation and adsorption play crucial roles in the microdroplet dynamics.

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