A Study of On-Chip Aqueous Two Phase System Formation and its Applications

2012 ◽  
Author(s):  
Pavithra A. L. Wijethunga ◽  
Hyejin Moon
Keyword(s):  
Microfluidic Chip ◽  
Biological Sample ◽  
Gravitational Force ◽  
Phase System ◽  
Single Chip ◽  
Two Phase ◽  
Micro Scale ◽  
Macro Scale ◽  
Two Phases ◽  
On Chip

Although there are several reports demonstrating the use of aqueous two-phase systems (ATPS) for biological sample separation in miniaturized devices, they only used ATPS prepared in macro scale by following the conventional way. Formation of ATPS in a confined micro scale environment and their characteristics has not been studied yet. While ATPS formation in macro scale is supported by vigorous mixing and gravitational force to form two phases, both mixing capability and gravitational force aid are insignificant in micro scale. Hence, in this study, we investigated the formation of ATPS under these inferior conditions of micro scale. An electrowetting on a dielectric (EWOD) digital microfluidic chip was used as the confined miniaturized environment. In an EWOD device, micro/nano scale droplets are manipulated on an array of electrodes by sequential application of voltages to the electrodes. The common polyethylene glycol (PEG) and dextran (DEX) polymer/polymer ATPS was used as the model system. Nanoliter volume droplets of the two pure polymer solutions were brought into contact, mixed, and successfully formed ATPS on an EWOD chip. Furthermore, it was possible to separate the two phases into two droplets, demonstrating the promising capability of on-chip biological sample separations effectively by integrating formation of ATPS and separation process using ATPS in a single chip. This study also compares the characteristics of ATPS generated in microfluidic chip with that generated in conventional macro scale. The effect of mixing performance on the ATPS formation is studied experimentally.

An automated centrifugal microfluidic assay for whole blood fractionation and isolation of multiple cell populations using an aqueous two-phase system

Lab on a Chip ◽  
2021 ◽  
Author(s):  
Byeong-Ui Moon ◽  
Liviu Clime ◽  
Daniel Brassard ◽  
Alex Boutin ◽  
Jamal Daoud ◽  
...  
Keyword(s):  
Human Blood ◽  
Whole Blood ◽  
Cell Populations ◽  
Phase System ◽  
Two Phase ◽  
Microfluidic Platform ◽  
Aqueous Two Phase System ◽  
Separation Layers ◽  
Multiple Cell ◽  
On Chip

This paper describes an advanced on-chip whole human blood fractionation and cell isolation process combining an aqueous two-phase system to create complex separation layers with a centrifugal microfluidic platform to control and automate the assay.

Activity coefficients, densities, dipole moments, and surface tensions of the system triethylamine–methylethylketone–water

1981 ◽  
Vol 59 (1) ◽  
pp. 127-131 ◽  
Author(s):  
Alan N. Campbell
Keyword(s):  
Surface Layer ◽  
Dipole Moments ◽  
Phase System ◽  
Constant Composition ◽  
Two Phase ◽  
Three Phase ◽  
Wide Range ◽  
Isothermal System ◽  
Total Composition ◽  
Two Phases

The properties named in the title have been determined by standard methods. Viscosity, molar volume, and orientation polarisation all indicate abnormalities of the nature of association between the components.The most interesting result is that of surface tension which indicates that, in the case of the binary system triethylamine–water, a surface layer of constant composition is formed over a wide range of total composition. When, by a rise in temperature of two or three degrees, this layer becomes unstable, it splits into two phases of different composition. The surface layer may then be instantaneously reformed and so on. A mechanism for the generation of a two-phase system is thus established. The data for the three-phase, isothermal, system are not so convincing, for reasons that are suggested.

Robotic Hardware and Software Integration for Changing Human Intentions

2012 ◽  
pp. 380-406 ◽  
Author(s):  
Akif Durdu ◽  
Ismet Erkmen ◽  
Aydan M. Erkmen ◽  
Alper Yilmaz
Keyword(s):  
Video Processing ◽  
Spatial Information ◽  
Human Robot Interaction ◽  
Phase System ◽  
Robot Interaction ◽  
Two Phase ◽  
Video Frames ◽  
Human Intention ◽  
Two Phases ◽  
Intention Estimation

Estimating and reshaping human intentions are among the most significant topics of research in the field of human-robot interaction. This chapter provides an overview of intention estimation literature on human-robot interaction, and introduces an approach on how robots can voluntarily reshape estimated intentions. The reshaping of the human intention is achieved by the robots moving in certain directions that have been a priori observed from the interactions of humans with the objects in the scene. Being among the only few studies on intention reshaping, the authors of this chapter exploit spatial information by learning a Hidden Markov Model (HMM) of motion, which is tailored for intelligent robotic interaction. The algorithmic design consists of two phases. At first, the approach detects and tracks human to estimate the current intention. Later, this information is used by autonomous robots that interact with detected human to change the estimated intention. In the tracking and intention estimation phase, postures and locations of the human are monitored by applying low-level video processing methods. In the latter phase, learned HMM models are used to reshape the estimated human intention. This two-phase system is tested on video frames taken from a real human-robot environment. The results obtained using the proposed approach shows promising performance in reshaping of detected intentions.

scholarly journals The interaction of insulin with phospholipids

1971 ◽  
Vol 125 (1) ◽  
pp. 179-187 ◽  
Author(s):  
M. C. Perry ◽  
W. Tampion ◽  
J. A. Lucy
Keyword(s):  
Phosphatidic Acid ◽  
Functional System ◽  
Buffer System ◽  
Phase System ◽  
Two Phase ◽  
Phospholipid Micelles ◽  
Structural And Functional Properties ◽  
Chloroform Phase ◽  
Two Phases ◽  
Triton X

1. A simple two-phase chloroform–aqueous buffer system was used to investigate the interaction of insulin with phospholipids and other amphipathic substances. 2. The distribution of 125I-labelled insulin in this system was determined after incubation at 37°C. Phosphatidic acid, dicetylphosphoric acid and, to a lesser extent, phosphatidylcholine and cetyltrimethylammonium bromide solubilized 125I-labelled insulin in the chloroform phase, indicating the formation of chloroform-soluble insulin–phospholipid or insulin–amphipath complexes. Phosphatidylethanolamine, sphingomyelin, cholesterol, stearylamine and Triton X-100 were without effect. 3. Formation of insulin–phospholipid complex was confirmed by paper chromatography. 4. The two-phase system was adapted to act as a simple functional system with which to investigate possible effects of insulin on the structural and functional properties of phospholipid micelles in chloroform, by using the distribution of [14C]glucose between the two phases as a monitor of phospholipid–insulin interactions. The ability of phospholipids to solubilize [14C]glucose in chloroform increased in the order phosphatidylcholine<sphingomyelin<phosphatidylethanolamine<phosphatidic acid. Insulin decreased the [14C]glucose solubilized by phosphatidylcholine, phosphatidylethanolamine and phosphatidic acid, but not by sphingomyelin. 5. The significance of these results and the molecular requirements for the formation of insulin–phospholipid complexes in chloroform are discussed.

scholarly journals Microfluidic Flow-through SPME Chip for Online Separation and MS Detection of Multiple Analyses in Complex Matrix

Micromachines ◽  
2020 ◽  
Vol 11 (2) ◽  
pp. 120
Author(s):  
Yujun Chen ◽  
Tao Gong ◽  
Cilong Yu ◽  
Xiang Qian ◽  
Xiaohao Wang
Keyword(s):  
Microfluidic Chip ◽  
Solid Phase Microextraction ◽  
Solid Phase ◽  
Sample Pretreatment ◽  
Annular Channel ◽  
Calibration Method ◽  
Extraction Process ◽  
Single Chip ◽  
Calibration Methods ◽  
On Chip

Simplifying tedious sample preparation procedures to improve analysis efficiency is a major challenge in contemporary analytical chemistry. Solid phase microextraction (SPME), a technology developed for rapid sample pretreatment, has flexibility in design, geometry, and calibration strategies, which makes it a useful tool in a variety of fields, especially environmental and life sciences. Therefore, it is important to study the coupling between the microfluidic electrospray ionization (ESI) chip integrated with the solid phase microextraction (SPME) module and the electrospray mass spectrometer (MS). In our previous work, we designed a solid phase microextraction (SPME) module on a microfluidic chip through geometric design. However, automation and calibration methods for the extraction process remain unresolved in the SPME on-chip domain, which will lead to faster and more accurate results. This paper discusses the necessity to design a micromixer structure that can produce different elution conditions on the microfluidic chip. By calculating the channel resistances, the microfluidic chip’s integrated module with the micromixer, SPME, and ESI emitters optimize the geometry structure. We propose the annular channel for SPME to perform the resistances balance of the entire chip. Finally, for SPME on a single chip, this work provides a quantitation calibration method to describe the distribution of the analytes between the sample and the extraction phase before reaching the adsorption equilibrium.

Ground substance mucopolysaccharides and plasma proteins: their role in capillary water balance

1976 ◽  
Vol 230 (4) ◽  
pp. 1121-1125 ◽  
Author(s):  
CA Wiederhielm ◽  
Fox ◽  
DR Lee
Keyword(s):  
Plasma Proteins ◽  
Ground Substance ◽  
Free Fluid ◽  
Phase System ◽  
Two Phase ◽  
Volume Measurements ◽  
Two Phases ◽  
Computer Simulation Studies ◽  
Tracer Molecules ◽  
Selection Of

The osmotic interaction of mucopolysaccharides and plasma proteins, normally present in the interstitium, has been investigated. It has been found that hyaluronate-plasma protein mixtures may be treated as a two-phase system and that the two phases are in osmotic equilibrium. The osmotic pressures exerted by these mixtures are higher than the algebraic sum of the two components. At concentrations normally present in the interstitium of skin and muscle (0.6% mucopolysaccharides and 2% protein), the osmotic pressure exerted by the mixture is on the order of 10 mmHg, which is in agreement with predictions from earlier computer-simulation studies. The partition of fluid between the gel-like mucopolysaccharide compartment and the free-fluid containing the protein is approximately 50% in the "gel" phase at concentrations found in the interstitium. The volume exclusion effects of the interstitial mucopolysaccharides are significant, both in terms of selection of tracer molecules for interstitial volume measurements and also as an osmotic buffering mechanism which aids in maintaining the partition of fluid between the circulation and the interstitial space.

scholarly journals Tiny Bubbles

2009 ◽  
Vol 17 (1) ◽  
pp. 3-5
Author(s):  
Stephen W. Carmichael
Keyword(s):  
Lower Energy ◽  
Critical Role ◽  
Interfacial Area ◽  
Consumer Products ◽  
Phase System ◽  
Two Phase ◽  
Liquid Phases ◽  
Phase Systems ◽  
Two Phases

This is not an article about the song made famous by the late (great) Don Ho. This is about a breakthrough in the understanding of how micrometer-sized bubbles can be stabilized for long periods of time. This can influence the taste, smell, and consistency of consumer products including food and cosmetics.In two-phase systems, which can include air (as bubbles) suspended within a liquid, the structures of the dispersed (bubbles) and continuous (liquid) phases play a critical role in determining the properties of the material. There is also the function of time in that the microstructure of the dispersed phase continuously evolves toward a state of lower energy by minimizing the surface area between the two phases (referred to as the interfacial area). In the long term, this time evolution diminishes the usefulness of two-phase systems. Emilie Dressaire, Rodney Bee, David Bell, Alex Lips, and Howard Stone have devised a way to stabilize a two-phase system for time periods of a year or longer.

WELL-POSEDNESS OF A PHASE TRANSITION MODEL WITH THE POSSIBILITY OF VOIDS

2006 ◽  
Vol 16 (04) ◽  
pp. 559-586 ◽  
Author(s):  
MICHEL FRÉMOND ◽  
ELISABETTA ROCCA
Keyword(s):  
Phase Transition ◽  
Balance Equation ◽  
Strain Tensor ◽  
Absolute Temperature ◽  
Phase System ◽  
Transition Model ◽  
Well Posedness ◽  
State Variables ◽  
Two Phase ◽  
Two Phases

The paper deals with a phase transition model applied to a two-phase system. There is a wide literature on the study of phase transition processes in case that no voids nor overlapping can occur between the two phases. The main novelty of our approach is the possibility of having voids during the phase change. This aspect is described in the model by the mass balance equation whose effects are included by means of the pressure of the system in the dynamical relations. The state variables are the absolute temperature (whose evolution is ruled by the entropy balance equation), the strain tensor (satisfying a quasi-static macroscopic equation of motion), and the volume fractions of the two phases (whose evolutions are described by a vectorial equation coming from the principle of virtual power and related to the microscopic motions). Well-posedness of the initial-boundary value problem associated to the PDEs system resulting from this model is proved.

scholarly journals Robotic Hardware and Software Integration for Changing Human Intentions

Robotics ◽  
2013 ◽  
pp. 1381-1406
Author(s):  
Akif Durdu ◽  
Ismet Erkmen ◽  
Aydan M. Erkmen ◽  
Alper Yilmaz
Keyword(s):  
Video Processing ◽  
Spatial Information ◽  
Human Robot Interaction ◽  
Phase System ◽  
Robot Interaction ◽  
Two Phase ◽  
Video Frames ◽  
Human Intention ◽  
Two Phases ◽  
Intention Estimation

Estimating and reshaping human intentions are among the most significant topics of research in the field of human-robot interaction. This chapter provides an overview of intention estimation literature on human-robot interaction, and introduces an approach on how robots can voluntarily reshape estimated intentions. The reshaping of the human intention is achieved by the robots moving in certain directions that have been a priori observed from the interactions of humans with the objects in the scene. Being among the only few studies on intention reshaping, the authors of this chapter exploit spatial information by learning a Hidden Markov Model (HMM) of motion, which is tailored for intelligent robotic interaction. The algorithmic design consists of two phases. At first, the approach detects and tracks human to estimate the current intention. Later, this information is used by autonomous robots that interact with detected human to change the estimated intention. In the tracking and intention estimation phase, postures and locations of the human are monitored by applying low-level video processing methods. In the latter phase, learned HMM models are used to reshape the estimated human intention. This two-phase system is tested on video frames taken from a real human-robot environment. The results obtained using the proposed approach shows promising performance in reshaping of detected intentions.

Probing the Mechanism of Aqueous Two-Phase System Formation for α-Elastin On-Chip

2003 ◽  
Vol 125 (50) ◽  
pp. 15630-15635 ◽  
Author(s):  
Yanjie Zhang ◽  
Hanbin Mao ◽  
Paul S. Cremer
Keyword(s):  
Phase System ◽  
Two Phase ◽  
Aqueous Two Phase System ◽  
System Formation ◽  
On Chip
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