Optically Induced Electrokinetic Trapping and Sorting of Colloids

2010 ◽  
Author(s):  
Stuart J. Williams ◽  
Aloke Kumar ◽  
Steven T. Wereley
Keyword(s):  
Electrical Conductivity ◽  
Surface Modification ◽  
Particle Diameter ◽  
Lab On A Chip ◽  
Particle Manipulation ◽  
Complete Understanding ◽  
Heating Source ◽  
Electrokinetic Trapping ◽  
Rapid Electrokinetic Patterning ◽  
Optically Induced

Recently, we have demonstrated electrothermal hydrodynamics with an external heating source of a highly focused 1,064 nm laser beam [1]. This phenomenon, when coupled with particle-electrode electrokinetic interactions, has led to the rapid and selective concentration of suspended colloids [2–6]. This technique, termed Rapid Electrokinetic Patterning (REP) was demonstrated without any additional surface modification or patterning of the electrodes. This dynamic, optically induced fluid and particle manipulation technique could be used for a variety of lab-on-a-chip applications. However, there are additional effects that have yet to be investigated that are important for a complete understanding of REP. This paper showcases experimental particle-particle behavior observations by varying particle diameter, electrode material, and preliminary results of varying fluid electrical conductivity.

Micro and Nano Particle Manipulation Using Optically Modulated Electrokinetic Flows

2009 ◽  
Author(s):  
Stuart J. Williams ◽  
Aloke Kumar ◽  
Steven T. Wereley
Keyword(s):  
Surface Modification ◽  
Parallel Plate ◽  
Near Infrared ◽  
Lab On A Chip ◽  
Nano Particle ◽  
Particle Manipulation ◽  
Physical Mechanisms ◽  
Particle Sorting ◽  
Electrokinetic Flows ◽  
Optically Induced

Recently, we have demonstrated an optically induced AC electrokinetic technique that rapidly, continuously and selectively concentrates colloids on an electrode surface [1–3]. This is demonstrated with a highly focused near-infrared (1,064 nm) laser beam applied to parallel plate electrodes separated by 50 μm without any additional surface modification or patterning of the electrodes. This dynamic optically-induced technique can be applied towards a variety of lab-on-a-chip applications. This paper will explain its physical mechanisms and showcase recent results regarding its particle sorting capabilities. This dynamic, optically induced fluid and particle manipulation technique could be used for a variety of lab-on-a-chip applications.

Optically Induced Electrohydrodynamics and Electrokinetic Colloidal Aggregation

2009 ◽  
Author(s):  
Stuart J. Williams ◽  
Aloke Kumar ◽  
Steven T. Wereley
Keyword(s):  
Laser Beam ◽  
Electrode Surface ◽  
Parallel Plate ◽  
Near Infrared ◽  
Lab On A Chip ◽  
Particle Manipulation ◽  
Colloidal Aggregation ◽  
Physical Mechanisms ◽  
Fundamental Physical ◽  
Optically Induced

Recently, we have demonstrated a novel optically induced AC electrokinetic technique that rapidly, continuously and selectively concentrates micro and nanoparticles on an electrode surface [1–3]. This is demonstrated with a highly focused near-infrared (1,064 nm) laser beam applied to parallel plate electrodes separated by 50 μm without the need for photosensitive materials. This dynamic optically-induced technique can be applied towards a variety of lab-on-a-chip applications. This paper will explain the fundamental physical mechanisms involved, necessary in order to replicate and implement this technique. This dynamic fluid and particle manipulation technique may prove valuable to a variety of applications in micro- and nanotechnology.

scholarly journals Recent Advances in Continuous-Flow Particle Manipulations Using Magnetic Fluids

Micromachines ◽  
2019 ◽  
Vol 10 (11) ◽  
pp. 744 ◽  
Author(s):  
Xiangchun Xuan
Keyword(s):  
Continuous Flow ◽  
Lab On A Chip ◽  
Microfluidic Devices ◽  
Magnetic Fluids ◽  
Label Free ◽  
Particle Manipulation ◽  
The Past ◽  
Recent Advances ◽  
Medium Exchange ◽  
Flow Particle

Magnetic field-induced particle manipulation is simple and economic as compared to other techniques (e.g., electric, acoustic, and optical) for lab-on-a-chip applications. However, traditional magnetic controls require the particles to be manipulated being magnetizable, which renders it necessary to magnetically label particles that are almost exclusively diamagnetic in nature. In the past decade, magnetic fluids including paramagnetic solutions and ferrofluids have been increasingly used in microfluidic devices to implement label-free manipulations of various types of particles (both synthetic and biological). We review herein the recent advances in this field with focus upon the continuous-flow particle manipulations. Specifically, we review the reported studies on the negative magnetophoresis-induced deflection, focusing, enrichment, separation, and medium exchange of diamagnetic particles in the continuous flow of magnetic fluids through microchannels.

scholarly journals The conductivity of uni-univalent salts in methyl alcohol at 25°C

1925 ◽  
Vol 109 (750) ◽  
pp. 351-368 ◽  
Keyword(s):  
Electrical Conductivity ◽  
Aqueous Solutions ◽  
Physical Properties ◽  
Methyl Alcohol ◽  
Experimental Work ◽  
Complete Understanding ◽  
Systematic Data ◽  
The Past ◽  
Aqueous Solvent ◽  
Solutions Of Electrolytes

The physical properties of solutions of electrolytes in non-aqueous solvents have been investigated in the past by a number of workers, but until recently the work in this field has been characterised to some extent by lack of accuracy and of co-ordination. The need for accurate experimental work in this direction is clear when it is realised that modern theories of the behaviour of electrolytes in solution are based almost entirely on data obtained for solutions in water. It is probable that a more complete understanding of the nature of solutions can come only through experimental work extending over a range of solvents: the peculiar properties of water as a solvent have tended hitherto to obscure many of the fundamental difficulties of the problem by cloaking them in the garb of simplicity. The work which forms the substance of this paper was undertaken with a view to obtaining some systematic data for the electrical conductivity of dilute solutions of uni-univalent salts in a non-aqueous solvent, of an accuracy comparable with that of Kohlrausch and his co-workers in the case of aqueous solutions. The choice of methyl alcohol as a solvent was governed by the fact that it is most closely allied to water in type, and is experimentally well suited for such an investigation.

Particle Manipulation Inside a Grooved Microfluidic Channel

2009 ◽  
Author(s):  
Hsiu-hung Chen ◽  
Dayong Gao
Keyword(s):  
Rapid Prototyping ◽  
Microfluidic Device ◽  
Microfluidic Channel ◽  
Lab On A Chip ◽  
Cell Suspensions ◽  
Microfluidic Channels ◽  
Particle Manipulation ◽  
Post Processing ◽  
Processing Stage ◽  
Submicron Structures

The manipulation of particles and cells in micro-fluids, such as cell suspensions, is a fundamental task in Lab-on-a-Chip applications. According to their analysis purposes in either the pre- or post-processing stage, particles/cells flowing inside a microfluidic channel are handled by means of enriching, trapping, separating or sorting. In this study, we report the use of patterning flows produced by a series of grooved surfaces with different geometrical setups integrated into a microfluidic device, to continuously manipulate the flowing particles (5 to 20 μm in diameters) of comparable sizes to the depth of the channel in ways of: 1) concentrating, 2) focusing, and 3) potential separating. The device is fabricated using soft lithographic techniques and is composed of inlets, microfluidic channels, and outlets for loading, manipulating and retrieving cell suspensions, respectively. Such fabrication methods allow rapid prototyping of micron or submicron structures with multiple layers and replica molding on those fabricated features in a clear polymer. The particles are evenly distributed in the entrance of the microchannel and illustrate the enriching, focusing, or size-selective profiles after passing through the patterning grooves. We expect that the techniques of manipulating cell suspensions from this study can facilitate the development of cell-based devices on 1) the visualization of counting, 2) the visualization of sizing, and 3) the particle separating.

Development of a Bead-Based Optoelectrokinetic Immunosensing Technique for Detection of Low-Abundance Analytes

2017 ◽  
Author(s):  
Han-Sheng Chuang ◽  
Hsiao-Neng Lin ◽  
Hu-Yao Ku
Keyword(s):  
Limit Of Detection ◽  
Point Of Care ◽  
Particle Manipulation ◽  
Great Flexibility ◽  
Point Of Care Diagnostics ◽  
Combined Use ◽  
Tnf Α ◽  
Rapid Electrokinetic Patterning ◽  
Sample Droplet ◽  
Made In

Bead-based immunosensing has been growing as a promising technology in the point-of-care diagnostics because of great flexibility. For dilute samples, functionalized particles can be used to collect dispersed analytes and act as carriers for particle manipulation. To carry out rapid and selective diagnosis, a bead-based optoelectrokinetic immunosensing technique was developed herein to detect biomarkers, lipocalin 1 (LCN1) and TNF-α, for diabetic retinopathy (DR). The measurement was made in a sample droplet sandwiched between two parallel electrodes. With an electric field and a focused laser beam simultaneously applying on the microchip, the immunocomplexes in the droplet were further concentrated within the region of irradiation to enhance the fluorescent signal. The optoelectrokinetic platform, termed rapid electrokinetic patterning (REP), is excellent in dynamic and programmable particle manipulation. Therefore, the detection could be complete in roughly 10 s. With an appropriate frequency modulation, the two DR biomarkers were detected at a time. The limit of detection (LOD) of the REP-enabled measurement reached as low as 100 pg/mL. The combined use of bead-based immunoassays and the optoelectrokinetic platform therefore provides an insightful measure to the early diagnosis of diseases.

Invention Using a Liposome of a Bio-Micromachine

2005 ◽  
Author(s):  
Matsunori Nara
Keyword(s):  
Electrical Conductivity ◽  
Lipid Bilayer ◽  
Particle Diameter ◽  
Conductivity Measurement ◽  
The Body ◽  
Hydrogen Ion ◽  
Average Particle ◽  
Electrical Conductivity Measurement ◽  
Living Body ◽  
Method Of Production

It is thought that a minus hydrogen ion is useful to the apotosis of a mitochondria and prevention of a necrosis, or prevention of the illness resulting from the oxygen radical in a human body. So, in this research, examination about the possibility and its practical use method of production of the hydrogen ion by which it was minus electrified was performed. First, the lipid bilayer as a medicine transporter of DDS (Drug Delivery System) was produced using the supercritical fluid. Next, experimental examination was performed for the purpose of enclosing the substance for hydrogen ion generating, and the substance for electronic accumulation with the inside of a lipid bilayer. Furthermore, fundamental examination was performed in order to use the enclosed minus hydrogen ion. In order to check what the electron of oxygen ion was taken into the hydrogen ion, and the minus hydrogen ion generated, electrical conductivity measurement was performed. By mixing and heating, 12CaO · 7Al2O3 and metal calcium, the electron was accumulated in the inside of the reaction object of 12CaO7Al2O3. The check of accumulation of the electron (anion) inside a reaction object was judged by measurement of the electrical conductivity before and behind processing. That is, when the electron was accumulated, I thought that the electrical conductivity of a reaction object increased. Moreover, this reaction object was used as an electronic transporter. In the range of the temperature set up in the liposome production experiment, and pressure, it could not say that the influence temperature and pressure affect the determination of the particle diameter of a liposome was large, but average particle diameter was about 10 micrometers. The following conclusions were obtained as a result of conducting a fundamental experiment for the purpose of production of a medicine which made the minus hydrogen ion include inside a lipid bilayer (liposome), and a confirmation of the validity as DDS in the living body. (1) The liposome suitable for DDS was able to be obtained. (2) By using metal magnesium and metal calcium, the minus hydrogen ion was able to be accumulated in the reaction inside of the body of alumina cement.

Surface modification of PE/PET by two-step method with graphene and silver nanoparticles for enhanced electrical conductivity

2021 ◽  
pp. 152808372098589
Author(s):  
Tingting Zhuo ◽  
Zhuoming Chen ◽  
Binjie Xin ◽  
Yingqi Xu ◽  
Yingjie Song ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Electrical Conductivity ◽  
Silver Nanoparticles ◽  
Surface Modification ◽  
Wearable Electronics ◽  
Step Method ◽  
Excellent Thermal Stability ◽  
Nonwoven Fabrics ◽  
Dipping Process ◽  
Composite Fabrics

Polyethylene/polyethylene terephthalate (PE/PET) nonwoven fabrics were first modified with a continuous graphene layer by using a dipping process, and then deposited with silver nanoparticles (AgNPs) by using magnetron sputtering, and that is a novel method called two-step method. Graphene/PE/PET (GPP) and AgNPs sputtered GPP (AGPP) were prepared to investigate the modification processes on the electrical conductivity of the nonwoven fabrics. The influence of the surface modification by silane coupling agent (KH-560) on the durability of conductive PE/PET composited fabrics is also studied. Surface morphology, chemical structure, thermal stability, electrical conductive and ultraviolet protection properties of the composite fabrics were investigated. The results indicated KH-560 treatment can obviously improve the interfacial adhesion between the graphene and PE/PET then contributes to the enhanced conductive durability of the composite fabrics. The combination of graphene and AgNPs provided more opportunities for the charge transfer paths of AGPP, leading to an improved conductive network and an increased electrical conductivity. In addition, graphene and AgNPs gave GPP and AGPP excellent thermal stability. The research exhibited the advantages of the two-step method, and also indicated AGPP has a promising application for the preparation of wearable electronics.

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