LED controlled flow photolysis for concentration gradients in microfluidic systems

2010 ◽  
Vol 46 (19) ◽  
pp. 3342 ◽  
Author(s):  
Oscar G. Potter ◽  
Mark E. Thomas ◽  
Michael C. Breadmore ◽  
Emily F. Hilder
Keyword(s):  
Microfluidic Systems ◽  
Concentration Gradients ◽  
Controlled Flow

Expansion channels for low-pass filtering of axial concentration gradients in microfluidic systems

Lab on a Chip ◽  
2009 ◽  
Vol 9 (16) ◽  
pp. 2332 ◽  
Author(s):  
Daniel M. Hartmann ◽  
J. Tanner Nevill ◽  
David Wyrick ◽  
Gregory A. Votaw ◽  
Hugh C. Crenshaw
Keyword(s):  
Microfluidic Systems ◽  
Concentration Gradients ◽  
Low Pass ◽  
Axial Concentration

scholarly journals Light-induced manipulation of passive and active microparticles

2021 ◽  
Vol 44 (4) ◽  
Author(s):  
Pooja Arya ◽  
Maren Umlandt ◽  
Joachim Jelken ◽  
David Feldmann ◽  
Nino Lomadze ◽  
...  
Keyword(s):  
Steady State ◽  
Colloidal Particles ◽  
Solid Wall ◽  
Ionic Surfactants ◽  
Concentration Gradients ◽  
Profile Shape ◽  
Osmotic Flow ◽  
Flow Generation ◽  
Controlled Flow ◽  
Shape And Size

Abstract We consider sedimented at a solid wall particles that are immersed in water containing small additives of photosensitive ionic surfactants. It is shown that illumination with an appropriate wavelength, a beam intensity profile, shape and size could lead to a variety of dynamic, both unsteady and steady state, configurations of particles. These dynamic, well-controlled and switchable particle patterns at the wall are due to an emerging diffusio-osmotic flow that takes its origin in the adjacent to the wall electrostatic diffuse layer, where the concentration gradients of surfactant are induced by light. The conventional nonporous particles are passive and can move only with already generated flow. However, porous colloids actively participate themselves in the flow generation mechanism at the wall, which also sets their interactions that can be very long ranged. This light-induced diffusio-osmosis opens novel avenues to manipulate colloidal particles and assemble them to various patterns. We show in particular how to create and split optically the confined regions of particles of tunable size and shape, where well-controlled flow-induced forces on the colloids could result in their crystalline packing, formation of dilute lattices of well-separated particles, and other states. Graphic Abstract

Electrokinetically controlled concentration gradients in micro-chambers in microfluidic systems

2005 ◽  
Vol 2 (2) ◽  
pp. 141-153 ◽  
Author(s):  
Yandong Hu ◽  
Jacky S.H. Lee ◽  
Carsten Werner ◽  
Dongqing Li
Keyword(s):  
Microfluidic Systems ◽  
Concentration Gradients

On the structural organization of biological pumps and channels

1984 ◽  
Vol 42 ◽  
pp. 138-141
Author(s):  
G. Zampighi ◽  
M. Kreman
Keyword(s):  
Active Transport ◽  
Transport System ◽  
Plasma Membranes ◽  
Transport Proteins ◽  
Molecular Organization ◽  
Passive Transport ◽  
Concentration Gradients ◽  
Cell Functions ◽  
Natural Concentration ◽  
Active Transport System

The plasma membranes of most animal cells contain transport proteins which function to provide passageways for the transported species across essentially impermeable lipid bilayers. The channel is a passive transport system which allows the movement of ions and low molecular weight molecules along their concentration gradients. The pump is an active transport system and can translocate cations against their natural concentration gradients. The actions and interplay of these two kinds of transport proteins control crucial cell functions such as active transport, excitability and cell communication. In this paper, we will describe and compare several features of the molecular organization of pumps and channels. As an example of an active transport system, we will discuss the structure of the sodium and potassium ion-activated triphosphatase [(Na+ +K+)-ATPase] and as an example of a passive transport system, the communicating channel of gap junctions and lens junctions.

Automated Microdensitometry And Protein Assays As Measures For Platelet Adhesion And Aggregation On Collagen Coated Slides Under Controlled Flow Conditions

1979 ◽  
Author(s):  
R Muggli ◽  
H Baumgartner ◽  
Th Tschopp
Keyword(s):  
Surface Coverage ◽  
Platelet Surface ◽  
En Face ◽  
Uncoated Surface ◽  
Unit Surface ◽  
Perfusion Time ◽  
Flowing Blood ◽  
Controlled Flow ◽  
Protein Assays ◽  
Microscope Slides

Microscope slides were homogeneously coated over a length of 2 cm with a mixture of soluble and fibrillar collagen and exposed at 37°C and under laminar flow to citrated whole rabbit blood at a flow-rate of 100 ml/min. Surface coverage with platelets (adhesion) and platelet accumulations higher than about 5 μm in height (aggregation) were determined by automated microdensitometry of fuchsine stained ‘en face’ preparations. The platelet mass per unit surface was measured with a modified Lowry technique whose sensitivity was equivalent to 5×l05platelets. Platelet number, amount of protein and surface coverage with platelet accumulations correlated. After a perfusion time of 10 min thrombi up to 30 μm in height and oriented in the direction of flow had developed on the collagen coated area. Surface coverage with platelets was 75% and the amount of deposited protein 1.4 μg/mm2(2×l06platelets/mm2). On the uncoated surface single platelets predominated; the surface coverage was 20% and the density of platelets 8×104/mm2. Acetyl- salicylic acid at 100 μm decreased platelet aggregation by about 80% without affecting adhesion.The new parallel plate perfusion system offers rapid quantitation of platelet-surface and platelet-platelet interaction after exposure to flowing blood and iftay also be diagnostically useful.

Maxwell’s Equations versus Newton’s Third Law

2018 ◽  
Author(s):  
Glyn Kennell ◽  
Richard Evitts
Keyword(s):  
Electric Fields ◽  
Maxwell’S Equations ◽  
Maxwell's Equations ◽  
Simulated Data ◽  
Numerical Data ◽  
Transport Equations ◽  
Concentration Gradients ◽  
Third Law

The presented simulated data compares concentration gradients and electric fields with experimental and numerical data of others. This data is simulated for cases involving liquid junctions and electrolytic transport. The objective of presenting this data is to support a model and theory. This theory demonstrates the incompatibility between conventional electrostatics inherent in Maxwell's equations with conventional transport equations. <br>

A Fluidic Motherboard for Multiplexed Simultaneous and Modular Detection in Microfluidic Systems for Biological Application

2010 ◽  
Vol 2 (4) ◽  
pp. 227-238 ◽  
Author(s):  
Gerardo Perozziello ◽  
Giuseppina Simone ◽  
Patrizio Candeloro ◽  
Francesco Gentile ◽  
Natalia Malara ◽  
...  
Keyword(s):  
Biological Application ◽  
Microfluidic Systems

Cell Culture in Microfluidic Systems

2013 ◽  
Vol 5 (2) ◽  
pp. 82-96 ◽  
Author(s):  
Yung-Shin Sun ◽  
Ji-Yen Cheng
Keyword(s):  
Cell Culture ◽  
Microfluidic Systems
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