Features | Partner Sites | Information | LinkXpress
Sign In
Bio-Rad Diabetes Division
FOCUS DIAGNOSTICS, INC.
RANDOX LABORATORIES

Microfluidic Devices Created from Ordinary, Inexpensive Components

By Labmedica International staff writers
Posted on 16 Feb 2012
Image: NIST scientists combined a glass slide, plastic sheets, and double-sided tape to create an inexpensive and simple-to-build microfluidic device for exposing an array of cells to different concentrations of a chemical (Photo courtesy of  Cooksey/NIST).
Image: NIST scientists combined a glass slide, plastic sheets, and double-sided tape to create an inexpensive and simple-to-build microfluidic device for exposing an array of cells to different concentrations of a chemical (Photo courtesy of Cooksey/NIST).
A glass slide, plastic sheets, and double-sided tape were combined to create a diffusion-based gradient generator, a tool that rapidly assesses how changing concentrations of specific chemicals affect living cells.

Exposing an array of cultured cells to a chemical gradient provides a solution where the chemical concentration changes gradually and predictably across the array. Such gradients are a rapid, high-throughput way to evaluate the effect on cell growth or toxicity.

Created by National Institute of Standards and Technology (NIST; Gaithersburg, MD, USA) engineer Javier Atencia the gradient generator is built in layers, with each section precisely positioned with an alignment tab. The base is a glass slide, upon which is attached a strip of double-sided tape cut to have a row of four micrometer-sized channels. On top of this is placed a polystyrene strip cut to have two lines each of four tiny circular "wells" where each pair lines up with the ends of the channel below it. The next layer is another strip of double-sided tape, this time with a Y-shaped canal cut into it to serve as the flow path for the chemical gradient. Finally, a Mylar strip cut to have an identical Y-canal serves as the cover.

The hinged cover allows access to the wells for adding test cells. Once done, the cover is lowered and affixed, sealing the gradient generator. Fluid flow in and out of the system is accomplished using magnetic connectors. Under constant pressure, the flow assures a steady-state stream through the device and creates a diffusion gradient in each buried channel. Cells in the channels are simultaneously exposed to a range of chemical concentrations from high to low.

Conventional microfluidic systems usually mix fluids by pumping them in a circular motion or by twisting and folding them together. The new NIST system's gradient is created by diffusion––the gentle movement of matter from one point to another by random molecular motion. This greatly reduces the risk of cells being swept away or damaged by shearing forces in the test fluid.

The device was tested by loading it with cells genetically engineered to produce large amounts of green fluorescent protein (GFP) and then introduced cycloheximide (CHX), a chemical that shuts down ribosomes, the cell's protein factories. Cells exposed to the toxin quickly stop synthesizing GFP, decreasing fluorescence by an amount directly related to the concentration of CHX.

This is what the scientists observed in the gradient generator assays. The cells were exposed three times to CHX, and each time, the level of GFP fluorescence increased as the concentration of CHX in the gradient decreased, and vice versa.

The new device was described in the 2012 edition of the journal Lab-on-a-Chip.

Related Links:
National Institute of Standards and Technology


DIASYS DIAGNOSTIC SYSTEMS
ADVANCED INSTRUMENTS
KARL HECHT GMBH & CO KG
WATERS CORPORATION

Channels

Genetic Tests

view channel

Overexpression of X Chromosome Genes Is Biomarker for Female Mental Disorders

A recent paper suggested that elevated expression of the genes XIST (X-inactive specific transcript) and KDM5C (lysine-specific demethylase 5C) could be used as a biological marker for diagnosis of major affective disorders in a significantly large subset of female patients from the general population. Xist is an RNA... Read more

Immunology

view channel

Powerful Innovations in Diagnostics Unveiled at EuroMedLab 2015

New systems presented by Roche include a new standard for immunology testing, an integrated platform for hematology diagnostics, and a high-throughput analyzer to perform HbA1c tests for blood glucose management. Also, evidence was presented for a high-sensitivity cardiac troponin test to provide earlier and more accurate... Read more

Industry News

view channel

Cloud-Based Systems Becoming Key Pillar in eHealth Strategy

Cloud-based laboratory information management systems (LIMS) are becoming a key pillar in Europe’s e-Health strategy as data-management solutions for modern testing will generate more demand for these systems. Investments in cloud-based LIMS are part of Europe’s e-Health strategy. New analysis from Frost & Sullivan... Read more
 
Copyright © 2000-2015 Globetech Media. All rights reserved.