Better diagnosis of parasitic infections: rapid, simple enrichment of rare cells by using ultrasound
Parasitic infections like malaria and sleeping sickness affect hundreds of millions of people, primarily in the poorest regions of the world. Diagnosis of these diseases is often difficult because the concentration of parasites in the blood can be very low.
British scientists have now developed a simple chip-based method for enriching rare cells in blood samples. As they report in the journal Angewandte Chemie, this allows the detection limit for the parasites that cause malaria and sleeping sickness to be lowered by two to three orders of magnitude.
Existing techniques for the separation and enrichment of parasites in blood samples are difficult to use in isolated regions and developing countries because they usually require complex chemistry for labeling cells, costly instruments, or extensive infrastructure. An inexpensive technique that requires only small amounts of power, works without labeling the cells, and uses just a drop of blood from a fingertip, is needed.
A team headed by Jonathan M. Cooper at the University of Glasgow has now developed such an approach. Their innovative method is based on an acoustically controlled microchip that is used in a battery-driven, hand-held device. The researchers successfully used their technique to enrich malaria-infected blood cells and the parasite that causes sleeping sickness in blood samples.
The chip contains a special electrode that produces ultrasound when a voltage is applied. If a drop of liquid is placed in a specific location on the device, the form of the acoustic field elicits a particular pattern of flow within the drop: a circular rotational motion.
Particles whose density is lower than that of the liquid are carried against gravity with the upward rising current and transported toward the outer edge of the drop, where they accumulate. In contrast, particles with a higher density collect in the center of the droplet, because they cannot be lifted up.
This works for cells too. Red blood cells infected with the malaria parasite are less dense than non-infected cells. If the density of the drop of blood being examined is adjusted by simply adding a small amount of reagent, the acoustic chip allows the infected red blood cells to be concentrated by a factor of one hundred to one thousand at the outer edge of the blood drop.
The non-infected red blood cells remain at the center of the drop. The method is also suitable for concentrating free-swimming parasites in blood. The researchers were able to enrich trypanosomes, the pathogens that cause sleeping sickness, by using their acoustic chip. Simple staining techniques then make it possible to detect the parasites.
In the future, the technique may be adapted to allow other infectious diseases and rare circulating tumor cells to be detected more readily use of this new technology.
About the Author
Professor Jon Cooper is a Fellow of the Royal Academy of Engineering and holds the Wolfson Chair in Bioengineering at the University of Glasgow. His academic interests include the use of micro- and nanotechnologies for the development of medical diagnostics.
Author: Jonathan M. Cooper, University of Glasgow (UK), http://www.gla.ac.uk/schools/engineering/staff/jonathancooper/
Title: Rare-Cell Enrichment by a Rapid, Label-Free, Ultrasonic Isopycnic Technique for Medical Diagnostics
Angewandte Chemie International Edition, Permalink to the article: http://dx.doi.org/10.1002/anie.201310401
Jonathan M. Cooper | Angewandte Chemie International Edition
The dense vessel network regulates formation of thrombocytes in the bone marrow
25.07.2017 | Rudolf-Virchow-Zentrum für Experimentelle Biomedizin der Universität Würzburg
Fungi that evolved to eat wood offer new biomass conversion tool
25.07.2017 | University of Massachusetts at Amherst
Strong light-matter coupling in these semiconducting tubes may hold the key to electrically pumped lasers
Light-matter quasi-particles can be generated electrically in semiconducting carbon nanotubes. Material scientists and physicists from Heidelberg University...
Fraunhofer IPA has developed a proximity sensor made from silicone and carbon nanotubes (CNT) which detects objects and determines their position. The materials and printing process used mean that the sensor is extremely flexible, economical and can be used for large surfaces. Industry and research partners can use and further develop this innovation straight away.
At first glance, the proximity sensor appears to be nothing special: a thin, elastic layer of silicone onto which black square surfaces are printed, but these...
3-D shape acquisition using water displacement as the shape sensor for the reconstruction of complex objects
A global team of computer scientists and engineers have developed an innovative technique that more completely reconstructs challenging 3D objects. An ancient...
Physicists have developed a new technique that uses electrical voltages to control the electron spin on a chip. The newly-developed method provides protection from spin decay, meaning that the contained information can be maintained and transmitted over comparatively large distances, as has been demonstrated by a team from the University of Basel’s Department of Physics and the Swiss Nanoscience Institute. The results have been published in Physical Review X.
For several years, researchers have been trying to use the spin of an electron to store and transmit information. The spin of each electron is always coupled...
What is the mass of a proton? Scientists from Germany and Japan successfully did an important step towards the most exact knowledge of this fundamental constant. By means of precision measurements on a single proton, they could improve the precision by a factor of three and also correct the existing value.
To determine the mass of a single proton still more accurate – a group of physicists led by Klaus Blaum and Sven Sturm of the Max Planck Institute for Nuclear...
21.07.2017 | Event News
19.07.2017 | Event News
12.07.2017 | Event News
25.07.2017 | Physics and Astronomy
25.07.2017 | Earth Sciences
25.07.2017 | Life Sciences