New cheaper, sensitive Ebola test to help curb disease spread

A new Ebola test that uses magnetic nanoparticles is 100 times more sensitive than the current test and could help curb the spread of the disease in western Africa.
Researchers from the Chinese Academy of Sciences said their new technology could be applied to the detection of any biological molecules, making it useful to diagnose other infectious diseases, like flu, and potentially detect tumours and even contamination in wastewater.
The current outbreak of Ebola, which started in March last year, has affected countries in west Africa. There is no vaccine for Ebola, so detecting the virus is key to controlling the outbreak: with an accurate diagnosis, patients can be isolated and treated properly, reducing risk of spread.

"Our new strip test is a simple, one-step test that is cheap and easy to use, and provides a visible signal, which means people don't need training to use it," said Professor Xiyun Yan, one of the authors of the study from the Chinese Academy of Sciences.
"We think it will be especially helpful in rural areas, where technical equipment and skills are not available," Yan said.
Currently there are two ways to test for the Ebola virus: using a method called polymerase chain reaction (PCR), which makes copies of the molecules for detection, and with antibody-capture enzyme-linked immunosorbent assay (ELISA) or gold strip test, which gives a visual indication when a given molecule is in a sample.

The new test, called the nanozyme test, uses magnetic nanoparticles, which work like enzymes to make the signal stronger, giving a clearer result one can see with naked eye.

The test can detect much smaller amounts of the virus, and is 100 times more sensitive than the gold strip test.
Strip tests work by attaching molecules called antibodies to gold particles to look for a particular molecule in a sample. When they attach to the molecule you're looking for, in this case a virus, they produce a signal, such as a colour change.
In order to find the virus, the particles need to be labelled with enzymes, which speed up detection and signalling.

With the new nanozyme test, the researchers applied magnetic nanoparticles as a nanozyme probe in place of gold nanoparticles.
After labeling with an antibody that attaches to the Ebola virus, this novel probe is able to recognise and separate the virus in a sample.
The nanoparticles are magnetic, so to concentrate the virus particles in a sample, all you need to do is hold the sample against a magnet; no expensive equipment is needed.
The nanozyme test can detect molecules called glycoproteins on the surface of the Ebola virus at concentrations as low as 1 nanogram per milliliter.
The researchers have applied for a patent for the new test, which is currently being taken to west Africa to use in the field.