Gene-editing tool CRISPR could be used to spot deadly viruses in under an hour from a single drop of blood, scientists claim.
Experts programmed the controversial technology to find human papillomavirus (HPV), known to cause several types of cancer.
Laboratory tests of the tool proved it could also spot parvovirus, which can lead to miscarriages in pregnant women.
The re-programmed CRISPR technology works by scouring blood for a specific acid carried by the virus it’s trained to look for.
If it detects the acid, the tool – famed for its ability to cut-and-paste parts of individual DNA strands – cuts part of the DNA, signalling the presence of the virus.
CRISPR is a DNA-editing technique in which scientists can programme a molecule to target and ‘snip’ a specific section or element of someone’s genetical material (illustrated in stock image – not to scale)
Yifan Dai, a PhD candidate in the chemistry department and lead author on a paper, said: ‘No virus – no cutting, it’s that simple.’
CRISPR has been both praised and bashed since it was invented in 2012.
Some scientists believe CRISPR could one day help cure patients of cancer or HIV, allowing doctors to fix faulty DNA.
While others have raised concerns that medics could cross an ethical line by using the tool to create ‘designer babies’ in the womb.
CRISPR is a technology in which tiny molecules can be trained to cut strands of DNA in order to remove or replace them.
In the researchers’ test they programmed CRISPR molecules to react to certain types of nucleic acids, which are essentially DNA strands.
Genetic material from different organisms will have different chemical compositions with elements which can be spotted to identify them.
When a person is infected with a virus, their cells will contain parts of that virus’s DNA which would not normally be found in the human cells.
This means tests can spot the chemical differences and detect the virus in the body.
In the Cleveland researchers’ test the CRISPR molecule was spurred into action when it encountered the virus it was looking for, which caused a surge in electrical activity in the tissue sample – a signal for the scientists.
Some types of virus may also insert parts of their own genes into the human cells’ DNA to enable them to use the body to reproduce and keep spreading.
Researchers at Case Western Reserve University trained a molecule to cut DNA only when it detected a specific part of the virus they were trying to detect.
When viruses infect humans they can embed parts of their own genetic material into our DNA, or their DNA can simply be detected in the cells they’re living in.
So when the CRISPR molecule came into contact with an infected drop of blood, the viral genetics triggered a reaction.
This led to a measurable spike in electrical activity in the blood, which is why the researchers call the technology an ‘electrochemical biosensor’.
The researchers in Cleveland, Ohio, said their invention could replace current viral testing which can take days to complete.
Quick and easy tests to spot viruses could improve people’s health by getting them quicker treatment and potentially reducing the need for overnight hospital stays.
One of the viruses used in the team’s tests – parvovirus – can cause anaemia or even miscarriage and stillbirth if it infects pregnant women.
And HPV, which is extremely common but cannot be cured, has been linked to an increased risk of cancers of the skin, genitals, anus and mouth and throat.
CRISPR has triggered criticism since it was invented in 2012 because it has potential to be used to edit unborn babies’ genes.
There have been claims it could be a miracle cure for deadly genetic disorders such as cystic fibrosis, sickle cell disease and haemophilia.
But its ability to alter any piece of DNA in a cut-and-paste manner has raised ethical concerns over ‘designer babies’ whose genes are manipulated for them to look exactly as their parents want them to.
The Cleveland researchers’ work was published in the prestigious German chemistry journal Angewandte Chemie.
The CRISPR gene editing technique is being used an increasing amount in health research because it can change the building blocks of the body.
At a basic level, CRISPR works as a DNA cutting-and-pasting operation.
Technically called CRISPR-Cas9, the process involves sending new strands of DNA and enzymes into organisms to edit their genes.
In humans, genes act as blueprints for many processes and characteristics in the body – they dictate everything from the colour of your eyes and hair to whether or not you have cancer.
The components of CRISPR-Cas9 – the DNA sequence and the enzymes needed to implant it – are often sent into the body on the back of a harmless virus so scientists can control where they go.
Cas9 enzymes can then cut strands of DNA, effectively turning off a gene, or remove sections of DNA to be replaced with the CRISPRs, which are new sections sent in to change the gene and have an effect they have been pre-programmed to produce.
But the process is controversial because it could be used to change babies in the womb – initially to treat diseases – but could lead to a rise in ‘designer babies’ as doctors offer ways to change embryos’ DNA.
Source: Broad Institute
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