Scientists have developed a new fluorescent probe that can be used to quickly detect tuberculosis bacteria from a sputum sample — using just a homemade LED box and a camera phone. Nature News reports.
In 2010, TB killed nearly 4,000 people a day, mostly in remote places around the world. Treatments are available, but diagnosis can take several weeks – during this time, patients can transmit the infection. (If a person with active TB goes untreated, that individual will infect up to 15 people a year, on average.)
The most common test for active TB is called the ‘sputum smear microscopy.’ That’s when your coughed-up saliva and mucus are examined under a microscope for the presence of TB bacteria (pictured). But this requires a lot of trained staff, and it can’t diagnose TB in children.
And, compared to chest X-rays or blood tests, this fluorescent molecule is a much cheaper and quicker diagnostic test, one that can be used in places that lack clinical infrastructure.
To create an efficient detection method, Stanford’s Jianghong Rao and colleagues developed a simple fluorescent molecule.
- In nature, a TB protein known as BlaC breaks down a particular class of chemicals called β-lactams. Here, the researchers designed their molecule to resemble a β-lactam so that it’s cut in half by BlaC.
- This probe is normally colorless, but when it’s cut by BlaC from TB bacteria, it releases a blue fluorescent product.
- And that’s detected using a homemade box containing a light-emitting diode and a couple of filters.
- The faint light that’s emitted can be captured by a camera phone, making it easy to share with clinicians. No microscope, no lab.
A prototype test is currently being developed by Global BioDiagnostics in Texas, with the product expected to be available by 2015.
The work was published in Nature Chemistry this week.
[Via Nature News]
Image: Mycobacterium tuberculosis / CDC via Wikimedia