Fluorescent nanomaterials for early TB diagnosis

Wednesday 20th April 2016

i-sense scientists in Professor Molly Stevens’ group at Imperial College London are developing a new nanoparticle-based assay that could diagnose Tuberculosis (TB), earlier than is currently possible.

When someone gets TB, certain genes are switched on to fight the infection and other genes are switched off. The combination of ‘on' and ‘off' genes makes up a 'genetic barcode' (transcriptional profiles) that can be detected in the blood of people with the disease. This could form the basis of a new diagnostic test for TB.

The Stevens Group recently published a study in the journal Nanoscale1, where they used fluorescent nanomaterials to provide excellent sensitivity, an important factor for successful detection of these molecular markers. The nanoparticles they used have extremely bright fluorescence, and the presence of each of the genetic markers changes the fluorescence according to the amount of target present. Therefore, the nanoparticle fluorescence can help us estimate the probability that a particular individual has TB.

Tuberculosis (TB) remains one of the world’s most significant public health challenges, killing over 1.5 million people every year. It now ranks alongside HIV as the leading cause of death worldwide due to infection.

Establishing if someone has TB is difficult as current diagnostic tests are outdated and insensitive. Furthermore, they cannot be relied upon to detect small amounts of Mycobacterium tuberculosis, the bacterium that causes TB. There is currently no point-of-care, TB test appropriate for use in resource-limited settings, therefore the disease is often diagnosed too late, severely decreasing the chances of successful treatment.

There still remain some key challenges to be overcome in the field of nanodiagnostics.  For example, predicting the behaviour of the nanoparticles in different conditions, like clinical samples, is important in order to make tests robust and reliable, and future  work of this project will focus on this area.

1 Gliddon, H.D., Howes, P.D., Kaforou, M., Levin, M., Stevens, M.M. 'A nucleic acid strand displacement system for the multiplexed detection of tuberculosis-specific mRNA using quantum dots' Nanoscale (2016); DOI: 10.1039/C6NR00484A