A new study led by UCL researchers in the i-sense McKendry group is revealing that nanodiamonds can be used to improve the sensitivity of paper-based diagnostic tests. This can potentially allow for earlier detection of diseases such as HIV and even COVID-19.
The researchers determined that low-cost nanodiamonds could be used to indicate the presence of an HIV disease marker with a sensitivity thousands of times greater than the gold nanoparticles most commonly used in these types of tests. But that's not all these diamonds could detect.
“Our proof-of-concept study shows how quantum technologies can be used to detect ultralow levels of virus in a patient sample, enabling much earlier diagnosis," said Lead author Professor Rachel McKendry, Professor of Biomedical Nanotechnology at UCL and Director of i-sense EPSRC IRC.
“We have focused on the detection of HIV, but our approach is very flexible and can be easily adapted to other diseases and biomarker types. We are working on adapting our approach to COVID-19. We believe that this transformative new technology will benefit patients and protect populations from infectious diseases.”
Only in the laboratory
For now, the nanodiamonds' many properties have only been demonstrated in a laboratory setting but the researchers are working on developing tests whose results could be read with a smartphone or a portable fluorescence reader. This means that in the future the test could be performed anywhere and at any time providing superior results without requiring many resources.
“Paper-based lateral flow tests with gold nanoparticles do not require laboratory analysis, making them particularly useful in low resource settings and where access to healthcare is limited," said first author Dr. Ben Miller, i-sense Postdoctoral Research Associate at the London Centre for Nanotechnology at UCL.
“However, these tests currently lack the sensitivity to detect very low levels of biomarkers. By replacing commonly used gold nanoparticles with fluorescent nanodiamonds in this new design, and selectively modulating their (already bright) emission of light, we have been able to separate their signal from the unwanted background fluorescence of the test strip, dramatically improving sensitivity.”