Naked Eye Test for Early Detection

Scientists have developed a prototype ultra-sensitive sensor that can enable doctors to detect the earliest stages of diseases and viruses with their naked eyes, according to research published on Oct. 28 in the journal Nature Nanotechnology.

The research team, from Imperial College London, report that their visual sensor technology has 10 times the sensitivity than the current gold standard methods for measuring biomarkers. These can forewarn the onset of diseases like prostate cancer and infection by viruses like HIV.

The sensor could ostensibly benefit countries where sophisticated detection equipment is scarce and paves the way way for cheaper and simpler detection and treatments for patients.

To perform the study, the team tested the effectiveness of the sensor by detecting a biomarker called p24 in blood samples, which indicates HIV infection.

Professor Molly Stevens, from the Departments of Materials and Bioengineering at Imperial College London, says:

"It is vital that patients get periodically tested in order to assess the success of retroviral therapies and check for new cases of infection. Unfortunately, the existing gold standard detection methods can be too expensive to be implemented in parts of the world where resources are scarce. Our approach affords for improved sensitivity, does not require sophisticated instrumentation and it is ten times cheaper, which could allow more tests to be performed for better screening of many diseases."

The researchers in the study also tested samples for the biomarker called Prostate Specific Antigen (PSA), which is an early indicator for Prostate Cancer. The team says the sensor can also be reconfigured and customized for other viruses and diseases where the specific biomarker is known.

The sensor works by analyzing blood derived serum in a disposable container. If the result is positive for p24 or PSA, there's a reaction that generates irregular clumps of nanoparticles. These clumps give off a distinctive blue hue in a solution inside the container. If the results are negative the nanoparticles separate into spherical shapes and create a reddish hue. Both reactions can easily be recognized with the naked eye.

The team also reports that the sensor was so sensitive that it could detect minute levels of p24 in samples where patients had low viral loads, which couldn't be diagnosed using existing tests like the Enzyme-linked Immunosorbent Assay (ELISA) test and the gold standard nucleic acid based test.

Dr Roberto de la Rica, co-author of the study from the Department of Materials at Imperial College London, adds:

"We have developed a test that we hope will enable previously undetectable HIV infections and indicators of cancer to be picked up, which would mean people could be treated sooner. We also believe that this test could be significantly cheaper to administer, which could pave the way for more widespread use of HIV testing in poorer parts of the world."

The next stage of the research will involve the team approaching non-profit global health organizations, which could provide strategic direction and funding for manufacturing and distributing the sensor to low income countries.

See and download the research paper here.