Ultra-sensitive sensor could allow doctors to see disease without a microscope

Researchers at Imperial College London have created an ultra-sensitive sensor that could allow doctors to see disease without a microscope. The sensor in so sensitive, in fact, that doctors could see diseases and viruses with the naked eye, according to a study detailed Monday in the journal Nature Nanotechnology.

The Imperial College researchers contend that their visual sensor technology is ten times more sensitive than the best available methods for measuring biomarkers. The visual sensor technology could detect the onset of diseases such as prostrate cancer and HIV.

Researchers hope that their ultra-sensitive sensor could be deployed in countries where sophisticated detection equipment is few and far between. The visual sensor technology would be a cheaper and simpler alternative for the detection of diseases and viruses.

The research team tested the efficacy of the extremely-sensitive sensor by identifying a biomarker named p24 in blood samples. Patients with this biomarker, researcher say, have HIV.

“It is vital that patients get periodically tested in order to assess the success of retroviral therapies and check for new cases of infection,” says Professor Molly Stevens, from the Departments of Materials and Bioengineering at Imperial College London. “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 research team also looked at blood samples for the biomarker named Prostate Specific Antigen (PSA), which is an early indicator for Prostate Cancer. The ultra-sensitive sensor can be reconfigured for other viruses and diseases as long as the specific biomarker is known to doctors.

The sensor examines serum, which comes from blood, in a disposable container. If the sensor detects p24 or PSA, a blue hue becomes visible in a solution inside the container. The blue hue is as a result of a reaction that creates irregular clumps of nanoparticles. However, if the sensor doesn’t detect p24 or PSA, nanoparticles are separated into ball-like shapes. This reaction creates a reddish hue.

The researchers found that their sensor was so sensitive that it was able to identify very small levels of p24 in samples where patients had low viral loads. Minute levels of p24 could not be diagnosed utilizing existing tests like the Enzyme-linked Immunosorbent Assay test and the nucleic acid based test.

“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,” says co-author Dr Roberto de la Rica of the Department of Materials at Imperial College London. “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 team hopes to market their product to not-for-profit global health organizations. These organizations, researchers believe, could provide funding for the manufacturing and distribution of the sensors as well as advice on how to get the most use out of them in low incomes countries.