Scientists from the Spanish National Research Council (CSIC) have engineered a groundbreaking biosensor that can detect the presence of HIV just one week after the patient was infected. In addition to vastly improving upon the timetable of current detection systems, the test can actually provide same-day results.
The sensor, a silicon chip with gold nanoparticles, works by targeting an antigen called p24, a protein that's one of the components of HIV-1. The detection methods we use today are to either search for viral RNA or a buildup of antigens and antibodies, but these can't detect the HIV until about a month after infection. The CSIC sensor can spot antigens at concentrations 100,000 times lower than existing tests. Results take just four hours and 45 minutes. A study detailing the research was published Wednesday in the journal PLOS ONE.
"We expect [FDA] approval in four years, more or less," says Priscila Monteiro Kosaka, one of the study's authors. "Then it can be widely used, we hope to find, in hospitals and clinics, and also in labs as a technique to discover new biomarkers. But we want to do something that's not expensive and can be used in developing [regions], in Africa for example where we have a high incidence of HIV."
More than half the world's HIV-positive population lives in sub-Saharan Africa; in Swaziland, the nation with the highest prevalence rate, more than a quarter of people are infected. Early detection is crucial for raising survival rates of HIV patients, but there are often cost barriers that prevent developing nations from outfitting local clinics with the necessary equipment. This sensor could change that—the technology has been around for ages, and the materials are cheap, meaning that in a few years this could be reducing HIV mortality rates around the world.
The sensor is awaiting FDA approval, though it's already been patented by the CSIC, which has been developing the same technology to detect cancer for years. This was an almost unintentional extension of that research; in pursuing their principal objective of using the sensor to test relevant proteins identified by cancer researchers, the CSIC team needed to test human serums more revealing than the samples they already had.
"The cancer biomarkers we have in the clinic, they're not very specific to cancer detection," Monteiro Kosaka says. "They can indicate you have cancer but also maybe it's some other reason, so we needed to test our sensor on something else to see if it could have a clinical use, and we decided to use HIV."
All that was needed to repurpose the sensor was to apply a different chemical solution that would react with the new target antibodies. The sensor turned out to be extremely sensitive to the detection of p24 in combination with the antibodies for HIV. It's already received funding from the Spanish Cancer Association, so the next steps, aside from testing with more clinical samples, are to get FDA approval and the various other government permissions needed to begin implementing it on a global scale.