The World’s Fastest HIV Test?

The digital age has spawned tremendous innovation in all markets, so it was just a matter of time before it benefited HIV testing — and it has, in a big way. Researchers from the Spanish National Research Council (Consejo Superior de Investigaciones Científicas or CSIC) have developed a biosensor that can detect HIV in someone’s blood as soon as 7 days after they seroconvert. It also produces results within five hours of testing. With this kind of early detection, people who are newly diagnosed could get treatment much sooner, thus limiting the disease’s progression. 

Most HIV tests aren’t able to find the virus in blood until a few weeks after it has entered the body, but the new chip from CSIC uses gold nanoparticles to target an antigen on virus particles called p24 (rather than targeting the virus itself). There are over 2,000 copies of the p24 protein on the HIV virus, but researchers had to find the correct method to detect them.

“We were looking for ultrasensitive methods for biological detection,” lead CSIC researcher Javier Tamayo tells Plus. “In this journey, we had many ideas — many failed, others were not robust enough. This technology leaves ‘the label-free’ fashion, and uses a sandwich immunoassay. Two antibodies enhance selectivity. The label, the gold nanoparticle is [both a]mass and optical label at the same time. So it was like one plus one equals two.”

Silicon micromechanical structures and gold nanoparticles were chemically modified with specific antibodies that bind to p24. The chip traps the p24 protein between the modified silicone and gold structures. The combination of these structures creates a signal that amplifies each other, leading to easier detection. 

The chip may also be used for early detection of some cancers, but, according to Tamayo, that’s a bit trickier. 

“We need to discover cancer biomarkers that predict the beginning of the disease,” he explains. “Once discovered, our technology is able to detect traces in our blood. So we are collaborating with oncologists to start clinical assays of some biomarkers, [but it’s] still not approved.” 

The new biosensor is able to detect p24 at very low concentrations (up to a hundred thousand lower concentrations than other tests). That enables earlier diagnoses and treatment, which can have dramatic long-term impacts on health outcomes. Tamayo and his team also hope the new technology will be distributed in developing countries. 

“If we manage to reduce costs of the assays, and the technology works in non ideal conditions, the hope is [to speed up diagnoses] in developing countries, where many lives can be saved since antiretroviral therapy is given at the beginning of infection,” Tamayo says. “This is particularly important for infants from mothers with AIDS.” 

Currently, the technology is licensed to a spin-off company to develop and seek Food and Drug Administration approval, which Tamayo and his team hope to have within 
five years.