Catching HIV with a ‘net’

Currently, the gold standard of testing for HIV — the virus that causes AIDS — is based on genomic detection through polymerase chain reaction (PCR) amplification. This type of testing can be expensive and time-consuming, limiting the accessibility of such a diagnostic.

Building on their successful experiments capturing COVID-19 viruses in 2021, Tibbs et al. showed how to catch HIV-like viruses in a designer DNA net.

A DNA net is made of DNA with extruding aptamers — short, single-stranded fragments which have an affinity for a target molecule.

“If you space the aptamers out in the same arrangement as the proteins on the outside of the virus, then the virus attaches to multiple aptamers at once in a multi-valent binding — something much more stable than the single interaction of an aptamer with a virus,” Tibbs said.

Using that same methodology, the researchers designed aptamers that bind to proteins on the surface of virions — inert HIV compounds. Then, they were able to identify the virions using a type of scattering technique called Photonic Resonator Interferometric Scattering Microscopy. They achieved a sensitivity of 10⁴ virions per milliliter, a number close to the current standard for genomic testing.

In this case, however, the researchers were testing virions in a buffer, not capturing HIV in a blood sample. Real life testing requires an additional step of filtering out the virus, which Tibbs said others in his lab are currently working on.

“This technology is not ready to rival PCR, but we do have collaborators who have an interesting filtration method,” Tibbs said.

Source: “Selective capture and digital counting of intact HIV pseudovirus using designer DNA nets, tethered motion, and photonic resonator interferometric scattering microscopy,” by Joseph Tibbs, Saurabh Umrao, Tingjie Song, Varada Anirudhan, Skye Shepherd, Katy Wolhaupter, Mengxi Zheng, Sydney Wiggins, Lijun Rong, Colin L. Hisey, Utkan Demirci, Xing Wang, and Brian T. Cunningham, APL Bioengineering (2026). The article can be accessed at https://doi.org/10.1063/5.0289982 .