Viral infections kill millions of people worldwide every year, but currently available antiviral drugs are limited in that they mostly act against one or a small handful of related viruses. A few broad-spectrum drugs that prevent viral entry into healthy cells exist, but they usually need to be taken continuously to prevent infection, and resistance through viral mutation is a serious risk.

Now, an international group of researchers, have designed new anti-viral nanoparticles that bind to a range of viruses, including herpes simplex virus, human papillomavirus, respiratory syncytial virus and Dengue and Lentiviruses. Unlike other broad-spectrum antivirals, which simply prevent viruses from infecting cells, the new nanoparticles destroy viruses.

The team's findings are reported in the journal Nature Materials.

The new nanoparticles mimic a cell surface protein called heparin sulfate proteoglycan (HSPG). A significant portion of viruses, including HIV, enter and infect healthy cells by first binding to HSPGs on the cell surface. Existing drugs that mimic HSPG bind to the virus and prevent it from binding to cells, but the strength of the bond is relatively weak. These drugs also can't destroy viruses, and the viruses can become reactivated when the drug concentration is decreased.

The researchers used advanced computational modeling techniques to generate precise structures of various target viruses and nanoparticles down to the location of each atom. A deep understanding of the interactions between individual groups of atoms within the viruses and nanoparticles allowed the researchers to estimate the strength and permanence of potential bonds that could form between the two entities, and helped them to predict how the bond could change over time and eventually destroy the virus.

The team's final "draft" of the anti-viral nanoparticle could bind irreversibly to a range of viruses, and caused lethal deformations to the viruses, but had no effect on healthy tissues or cells. In vitro experiments with the nanoparticles showed that they bound irreversibly to the herpes simplex virus, human papillomavirus, syncytial virus, Dengue virus and Lentivirus.