Designer gold nanoparticles could combat deadly viruses

Scientists have created designer gold anti-viral nanoparticles that can bind to a range of viruses - such as dengue and herpes - and prevent them from infecting cells.
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.
Researchers from University of Illinois at Chicago in the US 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.
Once injected in the body, these nanoparticles imitate human cells and "trick" the viruses.

When the viruses bind to them - in order to infect them - the nanoparticles use pressure produced locally by this link- up to "break" the viruses, rendering them innocuous.
Unlike other broad-spectrum antivirals, which simply prevent viruses from infecting cells, the new nanoparticles destroy viruses.

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 not destroy viruses, and the viruses can become reactivated when the drug concentration is decreased.
Researchers sought to design a new anti-viral nanoparticle based on HSPG, but one that would bind more tightly to viral particles and destroy them at the same time.
"We knew the general composition of the HSPG-binding viral domains the nanoparticles should bind to, and the structures of the nanoparticles, but we did not understand why different nanoparticles behave so differently in terms of both binding strength and preventing viral entry into cells," said Petr Kral, from UIC.
Through elaborate simulations, researchers helped solve these issues and guided the experimentalists in tweaking the nanoparticle design so that they worked better.

The researchers used advanced computational modeling techniques to generate precise structures of various target viruses and nanoparticles down to the location of each atom.
The team's 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.
"We were able to provide the data needed to the design team so that they could develop a prototype of what we hope will be a very effective and safe broad-spectrum anti-viral that can be used to save lives," said Kral.