Virus traps: New technology for fighting viruses
There is no effective drug against most viral infections. A German research team is therefore taking other approaches to render the pathogens harmless. Special hollow bodies made of DNA material are supposed to catch the viruses like in a cage.
Researchers from the Technical University of Munich (TUM), the Helmholtz Zentrum München and the Brandeis University (USA) present a completely new strategy for combating viruses. With the help of tailor-made nano-capsules made from genetic material, viruses are to be captured and rendered harmless. The method has already been successfully tested on hepatitis and adeno-associated viruses. According to the working group, the method could also be used against corona viruses. The research results can be read in the renowned journal “Nature Materials”.
Not an all-purpose weapon against viruses
Dangerous bacteria can usually be treated well with antibiotics – apart from the increasing resistance. There is no such thing as an all-purpose weapon with viruses. Vaccinations can protect against some viral infections. The research, production and testing of such vaccinations remains expensive and time-consuming.
Origami made of DNA
The research team therefore investigated a completely new principle for combating viruses. The researchers have developed nanostructures from DNA that can capture viruses and render them harmless. To do this, the working group used a technique known as DNA origami.
Research from 1962 as the basis
The foundations for the implementation go back to 1962. The biologist Donald Caspar and the biophysicist Aaron Klug discovered the geometrical principles according to which the protein envelopes of viruses are built. Based on these specifications, the researchers designed an artificial hollow body the size of a virus as part of the current study.
Development of the first virus trap
In the summer of 2019, the research team came up with the idea of lining these hollow bodies with binding sites for viruses. According to the principle, the viruses should bind to the hollow body and thus be withdrawn from circulation. For this, however, the hollow bodies would have to have sufficiently large openings so that the virus can get inside the hollow body.
“None of the objects that we had built using DNA origami technology to date would have been able to safely contain an entire virus – they were simply too small,” says Hendrik Dietz from the study team in retrospect. Building stable hollow bodies of this size presented the working group with a great challenge.
Finally, the team decided to build a hollow body from triangular surfaces based on the principle of the icosahedron. The individual triangular sides consist of genetic material. The special feature is that the bevelled sides of the individual triangular surfaces have been designed with special binding points so that the construct can be put together in the desired shape by itself. The cavity in the middle is big enough to hold viruses in it.
“In this way, we can now program the shape and size of the desired objects using the exact shape of the triangular plates,” emphasizes Dietz. The team can now create nano-objects with up to 180 subunits.
Nano construction kit
By varying the binding points at the edges of the triangles, not only closed hollow spheres can be created, but also open spheres or half-shells. These forms are suitable as virus traps.
The inside of these forms is lined with special virus-binding molecules that are aimed at specific viruses. The viruses recognize these binding sites, dock on the virus trap and are henceforth trapped.
First tests of the virus trap
In cooperation with researchers led by Professor Ulrike Protzer, Head of the Institute of Virology at TUM and Director of the Institute of Virology at the Helmholtz Center in Munich, the study team tested the virus traps on adeno-associated viruses and on nuclei of the hepatitis B virus.
Virus trap successfully blocked viruses
“Even a simple half-shell of the right size shows a measurable reduction in virus activity,” says Dietz. With five binding sites on the inside of the virus traps, 80 percent of the viruses were blocked in the tests. An increase in the binding sites even creates a complete blockage.
The researchers expect the nano-particles to remain stable for around 24 hours. The next step is to test the virus traps on living mice. “We are very confident that this material will also be well tolerated by the human body,” assures Dietz.
Why viruses are harder to fight than bacteria
“Bacteria have a metabolism,” adds Professor Protzer. It offers attack surfaces in different ways. Viruses wouldn’t have that. Antiviral drugs would therefore be directed almost exclusively against a specific enzyme from a single virus. The development of such drugs is therefore very time-consuming.
Eliminate viruses mechanically
“If the idea of simply mechanically eliminating viruses can be realized, it would be broadly applicable and thus an important breakthrough, especially for newly emerging viruses,” explains Protzer the benefits of the technology.
Biological mass production of virus traps
The starting materials for the virus traps could be mass-produced biotechnologically at a reasonable cost. “In addition to the proposed application as a virus trap, our programmable system also offers other options,” summarizes Dietz. It would be conceivable, for example, to use the body as a means of transport for vaccines or active substances. (vb)
Author and source information
This text complies with the requirements of specialist medical literature, medical guidelines and current studies and has been checked by medical professionals.
Diploma-Editor (FH) Volker Blasek
- Technical University of Munich (TUM): Hollow bodies made of DNA material could capture viruses and render them harmless (published: July 15, 2021), tum.de
- Christian Sigl, Elena M. Willner, Wouter Engelen, Hendrik Dietz, et al.: Programmable icosahedral shell system for virus trapping; in: Nature Materials, 2021., nature.com
This article is for general guidance only and is not intended to be used for self-diagnosis or self-treatment. He can not substitute a visit at the doctor.