#nanocages

Nanocages in the lab and in the computer: How DNA-based dendrimers transport nanoparticles

How to create nanocages, i.e., robust and stable objects with regular voids and tunable properties? Short segments of DNA molecules are perfect candidates for the controllable design of novel complex structures. Physicists from the University of Vienna, the Technical University of Vienna, the Jülich Research Center in Germany and Cornell University in the U.S.A., investigated methodologies to synthesize DNA-based dendrimers in the lab and to predict their behavior using detailed computer simulations. Their results are published in the high-impact journal Nanoscale.

Nanocages are highly interesting molecular constructs, from the point of view of both fundamental science and possible applications. The cavities of these nanometer-sized objects can be employed as carriers of smaller molecules, which is of critical importance in medicine for drug or gene delivery in living organisms. This idea brought together researchers from various interdisciplinary fields who have been investigating dendrimers as promising candidates for creating such nano-carriers. Their tree-like architecture and step-wise growth with repeating self-similar units results in dendrimers containing cavities, hollow objects with controllable design. Nevertheless, decades of research have showed that vast number of different dendrimer types experience back-folding of outer branches with growing dendrimer generations, giving rise to a higher density of constituents in the molecule's interior. The effect of back-folding is enhanced upon addition of salt in the solution, whereby flexible dendrimers undergo significant shrinking, becoming compact objects with no hollow spaces in their interior.

Professor Sangmin Lee from POSTECH’s Department of Chemical Engineering, in collaboration with 2024 Nobel Chemistry Laureate Professor David Baker from the University of Washington, has developed an innovative therapeutic platform by mimicking the intricate structures of viruses using artificial intelligence (AI). Their pioneering research was published in Nature on December 18 (local…

Large Protein Nanocages Could Improve Drug Design and Delivery  

Using novel computational and biochemical approaches, scientists have accurately designed and built from scratch 10 large protein icosahedra -- polyhedra with 20 faces -- similar to viral capsids that carry viral DNA. The designed structures are made of two different engineered proteins, present in 60 copies each, which self-assemble into icosahedra. They have a wide variety of potential applications, from targeted drug delivery to the development of more effective vaccines, the researchers say.  

The findings, reported on July 22, 2016 in Science, follow a report in Nature last month by the same team describing the creation of the first designed icosahedron made of 60 copies of a single protein subunit. The current paper describes the design and construction of 10 icosahedra from two different protein subunits.

“The remarkable thing is that the computational design model is really close to the actual structure,” said HHMI Investigator David Baker of the University of Washington Institute for Protein Design, who led the study. “These are definitely the largest structures that have been created using computational design methods … so it’s a real milestone for protein design, because we can design these really complicated structures from scratch on the computer and they come out exactly right.”