The method, based on designed DNA shells that coat a particle’s surface, can be used to manipulate the structure – and therefore the properties and potential uses – of numerous materials that may be of interest to industry. For example, such fine-tuning of materials at the molecular level promises applications in efficient energy conversion, cell-targeted systems for drug delivery, and bio-molecular sensing for environmental monitoring and medical applications.
The novel method, for which a patent application has been filed, was developed by Brookhaven researchers Mathew M. Maye, Dmytro Nykypanchuk, Daniel van der Lelie, and Oleg Gang and is described in the September 12 online edition of Small, a leading journal on nanoscience and nanotechnology.
“Our method is unique because we attached two types of DNA with different functions to particles’ surfaces,” said Gang, who leads the research team. “The first type – complementary single strands of DNA – forms a double helix. The second type is non-complementary, neutral DNA, which provides a repulsive force. In contrast to previous studies in which only complementary DNA strands are attached to the particles, the addition of the repulsive force allows for regulating the size of particle clusters and the speed of their self-assembly with more precision.”
“When two non-complementary DNA strands are brought together in a fixed volume that is typically occupied by one DNA strand, they compete for space,” said Maye. “Thus, the DNA acts as a molecular spring, and this results in the repulsive force among particles, which we can regulate. This force allows us to more easily manipulate particles into different formations.”
The researchers performed the experiments on gold nanoparticles – measuring billionths of a meter – and polystyrene (a type of plastic) microparticles – measuring millionths of a meter. These particles served as models for the possibility of using the technique with other small particles. The scientists synthesized DNA to chemically react with the particles. They controlled the assembly process by keeping the total amount of DNA constant, while varying the relative fraction of complementary and non-complementary DNA. This technique allowed for regulating assembly over a very broad range, from forming clusters consisting of millions of particles to almost keeping individual particles separate in a non-aggregating form.
“It is like adjusting molecular springs,” said Nykypanchuk. “If there are too many springs, particles will ‘bounce’ from each other, and if there are too few springs, particles will likely stick to each other.”
The method was tested separately on the nano- and micro-sized particles, and was equally successful in providing greater control than using only complementary DNA in assembling both types of particles into large or small groupings.
To determine the structure of the assembled particles and to learn how to modify them for particular uses, the researchers used transmission electron microscopy to visualize the clusters, as well as x-ray scattering at the National Synchrotron Light Source to study particles in solution, the DNA’s natural environment.
Diane Greenberg | EurekAlert!
Cryo-electron microscopy achieves unprecedented resolution using new computational methods
24.03.2017 | DOE/Lawrence Berkeley National Laboratory
How cheetahs stay fit and healthy
24.03.2017 | Forschungsverbund Berlin e.V.
Astronomers from Bonn and Tautenburg in Thuringia (Germany) used the 100-m radio telescope at Effelsberg to observe several galaxy clusters. At the edges of these large accumulations of dark matter, stellar systems (galaxies), hot gas, and charged particles, they found magnetic fields that are exceptionally ordered over distances of many million light years. This makes them the most extended magnetic fields in the universe known so far.
The results will be published on March 22 in the journal „Astronomy & Astrophysics“.
Galaxy clusters are the largest gravitationally bound structures in the universe. With a typical extent of about 10 million light years, i.e. 100 times the...
Researchers at the Goethe University Frankfurt, together with partners from the University of Tübingen in Germany and Queen Mary University as well as Francis Crick Institute from London (UK) have developed a novel technology to decipher the secret ubiquitin code.
Ubiquitin is a small protein that can be linked to other cellular proteins, thereby controlling and modulating their functions. The attachment occurs in many...
In the eternal search for next generation high-efficiency solar cells and LEDs, scientists at Los Alamos National Laboratory and their partners are creating...
Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are less stable. Now researchers at the Technical University of Munich (TUM) have, for the first time ever, produced a composite material combining silicon nanosheets and a polymer that is both UV-resistant and easy to process. This brings the scientists a significant step closer to industrial applications like flexible displays and photosensors.
Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are...
Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to simulate these confined natural conditions in artificial vesicles for the first time. As reported in the academic journal Small, the results are offering better insight into the development of nanoreactors and artificial organelles.
Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to...
20.03.2017 | Event News
14.03.2017 | Event News
07.03.2017 | Event News
24.03.2017 | Materials Sciences
24.03.2017 | Physics and Astronomy
24.03.2017 | Physics and Astronomy