New DNA-based technique for assembly of nano- and micro-sized...( UPTON NY Scientists at the U.S. Dep...)

UPTON, NY Scientists at the U.S. Department of Energys Brookhaven National Laboratory have developed a new method for controlling the self-assembly of nanometer and micrometer-sized particles. The method, based on designed DNA shells that coat a particles 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
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