Björn Högberg

DNA-scaffolded nanoparticle structures

DNA self-assembly is a powerful route to the production of very small, complex structures. When used in combination with nanoparticles it is likely to become a key technology in the production of nanoelectronics in the future. Previously, demonstrated nanoparticle assemblies have mainly been periodic and highly symmetric arrays, unsuited as building blocks for any complex circuits. With the invention of DNA-scaffolded origami reported earlier this year (Rothemund P W K 2006 Nature 440 (7082) 297–302), a new route to complex nanostructures using DNA has been opened. Here, we give a short review of the field and present the current status of our experiments were DNA origami is used in conjunction with nanoparticles. Gold nanoparticles are functionalized with thiolated single stranded DNA. Strands that are complementary to the gold particle strands can be positioned on the self-assembled DNA-structure in arbitrary patterns. This property should allow an accurate positioning of the particles by letting them hybridize on the lattice. We report on our recent experiments on this system and discuss open problems and future applications.

Programmable self-assembly:: Theoretical aspects and DNA-linked nanoparticles

Abstract We briefly present a method for the parameterization of assembly systems derived from their ability to form unique structures. The concept of bond uniqueness is introduced and we show how it influences the number of unique structures that a programmable, or algorithmic, self-assembly system can create. Further, we argue that programmable self-assembly systems create embedded, additional computation that is reflected in the complexity of the generated structures and show how this complexity is related to the bond uniqueness of the building blocks. A brief introduction to sticky graphs, a mathematical tool for modeling self-assembly systems, is given. From the theoretical discussions it becomes clear that building blocks for programmable self-assembly need to have at least four distinct, geometrically separated bonds. A scheme for the production of building blocks with well-directed bonds for programmable self-assembly using DNA-nanoparticles is presented. The introduced procedure is a completely bottom–up approach and can be used to produce quite advanced PSA building blocks like nanoparticle eight-mers with eight bonds. Initial experiments are presented.