8/3/2019 J. N. Harb, J. Liu, Y. Geng, E. Pound, J.R. Ashton, S. Gyawali and A.T. Woolley- Metallization of DNA Origami Templa

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Metallization of DNA Origami

Templates for the Fabricationof Nanoelectronic Circuits

J. N. Harb*, J. Liu, Y. Geng, E. Pound, J.R. Ashton,S. Gyawali, and A.T. Woolley

Department of Chemical EngineeringDepartment of Chemistry and Biochemistry

Brigham Young University, Provo, Utah 84602*Corresponding Author: john_harb@byu.edu

Integrated circuits have achieved increased speed andcomputing power through the reduction of feature sizes

and the corresponding increase in component density.While optimization and evolution of existing technologies

can yield improvements in the short term, the explorationof revolutionary methods, which have the potential to

achieve significant gains in miniaturization, is becomingan increasingly attractive pursuit. An intriguing

transformative alternative to conventional techniques is touse individual molecules as templates for the directed self

assembly of nanometer-scale structures.

Use of DNA as a circuit template was

demonstrated by Keren et al. who used metallized-DNAand carbon nanotubes to create a DNA-templated FET

[1]. While their pioneering work demonstrated proof-of-concept, it is not scaleable to the complex architectures

needed for future generations of devices. Increasedcomplexity at the template level can be achieved throughfolded DNA origami, which has been shown to be a

robust and simple method for designing patterned shapes[2]. As part of this study, we recently enhanced DNA

origami by: 1) devising an approach for the formation ofDNA origami having different sequences and scaffold

strand lengths through PCR amplification, and 2)constructing asymmetric square junctions in branched

origami designs that have largely open space with thin

(~10 nm) connecting features [3]. These characteristicsare ideal for use in nanoelectronic circuits.

The focus of this paper is the metallization of

DNA origami. A number of procedures for metallizing -

DNA have been explored in the literature and significantprogress has been demonstrated [e.g., 4-7]. However,

metallization of DNA origami presents several additionalchallenges, which include: 1) the stability of the origami

in the processes used for metallization, 2) the enhanced

selectivity required to metallize the small origamistructures, 3) the increased difficulty of adhering small

structures to the surface through multiple metallizationsteps, and 4) the influence of excess staple strands present

with the origami. This paper describes our efforts toaddress these challenges. Metallization of origami by two

different electroless plating procedures is described. Thefirst is an adaptation of the procedure used by Braun that

utilizes a silver seed followed by electroless plating witheither gold or silver [4]. The second uses a palladium

seed followed by electroless plating of palladium as

adapted from Ref. [7]. Successful metallization of DNAorigami with either gold or palladium has been

demonstrated. The interaction of the plating processes

with DNA origami has also been characterized andoptimized to produce the desired metallic structures.

These results represent an important step forward towardthe realization of nanoelectronic circuits formed via self-

assembled molecular templates.

ACKNOWLEDGMENTThis work was funded by the National Science

Foundation (CBET 0708347).

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