DNA nanomachines and DNA-directed assembly of nanostructures

Yi Chen, Purdue University

Abstract

DNA, apart from being a nature biological information carrier, has also been recognized as a useful material in the field of nanotechnology, such as molecular detection, nanofabrication, nanomechanical devices, directed organic synthesis, molecular computation, etc. In this research, two aspects of DNA technology were studied: DNA nanomachines and it’s applications, DNA-directed assembly of nanostructures. First an autonomous DNA nanomotor was constructed by integrating a catalytic DNA domain into a self-assembled DNA nanostructure. The multiple RNA cleavage of the DNAzyme powered the motor to move. Then a strategy was developed to reversibly switch on/off this autonomous DNA nanomotor. The basis of the reversible brake of this motor is strand displacement mechanism. This approach was also applied to regulate the enzyme activities of 10-23 RNA-cleaving DNAzymes in a enzyme complex. Another DNA nanomachine was constructed. The machine’s motion is triggered by changes in the solution pH value. Reversible formation and dissociation of a DNA triplex containing C+G-C triplets take place when the solution pH value changes between pH 5.0 and 8.0. The same strategy has been developed for switching chemical reactions between two identical reagents on the basis of DNA duplex-triplex transition. Then, DNA-directed assembly of nanostrutures was investigated. A switch mechanism relies on a pH-induced DNA conformational change was used to reversibly switch interparticle spacings in gold nanoparticles (AuNP) aggregates. Finally, a work along the effort of using biomacromolecules for controlled assembly of nanostructes was done. DNA hybridization was used to reversibly aggregate single-wall carbon nanotubes (SWNTs) and prepare heteroaggregates of SWNTs and gold nanoparticles (AuNPs).

Degree

Ph.D.

Subject Area

Biochemistry

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