UCSB scientists build nanoscale 'jigsaw' puzzles made of RNA

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UCSB scientists build nanoscale 'jigsaw' puzzles made of RNA

http://www.medicalnewstoday.com/medicalnews.php?newsid=18129

21 Dec 2004

Scientists at the University of California, Santa Barbara, working at the

leading edge of bionanotechnology, are using assembly and folding principles of

natural RNA, or ribonucleic acid, to build beautiful and potentially useful

artificial structures at the nano-scale. Possible applications include the

development of nanocircuits, medical implants, and improved medical testing.

This research, published in the December 17 issue of the journal Science, is led

by Luc Jaeger, assistant professor in the Department of Chemistry and

Biochemistry at UCSB and a member of UCSB's Biomolecular Science and Engineering

Program, and by Arkadiusz Chworos, a post-doctoral fellow studying in Jaeger's

lab.

" In our lab, we see ourselves as nano-architects " said Jaeger. " We are using the

lessons that nature teaches us about RNA assembly and folding principles to

create nano-scale buildings made of 'smart' molecular 'Lego-like' bricks. " This

concept, called RNA tectonics, led to the synthesis of RNA grids with finite

size and various patterns. Using atomic force microscopy, the UCSB team has been

able to visualize some of their assemblies made of square-shaped RNA units that

form beautiful patterns and nano-grids.

One of the aims of Jaeger's group is to address one of the great challenges in

supra-molecular chemistry: to attain total control of the arrangement of matter

at a molecular level. The artificial RNA molecular system is based on 'smart'

RNA pieces, which could self-assemble in a predictable manner into any possible

two-dimensional architecture with full control over size, shape and pattern

geometry, according to the scientists.

Thus, the final position of each piece can eventually be located within a

network lattice of finite size. In the human-scale world, a good parallel would

be a jigsaw puzzle game of different pieces for which all the pieces can

precisely self-assemble without direct human intervention.

" This task may seem daunting for us, but it is not for nature, " explained

Jaeger. Nature takes advantage of these properties for the assembly of thousands

of molecules in living organisms. Out of the three major biopolymers, RNA is

thought to be the most ancient one on which life is based. RNA is different from

DNA in both the stability of -Crick base pairing and in that it is

designed to function as a single-stranded molecule. In this way, RNA has some of

the nature and functionality of self-assembled proteins.

DNA has been extensively used to generate artificial geometrical objects.

Although more chemically labile than DNA, RNA is now gaining attention for its

potential in building molecular components with high precision. The ability of

RNA to fold into a richer treasure trove of rigid structural motifs, that can be

potential modules for supramolecular engineering, is particularly attractive to

scientists. Chworos, the first author of the paper, explained that aperiodic

nano-grids may eventually be used as a starting point to generate nanochips,

nanocircuits and nanocrystals with potential applications in nanotechnology and

materials science. For example, RNA-based materials could offer the unique

possibility to act as scaffoldings for precisely aligning quantum dots or

organic polymers.

Helen Hansma, co-author and adjunct associate professor of physics at UCSB, said

that this advance in the basic science could eventually lead to the use of RNA

supra-molecular assembly in medical applications and could be used to to help

heal or regenerate bone or other body parts. She also suggested the possibility

of miniaturizing some medical tests, allowing the tests to take up less space

and use fewer chemicals.

" Like DNA, RNA is now entering into the realm of nano-materials but many

technical challenges await us in the development of these applications, " said

Jaeger. " Our next immediate task is to develop 'smart' RNA pieces that will

assemble into responsive, self-assembling, three-dimensional materials. "

This research was sponsored by the National Science Foundation and the Materials

Research Laboratory at USCB.