.jpg)
Why DNA?
DNA is a truly amazing material. Biologically, it is an information storage
molecule carrying genetic codes for gene regulation and protein production. It
is essentially what life is made of. Mechanically, DNA can be rigid or flexible,
tunable by its composition and length. Physically, DNA is very small - only 2
nanometer in diameter; yet its length is customizable with a resolution about
0.34 nm.
|
Nucleic Acid is a macromolecule
composed of chains of monomeric nucleotides. In biochemistry these molecules
carry genetic information or form structures within cells. The most common
nucleic acids are deoxyribonucleic acid (DNA) and ribonucleic acid
(RNA)
Deoxyribonucleic acid (DNA) is a nucleic acid that
contains the genetic instructions used in the development and functioning of all
known living organisms and some viruses.
Ribonucleic acid (RNA) is a biologically important type
of molecule that consists of a long chain of nucleotide units. RNA is very
similar to DNA, but differs in a few important structural
details. |
Chemically, DNA is water soluble, stable (think of mummy), non-toxic (think
of sushi), biocompatible and biodegradable. DNA can be obtained from a variety
of sources including live cells and a machine (e.g., a DNA synthesizer). DNA can
also be programmed. Most uniquely, thousands of different enzymes have been
evolved that can be employed to manipulate DNA at the angstrom level
accuracy.
Thus, DNA provides an ideal platform as an additional materials building
block for both nanotechnology and nanobiotechnology. Since the pioneering work
of Prof. Nadrian Seeman and others, DNA has been used in so many ways that it is
no longer regarded as a sole biomolecule.
Nucleic Acid Engineering
Prof. Dan Luo's group
at Cornell has been focused on engineering nucleic acids (DNA and RNA) as a
true polymer for real world applications. Their work aims at creating novel,
bulk-scale DNA materials in high yield and low cost and with simple design that
fully utilizes both DNA's biological and non-biological properties.
Using branched DNA (X-shaped, Y-shaped, etc.), the Luo group has built
tree-shaped DNA (dendrimers-like DNA, or DL-DNA), DNA nanobarcodes, DNA
hydrogels, DNA liposomes, and DNA-organized nanoparticles. Recently, the Luo group has
developed a DNA-based, anisotropic, branched, and crosslinkable monomer (termed
"ABC monomer") as a universal nanoscale material building block.
Using these DNA ABC monomers, the Luo group invented "target-driven polymerization" process
where DNA polymers can only be synthesized in the presence of a pathogen DNA.
The polymerization process amplifies signal within polymer itself, enabling
accurate and sensitive molecular sensing. The technology will have wide
applications in diagnostics as well as in multi-drug delivery.
In addition, 1D nano-wires, 2D superlattices, 3D supracrystals, and
free-standing monolayer sheets have been achieved through soft-lithography but
with a nanometer feature size by using DNA as an organizer. Very recently (in
2009), the Luo group
has created a DNA gel that can produce large amounts of proteins without any
living cells (termed "protein producing gel" or "P-gel"). P-gel successfully
converts the central dogma from inside a cell to a gel-based chemical reaction
in a test tube. Cloning, transformation and cell culturing are no longer needed
for protein production.
The Luo group
envisions that P-gel will become a platform technology for producing as well as
engineering proteins efficiently and effectively. Furthermore, the Luo group has
created an "unforgettable" DNA gel. These examples illustrate the fact that DNA
is both a genetic and a generic material and that through Nucleic Acid
Engineering one can create new materials via DNA with novel properties and
real-world applications. For more information, please refer to the recent (in
last 5 years) publications from the Luo group.
References
1. N. Park, J.S. Kahn, E.J. Rice, M.R. Hartman, H. Funabashi, J. Xu, S.H. Um,
D. Luo, High-yield cell-free protein production from P-gel, Nature Protocols, 4,
1759-1770 (2009)
2. J.B. Lee, Y.H. Roh, S. Um, H. Funabashi, W. Cheng, J.J.
Cha, P. Kiatwuthinon, D.A. Muller, D. Luo, Multifunctional nano-architectures
from DNA-based ABC monomers, Nature Nanotechnology, 4, 430-436 (2009)
3. W.
Cheng, M. J. Campolongo, J. J. Cha, S. J. Tan, C. C. Umbach, D. A. Muller, D.
Luo, Free-Standing Nanoparticle Superlattice Sheets Controlled by DNA (Article),
Nature Materials, 8, 519-525 (2009)
4. N. Park, S. H. Um, H. Funabashi, J.
Xu, D. Luo, A Cell-free Protein Producing Gel, (Article), Nature Materials, 8,
432-437 (2009)
5. W. Cheng, N. Park, M.T. Walter, M.R. Hartman, D. Luo,
Nanopatterning Self-Assembled Nanoparticle Superlattices by Molding
Microdroplets (Cover Article) Nature Nanotechnology, 3, 682-690 (2008)
6. S.
Um, J. Lee, N. Park, S. Kwon, C. Umbach, D. Luo, Enzyme catalyzed assembly of
DNA hydrogels, Nature Materials 5, 797-801 (2006)
7. S. Um, J. Lee, S. Kwon,
D. Luo, DNA nanobarcodes, Nature Protocols 1, 995-1000 (2006)
8. Y. Li, Y. Cu
and D. Luo, DNA fluorescence nanobarcodes for multiplexed pathogen detection,
Nature Biotechnology 23, 885-889 (2005)
9. Y. Li, Y.D. Tseng, S.Y. Kown, L.
d'Espaux, J.S. Bunch, P.L McEuen and D. Luo. Controlled assembly of
dendrimer-like DNA. Nature Materials, 3, 38-42 (2004)
Copyright AZoNano.com, Professor Dan Luo(Cornell
University)