DNA-Surfaces-Nanotech

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Process Measurements Division
Surface Immobilization of Biopolymers
Patent 5,942,397Issued Aug. 24, 1999
Inventors Michael J. Tarlov, Tonya M. Herne,
Keith H. McKenney National Institute of Standards
and Technology Gaithersburg, MD 20899
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What is it?

• A method for forming a biopolymer-containing
  monolayerand organic thiol

Biopolymer" refers to any oligonucleotide,
polypeptide, polysaccharide, and derivatives
thereof.
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The 2-Step Method DNA Monolayers on Gold
ss-DNA
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3
HS - (CH2)6 -
Au
Probe Self-Assembly

• Control DNA probe coverage by varying probe
  assembly time
• Passivation step activates DNA probes for
  hybridization passivates surface

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What Its Good ForFabrication of Nucleic Arrays
Microarrays or Biological Sensors/Diagnostics
DNA nanoparticle based sensors
DNA microarrays
100 nm
Applications

• Gene expression profiling
• Genetic disease screening
• Infectious disease monitoring
• Cancer treatment
• Drug development

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Advantages over other monolayersystems and
monolayer formation methods

• Au-thiol chemistry happens excellent
  reproducibility compared to organosilane
  monolayers or other covalent coupling schemes

• Au-thiol monolayers can be patterned with
  micrometer resolution to fabricate arrays of
  biological ligands for high through-put screening
  applications

• Gold (Ag, Pt, Pd, Ru, Ir alloys) is good
  substrate
• inert amenable to detection via surface
  plasmon resonance, electrochemical,
  enhanced-fluorescence, other methods

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Invention Status

• Patent issued Aug. 99
• Reduced to practice with DNA
• System/method extensively studied/used by us
  others

• T. M. Herne, et al. JACS, 1997
• R. Levicky, et al. JACS, 1998
• A. B. Steele, et al. Anal. Chem., 1998
• A. B. Steele, et al. Biophysical Journal, 2000

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(No Transcript)
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DNA Concentration Profile Determined by Neutron
Reflectivity
TE Buffer, 1 M NaCl
DNA adsorption
Add mercaptohexanol
Hybridize
R. Levicky, et al. JACS 120 (1998) 9787
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XPS Evidence for End-Tethering of HS-DNA
N 1s
Intensity (Arb. Units)
410
405
400
395
390
Binding Energy (eV)
T. M. Herne, et al. JACS 119 (1997) 8916
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Model System Thiol-Derivatized DNA on Gold
Synthetic Thiol-Derivatized Oligonucleotides

• Thiol attachment to Au is stable and
  well-characterized
• Au surfaces are amenable to surface
  characterization

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DNA A Programmable Nanoscale Assembly Material?

• Attractive Nanomaterial Properties of DNA
• Molecular zip code for linking directing
  placement of nanoscale objects
• Synthetic versatility vary length, sequence,
  backbone, branched, dendrimers
• Easily modified for conjugation to molecules,
  nanoparticles, surfaces

DNA Programmed-Assembly Review Gothelf, LaBean
Org. Biomol. Chem. 3 (2005) 2043.
DNA-Based Nanoarchitectures and Nanomachines,
Org. Biomol. Chem. 4(18), Sept. 21, 2006
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DNA Microarrays