Synthesis and Characterization of Synthesis and Characterization of DNA-Dendrimer Building Blocks for the DNA-Dendrimer Building Blocks for the Creation of DNA-based Nanostructures Creation of DNA-based Nanostructures Shiping Fang, Hye Jin Lee, Ming Li, Richard M. Crooks and Robert M. Shiping Fang, Hye Jin Lee, Ming Li, Richard M. Crooks and Robert M. Corn Corn June 23, 2003 June 23, 2003 Summarized by Ji-Yoon Park Summarized by Ji-Yoon Park
Transcript
Synthesis and Characterization of DNA-Synthesis and Characterization of DNA-Dendrimer Building Blocks for the Dendrimer Building Blocks for the
Creation of DNA-based NanostructuresCreation of DNA-based Nanostructures
Shiping Fang, Hye Jin Lee, Ming Li, Richard M. Crooks and Robert M. Shiping Fang, Hye Jin Lee, Ming Li, Richard M. Crooks and Robert M. CornCorn
June 23, 2003 June 23, 2003
Summarized by Ji-Yoon Park Summarized by Ji-Yoon Park
June 23, 2003June 23, 2003 APRL http://gene.hanyang.ac.kr APRL http://gene.hanyang.ac.kr
Goal: Goal: Directed assembly of surface nanostructureDirected assembly of surface nanostructure 2 DNA-dendrimer conjugates and the adsorption of DNA-based building 2 DNA-dendrimer conjugates and the adsorption of DNA-based building
2 Type of 2 Type of poly dendrimer:poly dendrimer: PAMAM-NH2 , PAMAM-COOH
SPR(Surface Plasma Resonance) ImagingSPR(Surface Plasma Resonance) Imaging To monitor the formation of DNA-dendrimer monolayer by hybridization by hybridization
onto ssDNA microarray on gold film onto ssDNA microarray on gold film
DNA-dendrimer conjugate: 4~7 times higher signal than oligomerDNA-dendrimer conjugate: 4~7 times higher signal than oligomer
For the creation of 2-D and 3-D DNA-based nanostructures For the creation of 2-D and 3-D DNA-based nanostructures by programmable self-assembly processby programmable self-assembly process
Abstract
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Snowflakes and Dendrimers
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Dendrimers
Dendrimers have a Dendrimers have a branchlike structurebranchlike structure
Highly branched molecules that combine the properties of polymers as well as small discrete molecules
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Convergent dendrimer synthesis Jean Frechet Science 263, 1710 (1994)
The generation 1 fragments (G-1) react with the OH groups on the monomer that are directly attached to the aromatic ring. This creates a G-2 fragment.
The OH group is replaced with Br so that the G-2 fragments can be attached to another monomer to make G-3. After G-3 is made, the process is repeated to make G-4.
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Finishing the dendrimer
A complete dendrimer is made by attaching fragments that have a reactive focal point. The two fragments do not have to be the same. For example, a fragment with a hydrophilic surface can be attached to a fragment with a hydrophobic surface to make an amphiphilic dendrimer that will be oriented at a water-oil interface.
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Control of interaction by dendrimer branching
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Synthesis of DNA-PAMAM-NHSynthesis of DNA-PAMAM-NH2 conjugates conjugates
Ninhydrin & Ellman’s testNinhydrin & Ellman’s test Characterization of the amount of DNA attached to theCharacterization of the amount of DNA attached to the
PAMAM-NHPAMAM-NH22
Synthesis of DNA-PAMAM-COOHSynthesis of DNA-PAMAM-COOH
DNA array fabricationDNA array fabrication
SPR imaging SPR imaging
Experimental Procedure
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The Attachment of ssDNA on PAMAM-NH2
PAMAM-NH2 + ester group of SSMCC (Fig. 1) → maleimide + thiol-modified DNA → covalent link
The amount of DNA attached to the PAMAM-NH2
Ninhydrin & Ellman’s test Different ratio of SSMCC to dendrimer; 30: 1 The number of DNA attached to each dendrimer
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Monitoring of DNA-PAMAM-NH2
Adsorption
SPR difference image (Fig. 2) Complementary 31mer DNA DNA-PAMAM-NH2
Hybridize to the two-component DNA array - DNA 1: complementary seq of ssDNA-
dendrimer - DNA 2: 8-base mismatch to DNA 1 seq
SPR signal DNA-dendrimer(> 7 times higher) > complem.
DNA
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Electrostatic interaction between DNA and dendrimer
UV-vis absorption spectrum (Fig. 3) PAMAM-NH2, DNA, and mixed DNA & dendrimer (Fig.
3a) Mixed solution
Strong electrostatic interaction
PAMAM-COOH, DNA, and mixed DNA & dendrimer (Fig. 3b)
No electrostatic attraction COOH-terminated dendrimer
Less elctrostatic interation near neutral pH
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Monitoring of DNA-PAMAM-COOH
Adsorption
SPR difference image (Fig. 4) Complementary 31mer DNA DNA-PAMAM-COOH
Hybridize to the two-component DNA array - DNA 1: complementary seq of ssDNA-dendrimer - DNA 2: control DNA
SPR signal DNA-dendrimer(> 4 times higher) > complem. DNA
Much lower nonspecific adsorption on the control DNA array compared to DNA-PAMAM-NH2 conjugate
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Dendrimer: Summary Dendrimer: Summary
Highly branched molecules-like snowflakes
Surface defines processing
Molecular “lego”
Synthetic route for DNA-dendrimer conjugates by covalent linking
