1. A DNA-Templated Carbon Nanotube Field Effect Transistor Erez BraunUri Sivan Rotem BermanEvgeny Buchstab Gidi Ben-Yoseph Kinneret Keren Physics Department Technion- Israel Institute of Technology AGTTCTCGAA gold

2. Self assembly Bottom-up assembly based on recognition between molecular building blocks. All the information is encoded into the building blocks (no blue-prints, no supervisor) The assembly process proceeds autonomously (no molecular-scale external manipulations) One of the major challenges: Integration of a large number of molecular devices into functional circuits A possible route, Molecular Electronics

3. Can we harness the biological machinery and working principles to self-assemble electronic devices and circuits? Self-assembly in Biology: Complex functional systems assembled from molecular building blocks

4. Outline: DNA-templated electronics A biological framework- Homologous genetic recombination Sequence-specific molecular lithography Self-assembly of a DNA-templated transistor Outlook

5. Circuit organization Inter-device wiring Interface to the macroscopic world 10  m ~nm  ms ~nm DNA-Templated Electronics electrodes (lithography) DNA molecular devices

6. What do we need to realize ? Assemble a DNA network Localize molecular-scale electronic components Transform DNA into conducting wires

7. DNA-templated wires Silver clusters formed on aldehyde-derivatized DNA 1m1m Continuous gold wire 1m1m Silver clusters catalyze further gold deposition

8. DNA-templated gold wires wire width ~50 nm (DNA width ~2 nm)  ~1.5 x 10 -7  m polycrystalline gold  =2.2 x 10 -8  m 012 0 25 50 1  m V [  V] I [nA] R ~26 

9. What do we need to realize ? Assemble a DNA network Localize molecular-scale electronic components Transform DNA into conducting wires Electrically contact the components

10. Sequence-Specific Molecular Lithography DNA junction formation Science 297, 72-75 (2002) Patterning of DNA metallization AGTTCTCGAA gold Localization of molecular objects on DNA

11. Major biological concept: Homologous genetic recombination

12. Mechanism of RecA-promoted Recombination Reaction

13. RecA polymerized on DNA (cryo-TEM) Marina Konorty Ishi Talmon’s group Dept. of Chemical Engineering Technion

14. Sequence-Specific Molecular Lithography DNA junction formation

15. 3-Armed Junction Formation 15kbp 4kbp 50b branch migration building blocks final product synapsis

16. 0.25  m AFM images: 3-armed junction 50 nm

17. Sequence-Specific Molecular Lithography Patterning of DNA metallization AGTTCTCGAA gold

18. + (i) Polymerization ssDNA probe RecA monomers Nucleoprotein filament (ii) Homologous recombination + Aldehyde-derivatized dsDNA substrate (iii) Molecular lithography + AgNO 3 Ag aggregates (iv) Gold metallization + KAuCl 4 +KSCN+HQ Au wire Exposed DNA Schematics of Sequence-Specific Patterning of DNA Metallization

19. Ag DNA Sample after silver deposition 0.5  m RecA nucleoprotein filament localized on aldehyde-derivatized DNA RecA DNA 0.5  m Au insulating gap (dsDNA) Au Sample after gold metallization AFM SEM 0.5  m 0.25  m

20. Optical LithographyMolecular Lithography Patterning information Resist ssDNA Aldehyde-derivitized dsDNA acggtc... RecA as a sequence-specific resist metallization Au Silicon Au Light Mask Silicon photoresist Silicon metallization developing

21. Sequence-Specific Molecular Lithography Localization of molecular objects on DNA

22. Sequence-specific localization of molecular objects on any dsDNA molecule without prior modifications Strand-exchange with labeled ssDNA ds DNA labeled ss DNA RecA+ATP

23. Localization of streptavidin-conjugated gold nanoparticles after strand-exchange with biotin-labeled ssDNA 0.2  m 1  m DNA Au Au nanoparticles

24. Sequence-Specific Molecular Lithography Patterning of DNA metallization DNA junction formation Localization of molecular objects on DNA

25. Self-assembly of a DNA-templated carbon nanotube field effect transistor AGTTCTCGAA gold Science 302, 1380-1382 (2003)

26. Self-assembly of a DNA-templated transistor: Localization of a semiconducting single-wall carbon nanotube Instill biological recognition to the carbon nanotube. Use homologous recombination to localize it on DNA. Wiring and contacting it Use sequence-specific DNA metallization to form extended DNA-templated wires contacting the nanotube.

27. + (i) RecA Polymerization ssDNA probe RecA monomers Nucleoprotein filament (ii) Homologous recombination + Aldehyde-derivatized dsDNA substrate (iii) Localization of carbon nanotube using antibodies Streptavidin coated carbon nanotube + anti RecA Biotin antimouse

28. 0.3  m Localization of a streptavidin-functionalized single wall carbon nanotube using antiRecA antibody and a biotin conjugated secondary antibody 0.2  m 0.3  m carbon nanotube RecA DNA

29. + (i) RecA Polymerization ssDNA probe RecA monomers Nucleoprotein filament (ii) Homologous recombination + Aldehyde-derivatized dsDNA substrate (iii) Localization of carbon nanotube using antibodies + Streptavidin coated carbon nanotube anti RecA Biotin antimouse (iv) RecA serves as a sequence specific resist protecting against silver reduction AgNO 3 Ag aggregates + (v) Gold metallization + KAuCl 4 +KSCN +HQ Au wire Carbon nanotube

30. Self-assembly of a DNA-templated carbon nanotube FET A single wall carbon nanotube bound to RecA localized at a specific address on a DNA molecule 0.3  m carbon nanotube DNA DNA-templated gold wires contacting the single wall carbon nanotube are formed by specific metallization using the RecA as a resist 0.1  m carbon nanotube Au

31. Electrical characteristics of the DNA-templated carbon nanotube FET Carbon nanotube SiO 2 p + Si substrate source drain V DS VGVG the measurement circuit:

32. a rope device containing both semiconducting and metallic nanotubes Electrical measurements:

33. 0.1  m Electrical measurements: a single semiconducting nanotube device

34. What next: Other self-assembled molecular devices (e.g. SET) 3-terminal FET device on a DNA junction (will allow individual gating of each device) DNA-templated circuits- in principle, molecular lithography can be applied to localize several devices on a scaffold DNA network and incorporate them into a circuit. AGTTCT source drain gate ?

35. Can we realize complex DNA-templated electronics? Can we introduce additional biological concepts: feedback from functionality to the assembly process, error correction, modularity, selection, replication, evolution …? As in biology, assembly of complex functional systems will probably require more than just “passive” self-assembly

36. Thanks to: Erez Braun Uri Sivan Rotem Berman Marina Konorty Gidi Ben-Yoseph Evgeny Buchstab Michael Krueger Rachel Yechieli