Biomod/2013/LMU/nanodiamonds: Difference between revisions

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Nanodiamonds are allotropes (sp3) of carbon and possess a series of distinct properties compared to other carbon–based materials. Their outstanding characteristics include extreme hardness, high thermal conductivity, transparency at all optical wavelengths, biocompatibility, and chemical robustness <sup><cite>1</cite></sup>. Pure diamond is an electric insulator while doped diamond becomes a semiconductor with a large bandgap (5.5 eV at room temperature). Doped impurities additionally can create optically active defects – also called color centers – within the diamonds. If in particular two adjacent positions in the atomic lattice of a nanodiamond are replaced, one with nitrogen, the other with an empty space, a nitrogen–vacancy (NV) center is formed. Under excitation with appropriate light sources, such NV centers can act as reliable single-photon sources where the emitted photons carry defined spin information related to the spin state of the NV center. The widely used nanodiamonds production method was by detonation of TNT–hexogene mixtures and during the detonation process, nitrogen defects were introduced <sup><cite>2</cite></sup>.<br />
 
Although nanodiamonds are sp3 allotrope of carbon materials, due to their high surface energy, many residual groups, such as hydroxyl, carboxyl, lactone, ketone, exist on nanodiamonds surface and these groups provided initial functional sites for further modification.<br />
=Properties of Nanodiamonds=
The surface modification of the nanodiamonds can be divided in two main categories: wet methods <sup><cite>3 4</cite></sup> and dry methods <sup><cite>5 6</cite></sup>.The dry methods usually employ gas plasma or high temperatures to remove the surface impurities and embed functional radicals. The wet methods usually employ mineral acids to oxidize the surface and then further conjugate the oxidized surfaces with other groups by non-covalent or covalent interaction.<br />
 
Both procedures modify the nanodiamonds surface by introducing carboxyl or amino groups to enable an attachment. For our project, we used nanodiamonds that were already modified with wet method by another group.
[[Image:130309 nanodiamonds_05.jpg|thumb|border|250px|right|baseline|TEM-Image of Nanodiamonds, which were modified with wet method (Scaling: 100nm)]]
Nanodiamonds are allotropes (sp3) of carbon and possess a series of distinct properties compared to other carbon–based materials. Their outstanding characteristics include extreme hardness, high thermal conductivity, transparency at all optical wavelengths, biocompatibility, and chemical robustness <sup><cite>1</cite></sup>. Pure diamond is an electric insulator while doped diamond is a semiconductor with a large bandgap (5.5 eV at room temperature). In addition doped impurities can create optically active defects – also called color centers – within the diamond. A nitrogen vacancy center (NV) consists of two adjacent positions in the atomic lattice of a diamond one replaced by a nitrogen atom while the other remains vacant. Under excitation with an appropriate light source, NV centers are a reliable single-photon source. The emitted photons carry defined spin information related to the spin state of the NV center. During the production of nanodiamonds by detonation of TNT-hexogen mixtures nitrogen defects are added. <sup><cite>2</cite></sup>.<br />
Although nanodiamonds are sp3 allotropes of carbon materials many residual groups, such as hydroxyl, carboxyl, lactone, ketone, exist on nanodiamonds due to their high surface energy. These groups provide initial functional sites for further modification.<br />
[[Image:NDsurface.png|thumb|border|250px|right|baseline|Functional groups of a nanodiamonds, which was modified with wet method]]
The surface modification of the nanodiamonds can be divided into two main categories: wet methods <sup><cite>3 4</cite></sup> and dry methods <sup><cite>5 6</cite></sup>.The dry methods usually employ gas plasma or high temperatures to remove the surface impurities and embedded functional radicals. The wet methods usually employ mineral acids to oxidize the surface and then further conjugate the oxidized surfaces with other groups by non-covalent or covalent interaction.<br />
Both procedures modify the nanodiamonds surface by introducing carboxyl or amino groups to enable an attachment. For our project, we used nanodiamonds that were already modified by wet method by [http://www.uni-ulm.de/nawi/institut-fuer-organische-chemie-iii/prof-dr-tanja-weil.html Tanja Weil's group] from Ulm Univeristy.  
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<biblio>
<biblio>
#1 Krueger, A. J.Mater. Chem. 2008, 18, 1485-1492
#1 Krueger, A. "The structure and reactivity of nanoscale diamond", J. Mater. Chem., 2008, 18, 1485-1492.
</biblio>
<biblio>
#2 Osawa, E. "Monodisperse single nanodiamond particulates", Pure Appl. Chem., 2008, 80, 1365–1379.
</biblio>
<biblio>
#3 Ushizawa, K. et. al. "Covalent immobilization of DNA on diamond and its verification by diffuse reflectance infrared spectroscopy", Chem. Phys. Lett., 2002, 351, 105-108
</biblio>
</biblio>
<biblio>
<biblio>
#2 Osawa, E. Pure App. Chem. 2008, 80, 1365-1379
#4 Kruger, A. et. al., "Surface functionalisation of detonation diamond suitable for biological applications", J. Mater. Chem., 2006, 16, 2322-2328.
</biblio>
</biblio>
<biblio>
<biblio>
#3 Ushizawa, K.; Sato, Y.; Mitsumori, T.; Machinami, T.; Ueda, T.; Ando, T. Chem. Phys. Lett. 2002, 351, 105-108
#5 Wenmackers, S. et. al., "Diamond-based DNA sensors: surface functionalization and read-out strategies", P. Phys. Status Solidi A, 2009, 206, 391-408.
</biblio>
</biblio>
<biblio>
<biblio>
#4 Kruger, A.; Liang, Y.; Jarre, G.; Stegk, J. J. Mater. Chem. 2006, 16, 2322-2328
#6 Takahashi, K. et. al., "DNA preservation using diamond chips", Diam. Relat. Mater. 2003, 12, 572-576.
</biblio>
</biblio>
<biblio>
<biblio>
#5 Wenmackers, S.; Vermeeren, V.; vandeVen, M.; Ameloot, M.; Bijnens, N.; Haenen, K.; Michiels, L.; Wagner, P. Phys. Status Solidi A 2009, 206, 391-408
#7 Vadym N. Mochalin, Olga Shenderova, Dean Ho & Yury Gogotsi, "The properties and applications of nanodiamonds", Nature Nanotechnology 7, 11-23 (2012)
</biblio>
</biblio>
<biblio>
<biblio>
#6 Takahashi, K.; Tanga, M.; Takai, O.; Okamura, H. Diam. Relat. Mater. 2003, 12, 572-576
#8 Igor Ahronovich, Andrew D. Greentree & Steven Prawer, "Diamond photonics", Nature photonics 5, 391-405 (2011)
</biblio>
</biblio>

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Properties of Nanodiamonds

TEM-Image of Nanodiamonds, which were modified with wet method (Scaling: 100nm)

Nanodiamonds are allotropes (sp3) of carbon and possess a series of distinct properties compared to other carbon–based materials. Their outstanding characteristics include extreme hardness, high thermal conductivity, transparency at all optical wavelengths, biocompatibility, and chemical robustness [1]. Pure diamond is an electric insulator while doped diamond is a semiconductor with a large bandgap (5.5 eV at room temperature). In addition doped impurities can create optically active defects – also called color centers – within the diamond. A nitrogen vacancy center (NV) consists of two adjacent positions in the atomic lattice of a diamond one replaced by a nitrogen atom while the other remains vacant. Under excitation with an appropriate light source, NV centers are a reliable single-photon source. The emitted photons carry defined spin information related to the spin state of the NV center. During the production of nanodiamonds by detonation of TNT-hexogen mixtures nitrogen defects are added. [2].
Although nanodiamonds are sp3 allotropes of carbon materials many residual groups, such as hydroxyl, carboxyl, lactone, ketone, exist on nanodiamonds due to their high surface energy. These groups provide initial functional sites for further modification.

Functional groups of a nanodiamonds, which was modified with wet method

The surface modification of the nanodiamonds can be divided into two main categories: wet methods [3, 4] and dry methods [5, 6].The dry methods usually employ gas plasma or high temperatures to remove the surface impurities and embedded functional radicals. The wet methods usually employ mineral acids to oxidize the surface and then further conjugate the oxidized surfaces with other groups by non-covalent or covalent interaction.
Both procedures modify the nanodiamonds surface by introducing carboxyl or amino groups to enable an attachment. For our project, we used nanodiamonds that were already modified by wet method by Tanja Weil's group from Ulm Univeristy.

References

  1. Krueger, A. "The structure and reactivity of nanoscale diamond", J. Mater. Chem., 2008, 18, 1485-1492.

    [1]
  1. Osawa, E. "Monodisperse single nanodiamond particulates", Pure Appl. Chem., 2008, 80, 1365–1379.

    [2]
  1. Ushizawa, K. et. al. "Covalent immobilization of DNA on diamond and its verification by diffuse reflectance infrared spectroscopy", Chem. Phys. Lett., 2002, 351, 105-108

    [3]
  1. Kruger, A. et. al., "Surface functionalisation of detonation diamond suitable for biological applications", J. Mater. Chem., 2006, 16, 2322-2328.

    [4]
  1. Wenmackers, S. et. al., "Diamond-based DNA sensors: surface functionalization and read-out strategies", P. Phys. Status Solidi A, 2009, 206, 391-408.

    [5]
  1. Takahashi, K. et. al., "DNA preservation using diamond chips", Diam. Relat. Mater. 2003, 12, 572-576.

    [6]
  1. Vadym N. Mochalin, Olga Shenderova, Dean Ho & Yury Gogotsi, "The properties and applications of nanodiamonds", Nature Nanotechnology 7, 11-23 (2012)

    [7]
  1. Igor Ahronovich, Andrew D. Greentree & Steven Prawer, "Diamond photonics", Nature photonics 5, 391-405 (2011)

    [8]