OBIS Research

Application of luminescent nanodiamonds to intracelluar imaging

Functional intracellular imaging on the molecular level has become possible by application of optical labels, which tag specific molecular sites to enhance their visibility dramatically on the non-specific cellular background. The optical labels can be either ultrabright scatterers, e.g. plasmon nanoparticles, or fluorophores, e.g. fluorescent dyes and quantum dots. Photoinstability, low cross-section, and toxicity of existing optical labels limit the scope of optical imaging, especially in the context of tracking individual molecules in the cells.

An alternative optical label is termed luminescent nanodiamond (LND). It represents a diamond nanocrystal that features a nitrogen-associated vacancy defect (Yu et al., 2005). The luminescence properties of LND, including its lifetime and near-infrared emission band, ensure the LND high visibility on the cell morphological and autofluorescence background. The scattering properties of highly refractile diamond nanocrystals render them visible in the cells (see Figure). LND is extremely photostable. In virtue of their carbon composition, nanodiamonds are biologically compatible, and their bioconjugation is straightforward. We carry out collaborative research into production, characterisation of luminescent nanodiamonds, and LND-assisted intracellular imaging.

Differential interference contrast (DIC) image of scattering nanodiamonds transfected through cells visible as bright rims around the dim nuclei (Smith et al.).

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Our collaborators:

Dr James Rabeau, Physics, Macquarie University

Dr Taras Plakhotnik, Bradley Smith, a PhD student, Physics, The University of Queenlsand

Prof Eiji Osawa, NanoCarbon Research Institute Ltd., Japan

References

Yu, S.J., M.W. Kang, H.C. Chang, K.M. Chen, and Y.C. Yu. . Bright fluorescent nanodiamonds: No photobleaching and low cytotoxicity. Journal of the American Chemical Society 127, 17604-17605 (2005).

B. R. Smith, M. Niebert, T. Plakhotnik, A. V. Zvyagin, “Transfection and imaging of diamond nanocrystals as scattering optical labels”, J. Luminesc ., 127, pp.260-263, 2007.

For more details on this project, please contact us.

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Last modified: 14 August, 2007