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Proceedings Paper

Nanocluster: photothermal bubble as optical probes for cytometric and microscopic applications
Author(s): Dmitri O. Lapotko; Ekaterina Y. Lukianova-Hleb; Jason H. Hafner
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Paper Abstract

The ability to detect optical signals form a cellular target depends upon the amount of optical energy that can be generated by this target as the signal. Given that the sensitivity of optical detectors has some finite limit, further increase of the sensitivity of optical diagnostic methods requires increasing the energy of target-generated signal. Usually this energy is converted by the cellular target upon its optical excitation and is limited by many factors such as: cell and target damage thresholds, efficiency of excitation energy conversion, size of the target etc. All these put principal limitation on sensing small targets (like molecules) in living cells with any optical method because the energy that can be safely converted by the target into a signal is limited. To overcome this limitation and to improve the sensitivity of optical microscopy of living cells (and cytometry in general) we propose the concept of intracellular amplification of the optical signal. This concept includes two major steps. First, primary (pump) optical radiation interacts with the target (a probe molecule) to generate a transient target. Second, the transient target is sensed with additional optical radiation that does not interact strongly with primary target or the cell, and, hence, may have high enough energy to increase the signal from transient target even above the energy of pump radiation, which is limited by cell and target damage thresholds. We propose to use optical scattering from clusters of gold nanoparticles (the target) that are selectively formed in specific cells through antibody-receptor interaction and through endocytosis. To amplify this optical signal we propose to generate photothermal bubbles (the transient target) around those clusters. In experiments with water suspensions and with individual tumor K562 cells we have achieved optical signal amplification in individual cells (relatively to the scattering signal from intact cells): with gold nanorod intracellular clusters, 14.8 times, with photothermal bubbles, generated around those clusters, more than 100 times. Those signals were much higher than corresponding fluorescent signals and were obtained from living cells.

Paper Details

Date Published: 1 August 2007
PDF: 8 pages
Proc. SPIE 6734, International Conference on Lasers, Applications, and Technologies 2007: Laser Technologies for Medicine, 67340E (1 August 2007); doi: 10.1117/12.753159
Show Author Affiliations
Dmitri O. Lapotko, Lykov Heat and Mass Transfer Institute (Belarus)
Ekaterina Y. Lukianova-Hleb, Lykov Heat and Mass Transfer Institute (Belarus)
Jason H. Hafner, Rice Univ. (United States)

Published in SPIE Proceedings Vol. 6734:
International Conference on Lasers, Applications, and Technologies 2007: Laser Technologies for Medicine
Vladislav Panchenko; Andrey Larichev; George Zheltov, Editor(s)

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