Self-assembling nanoclusters in living systems: application for integrated photothermal nanodiagnostics and nanotherapy

In vivo photothermal flow cytometry: Imaging and detection of individual cells in blood and lymph flow

“…In particular, the PT responses from cells with these gold PT labels show specific negative peaks in nonlinear PT responses (associated with microbubble formation around overheated particles) compared to the positive amplitude peaks of linear PT responses from non-labeled cells at the same laser energy level (Fig. 4, right) [Zharov et al, 2005d]. Simultaneous monitoring of PT images from the same cells confirmed that cells tagged with gold PT labels (Fig.…”

“…The high absorption sensitivity of the PT technique offers an opportunity to consider gold nanoparticles as a new type of PT label [Zharov et al, 2005d]. These particles have unique properties for studying cells, especially in vivo; they are strong absorbers (four to six orders of magnitude greater than any conventional fluorescent label), which makes it possible to detect single particles even as small as 2 nm.…”

“…In addition, they are nontoxic, biocompatible, and photostable (i.e., absence of photobleaching or blinking); have a fast thermal response time (up to 10 À12 s); and can easily be conjugated with proteins and antibodies to label many specific cellular markers. Additionally, they may have adjustable absorption properties in the spectral range of 0.5-1 mm, providing high image contrast for their reliable detection against the absorbing cellular background from water, DNA, and lipids [Zharov et al, 2005d]. When closely located or during aggregation, gold nanoclusters demonstrate red-shift effects; this allows gold nanoparticles, in combination with the PT technique, to be used for aggregation immunoassay at the single-cell level [Zharov et al, 2005d].…”

“…Additionally, they may have adjustable absorption properties in the spectral range of 0.5-1 mm, providing high image contrast for their reliable detection against the absorbing cellular background from water, DNA, and lipids [Zharov et al, 2005d]. When closely located or during aggregation, gold nanoclusters demonstrate red-shift effects; this allows gold nanoparticles, in combination with the PT technique, to be used for aggregation immunoassay at the single-cell level [Zharov et al, 2005d]. The absorption bands of gold nanospheres and nanorods, with adjustable spectral properties, are 60-100 nm and 30-50 nm, respectively.…”

“…For example, the WTY-6 subpopulation of the MDA-MB-231 human breast adenocarcinoma cell line was engineered to express separase, a clustered cellsurface protein [Zharov et al, 2005d], which was targeted with a primary F19 monoclonal antibody (Ab). Goat anti-mouse immunoglobulin G (H þ L) conjugated with 40-nm gold nanoparticles was used as a secondary Ab to selectively target the primary Ab.…”