Photothermal release of small molecules from gold nanoparticles in live cells

The ability of gold (Au) nanoparticles (NPs) to generate heat efficiently by absorbing visible and near-infrared (NIR) light holds great promise as a means to trigger chemical and biochemical events near the NPs. Previous demonstrations show that pulsed laser irradiation can selectively elicit the release of a fluorescent dye covalently anchored to the NP surface through a heat-labile linker without measurably changing the temperature of the surroundings. This article reports that the authors demonstrate the biological efficacy of this approach to photodelivery by showing that the decorated Au NPs are rapidly internalized by cells, are stable under physiological conditions, are nontoxic, and exhibit nonlethal photorelease following exposure to pulsed laser radiation. These observations, further supported by the versatility of our delivery motif, reaffirm the potential for further development of nonlethal photothermal therapeutics and their future relevance to such fields as gene therapy and stem-cell differentiation.From the Clinical EditorThe authors further refine previous observations suggesting that Au NP-s may be useful in targeted drug or gene delivery systems. Due to a strong photothermal release effect and their generally low toxicity, Au NP-s may become an important subject of choice in targeted delivery systems.

Graphical AbstractSpherical 15-nm gold nanoparticles (Au NPs) were decorated with a modified fluorescent dye anchored to the particle surface by a mercaptoalkyl chain and an intervening, heat-labile oxabicycloheptene linker. Solutions containing the decorated NPs were injected into live oocytes and introduced to Chinese hamster ovary cells via their growth media. Both cell cultures were shown to be viable following exposure to the NP solutions and subsequent pulsed laser irradiation, which resulted in visible increases in fluorescence attributable to diffusion of the dye away from the NP surface following cleavage of the oxabicycloheptene structure elicited by photothermal heating of the Au NPs.Figure optionsDownload high-quality image (92 K)Download as PowerPoint slide