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 Editor: The 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. (C) 2012 Elsevier Inc. All rights reserved.