Department of Mechanical Engineering and Materials Science, Washington University in St. Louis, 1 Brooking Drive, St. Louis, MO 63130 (USA).
Angew Chem Int Ed Engl. 2014 Jan 13;53(3):866-70. doi: 10.1002/anie.201308516. Epub 2013 Dec 2.
Owing to their applications in biodetection and molecular bioimaging, near-infrared (NIR) fluorescent dyes are being extensively investigated. Most of the existing NIR dyes exhibit poor quantum yield, which hinders their translation to preclinical and clinical settings. Plasmonic nanostructures are known to act as tiny antennae for efficiently focusing the electromagnetic field into nanoscale volumes. The fluorescence emission from NIR dyes can be enhanced by more than thousand times by precisely placing them in proximity to gold nanorods. We have employed polyelectrolyte multilayers fabricated using layer-by-layer assembly as dielectric spacers for precisely tuning the distance between gold nanorods and NIR dyes. The aspect ratio of the gold nanorods was tuned to match the longitudinal localized surface plasmon resonance wavelength with the absorption maximum of the NIR dye to maximize the plasmonically enhanced fluorescence. The design criteria derived from this study lays the groundwork for ultrabright fluorescence bullets for in vitro and in vivo molecular bioimaging.
由于它们在生物检测和分子生物成像中的应用，近红外（NIR）荧光染料正在被广泛研究。大多数现有的 NIR 染料表现出较差的量子产率，这阻碍了它们向临床前和临床环境的转化。众所周知，等离子体纳米结构可以作为微小的天线，将电磁场有效地聚焦到纳米级体积中。通过将 NIR 染料精确地放置在金纳米棒附近，可以将其荧光发射增强一千多倍。我们使用层层组装制备的聚电解质多层作为介电间隔物，精确地调节金纳米棒和 NIR 染料之间的距离。通过调整金纳米棒的纵横比，使其与 NIR 染料的吸收最大值相匹配，以最大化等离子体增强荧光。从这项研究中得出的设计标准为体外和体内分子生物成像的超高亮度荧光子弹奠定了基础。
