Two-Photon Fluorescence Imaging Super-Enhanced by Multishell Nanophotonic Particles, with Application to Subcellular pH
Two-Photon Fluorescence Imaging Super-Enhanced by Multishell Nanophotonic Particles, with Application to Subcellular pH
复制标题
DOI：
10.1002/smll.201102664
复制
发表时间：
2012-07-23
期刊：
影响因子：
13.3
通讯作者：
Kopelman, Raoul
中科院分区：
文献类型：
--
作者：
Ray, Aniruddha;Lee, Yong-Eun Koo;Kopelman, Raoul
提出了一种增强荧光团双光子荧光信号的新型纳米光子方法。它利用近场放置染料分子的贵金属纳米球产生的激发光的二次谐波（SH），除了通常的金属增强荧光现象之外，进一步增强染料的荧光信号。该方法首次能够演示生物系统（即活细胞）内的双光子荧光增强。采用含有银核、保护性柠檬酸盐封端（也用作激发猝灭抑制剂间隔基）、pH指示剂染料壳和聚丙烯酰胺包层的多壳水凝胶纳米颗粒。利用该技术，观察到指示剂染料的双光子荧光增强高达 20 倍。虽然增强的荧光信号的很大一部分是由于伴随激发光的 SH 产生的单光子过程，但该方法保留了红外激发双光子显微镜的所有优点：增强的穿透深度、局部激发、低光漂白、低自发荧光和低细胞损伤。
A novel nanophotonic method for enhancing the two-photon fluorescence signal of a fluorophore is presented. It utilizes the second harmonic (SH) of the exciting light generated by noble metal nanospheres in whose near-field the dye molecules are placed, to further enhance the dye's fluorescence signal in addition to the usual metal-enhanced fluorescence phenomenon. This method enables demonstration, for the first time, of two-photon fluorescence enhancement inside a biological system, namely live cells. A multishell hydrogel nanoparticle containing a silver core, a protective citrate capping, which serves also as an excitation quenching inhibitor spacer, a pH indicator dye shell, and a polyacrylamide cladding are employed. Utilizing this technique, an enhancement of up to 20 times in the two-photon fluorescence of the indicator dye is observed. Although a significant portion of the enhanced fluorescence signal is due to one-photon processes accompanying the SH generation of the exciting light, this method preserves all the advantages of infrared-excited, two-photon microscopy: enhanced penetration depth, localized excitation, low photobleaching, low autofluorescence, and low cellular damage.