Metal-Enhanced Fluorescence of Rhodamine B Isothiocyanate from Micrometer-Sized Silver Powders

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• 作者：Kwan Kim*^† ; ; Yoon Mi Lee^† ; ; Ji Won Lee^† ; ; Kuan Soo Shin*^‡ ;
• 刊名：Langmuir
• 出版年：2009
• 出版时间：March 3, 2009
• 年：2009
• 卷：25
• 期：5
• 页码：2641-2645
• 全文大小：187K
• 年卷期：v.25,no.5(March 3, 2009)
• ISSN：1520-5827

文摘

We report here the use of micrometer-sized silver (μAg) powders to enhance the fluorescence emission of rhodamine B isothiocyanate (RhBITC). Our findings clearly show that the RhBITC displays up to a 36-fold increase in fluorescence emission intensity when RhBITC-labeled poly(allylamine hydrochloride) (RhBITC-PAH) is assembled onto a polyelectrolyte layer (about 30 nm thick) above μAg, when compared to that measured for RhBITC-PAH assembled directly onto a glass slide. A similar experiment conducted using a vacuum-evaporated Ag film displayed only a 5-fold increase. The enhanced fluorescence observed for μAg powders is obviously due to their ability to concentrate the electric fields. This suggests that metal-enhanced fluorescence (MEF) can potentially be employed to increase the sensitivity and detection limit of various bioassays that employ RhBITC as a fluorescence label. Since μAg powders are also an efficient substrate for surface-enhanced Raman scattering (SERS), molecular sensors operating via both SERS and MEF may then be able to be fabricated using μAg powders.