Development of Ultrabright Semiconducting Polymer Dots for Ratiometric pH Sensing

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• 作者：Yang-Hsiang Chan ; Changfeng Wu ; Fangmao Ye ; Yuhui Jin ; Polina B. Smith ; Daniel T. Chiu
• 刊名：Analytical Chemistry
• 出版年：2011
• 出版时间：February 15, 2011
• 年：2011
• 卷：83
• 期：4
• 页码：1448-1455
• 全文大小：1036K
• 年卷期：v.83,no.4(February 15, 2011)
• ISSN：1520-6882

文摘

Semiconducting polymer-based nanoparticles (Pdots) have recently emerged as a new class of ultrabright probes for biological detection and imaging. This paper describes the development of poly(2,5-di(3鈥?7鈥?dimethyloctyl)phenylene-1,4-ethynylene) (PPE) Pdots as a platform for designing F枚rster resonance energy transfer (FRET)-based ratiometric pH nanoprobes. We describe and compare three routes for coupling the pH-sensitive dye, fluorescein, to PPE Pdots, which is a pH-insensitive semiconducting polymer. This approach offers a rapid and robust sensor for pH determination using the ratiometric methodology where excitation at a single wavelength results in two emission peaks, one that is pH sensitive and the other one that is pH insensitive for use as an internal reference. The linear range for pH sensing of the fluorescein-coupled Pdots is between pH 5.0 and 8.0, which is suitable for most cellular studies. The pH-sensitive Pdots show excellent reversibility and stability in pH measurements. In this paper, we use them to measure the intracellular pH in HeLa cells following their uptake by endocytosis, thus demonstrating their utility for use in cellular and imaging experiments.