title: Construction of single fluorophore ratiometric pH sensors using dual-emission Mn(2+)-doped quantum dots.
abstract: We present a novel ratiometric pH sensor design using water-soluble, dual-emission, Mn(2+)-doped quantum dots (Qdots) decorated with D-penicillamine (DPA-MnQdots). In contrast to more commonly used ratiometric pH sensors that rely on the coupling of two fluorophores, our design uses only a single emitter, which simplifies ratiometric sensing and broadens the applications of the sensor. Our single-emitter DPA-MnQdots exhibit two emission bands, at 510nm (green) and 610nm (red), which are, respectively, attributable to exciton recombination and emission of the Mn(2+) dopants. The emission intensity ratio (I510/I610) of the DPA-MnQdots depends linearly on surrounding pH values within physiological conditions (from pH 4.5 to 8.5). Moreover, the biocompatible DPA-MnQdots were used for long-term monitoring of local pH values in HeLa cells.
authors: Department of Chemistry, National Taiwan University, 1, Section 4, Roosevelt Road, Taipei, Taiwan; Nano Science and Technology Program, Taiwan International Graduate Program, Academia Sinica and National Taiwan University, Taiwan; Research Center for Applied Sciences, Academia Sinica, Taipei, Taiwan.
authors: Feby Wijaya
authors: FW
authors: Pratiwi
authors: Research Center for Applied Sciences, Academia Sinica, Taipei, Taiwan.
authors: Chih-Hao
authors: CH
authors: Hsia
authors: Research Center for Applied Sciences, Academia Sinica, Taipei, Taiwan. Electronic address: kuo55@gate.sinica.edu.tw.
authors: Chiung Wen
authors: CW
authors: Kuo
authors: Institute of Physics, Academia Sinica, Taipei, Taiwan.
authors: Shun-Min
authors: SM
authors: Yang
authors: Institute of Physics, Academia Sinica, Taipei, Taiwan.
authors: Yeu-Kuang
authors: YK
authors: Hwu
authors: Research Center for Applied Sciences, Academia Sinica, Taipei, Taiwan. Electronic address: peilin@gate.sinica.edu.tw.
authors: Peilin
authors: P
authors: Chen
mesh_terms: D015374:Biosensing Techniques / Q000379:methods*; D002413:Cations, Divalent / Q000737:chemistry; D005456:Fluorescent Dyes / Q000737:chemistry*; D006367:HeLa Cells; D006801:Humans; D006863:Hydrogen-Ion Concentration; D008345:Manganese / Q000737:chemistry*; D008856:Microscopy, Fluorescence / Q000379:methods; D061848:Optical Imaging / Q000379:methods; D010396:Penicillamine / Q000737:chemistry*; D045663:Quantum Dots / Q000737:chemistry*; D013050:Spectrometry, Fluorescence / Q000379:methods
chemical_list: D002413:Cations, Divalent; D005456:Fluorescent Dyes; D008345:Manganese; D010396:Penicillamine
keywords: D-penicillamine; Intracellular pH; Mn(2+) quantum dots; Ratiometric sensing; Single fluorophore