News Column

Investigators from Saitama University Have Reported New Data on Luminescent Agents

June 27, 2014

By a News Reporter-Staff News Editor at Science Letter -- Current study results on Luminescent Agents have been published. According to news reporting from Saitama, Japan, by NewsRx journalists, research stated, "Dual pH-dependent fluorescence peaks from a semiconductor quantum dot (QD) and a pH-dependent fluorescent dye can be measured by irradiating with a single wavelength light, and the pH can be estimated from the ratio of the fluorescent intensity of the two peaks. In this work, ratiometric pH sensing was achieved in an aqueous environment by a fluorescent CdSe/ZnS QD appended with a pH-sensitive organic dye, based on fluorescence resonance energy transfer (FRET)."

The news correspondents obtained a quote from the research from Saitama University, "By functionalizing the CdSe/ZnS QD with 5-(and 6)-carboxynaphthofluorescein succinimidyl ester as a pH-dependent fluorescent dye, we succeeded in fabricating sensitive nanocomplexes with a linear response to a broad range of physiological pH levels (7.5 - 9.5) when excited at 450 rim. We found that a purification process is important for increasing the high-fluorescence intensity ratio of a ratiometric fluorescence pH-sensor, and the fluorescence intensity ratio was improved up to 1.0 at pH 8.0 after the purification process to remove unreacted CdSe/ZnS QDs even though the fluorescence of the dye could not be observed without the purification process. The fluorescence intensity ratio corresponds to the fluorescence intensity of the dye, and this fluorescent dye exhibited pH-dependent fluorescence intensity changes. These facts indicate that the fluorescence intensity ratio linearly increased with increasing pH value of the buffer solution containing the QD and the dye."

According to the news reporters, the research concluded: "The FRET efficiencies changed from 0.3 (pH 7.5) to 6.2 (pH 9.5)."

For more information on this research see: CdSe/ZnS Quantum Dots Conjugated with a Fluorescein Derivative: a FRET-based pH Sensor for Physiological Alkaline Conditions. Analytical Sciences, 2014;30(5):545-550. Analytical Sciences can be contacted at: Japan Soc Analytical Chemistry, 26-2 Nishigotanda 1 Chome Shinagawa-Ku, Tokyo, 141, Japan (see also Luminescent Agents).

Our news journalists report that additional information may be obtained by contacting T. Kurabayashi, Saitama Univ, Dept. of Funct Mat Sci, Sakura Ku, Saitama 3388570, Japan. Additional authors for this research include N. Funaki, T. Fukuda, S. Akiyama and M. Suzuki.

Keywords for this news article include: Asia, Japan, Saitama, Quantum Dots, Nanotechnology, Coloring Agents, Quantum Physics, Fluorescent Dyes, Luminescent Agents, Laboratory Chemicals, Emerging Technologies

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Source: Science Letter

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