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FITC and Ru(phen)3 2+ co-doped silica particles as visualized ratiometric pH indicator

Jianquan Xu1, Lei Sun2, Jun Li1, Jinglun Liang1, Huimao Zhang3* and Wensheng Yang1*

Author Affiliations

1 State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University, Changchun 130012, People's Republic of China

2 College of Public Health, Jilin University, Changchun, Jilin, 130021, People's Republic of China

3 China-Japan Union Hospital, Jilin University, Changchun 130033, People's Republic of China

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Nanoscale Research Letters 2011, 6:561  doi:10.1186/1556-276X-6-561

Published: 25 October 2011


The performance of fluorescein isothiocyanate (FITC) and tris(1, 10-phenanathroline) ruthenium ion (Ru(phen)32+) co-doped silica particles as pH indicator was evaluated. The emission intensity ratios of the pH sensitive dye (FITC) and the reference dye (Ru(phen)32+) in the particles were dependent on pH of the environment. The changes in emission intensity ratios of the two dyes under different pH could be measured under single excitation wavelength and readily visualized by naked eye under a 365-nm UV lamp. In particular, such FITC and Ru(phen)32+ co-doped silica particles were identified to show high sensitivity to pH around the pKa of FITC (6.4), making them be potential useful as visualized pH indicator for detection of intracellular pH micro-circumstance.

pH indicator; visualized; silica particles; ratiometric; fluorescein; ruthenium complex