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. Author manuscript; available in PMC: 2012 Feb 29.
Published in final edited form as: Adv Funct Mater. 2010 Nov 9;20(21):3721–3726. doi: 10.1002/adfm.201000711

Figure 5.

Figure 5

Stability comparison of QDMMs before and after silica encapsulation. (a) Relative fluorescence intensity of QDMM, QDMM@SiO2 and QDMM@SiO2-FITC in solutions with pH ranging from 1 to 12. Between pH 5 and 8, the fluorescence fluctuation of QDMM@SiO2 and QDMM@SiO2-FITC was below the measurement standard deviations; whereas at pH 5, the fluorescence of uncoated QDMMs decreased by more than 50%. Under strongly acidic or basic conditions, the fluorescence of QDMM@SiO2 fluctuated at a lesser degree compared with QDMMs. (b) In situ microscopy imaging of QDMM and QDMM@SiO2-FITC at pH 4. The QDMMs were quenched significantly faster than the silica encapsulated microbeads. The two sets of microbeads were distinguishable when excited at 480 nm due to the FITC emission. (c) Chemical stability of QDMM, QDMM@SiO2 and QDMM@SiO2-FITC when treated with common bioconjugation reagents.