Ratiometric Fluorescence pH Sensing and Single-particle Tracking in Cancer Cell
Date Issued
2012
Date
2012
Author(s)
Chu, Jia-Yin
Abstract
The intracellular pH is an important modulator of cell functions. Since the activities of most proteins are affected by very small changes of the proton concentration, there are a number of cellular mechanisms that finely regulate the intracellular pH values (pHi). Therefore, monitoring pHi with high spatial resolution could help us to elucidate many physiological or pathogenic processes taking place within cells.
We synthesized 100 nm mesoporous silica nanoparticles with a pH-sensitive dye, FITC and a pH-insensitive dye, RITC. This nanoparticle was employed to estimate the pHi by the fluorescence intensity ratio of FITC to RITC. We conjugated high amount of dyes to improve the photostability of the dyed nanoparticles. Besides, we modified the surface by post-modification to form two different nanoparticles, positively charged TA-hMSN and negatively charged THPMP-hMSN. The nanoparticles were characterized with various physical methods. Then, we used the single-particle tracking (SPT) system to examine the interaction between the nanoparticles and HeLa cells. We obtained the trajectories of nanoparticles during the uptake process and were able to estimate the fluorescence ratio in the local environment simultaneously.
Subjects
silica nanoparticles
ratiometric fluorescence
intracellular pH value
single-particle tracking
SDGs
Type
thesis
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