Precise lysosome pH indicator based on self-decomposable nanoparticles

Abstract

Background Acidic pH of lysosomes are closely related to the autophagy, thus well known of the precise lysosomes pH changes will give more information on the autophagy process and status. So far, however, only pH changes in a relative broad range could be indicated, the exactly lysosomes pH detection has never arrived. Methods In our study, we established an endo/lysosome pH indicator based on self-decomposable SiO 2 nanoparticle system with specific synthesis parameters. The central concentrated MB in the central-hollow structural nanoparticles presented sensitive release as a function of pH values from pH 4.0-4.8, which is the exactly the pH range of lysosomes. The linear correlation of the OD values and the pH values has been built up, which has been used for detection of lysosomes pH in 6 different cell lines. Results By this system, we succeeded in precise detecting the pH average changes of lysosomes before and after BPSi NPs endocytosis, clarifying the mechanism of the autophagy termination after BPSi endocytosis. Conclusions The self-decomposable nanoparticles based luminal pH indicator may provide a new methodology and strategy to know better of the lysosome pH, then indicate more details on autophagy process or other important signaling about metabolism.