Carbon Nanotube-Based Nanosensor Reports Lysosomal pH and Autophagy Activation in vivo

Abstract

One of the major challenges in studying biological systems is the dearth of robust tools available to monitor dynamic biological processes in live cells and animals. For example, current techniques to measure autophagy are either ex vivo or involve conventional fluorophores/fluorescent proteins, which can be used for in vitro measurements but present problems in vivo. In this presentation, we show the development of optical nanosensors that non-invasively monitor autophagy-associated lysosomal pH changes. The sensor technology is based on quantum-defect-modified fluorescent carbon nanotubes, often called organic color centers (OCCs). OCC fluorescence is bright, photostable, and optically tunable by the chemical nature of the color center. We designed the OCC-nanosensors to be sensitive and selective to endolysosomal pH. Their unique chemical and photophysical properties enabled dynamic and quantitative measurements of lysosomal pH in live cells and in vivo. We will discuss how we utilize these capabilities to facilitate previously inaccessible mechanistic insights in the fields of cancer biology.