A reversible plasmonic nanoprobe for dynamic imaging of intracellular pH during endocytosis

Understanding the pH evolution during endocytosis is essential for our comprehension of the fundamental processes of biology as well as effective nanotherapeutic design. Herein, we constructed a plasmonic Au@PANI core–shell nanoprobe, which possessed significantly different scattering properties under acidic and basic conditions. Encouragingly, the scattering signal of Au@PANI nanoprobes displayed a positive linear correlation with the pH value not only in PBS but also in nigericin-treated cells. Ultimately, benefiting from the excellent response properties as well as the excellent biocompatibility and stability, the Au@PANI nanoprobes have successfully enabled a dynamic assessment of the evolving pH in the endosomal package as the endosome matured from early to late, and eventually to the lysosome, by reporting scattering signal changes.