Real-time monitoring of vesicle pH in an endocytic pathway using an EGF-conjugated two-photon probeElectronic supplementary information (ESI) available: Synthesis, additional methods, scheme, figures, table and videos (Scheme S1, Fig. S1-S13, Table S1 and Videos S1 and S2). See DOI: 10.1039/c6cc08036g

Herein, we developed a ratiometric two-photon probe ( BHS3-EGF ), derived from a pH sensitive dye and epidermal growth factor (EGF), for real-time monitoring and quantitative analysis of acidic luminal pH values during endocytic pathway activity. Two-photon microscopy imaging with BHS3-EGF allows the quantitative analysis of pH distributions of single vesicles and their dynamics in receptor-mediated endocytosis in real-time. An EGF-conjugated two-photon probe for real-time monitoring and quantitative analysis of luminal pH values during endocytic pathway activity was reported.