Figure 4: Cellular uptake responsive NIR-fluorescence.
From: Lysosome triggered near-infrared fluorescence imaging of cellular trafficking processes in real time
(a) Emission spectra of 2 (5 × 10−6 M) in DMEM (10% FBS) at pH ranging from 8 (grey) to 2 (red). Exc: 625 nm. Inset: fluorescence intensity at λmax=707 nm versus pH; sigmoidal plot fit resulted in apparent pKa=4.0. (b) Corresponding FEF values from differing pH solutions applying Cy5.5 filter parameters. (c) Diagram represents the pH changes and increasing fluorescence intensity along endocytic path towards lysosomes.
