Nanoscale Metal-Organic Frameworks For Ratiometric Oxygen Sensing In Live Cells

We report the design of a phosphorescence/fluorescence dual-emissive nanoscale metal-organic framework (NMOF), R-UiO, as an intracellular oxygen (O-2) sensor. R-UiO contains a Pt(II)-porphyrin ligand as an O-2-sensitive probe and a Rhodamine-B isothiocyanate ligand as an O-2-insensitive reference probe. It exhibits good crystallinity, high stability, and excellent ratiometric luminescence response to O-2 partial pressure. In vitro experiments confirmed the applicability of R-UiO as an intracellular O-2 biosensor. This work is the first report of a NMOF-based intracellular oxygen sensor and should inspire the design of ratiometric NMOF sensors for other important analytes in biological systems.