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[摘要]：Ratiometric fluorescent core-shell nanoparticles (NPs) with good biocompatibility are successfully prepared by a one-step reprecipitation-encapsulation method for sensing dissolved oxygen. The particle core comprises the oxygen probe platinum(II) octaethylporphine (PtOEP), the reference dye coumarin 6 (C6) and a third fluorophore dinaphthoylmethane (DNM). Upon single 381 nm excitation, C6 gives oxygen-insensitive referenced green fluorescence via intraparticle FRET from DNM, whilst PtOEP yields highly oxygen-sensitive red phosphorescence with a quenching response of 94%. The fluorescence quenching of the NPs against oxygen follows a linear Stern-Volmer behavior, which is fundamental for practical sensing. Moreover, positively charged poly-L-lysine molecules are in situ self-assembled onto the surface of NPs during synthesis. The resultant core-shell NPs with functional groups exhibit low cytotoxic effects as well as effortless cellular uptake, indicating targeted intracellular oxygen sensing is very promising using the oxygen nanosensors. |
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