The Study Of Fluorescent Oxygen Nanosensors Based On Pyrene Dyes

Because of the advantages of high sensitivity, short response time and non-invasive, the oxygen fluorescence detection has important application value in many fields such as industrial production, food, and biomedical. And at the same time, a variety of fluorescent oxygen probe molecule have been applied in optical oxygen sensors. Pyrene is an aromatic, polycyclic hydrocarbon with planer structure, which has been applied in organic solvent and film oxygen sensors because of the characteristic photophysical properties such as high quantum yield and oxygen-sensitive fluorescence.This paper also adopts the pyrene molecular as a fluorescence oxygen probe, but there are two innovation.(1) The as-prepared sensors have nanometer size in diameter, which is beneficial to increase the oxygen diffusion rate and shorten the response time;(2) Modulating the sensor lend to fluorescence redshift from monomer to excimer, which increase the Stokes shift and reduce the background. This improves the detection accuracy of the sensor. The main task of this research are:(1) Fluorescent oxygen nanosensors are prepared by a one-step reprecipitation-encapsulation method, which are based on polystyrene and silicone hybrid material as a substrate doped pyrene. The diameter of the nanosensor is about105nm. Since both the pyrene monomer and excimer are sensitive to oxygen, the nanosensors based on monomer emission and excimer emission respectively are designed. Oxygen sensitivity are studied based on fluorescence intensity. The study found that in the solid nanoparticles matrix, the oxygen sensitivity of pyrene monomer fluorescence intensity is24%, but it is not easy occurring predominantly excimer emission oxygen sensor.(2) Pyrene oxygen nanosensors are prepared based on CTAB micelles by direct dissolution method in the aqueous phase. The diameter of micelle sensor is about348nm. By adjusting the concentration of pyrene molecules in micelle can be easily achieved pyrene monomer emission and excimer emission. The critical concentration of excimer emission is0.3mM. The excimer fluorescence is sensitive to dissolved oxygen in both intensity and lifetime, and the respective Stern-Volmer plot follows a nonlinear behavior justified by a two-site model. This work studied the luminescent properties of pyrene molecules in the solid nanoparticles and dynamic micelles. And the corresponding oxygen-sensitive characteristics are studied. The results obtained have some reference for building pyrene and its derivatives as a probe molecule.