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Optical oxygen sensing by MPA-capped CdTe quantum dots immobilized in mesoporous silica
摘要： A novel nanocomposite luminescent material was prepared by taking advantage of the versatile wet impregnation method for the dispersion of CdTe quantum dots (QDs) into mesoporous silica host matrix and thus providing great interaction between oxygen and QDs, with potential application in an optical oxygen sensor. The optical/spectroscopic properties of the QDs suspended in aqueous media and incorporated in mesoporous silica were evaluated as a function of aging time, temperature variation and oxygen concentration. Luminescence quenching studies were carried out for both QDs suspended in solution and loaded into the silica matrix, in the presence of varying O2 concentration. By Stern-Volmer plot analysis, obtained at different temperatures, it was possible to verify the existence of two types of emission quenching mechanisms for CdTe QDs. After aging for 120 days at room temperature, the QDs in colloidal suspension displayed a small red-shifted emission, which was interpreted as a decreased bandgap energy owing to the increase in the nanocrystal size. In contrast, the emission spectrum of CdTe QDs loaded into the mesoporous SiO2 matrix remained unchanged after aging for the same time at ambient temperature. The presented results will contribute to the discernment of oxygen quenching mechanisms and chemical stability of optical sensors based on CdTe QDs.
关键词： oxygen sensors,mesoporous silica,Quantum Dots,CdTe,wet impregnation,fluorescence quenching
更新于2025-09-23 15:21:01
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Amphiphilic Fluorine-Containing Block Copolymers as Carriers for Hydrophobic PtTFPP for Dissolved Oxygen Sensing, Cell Respiration Monitoring and In Vivo Hypoxia Imaging with High Quantum Efficiency and Long Lifetime
摘要： New amphiphilic star or multi-arm block copolymers with different structures were synthesized for enabling the use of hydrophobic oxygen probe of platinum (II)-tetrakis (pentafluorophenyl) porphyrin (PtTFPP) for bioanalysis. The amphiphilic star polymers were prepared through the Atom Transfer Radical Polymerization (ATRP) method by using hydrophilic 4-arm polyethylene glycol (4-arm-PEG) as an initiator. Among the five block copolymers, P1 series (P1a, P1b, and P1c) and P3 possess fluorine-containing moieties to improve the oxygen sensitivity with its excellent capacity to dissolve and carry oxygen. A polymer P2 without fluorine units was also synthesized for comparison. The structure-property relationship was investigated. Under nitrogen atmosphere, high quantum efficiency of PtTFPP in fluorine-containing micelles could reach to 22% and long lifetime could reach to 76 μs. One kind of representative PtTFPP-containing micelles was used to detect the respiration of Escherichia coli (E. coli) JM109 and macrophage cell J774A.1 by a high throughput plate reader. In vivo hypoxic imaging of tumor-bearing mice was also achieved successfully. This study demonstrated that using well-designed fluoropolymers to load PtTFPP could achieve high oxygen sensing properties, and long lifetime, showing the great capability for further in vivo sensing and imaging.
关键词： fluoropolymers,tumor imaging,cell respiration monitoring,dissolved oxygen sensors,micelles
更新于2025-09-10 09:29:36
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Impact of bidentate N,C-Chelate ligands on the performance of phosphorescent Pt(II) complexes as oxygen sensors
摘要： A library of 1,2- cyclometalated Pt(II) complexes based on various bidentate N,C-chelate chromophores have been studied for their uses as luminescent oxygen sensing probes (OSPs). The bidentate chelate ligands have been found to have a distinct impact on the performance of the Pt(II) compounds as OSPs. For some of the complexes, attachment of a dimesityl boron group (BMes2) to the chelate ligands enhances their oxygen sensitivity. For phenyl-1,2,3-triazole (Phtrz) based Pt(II) complexes, the attachment of a diphenyl amino moiety to the N,C-chelate ligand substantially enhances phosphorescence quenching and the performance of the OSP. A high (cid:1)(cid:2)(cid:3) (cid:4)(cid:5)(cid:5) value (0.0667 Torr-1) for the OSP based on the diphenyl amino functionalized Pt(II) complex was achieved, which is the highest value reported to date for OSPs based on bidentate Pt(II) complexes.
关键词： C-chelate ligands,N,phosphorescence,Pt(II) complexes,oxygen sensors
更新于2025-09-09 09:28:46