ABSTRACT
Covalent organic frameworks (COFs) for detecting biological macromolecules in water or biological environments are generally challenging. In this work, a composite material IEP-MnO2 is obtained by combining manganese dioxide (MnO2) nanocrystals and a fluorescent COF (IEP), which is synthesized by using 2,4,6-tris(4-aminophenyl)-s-triazine and 2,5-dimethoxyterephthalaldehyde. By the addition of biothiols, such as glutathione, cysteine or homocysteine with different sizes, the fluorescence emission spectra of IEP-MnO2 changed ("turn-on" or "turn-off") via different mechanisms. The fluorescence emission of IEP-MnO2 increased in the presence of GSH by the elimination of the FRET (Förster resonance energy transfer) effect between MnO2 and IEP. Surprisingly, due to the formation of a hydrogen bond between Cys/Hcy and IEP, the fluorescence quenching for IEP-MnO2 + Cys/Hcy may be explained via the photoelectron transfer (PET) process, which endows IEP-MnO2 with specificity in distinguishing the detection of GSH and Cys/Hcy compared to other MnO2 complex materials. Therefore, IEP-MnO2 was used to detect GSH and Cys in human whole blood and serum, respectively. The limit of detection for GSH in whole blood and Cys in human serum was calculated to be 25.58 µM and 4.43 µM, which indicates that IEP-MnO2 can be used to investigate some diseases related to GSH and Cys concentration. Moreover, the research expands the application of covalent organic frameworks in the fluorescence sensing field.
ABSTRACT
Improving the luminescence properties of covalent organic frameworks (COFs) has always been an important issue. Here, a series of COFs (([OMe]x -TzDa (TzDa is composed only by monomerics Tz and Da, OMe represents the incorporation of monomeric Dm)) with different ratios of OMe and OH were designed and synthesized. The photochemical behavior of [OMe]x -TzDa changed significantly due to the synergistic effect of aggregation induced emission (AIE), intramolecular charge transfer (ICT), and excited-state intramolecular proton transfer (ESIPT) effects. [OMe]2 -TzDa, which contained a ratio of 2/1 of OMe/OH, showed the strongest fluorescence emission in water and the best linear relationship for the detection of pH. Furthermore, [OMe]2 -TzDa was used to monitor HCl and NH3 gases and showed a color change, visible to the naked eye. Therefore, a "confidential pigment" was successfully made. Moreover, [OMe]2 -TzDa was also applied to detect N2 H4 . The work indicates the [OMe]2 -TzDa can serve as the first fluorescence sensor to detect pH, HCl and NH3 gases, which also shows a good response to N2 H4 .
ABSTRACT
BACKGROUND: To investigate the efficacy of glucocorticoid and terbutaline in the treatment of acute exacerbation of chronic obstructive pulmonary disease (AECOPD). METHODS: 248 patients with AECOPD were assigned into two groups, 124 patients in the control group were only given terbutaline treatment, while 124 patients in the experimental group were treated with glucocorticoid and terbutaline. The effect on lung function and blood gas indexes were compared between the two groups. RESULTS: The total effective rate of the treatment with glucocorticoid and terbutaline was higher than that of control group (P < 0.05). After treatment, the pulmonary function indexes such as FEV1, FVC and PaO2 levels in the two groups were significantly higher than those before treatment, PaCO2 levels were significantly lower than that before the treatment (P < 0.05). CONCLUSIONS: The combined use of glucocorticoid and terbutaline could effectively improve the lung function and blood gas indexes. It's of great significance to promote the rehabilitation of patients with AECOPD, and it provides insights for future clinical practice.
