Lan Guo,Yuan Liu,Rongmei Kong,Guang Chen,Hao Wang,Xiuli Wang,Lian Xia,Fengli Qu
β-Glucuronidase (β-GCU) is closely related to the occurrence of multiple diseases, and it has been applied as a biomarker and therapeutic target in clinical diagnosis. However, reliable methods with high selectivity and sensitivity for monitoring β-GCU are still lacked. Herein, we designed a novel fluorescent nanoprobe, rhodamine B encapsulated MOF-5 (RhB@MOF-5) for the first time, to detect β-GCU through the synergistic effect of inner filter effect (IFE) and static quenching effect (SQE) by employing 4-nitrophenyl-β-D-glucuronide (PNPG) as the substrate. After encapsulating into MOF-5, the fluorescence emission of RhB at 550 nm excited by 320 nm was greatly enhanced. The major overlap between the fluorescence excitation spectrum of RhB@MOF-5 (about 320 nm) and the ultraviolet absorption spectrum of PNPG (about 310 nm) lead to PNPG being a good IFE absorber in this sensing system. Under the optimized conditions, the excitation spectrum of the RhB@MOF-5 could be absorbed by PNPG, resulting in the dramatically decrease of fluorescence emission. After adding β-GCU into the system, the substrate of PNPG would be enzymatic hydrolyzed to p -nitrophenol (PNP) and glucose, then the IFE disappearance and the fluorescence recovered. The current sensing platform was interference-free and exhibited a broad linearity relationship for β-GCU range of 0.1–10 U L −1 (R 2 = 0.9957) with a limit of detection as low as 0.03 U L −1 , which was reduced by more than one orders compared with the reported methods. Moreover, the encapsulation of dyes using porous nanoparticles to achieve some tailor-made characteristics will enrich experimental design inspiration.
Jingyi Li,Ning Zhang,Xin Yang,Xinting Yang,Zengli Wang,Huan Liu
This study presents a novel composite thin film based on rhodamine B encapsulated into MOF-5 (Metal Organic Frameworks) as a fluorescence sensor for the real-time detection of the freshness of chilled pork. The composite film can adsorb and respond to the volatile amines produced by the quality deterioration of pork during storage at 4 °C, with the fluorescence intensity of RhB decreasing over time. The quantitative model used for predicting the freshness indicator (total volatile base nitrogen) of pork was built using the fluorescence spectra (excited at 340 nm) of the RhB@MOF-5 composite film combined with the partial least squares (PLS) algorithm, providing Rc2and Rp2values of 0.908 and 0.821 and RMSEC(root mean square error of calibration) and RMSEP (root mean square error of prediction) values of 3.435 mg/100 g and 3.647 mg/100 g, respectively. The qualitative model established by the partial least squares discriminant analysis (PLS-DA) algorithm was able to accurately classify pork samples as fresh, acceptable or spoiled, and the accuracy was 86.67%.
危险品化学品经营许可证（带存储）