A simple and sensitive sensor for lactose based on cascade reactions in Au nanoclusters and enzymes co-encapsulated metal-organic frameworks
Authors: Guo, Manli; Chi, Jingtian; Zhang, Chi; Wang, Minglin; Liang, Hui; Hou, Juying; Ai, Shiyun; Li, Xiangyang
In this work, one kind of zeolite imidazole frameworks containing bovine serum albumin stabilized Au nanoclusters (AuNCs), beta-galactosidase (beta-Gal) and glucose oxidase (GOx) (AuNCs/beta-Gal/GOx@ZIF-8) were obtained to detect lactose. Compared with other fluorescent nano-materials, AuNCs show distinct advantages as a guest species in ZIF-8, specifically their extremely small size ( < 1 nm), simple synthesis, excellent biocompatibility and high stability. Furthermore, the bovine serum albumin on their surfaces can promote the formation of ZIF-8 coating; thus, AuNCs were co-encapsulated in ZIF-8 with the enzymes together. X-ray diffraction (XRD) analysis indicates the composite possesses the similar crystalline structure with pure ZIF-8. Fluorescence microscope images, Fourier transform infrared spectra and energy dispersive X-ray spectroscopy indicate the presence of AuNCs in the composite. Owing to the high local concentrations of the fluorescent probe and the quenching agent in AuNCs/beta-Gal/GOx@ZIF-8, the quenching rate was enhanced 3.4-fold that of free AuNCs and enzymes in solution.
Urchin-like trimanganese tetraoxide particles with oxidase-like activity for glutathione detection
COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
Authors: Zheng, Xuefang; Lian, Qi; Zhou, Liya; Jiang, Yanjun; Gao, Jing
Urchin-like trimanganese tetroxide (Mn3O4) particles were synthesized through a simple and gentle method, and characterized by XRD, XPS, FTIR, SEM, TEM, and UV-vis absorption. The intrinsic enzyme-like activity of urchin-like Mn3O4 particles was evaluated by 3, 3', 5, 5'-tetramethylbenzidine (TMB) in the absence of H2O2. The optimization of experiment conditions of urchin-like Mn3O4 particles on the oxidase-like activity was further investigated. It was exhibited that urchin-like Mn3O4 particles were best-performing with a highly oxidase-like catalytic activity in the model reaction. Due to the selective inhibition of glutathione (GSH) on the high oxidase-like activity of urchin-like Mn3O4 particles, a selective and sensitive colorimetric assay for GSH had been established. The method exhibited linear relationship over the GSH concentration range from 0.1 mu M to 30 mu M, with a low detection limit of 20.0 nM and a rapid response of less than 3 min. Based on high specificity of GSH inhibition, urchin-like Mn3O4 particles could be used to detect GSH concentration in human serum samples. [GRAPHICS]