Rapid synthesis of fluorescent bovine serum albumin-gold nanoclusters complex for glutathione determination

A facile one-pot method for synthesis of bovine serum albumin (BSA)-gold nanoclusters (AuNCs) has been developed. The formation of BSA-AuNCs took only 30 s under mild conditions. BSA-AuNCs exhibited strong orange-yellow fluorescence, and the excitation and emission peaks were at 370 nm and 564 nm, respectively. In the process of forming BSA-AuNCs, the molecular chain of BSA has not been destroyed. Moreover, there were a large number of Au cations on the surface of BSA-AuNCs, which had strong oxidizing abilities. The reason for the ultrabright fluorescence of BSA-AuNCs was attributed to the Au(0)@Au(I)@Au(III)-ligand structure on the surface of BSA. In order to evaluate the fluorescence performance of BSA-AuNCs, BSA-AuNCs was used as a probe, realizing the sensitive and selective determination of glutathione (GSH) in a wide linear range of 0.01-0.48 μM and a detection limit of 3.3 nM. The proposed method not only offers a brand-new scheme for synthesizing BSA-AuNCs, but also provides a platform for studying the interaction between metal core and proteins. A facile one-pot method to synthesize ultrabright fluorescent BSA-AuNCs in tens of seconds has been introduced by mixing BSA suspension, KSCN, and HAuCl₄. The as-prepared BSA-AuNCs showed intensive orange-yellow fluorescence under a UV lamp (365 nm)_, and BSA still keeps the integral molecular chains during the whole synthesis process. Moreover, the as-prepared BSA-AuNCs have realized the sensitive and selective detection of glutathione (GSH) in a wide linear range of 0.01-0.48 μM and a detection limit of 3.3 nM.

Removal of benzene by non-thermal plasma catalysis over manganese oxides through a facile synthesis method

Three manganese oxide catalysts (MnO_x) were synthesized via a simple method, and then they were introduced into the non-thermal plasma (NTP) system for benzene removal. The XRD and EXAFS results showed the MnO_x were mainly in the Mn₃O₄ phase, and from the analysis of N₂ adsorption/desorption isotherms, we knew the MnO_x calcined at 250 °C (Mn250) had the largest surface area of 274.5 m² g^-1. Besides, Mn250 also exerted higher benzene adsorption capacity (0.430 mmol g^-1) according to C₆H₆-TPD. O₂-TPD indicated that Mn250 showed better oxygen mobility than Mn300. Moreover, by analyzing XPS results, it revealed that Mn250 exhibited rich abundant of surface adsorbed oxygen species (O_ads) and moderate ratio of Mn⁴⁺/Mn³⁺, and the reducibility temperature was also the lowest among all the MnO_x catalysts drawn by H₂-TPR profiles. As a result, Mn250 combined with NTP could remove 96.9% of benzene at a low input power of 3 W (benzene concentration 200 ppm, and GHSV 60,000 mL g_cat.^-1 h^-1), performing the best catalytic activity among the three catalysts and plasma only. Furthermore, the "NTP + Mn250" system also produced the highest CO₂ concentration and lowest CO concentration in downstream, and the residual O₃ after catalytic reaction was also the lowest, that is to say, the synergistic effect between NTP and Mn250 was more effective than other catalysts in benzene removal. Graphical abstract.