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In this work, the binding characteristics of methylene blue (MB) to human serum albumin (HSA) and the influence of Cu(2+) and Fe(3+) on the binding affinity of MB to HSA were investigated using fluorescence, absorption, circular dichroism (CD) spectroscopy and molecular modelling. The results of competitive binding experiments using the site probes ketoprofen and ibuprofen as specific markers suggested that MB was located in site I within sub-domain IIA of HSA. The molecular modelling results agreed with the results of competitive site marker experiments and the results of CD spectra indicated that the interaction between MB and HSA caused the conformational changes in HSA. The binding affinity of MB to HSA was enhanced but to a different extent in the presence of Cu(2+) and Fe(3+), respectively, which indicated that the influence of different metal ions varied. Enhancement of the binding affinity of MB to HSA in the presence of Cu(2+) is due to the formation of Cu(2+)-HSA complex leading to the conformational changes in HSA, whereas in the presence of Fe(3+), enhancement of the binding affinity is due to the greater stability of the Fe(3+)-HSA-MB complex compared with the MB-HSA complex., (Copyright © 2015 John Wiley & Sons, Ltd.)

The sonodynamic damage to protein in the presence of methylene blue (MB) and the various influencing factors including ultrasonic irradiation time and MB concentration on the damage of protein were studied by fluorescence and absorption spectra. In addition, the mechanisms of the synergistic effects of ultrasound and MB were studied by oxidation-extraction photometry with several reactive oxygen species (ROS) scavengers. The results indicated that the damage of protein induced by the synergistic effects of ultrasound and MB were more serious than those that ultrasound or MB alone was applied. The damage of protein could be mainly due to the generation of ROS. The damage degree of protein increased with the increase of ultrasonic irradiation time and MB concentration because of the increased quantities of ROS generation. Both (1)O₂ and ·OH were the important mediators of the ultrasound-inducing protein damage in the presence of MB., (Copyright © 2014 Elsevier B.V. All rights reserved.)

Synthesis of three-dimensional flower-like BiFeO 3 and its removal of methylene blue (MB) by sonocatalysis. [Display omitted] • Sonocatalytic activity of BiFeO 3 was effectively enhanced by morphology control. • Sonocatalytic degradation ratio of MB reached 94.24 ± 1.98 % using BiFeO 3. • BiFeO 3 showed good application potential in environmental remediation. In this paper, three-dimensional flower-like BiFeO 3 was prepared by hydrothermal method by controlling the synthesis temperature and the concentration of precursor and adjusting the morphology of BiFeO 3. When the synthesis temperature was 433 K and the precursor concentration was 0.20 mol/L, the prepared BiFeO 3 -0.20 had the best sonocatalytic performance. Under the optimal conditions of catalyst dosage of 0.67 g/L, methylene blue (MB) initial concentration of 5 mg/L, MB solution initial pH of 7, ultrasonic power of 500 W and ultrasonic time of 120 min, the maximum removal rate of MB by BiFeO 3 -0.20 as a sonocatalyst could reach 94.24 ± 1.98 %. The prepared BiFeO 3 had excellent reusability and good stability. Moreover, the possible degradation pathways of MB were suggested according to the results of liquid chromatography-mass spectrometry and ion chromatography. The results indicated that morphology control was an effective method to improve the sonocatalytic performance of catalysts. It is hoped that the research results can provide an effective reference for the development of efficient sonocatalysts and the practical application of sonocatalysis technology. [ABSTRACT FROM AUTHOR]

In this work, the binding characteristics of methylene blue (MB) to human serum albumin (HSA) and the influence of Cu2+ and Fe3+ on the binding affinity ofMBto HSAwere investigated using fluorescence, absorption, circular dichroism(CD) spectroscopy andmolecular modelling. The results of competitive binding experiments using the site probes ketoprofen and ibuprofen as specific markers suggested that MB was located in site I within sub-domain IIA of HSA. The molecular modelling results agreed with the results of competitive site marker experiments and the results of CD spectra indicated that the interaction betweenMB and HSA caused the conformational changes in HSA. The binding affinity ofMB to HSAwas enhanced but to a different extent in the presence of Cu2+ and Fe3+, respectively, which indicated that the influence of different metal ions varied. Enhancement of the binding affinity of MB to HSA in the presence of Cu2+ is due to the formation of Cu2+-HSA complex leading to the conformational changes in HSA, whereas in the presence of Fe3+, enhancement of the binding affinity is due to the greater stability of the Fe3+-HSA-MB complex compared with the MB-HSA complex. [ABSTRACT FROM AUTHOR]

Preparation of Ag 2 O/CaMoO 4 S-type heterojunction and its sonocatalytic degradation of crystal violet (CV). [Display omitted] • S-type of Ag 2 O/CaMoO 4 heterojunction had excellent sonocatalytic activity. • Degradation rate of CV reached 97.36 ± 1.46(%) using Ag 2 O/CaMoO 4 as sonocatalyst. • O 2 –, OH and h + generated during sonocatalysis played major roles for CV degradation. • Ag 2 O/CaMoO 4 was an appropriate sonocatalyst for degradation of organic pollutants. Herein, an S-type of Ag 2 O/CaMoO 4 heterojunction was prepared by combining CaMoO 4 with Ag 2 O and characterized. The sonocatalytic performance of the Ag 2 O/CaMoO 4 composite was evaluated by analyzing the degradation of basic dye crystal violet (CV). The results showed that the Ag 2 O/CaMoO 4 composite had the best sonocatalytic performance when the molar ratio of Ag 2 O to CaMoO 4 in the Ag 2 O/CaMoO 4 composite was 10 %. When the ultrasonic time was 120 min, the ultrasonic power was 200 W, the addition amount of 10 % Ag 2 O/CaMoO 4 composite was 1.00 g/L and the initial concentration of CV solution was 5 mg/L, the removal rate of CV could reach 97.36 ± 1.46(%). In addition, 10 % Ag 2 O/CaMoO 4 composite showed excellent sonocatalytic degradation performance to cationic dyes Rhodamine B (RhB) and methylene blue (MB), anionic dye Orange II (AO II) and azo dye Congo red (CR), indicating that the catalyst had a wide range of application. The study on the mechanism of sonocatalysis showed that the construction of S-type Ag 2 O/CaMoO 4 heterojunction effectively separated the electron-hole (e −- h +) pairs in the sonocatalysis process, significantly improved the sonocatalytic performance of CaMoO 4 , and effectively degraded CV, and the degradation of CV was caused by the active components such as h +, superoxide anion radical (O 2 –) and hydroxyl radical (OH). Furthermore, the 10% Ag 2 O/CaMoO 4 composite showed excellent repeatability and stability. In addition, the sonocatalytic degradation products of CV were detected and the possible degradation pathways of CV were summarized. These results suggested that the Ag 2 O/CaMoO 4 composite was an extremely appropriate sonocatalyst for sonocatalytic degradation of organic pollutants and would provide a valuable research basis for the development of efficient sonocatalysts. [ABSTRACT FROM AUTHOR]

We present a non-modification electrochemical DNA sensing strategy, which used Potential-Assisted Au-S Deposition and a clamp-like DNA probe. The dual-hairpin probe DNA was tagged with a methylene blue (MB) at the 3′ terminal and a thiol at the 5′ terminal., Without being hybridized with target DNA, the loop of probe prevented the thiol from reaching the bare gold electrode surface with an applied potential., After hybridization with the target DNA, the probe’ s loop–stem structure opened through two distinct and sequential events, which led to the formation of a triplex DNA structure. Then the thiol easily contacted with electrode and resulted in potential-assisted Au-S self-assembly. Electrochemical signals of MB were measured by differential pulse voltammetry (DPV) and used for target quantitative detection. This strategy offered a detection limit down to 2.3 pM. and an inherently high specificity for detecting even single mismatch. [ABSTRACT FROM AUTHOR]