Yuwei Guo

Detection and analysis of reactive oxygen species (ROS) generated by nano-sized TiO2 powder under ultrasonic irradiation and application in sonocatalytic degradation of organic dyes

Recently, the sonocatalytic technology using various semiconductors combined with ultrasonic irradiation has been received much attention to solve the environmental problems. In this paper, nano-sized titanium dioxide (TiO(2)) powder as a sonocatalyst was irradiated by ultrasound and the generation of reactive oxygen species (ROS) during sonocatalytic reaction process has been estimated by the method of Oxidation-Extraction Photometry (OEP). That is, the 1,5-diphenylcarbohydrazide (DPCI) can be oxidized by ROS into diphenylcarbonzone (DPCO), which can be extracted by the mixed solution of benzene and carbon tetrachloride and show the great absorbance at 563 nm wavelength. The synergistic effect of TiO(2) and ultrasonic irradiation was estimated and some influencing factors, such as ultrasonic irradiation time and TiO(2) addition amount on the generation of ROS were reviewed. The results indicate that the quantities of generated ROS increase with the increase of ultrasonic irradiation time and TiO(2) addition amount. Moreover, the relationship between quantities of generated ROS and DPCI concentration was also studied. And then, several quenchers were used to determine the kind of the generated ROS. At last, the researches on the sonocatalytic degradation of organic dyes and the corresponding reaction kinetics have also been performed, which is found to follow the pseudo first-order kinetics approximately. This paper may offer some important subjects for broadening the applications of sonocatalytic technology.

Detection of reactive oxygen species (ROS) generated by TiO2(R), TiO2(R/A) and TiO2(A) under ultrasonic and solar light irradiation and application in degradation of organic dyes

In the present work, the rutile, anatase and mixed (rutile and anatase) crystal phase TiO(2) powders were irradiated by ultrasound and solar light, respectively, and the generation of reactive oxygen species (ROS) were detected through the oxidation reaction from 1,5-diphenyl carbazide (DPCI) to 1,5-diphenyl carbazone (DPCO). The DPCO can be extracted by the mixed solvent of benzene and carbon tetrachloride and the extract liquors display an obvious absorption peak around 563nm. In addition, the influences of (ultrasonic or solar light) irradiation time, TiO(2) addition amount and DPCI concentration on the quantities of generated ROS were also reviewed. The kinds of generated ROS were determined by using several radical scavengers. At last, the researches on the sonocatalytic and photocatalytic degradation of several organic dyes were also performed. It is wished that this paper might offer some important subjects for broadening the applications of sonocatalytic and photocatalytic technologies.

Spectroscopic analyses on interaction of o-Vanillin-d-Phenylalanine, o-Vanillin-l-Tyrosine and o-Vanillin-l-Levodopa Schiff Bases with bovine serum albumin (BSA)

In this work, three o-Vanillin Schiff Bases (o-VSB: o-Vanillin-D-Phenylalanine (o-VDP), o-Vanillin-L-Tyrosine (o-VLT) and o-Vanillin-L-Levodopa (o-VLL)) with alanine constituent were synthesized by direct reflux method in ethanol solution, and then were used to study the interaction to bovine serum albumin (BSA) molecules by fluorescence spectroscopy. Based on the fluorescence quenching calculation, the bimolecular quenching constant (K(q)), apparent quenching constant (K(sv)), effective binding constant (K(A)) and corresponding dissociation constant (K(D)) as well as binding site number (n) were obtained. In addition, the binding distance (r) was also calculated according to Fosters non-radioactive energy transfer theory. The results show that these three o-VSB can efficiently bind to BSA molecules, but the binding array order is o-VDP-BSA>o-VLT-BSA>o-VLL-BSA. Synchronous fluorescence spectroscopy indicates that the o-VDP is more accessibility to tryptophan (Trp) residues of BSA molecules than to tyrosine (Tyr) residues. Nevertheless, the o-VLT and o-VLL are more accessibility to Tyr residues than to Trp residues.

Detection and comparison of reactive oxygen species (ROS) generated by chlorophyllin metal (Fe, Mg and Cu) complexes under ultrasonic and visible-light irradiation

In this paper, in order to examine the mechanisms of sonodynamic and photodynamic reactions, the chlorophyllin metal (Chl-M (M=Fe, Mg and Cu)) complexes were irradiated by ultrasound (US) and visible-light (VL), respectively, and the generation of reactive oxygen species (ROS) were detected by the method of Oxidation-Extraction Spectrometry (OES). That is, the 1,5-diphenyl carbazide (DPCI) is oxidized by the generated ROS into 1,5-diphenyl carbazone (DPCO), which can display a various visible absorption around 563 nm wavelength. Besides, some influence parameters on the generation of ROS were also reviewed. The results demonstrated an apparent synergistic effect of Chl-M and ultrasonic or visible-light irradiation for the generation of ROS. Moreover, the quantities of generated ROS increase with the increase of (ultrasonic or visible-light) irradiation time and Chl-M (M=Fe, Mg and Cu) concentration. Finally, several quenchers were used to determine the kind of the generated ROS. It is wished that this paper might offer some valuable references for the study on the sonodynamic therapy (SDT) and photodynamic therapy (PDT) mechanisms and the application of Chl-M in tumor treatment.

An effective quaternary nano-sized Er3+:Y3Al5O12/Pt–PdS/ZnS visible-light photocatalyst for H2 production

A highly effective and stable up-conversion luminescence agent, Er3+:Y3Al5O12, was synthesized by sol–gel and calcination methods. Then, as a novel visible-light photocatalyst, Er3+:Y3Al5O12, Pt and PdS (as dual co-catalysts) decorated ZnS nano-sized composites, Er3+:Y3Al5O12/Pt–PdS/ZnS, were fabricated by deposition–precipitation and ultrasonic dispersion methods. All prepared samples were characterized by X-ray diffractometry (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS) and energy dispersive X-ray spectroscopy (EDX). UV-vis absorption and PL spectra of Er3+:Y3Al5O12 were also determined. The visible-light photocatalytic H2 production activity of the prepared Er3+:Y3Al5O12/Pt–PdS/ZnS was evaluated by using Na2S and Na2SO3 as sacrificial reagents in an aqueous solution under 300 W irradiation from a xenon lamp. In addition, some influential factors such as Er3+:Y3Al5O12 and ZnS mass ratio, catalyst amount, irradiation time and irradiation intensity on visible-light photocatalytic H2 production of Er3+:Y3Al5O12/Pt–PdS/ZnS were investigated in detail. It was found that Er3+:Y3Al5O12 can effectively improve the visible-light photocatalytic activity of ZnS. Particularly, Er3+:Y3Al5O12/Pt–PdS/ZnS with 0.13 wt% PdS and 0.3 wt% Pt and a 0.30 : 1.00 mass ratio shows the highest photocatalytic H2 production activity in the sulfide/sulfite (0.2 mol L−1 Na2S and 0.3 mol L−1 Na2SO3) aqueous solution as sacrificial reagents.

Spectroscopic studies on interaction and sonodynamic damage of metallochlorophyllin (Chl-M (M = Fe, Zn and Cu)) to protein under ultrasonic irradiation

In this paper, the chlorophyll derivatives, metallochlorophyllin (Chl-M) (M=Fe, Zn and Cu) including chlorophyllin iron (Chl-Fe), chlorophyllin zinc (Chl-Zn) and chlorophyllin copper (Chl-Cu), were adopted as sonosensitizers to combine with ultrasonic irradiation, and the sonodynamic damage of bovine serum albumin (BSA) was investigated. At first, the interaction of Chl-M with BSA was studied by fluorescence spectroscopy. The results show that the quenching mechanism belongs to a static process and among them the affinity of Chl-Fe to BSA is the most obvious. Then, some influence factors on the sonodynamic damage of BSA molecules in the presence of Chl-M under ultrasonic irradiation were also studied. Synchronous fluorescence spectra show that the binding and damage sites of Chl-M to BSA molecule are mainly on the tryptophan (Trp) residues. The generation of ROS in Chl-M sonodynamic process is estimated by the method of Oxidation-Extraction Spectrometry (OEP). This paper may offer some valuable references for the study of the sonodynamic activity of Chl-M and the effect of the central metals. Synchronously, it contributes to the application of Chl-M in SDT for tumor treatment.

Oxidation-extraction spectrometry of reactive oxygen species (ROS) generated by chlorophyllin magnesium (Chl-Mg) under ultrasonic irradiation.

In order to examine the mechanism and process of sonodynamic reaction, the chlorophyllin magnesium (Chl-Mg) acting as a sonosensitizer was irradiated by ultrasound, and the generation of reactive oxygen species (ROS) were detected by the method of oxidation-extraction spectrometry (OES). That is, under ultrasonic irradiation in the presence of Chl-Mg, the 1,5-diphenyl carbazide (DPCI) is oxidized by generated ROS into 1,5-diphenyl carbazone (DPCO), which can be extracted by mixed organic solvent and display a obvious visible absorption at 563 nm wavelength. Besides, the generation conditions of ROS were also reviewed. The results demonstrated that the quantities of generated ROS increased with the increase of ultrasonic irradiation time, Chl-Mg concentration and DPCI concentration. Finally, several radical scavengers (l-Histidine (His), 2,6-Di-tert-butyl-methylphenol (BHT) and Vitamin C (VC)) were used to determine the kind of the generated ROS. It was found that at least the hydroxyl radical (OH) and singlet oxygen (1O2) were generated in the presence of Chl-Mg under ultrasonic irradiation. It is wish that this paper might offer some valuable references for the study on the mechanism of SDT and the application of Chl-Mg in tumor treatment.

Catalytic damage of bovine serum albumin by metronidazole under ultrasonic irradiation in the presence of nano-sized TiO2 powder

In previous work, it was found that the bovine serum albumin (BSA) could obviously be damaged by nano-sized TiO2 powder as a sonocatalyst under ultrasonic irradiation. In this work, metronidazole (MTZ) was adopted as a sensitizer to intensify the damage of BSA molecules. It was found that the damage degree of BSA molecules in the presence of MTZ was more serious than in the absence of MTZ. That is, under ultrasonic irradiation combined with nano-sized TiO2 powder, the addition of MTZ could remarkably aggravate the damage to BSA molecules. Meanwhile, the damage degree was also affected by some influence factors, such as ultrasonic irradiation time, ultrasonic irradiation power, MTZ concentration, solution acidity, ionic strength and solution temperature. In addition, the damage site of BSA molecules was also estimated by synchronous fluorescence spectra. It was found that the damage site of BSA molecules was mainly at tyrosine (Tyr) residue.

Investigation on Interaction and Sonodynamic Activity of Chlorophyll-Magnesium-Metronidazole (Chl-Mg-MTZ) with Bovine Serum Albumin (BSA) in Aqueous Solution

Sonodynamic therapy (SDT) is an innovative cancer treatment involving a tumor-localizing sonosensitizer. The synthesis, modification and activity of novel sonosensitizers have attracted more and more researchers’ attention. In the present study, chlorophyll-magnesium (Chl-Mg) and metronidazole (MTZ) were used as reactants and the chlorophyll-magnesium linked metronidazole complex (chlorophyll-magnesium-metronidazole, Chl-Mg-MTZ) was synthesized and characterized. Bovine serum albumin (BSA) was selected as the target protein; the biomolecule affinity and sonodynamic activity of Chl-Mg-MTZ were assessed by their UV–vis and fluorescence spectra. The results indicate that the interaction of Chl-Mg-MTZ to BSA is comparable with that of chlorophyll-magnesium (Chl-Mg). However, during damage of BSA, Chl-Mg-MTZ shows a higher sonodynamic activity than chlorophyll-magnesium (Chl-Mg). Moreover, synchronous fluorescence spectroscopy indicates that Chl-Mg-MTZ has similar binding ability with the tyrosine (Tyr) and tryptophan (Trp) residues of BSA molecules. However, the damage is mainly focused on the Trp residues. In addition, the production of reactive oxygen species (ROS) in the sonodynamic process was detected through the oxidation-extraction of 1,5-diphenylcarbazide (DPCI). The results promote the potential of Chl-Mg-MTZ as a new sonosensitive drug for use in SDT, encouraging further study on tumor treatment.

Investigation on sonocatalytic damage of BSA under ultrasonic irradiation by FeIII complexes with some aminocarboxylic acid

The interaction of BSA and FeIII complexes ([FeIII(gly)(H2O)4]2+, [FeIII(ida)(H2O)3]+, and [FeIII(nta)(H2O)2], gly—glyane, ida—iminodiacetic acid, nta—triglycolamic acid) as well as the sonocatalytic damage to BSA was studied by UV-vis and fluorescence spectra. In addition, the influences of ultrasonic irradiation time and FeIII complex concentration were also examined on the sonocatalytic damage to BSA. The results showed that the fluorescence quenching of BSA solution caused by the FeIII complexes belonged to the static quenching process. The BSA and FeIII complexes interacted with each other mainly through weak interaction and coordinate actions. The binding association constants (K) and binding site numbers (n) were calculated. The results were as follows: K1 = 0.5353 × 104 l mol−1 and n1 = 0.9812 for [FeIII(gly)(H2O)4]2+, K2 = 1.4285 × 104 l mol−1 and n2 = 1.0899 for [FeIII(ida)(H2O)3, and K3 = 0.4411 × 104 l mol−1 and n3 = 0.9471 for [FeIII(nta)(H2O)2]. Otherwise, under ultrasonic irradiation the BSA were obviously damaged by the FeIII complexes. The damage degree rose up with the increase of ultrasonic irradiation time and FeIII complex concentration. And that, [FeIII(nta)(H2O)2] exhibited in a way higher sonocatalytic activity than [FeIII(gly)(H2O)4]2+ and [FeIII(ida)(H2O)3]+.