Fluorescent intracellular imaging of reactive oxygen species and pH levels moderated by a hydrogenase mimic in living cells / 药物分析学报

The catalytic generation of H2 in living cells provides a method for antioxidant therapy.In this study,an[FeFe]-hydrogenase mimic[Ru+Fe2S2@F127(80)]was synthesized by self-assembling polymeric plur-onic F-127,catalytic[Fe2S2]sites,and photosensitizer Ru(bpy)32+.Under blue light irradiation,hydrated protons were photochemically reduced to H2,which increased the local pH in living cells(HeLa cells).The generated H2 was subsequently used as an antioxidant to decrease reactive oxygen species(ROS)levels in living cells(HEK 293T,HepG2,MCF-7,and HeLa cells).Our findings revealed that the proliferation of HEK 293T cells increased by a factor of about six times,relative to that of other cells(HepG2,MCF-7,and HeLa cells).Intracellular ROS and pH levels were then monitored using fluorescent cell imaging.Our study showed that cell imaging can be used to evaluate the ability of Ru+Fe2S2@F127 to eliminate oxidative stress and prevent ROS-related diseases.

Aplicação do dióxido de titânio como fotocatalisador na degradação do diuron: avaliação das variáveis operacionais e estudo mecanístico / Application of titanium dioxide as photocatalyst in diuron degradation: operational variables evaluation and mechanistic study

RESUMO O diuron (DI) é um herbicida utilizado em culturas agrícolas para o controle de ervas daninhas que podem causar desde irritações na pele até problemas cancerígenos. Neste estudo, a fotocatálise heterogênea foi utilizada para a degradação do DI aplicando o dióxido de titânio (TiO2) como catalisador em um reator em batelada. Planejamentos experimentais foram realizados a fim de avaliar a influência do pH, da concentração do catalisador e do substrato, e de maximizar a degradação do DI. Depois de 3 horas de reação, foi possível observar que o pH foi a variável com maior influência na degradação do herbicida utilizando o TiO2 como catalisador. Com o estudo mecanístico foi possível propor que a degradação desse herbicida é realizada pelos radicais hidroxilas gerados da redução do O2. O modelo estatístico realizado neste estudo pode ser aplicado para o aprimoramento do processo de tratamento de efluentes industriais e agrícolas utilizando a fotocatálise heterogênea.

ABSTRACT Diuron (DI) is a herbicide used in agricultural fields for weed control that can cause skin irritations and carcinogenic problems. In this study, heterogeneous photocatalysis was used for the degradation of the DI applying TiO2 as catalysts in a batch reactor. Experimental designs were performed to evaluate the influence of pH, catalyst concentration and substrate, also to maximize DI degradation results. After 3 hours of reaction, it was possible to observe that pH was the variable with the significant influence on the degradation of the DI using TiO2 as a catalyst. With the mechanistic study it was possible to propose that the degradation of this herbicide is carried out by the hydroxyl radicals generated from the O2 reduction. The statistical models performed in this study can be applied to improve the process of treatment of industrial and agricultural effluents using heterogeneous photocatalysis.

Material cimentício fotocatalítico com atividade antimicrobiana: avanços e desafios no ambiente da área da saúde / Photocatalytic cement material with antimicrobial activity: advances and challenges in the healthcare environment

O material cimentício com dióxido de titânio (TiO2) pode representar uma opção viável devido suas propriedades fotocatalítica, autolimpante e antimicrobiana no ambiente da área da saúde. O objetivo desta pesquisa foi determinar os avanços e desafios da atividade antimicrobiana do material cimentício fotocatalítico com TiO2, no que concerne a possível aplicabilidade no ambiente da área da saúde. Uma revisão integrativa foi efetuada acerca da possível aplicabilidade do material cimentício fotocatalítico com TiO2 no ambiente da área da saúde. Além disso, a atividade antibacteriana de soluções aquosas e material cimentício fotocatalítico com TiO2 em diferentes concentrações e exposições a radiações luminosas foram avaliadas, por meio da técnica de difusão em camada dupla de ágar. A revisão integrativa foi realizada no portal PubMed e nas bases Web of Science, SCOPUS, EMBASE e Engineering Village com a inclusão de estudos primários quanto a temática, publicados online até março de 2021, em português e inglês. A etapa experimental / laboratorial foi realizada em triplicata com o emprego da cepa padrão Escherichia coli (ATCC 25922) e as soluções aquosas e material cimentício fotocatalítico com TiO2 em diferentes concentrações (0, 5 e 15%) e exposições às radiações ultravioleta A (UV-A) a 15W e 365nm e diodo emissor de luz (LED) a 18W durante 8 e 10h. Cabe salientar que houve a inclusão de solução de clorexidina a 0,12% e amostras submetidas à ausência de exposição à radiação luminosa (escuro) como controles experimentais. Na técnica de difusão em camada dupla de ágar, Mueller Hinton Agar foi distribuído em placas de Petri (90x15mm) esterilizadas formando uma camada base de 12,0mL. Após a solidificação do meio de cultura, 8,0mL de Mueller Hinton Agar contendo 106UFC/mL do inóculo bacteriano foi distribuído sobre a camada base para formar a camada seed. Em seguida, em cada placa foram confeccionados poços para adição de 20,0µL das soluções ou dos espécimes do material cimentício fotocatalítico. Decorrido os períodos pré-incubação das amostras à temperatura ambiente por 2h, as placas foram incubadas a 37ºC por 24h e a leitura dos diâmetros dos halos de inibição (mm) mensurada. Na revisão integrativa, os resultados mostraram um total de sete estudos primários com diferentes metodologias microbiológicas in vitro, concentrações e exposições a radiações luminosas de soluções e materiais cimentícios fotocatalíticos. Em referência à etapa experimental / laboratorial, não houve atividade antibacteriana conclusiva de qualquer solução ou material cimentício fotocatalítico com TiO2, apesar de alguns resultados terem demonstrado halos de inibição tênues ao redor de algumas amostras do material cimentício fotocatalítico. Em conclusão, não há consenso na literatura científica acerca da atividade antimicrobiana de material cimentício fotocatalítico com TiO2. Ainda, conforme a metodologia empregada neste estudo, a atividade contra E. coli das soluções aquosas e do material cimentício fotocatalítico com TiO2 não foi evidenciada, sendo que avanços e desafios no controle de contaminação e risco de infecção microbiana no ambiente da área da saúde continuam

The cementitious material with titanium dioxide (TiO2) may represent a viable option due to its photocatalytic, self-cleaning and antimicrobial properties in the healthcare environment. The objective of this research was to determine the advances and challenges of the antimicrobial activity of the photocatalytic cement material with TiO2, with regard to the possible applicability in the health area. An integrative review was carried out on the possible applicability of the photocatalytic cement material with TiO2 in the healthcare environment. In addition, the antibacterial activity of aqueous solutions and photocatalytic cementitious material with TiO2 in different concentrations and exposures to light radiation were evaluated using the double layer agar diffusion technique. The integrative review was carried out on the PubMed portal and on the Web of Science, SCOPUS, EMBASE and Engineering Village databases with the inclusion of primary studies on the subject, published online until March 2021, in Portuguese and English. The experimental / laboratory stage was carried out in triplicate using the standard strain Escherichia coli (ATCC 25922) and aqueous solutions and photocatalytic cement material with TiO2 in different concentrations (0, 5 and 15%) and radiation exposures to ultraviolet A (UV-A) at 15W and 365nm and light emitting diode (LED) at 18W for 8 and 10am. It should be noted that there was the inclusion of 0.12% chlorhexidine solution and samples subjected to the absence of exposure to light radiation (dark) as experimental controls. In the double agar diffusion technique, Mueller Hinton Agar was distributed in sterile Petri dishes (90x15mm) forming a base layer of 12.0mL. After solidification of the culture medium, 8.0mL of Mueller Hinton Agar containing 106CFU/mL of the bacterial inoculum was distributed onto the base layer to form the seed layer. Then, in each plate, wells were made to add 20.0µL of the solutions or specimens of the photocatalytic cement material. After the pre-incubation periods of the samples at room temperature for 2h, the plates were incubated at 37ºC for 24h and the reading of the diameter of the inhibition halos (mm) was measured. In the integrative review, the results showed a total of seven primary studies with different in vitro microbiological methodologies, concentrations, and exposures to light radiation of solutions and photocatalytic cement materials. In reference to the experimental / laboratory stage, there was no conclusive antibacterial activity of any solution or photocatalytic cement material with TiO2, although some results have shown faint inhibition halos around some samples of the photocatalytic cement material. In conclusion, there is no consensus in the scientific literature about the antimicrobial activity of photocatalytic cement material with TiO2. Moreover, according to the methodology used in this study, the activity against E. coli from aqueous solutions and the photocatalytic cement material with TiO2 was not evidenced, and advances and challenges in the contamination control and microbial infection risk in the health area continue

Simarouba Glauca Bark Extract Mediated Synthesis And Characterisation Of Iron Oxide And Silver Nanoparticles And Their Antibacterial, Cytotoxic And Photocatalytic Activity

Objective: The objective of the present study is the synthesis of iron oxide and silver nanoparticles using Simarouba glauca aqueous bark extract, characterization of the synthesized nanoparticles and evaluation of their antimicrobial, photocatalytic activity and cytotoxicity. Methods: The iron oxide and silver nanoparticles were synthesized using Simarouba glauca aqueous bark extract and crystal structures of the nanoparticles were determined by UV-Visible spectroscopy, Transmission Electron Microscopy, Scanning Electron Microscopy, X-ray Diffraction and Fourier Transform Infrared Spectroscopy. The in vitro cytotoxicity of the silver nanoparticles was evaluated using Dalton’s lymphoma ascites cells. The antibacterial assay of the silver nanoparticles was conducted using agar well diffusion method. Results: The UV-Visible spectrum of iron oxide nanoparticle showed an absorption maximum at 280 nm and silver nanoparticles showed an absorption maximum at 436 nm. This is XRD pattern of iron oxide nanoparticles exhibited a characteristic peak at 26.85 is of maghemite the corresponding miller indices is (211) and the synthesized iron oxide nanoparticles are amorphous in nature. TEM image reveals the size of the synthesized iron oxide nanoparticles in the range of 26-30 nm and the size of silver nanoparticles is in the range of 120-140 nm. Green synthesized iron nanoparticles using Simarouba glauca bark extract effectively degraded methylene blue dye. Conclusion: This study showed that the synthesized iron oxide and silver nanoparticles using Simarouba glauca aqueous bark extract exhibited pronounced antibacterial, anticancer and photocatalytic activity and can be used in the textile industry and also as an external antiseptic in prevention and treatment of bacterial infections.

Preparation and antibacterial properties of La-doped TiO2 films on 3Y-TZP ceramic surface / 口腔疾病防治

Objective @#To prepare the La-doped TiO2 film on the surface of 3Y-TZP ceramics in order to observe its antibacterial properties, providing an experimental basis for the application of antibacterial zirconia ceramics in the clinic.@*Method@# A cylindrical 3Y-TZP specimen with a diameter of 20 mm and a height of 3 mm was prepared. The sol-gel method was used to prepare 1% lanthanum (La)-doped TiO2 sol, and the La-TiO2 film-3Y-TZP ceramic was prepared by dip coating on the surface of 3Y-TZP. The TiO2 thin film-3Y-TZP ceramic was prepared by adding no lanthanum nitrate solution in the same way. The surface morphology of 3Y-TZP ceramic specimens (3Y-TZP group), TiO2 thin film-3Y-TZP ceramic specimens (TiO2 film group), and La-TiO2 thin film-3Y-TZP ceramic specimens (La-TiO2 film group) was observed by scanning electron microscopy, and photocatalysis, antibacterial and cytotoxicity experiments were carried out. For the photocatalytic experiment, four specimens were randomly selected from the La-TiO2 film group and TiO2 film group to observe the degradation rate of methylene blue at different time points under sunlight. In the antimicrobial experiment, five specimens were randomly selected from the La-TiO2 film group, TiO2 film group and 3Y-TZP group. The antimicrobial activity of each group was tested using the bacteriostatic circle method, and the bacteriostatic distance of each group was compared. In the cytotoxicity experiment, three samples were randomly selected from the La-TiO2 film group, TiO2 film group and 3Y-TZP group (negative control group), and the extracts were prepared. Here, 0.064% phenol solution were served as the positive control group. Morphological observation of L-929 cells in four groups was performed after 3 d of culture. Cell viability and relative cell proliferation were measured by MTT assay.@*Results@#La-TiO2 films with uniform distribution can be prepared on a 3Y-TZP surface by the dipping-drawing method. Photocatalytic experiments showed that the degradation rate of methylene blue in the La-TiO2 film group was (41.2 ± 1.5)% in daylight for 2 hours, which was higher than that in TiO2 film group (36.5 ± 2.4)%. A significant difference was noted between the two groups (t=3.321, P=0.016). The antimicrobial experiment showed that the antimicrobial distance of La-TiO2 group was (0.34 ± 0.08) mm, which was larger than that of TiO2 group (0.12 ± 0.02) mm. No obvious antimicrobial circle was noted in 3Y-TZP group, and the antimicrobial distance of the La-TiO2 film group was larger than that of TiO2 film group (F=63.798, P < 0.001). Cytotoxicity test showed that the relative proliferation rate of cells in La-TiO2 film group was (89.5 ± 1.3)%, and the cytotoxicity rating was grade 1. Significant differences were noted among the four groups (F=68.250, P < 0.001).@*Conclusion @#The La-doped TiO2 film can improve its photocatalytic activity and enhance the antibacterial activity of 3Y-TZP without obvious cytotoxicity.

Study on Morphological Distribution of Photogenerated Superoxide Radicals Produced by Different Crystal Titanium Dioxide / 分析化学

Superoxide radical ( O·-2 ) , is one of reactive oxygen species ( ROS ) produced in TiO2 photocatalytic reactions, and plays an important role in the photodegradation of pollutants. In this work, we constructed two different procedures to study the generation of total O·-2 and surface-adsorbed O·-2 during TiO2 photocatalytic reaction using nitroblue tetrazolium ( NBT) as capture probe. Furthermore, three different TiO2 ( anatase, rutile and P25 ) were selected as model, and O·-2 generation and its existence form were all studied. The results showed that the generation of total O·-2 was followed by the order P25> anatase> rutile, but the surface-adsorbed O·-2 was nearly the same. The study of surface-adsorbed ROS is very important due to their probably persistence for the pollutants photodegradation or antibacterial activity.

Facile Solvothermal Synthesis of Reduced Graphene Oxide-BiPO4 Nanocomposite with Enhanced Photocatalytic Activity / 分析化学

Reduced graphene oxide-BiPO4 ( RGO-BiPO4 ) nanocomposite was synthesized successfully via a one-pot solvothermal method using graphene oxide and bismuth nitrate as precursors and glycerin as solvent at 200℃ for 1 h. The morphology and structure of as-prepared nanocomposite were characterized by SEM, TEM, XRD, XPS, SERS and UV-Visible spectrum. The photocatalytic activity of the nanocomposite was evaluated by the photodegradation of Rhodamine B ( RhB) dye under UV irradiation and it was found that RGO-BiPO4 nanocomposite possessed higher photocatalytic activity than that of pure BiPO4 . RhB could be decomposed 87. 5% within 2 h. Under the same conditions, only 45. 7% of the RhB dye could be decomposed by BiPO4 . The enhancement of photocatalytic activity could be attributed to the effective charge separation due to the electron-accepting and transporting properties of graphene.

Nanopartículas para materiales antibacterianos y aplicaciones del dióxido de titanio / Nanoparticles for antibacterial materials and titanium dioxide applications

La aparición constante de microorganismos multiresistentes (bacterias, virus, hongos), ha elevado el esfuerzo por la búsqueda de materiales antibacterianos, que sean efectivos para su aplicación en áreas tan diversas como la industria textil, alimentación animal, el tratamiento de aguas, industria médica, farmacéutica y cosmética. Es bien conocido que agentes antibacterianos inorgánicos tales como las nanopartículas de plata, de cobre, de óxido de zinc y de óxido de cobre, han atraído una atención especial a lo largo del tiempo, debido a su estabilidad y a que no presentan problemas de bioseguridad. Aun así, recién las nanopartículas de dióxido de titanio han venido ganando atención para aplicaciones biomédicas, dado que estas partículas se vuelven antibacteriales mediante un proceso de fotoactivación y presentan absorción de ciertas longitudes de onda que dependen de su fase inorgánica (anatasa, rutilo o brookita). No obstante, la actividad fotocatalítica del dióxido de titanio oscila en la región UV (ƛ>387nm), y ello ha representado el mayor esfuerzo en investigación, en búsqueda de conseguir que el dióxido de titanio tenga función de autodesinfección en la región de luz visible, aumentándose así sus aplicaciones en la industria biomédica. En este artículo se realizó una revisión crítica de la literatura disponible, sobre el uso de nanopartículas para materiales antibacterianos y aplicaciones del dióxido de titanio, haciéndose énfasis en el mecanismo de acción de estas partículas con sistemas biológicos y posibles modificaciones para mejorar su actividad fotocatalítica mediante la interacción con luz visible.

The constant occurrence of multiresistant microorganisms (bacteria, viruses, fungi) has increased the search for antibacterial materials that may be effective to be applied in various areas such as textile industry, animal feeding, water treatment, medical, drug and cosmetic industry. It is well known that inorganic antibacterial agents as silver, copper, zinc oxide and copper oxide nanoparticles have attired special attention in the course of time due to their stability and the absence of biosafety problems. Despite this, just recently, have the titanium dioxide nanoparticles been gaining more attention for biomedical application, since these particles become antibacterial agents through a process of photo-activation and present absorption of certain wavelengths depending on their inorganic phase (anatase, rutile or brookite). Nevertheless, the photocatalytic activity of the titanium dioxide ranges in the UV zone ((?>387nm), and this has required greater efforts in terms of research, to make the titanium dioxide have the auto-disinfection function in the visible light zone, so as to increase the number of uses in the biomedical industry. This article was aimed at making a critical literature review on the use of nanoparticles for antibacterial materials, and the applications of titanium dioxide, thus making emphasis on the mechanism of action of these particles with the biological systems and the possible changes with a view to improving its photocatalytic activity by means of the interaction with the visible light.

Application of Nano-TiO2 /LDPE composite film on photocatalytic oxidation degradation of dichloromethane.

This study focused on the photocatalytic destruction of dichloromethane (DCM) in indoor air using the nano-TiO2 /LDPE composite film as an economical photocatalyst. The nano-TiO2 was dispersed in a polyethylene matrix to form composite film. The photocatalytic activity of the nano-TiO2/LDPE composite films was evaluated through the degradation of dichloromethane (DCM) under UV-C irradiance at specific wavelength of 254 nm. The percentage of nano-TiO2 contents varied from 0, 5, and 10% (wt cat./wt LDPE composite film). The results derived from the kinetic model revealed that the photocatalytic rates of 5 and 10 wt.% nano-TiO2/LDPE composite films follow the first order reaction while the rate of the film without TiO2 followed the zero order reaction. At low concentration of DCM, the rate of photocatalytic degradation of the DCM was slower than that at high DCM concentration. The 10 wt.% of TiO2 content of the nano-TiO2/LDPE composite film yielded the highest degradation efficiency of 78%, followed by the removal efficiency of 55% for the 5 wt.% of TiO2 content of the nano-TiO2/LDPE composite film. In contrast with the composite film containing nano-TiO2, the LDPE film without adding nano-TiO2 expressed the degradation efficiency of 28%.

Titamium oxide (TiO2) assisted photocatalytic degradation of methylene blue.

The aqueous solution of methylene blue(MB) has been subjected to Photocatalytic degradation by UV radiation in presence of TiO2 photo-catalyst containing different concentrations of H2O2. The experiments conducted at different dye concentrations (12 and 20 ppm), catalyst loading, pH and H2O2 dosage (1-10 ml l-1), revealed that the degradation rate is strongly influenced by respective experimental parameters. However the influence of catalyst alone is not predominant in degradation. The decolorization of dye proceed to near completeness when H2O2 is used. The best degradation results are observed at 0.1 wt% of catalyst loading at pH 2 for TiO2/UV system. It has been found that the optimum concentration of H2O2 for 12 ppm and 20 ppm amount of the dye was 2ml l-1 for UV/H2O2 system. The kinetic of degradation of the dye followed the pseudo first order rate. The degradation studies using TiO2/UV/H2O2 system, indicates enhancement in the degradation rate of the dye compared to that of UV/H2O2 system alone.

Efficacy of an air cleaning device equipped with an electrostatic precipitator and photocatalytic plasma filter in respiratory allergic patients / 천식및알레르기

OBJECTIVE: To evaluate the clinical efficacy of a new air cleaning device (LG Electronics, Korea) equipped with electrostatic precipitator (EP) and photocatalytic plasma filter (PCP) in 24 respiratory allergic subjects. MATERIAL AND METHOD: Air cleaning conditioner and air cleaner were placed in living room and bedroom. Both EP and PCP (EP/PCP) filters were used for the first 4 weeks and for another 4 weeks, PCP without EP filter (PCP) was used. We measured symptom scores of asthma and rhinitis, peak expiratory flow rate (PEFR), serum eosinophil cataionic prote in? in ECP, Dermatophagoides farinae (DF) specific IgE and IgG in sera, concentrations of major allergens of DF in floor dust of living room, bedroom and in airborne dust. RESULTS: Both asthma and rhinitis symptom scores were significantly improved not only with EP/PCP filters but also with PCP filter. The morning PEFR was significantly improved with EP/PCP filters, but not with PCP filter. Frequency of salbutamol inhalation by air cleaner with EP/PCP filter tended to de crease(p=0.051), with no significant difference in serum ECP concentration. DF specific IgE significantly decreased at the 8th week with no differences in specific IgG. However, the mean Der f I levels in floor dust of bedroom (1, 128 vs. 374 ng/gm dust, p<0.01) and living room (1,516 vs 812 ng/gm dust, p<0.01) decreased, Der f1 in airborne dust measured only in 8 out of 22 subjects, and they decreased significantly with the trial of EP/PCP filter (172.2 pg/4.5m vs. 62.1 pg/4.5m, p<0.01). CONCLUSION: These results suggest that the EP/PCP air cleaner may be an effective tool for environmental control in respiratory allergic subjects.

Research Advancement in Gas-phase Pollutant Treatment by Photocatalytic Oxidation / 环境与健康杂志

Much attention has been paid to photocatalytic oxidation in the field of air and water purification. Photocatalytic oxidation employs semiconductors such as TiO2, ZnO as a photocatalyst in ultraviolet radiation. Several factors which affect photocatalytic decomposition were discussed in the present paper. Photocatalytic oxidation technique is applicable for the elimination of gas-phase contamination in air.

TiO_2 Photocatalyst and Its Application in Water Treatment / 环境与健康杂志

The paper reviews the basic mechanism of photocatalytic oxidation, the kinds of photocatalyst, the characteristics of TiO2 and the commonly used carriers of TiO 2 photocatalytic oxidation in water treatment, the degradation of organic pollutants in water by photocatalytic oxidation and the applications of this new technique in tap water purification. The photocatalytic oxidation as a new technique of environmental protection is being much con-cerned widely.