ABSTRACT
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.
ABSTRACT
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.
ABSTRACT
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.
ABSTRACT
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.