High antibacterial activity of ultrafine TiO2/graphene sheets nanocomposites under visible light irradiation

2013 ◽  
Vol 93 ◽  
pp. 349-352 ◽  
Author(s):  
Baocheng Cao ◽  
Shuai Cao ◽  
Pengyu Dong ◽  
Jing Gao ◽  
Jing Wang
Keyword(s):  
Antibacterial Activity ◽  
Visible Light ◽  
Visible Light Irradiation ◽  
Light Irradiation ◽  
Graphene Sheets ◽  
High Antibacterial Activity ◽  
Ultrafine Tio2

scholarly journals Noble metal-modified titania with visible-light activity for the decomposition of microorganisms

2018 ◽  
Vol 9 ◽  
pp. 829-841 ◽  
Author(s):  
Maya Endo ◽  
Zhishun Wei ◽  
Kunlei Wang ◽  
Baris Karabiyik ◽  
Kenta Yoshiiri ◽  
...  
Keyword(s):  
Antibacterial Activity ◽  
Visible Light ◽  
Noble Metal ◽  
Visible Light Irradiation ◽  
Photoelectron Spectroscopy ◽  
Diffuse Reflectance Spectroscopy ◽  
Light Irradiation ◽  
Localized Surface Plasmon ◽  
Mycelium Growth ◽  
X Ray

Commercial titania photocatalysts were modified with silver and gold by photodeposition, and characterized by diffuse reflectance spectroscopy (DRS), X-ray powder diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and scanning transmission electron microscopy (STEM). It was found that silver co-existed in zero valent (core) and oxidized (shell) forms, whereas gold was mainly zero valent. The obtained noble metal-modified samples were examined with regard to antibacterial (Escherichia coli(E. coli)) and antifungal (Aspergillus niger(A. niger),Aspergillus melleus(A. melleus),Penicillium chrysogenum(P. chrysogenum),Candida albicans(C. albicans)) activity under visible-light irradiation and in the dark using disk diffusion, suspension, colony growth (“poisoned food”) and sporulation methods. It was found that silver-modified titania, besides remarkably high antibacterial activity (inhibition of bacterial proliferation), could also decompose bacterial cells under visible-light irradiation, possibly due to an enhanced generation of reactive oxygen species and the intrinsic properties of silver. Gold-modified samples were almost inactive against bacteria in the dark, whereas significant bactericidal effect under visible-light irradiation suggested that the mechanism of bacteria inactivation was initiated by plasmonic excitation of titania by localized surface plasmon resonance of gold. The antifungal activity tests showed efficient suppression of mycelium growth by bare titania, and suppression of mycotoxin generation and sporulation by gold-modified titania. Although, the growth of fungi was hardly inhibited through disc diffusion (inhibition zones around discs), it indicates that gold does not penetrate into the media, and thus, a good stability of plasmonic photocatalysts has been confirmed. In summary, it was found that silver-modified titania showed superior antibacterial activity, whereas gold-modified samples were very active against fungi, suggesting that bimetallic photocatalysts containing both gold and silver should exhibit excellent antimicrobial properties.

scholarly journals Novel Pt-Ag3PO4/CdS/Chitosan Nanocomposite with Enhanced Photocatalytic and Biological Activities

Nanomaterials ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 2320
Author(s):  
Mahsa Kiani ◽  
Mojtaba Bagherzadeh ◽  
Reyhaneh Kaveh ◽  
Navid Rabiee ◽  
Yousef Fatahi ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Pseudomonas Aeruginosa ◽  
Antibacterial Activity ◽  
Photocatalytic Activity ◽  
Klebsiella Pneumoniae ◽  
Visible Light ◽  
Salmonella Typhimurium ◽  
Bacillus Cereus ◽  
Visible Light Irradiation ◽  
Light Irradiation

Decorating photocatalysts with noble metal nanoparticles (e.g., Pt) often increases the catalysts’ photocatalytic activity and biomedical properties. Here, a simple and inexpensive method has been developed to prepare a Pt-Ag3PO4/CdS/chitosan composite, which was characterized and used for the visible light-induced photocatalytic and antibacterial studies. This synthesized composite showed superior photocatalytic activity for methylene blue degradation as a hazardous pollutant (the maximum dye degradation was observed in 90 min of treatment) and killing of Gram positive bacterial (Staphylococcus aureus and Bacillus cereus) as well as Gram negative bacteria (Klebsiella pneumoniae, Salmonella typhimurium, Escherichia coli, and Pseudomonas aeruginosa) under visible light irradiation. The antibacterial activity of CdS, CdS/Ag3PO4, and Pt-Ag3PO4/CdS/chitosan against E. coli, Pseudomonas aeruginosa, Salmonella typhimurium, Klebsiella pneumoniae, Staphylococcus aureus, and Bacillus cereus showed the zone of inhibition (mm) under visible light and under dark conditions at a concentration of 20 µg mL−1. Furthermore, the cell viability of the CdS/chitosan, Ag3PO4, Ag3PO4/CdS/chitosan, and Pt-Ag3PO4/CdS/chitosan were investigated on the human embryonic kidney 293 cells (HEK-293), Henrietta Lacks (HeLa), human liver cancer cell line (HepG2), and pheochromocytoma (PC12) cell lines. In addition, the results indicated that the photodegradation rate for Pt-Ag3PO4/CdS/chitosan is 3.53 times higher than that of CdS and 1.73 times higher than that of the CdS/Ag3PO4 composite. Moreover, Pt-Ag3PO4/CdS/chitosan with an optimal amount of CdS killed large areas of different bacteria and different cells separately in a shorter time period under visible-light irradiation, which shows significantly higher efficiency than pure CdS and other CdS/Ag3PO4 composites. The superb performances of this composite are attributed to its privileged properties, such as retarded recombination of photoinduced electron/hole pairs and a large specific surface area, making Pt-Ag3PO4/CdS/chitosan a valuable composite that can be deployed for a range of important applications, such as visible light-induced photocatalysis and antibacterial activity.

Nanostructured composite material graphite/TiO2 and its antibacterial activity under visible light irradiation

2015 ◽  
Vol 149 ◽  
pp. 265-271 ◽  
Author(s):  
Kateřina Dědková ◽  
Jaroslav Lang ◽  
Kateřina Matějová ◽  
Pavlína Peikertová ◽  
Jan Holešinský ◽  
...  
Keyword(s):  
Antibacterial Activity ◽  
Composite Material ◽  
Visible Light ◽  
Visible Light Irradiation ◽  
Light Irradiation ◽  
Nanostructured Composite

scholarly journals Visible Light-Enhanced Antibacterial and Osteogenic Functionality of Au and Pt Nanoparticles Deposited on TiO2 Nanotubes

Materials ◽  
2020 ◽  
Vol 13 (17) ◽  
pp. 3721 ◽  
Author(s):  
Kyoung-Suk Moon ◽  
Eun-Joo Choi ◽  
Ji-Myung Bae ◽  
Young-Bum Park ◽  
Seunghan Oh
Keyword(s):  
Antibacterial Activity ◽  
Visible Light ◽  
Noble Metal ◽  
Visible Light Irradiation ◽  
Tio2 Nanotubes ◽  
Pt Nanoparticles ◽  
Light Irradiation ◽  
Noble Metal Nanoparticles ◽  
Activity Test ◽  
Tio2 Nts

This study aimed at evaluating the visible light mediated antimicrobial and osteogenic applications of noble metal, such as gold (Au) and platinum (Pt) coated titania (TiO2) nanotubes (NTs). In this study, the Au and Pt nanoparticles (NPs) were deposited on anodized 100 nm TiO2 NTs by ion plasma sputtering. The Au and Pt NPs were mainly deposited on the top surface layer of TiO2 NTs and showed light absorbance peaks around the 470 and 600 nm visible light region used in this study, as seen from the surface characterization. From the results of antibacterial activity test, Au and Pt NPs that were deposited on TiO2 NTs showed excellent antibacterial activity under 470 nm visible light irradiation due to the plasmonic photocatalysis based on the localized surface plasmon resonance effect of the Au and Pt NPs. In addition, alkaline phosphate activity test and quantitative real-time PCR assay of osteogenic related genes resulted that these NPs promoted the osteogenic functionality of human mesenchymal stem cells (hMSCs) under 600 nm visible light irradiation, because of the synergic effect of the photothermal scattering of noble metal nanoparticles and visible light low-level laser therapy (LLLT). Therefore, the combination of noble metal coated TiO2 NTs and visible light irradiation would be expected to perform permanent antibacterial activity without the need of an antibacterial agent besides promoting osteogenic functionality.

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