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.

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.

Noble-metal-free Ni3N/g-C3N4 photocatalysts with enhanced hydrogen production under visible light irradiation

2018 ◽  
Vol 47 (35) ◽  
pp. 12188-12196 ◽  
Author(s):  
Lu Chen ◽  
Huijuan Huang ◽  
Yuanhui Zheng ◽  
Wenhao Sun ◽  
Yi Zhao ◽  
...  
Keyword(s):  
Hydrogen Production ◽  
Visible Light ◽  
Hydrogen Evolution ◽  
Noble Metal ◽  
Visible Light Irradiation ◽  
Light Irradiation ◽  
Photocatalytic Hydrogen Evolution ◽  
Metal Free

Noble-metal-free Ni3N/g-C3N4 heterojunctions that show high photocatalytic hydrogen evolution activity comparable to platinized g-C3N4 were successfully synthesized.

Photocatalytic Activities of Noble Metal Ion Doped SrTiO3under Visible Light Irradiation

2004 ◽  
Vol 108 (26) ◽  
pp. 8992-8995 ◽  
Author(s):  
Ryoko Konta ◽  
Tatsuya Ishii ◽  
Hideki Kato ◽  
Akihiko Kudo
Keyword(s):  
Visible Light ◽  
Noble Metal ◽  
Visible Light Irradiation ◽  
Metal Ion ◽  
Light Irradiation ◽  
Photocatalytic Activities

A non-noble metal MoS2–Cd0.5Zn0.5S photocatalyst with efficient activity for high H2 evolution under visible light irradiation

2016 ◽  
Vol 4 (1) ◽  
pp. 193-199 ◽  
Author(s):  
Shaojian Zhao ◽  
Junjian Huang ◽  
Qiuyue Huo ◽  
Xiaozhou Zhou ◽  
Weixia Tu
Keyword(s):  
Visible Light ◽  
Noble Metal ◽  
Solid Solutions ◽  
Visible Light Irradiation ◽  
Light Irradiation ◽  
Evolution Rate ◽  
H2 Evolution ◽  
Metal Free ◽  
Highly Active

ZnxCd1−xS solid solutions with uniform sizes and shapes were synthesized. Subsequent loading of MoS2 to one solution yielded a highly-active MoS2–Cd0.5Zn0.5S noble-metal-free photocatalyst; the highest H2 evolution rate was 12.30 mmol h−1 g−1 from water under visible light irradiation.

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