Enhanced Antibacterial Property of Facet-Engineered TiO2 Nanosheet in Presence and Absence of Ultraviolet Irradiation
Enhanced Antibacterial Property of Facet-Engineered TiO2 Nanosheet in Presence and Absence of Ultraviolet Irradiation
复制标题
DOI：
10.3390/ma13010078
复制
发表时间：
2020-01-01
期刊：
影响因子：
3.4
通讯作者：
Ohara, Satoshi
中科院分区：
文献类型：
--
作者：
Hayashi, Kenichiro;Nozaki, Kosuke;Ohara, Satoshi
二氧化钛(TiO2O2)在紫外光照射下通过产生活性氧(ROS)来减少细菌疾病，近年来引起了人们的广泛关注。然而，由于电子和空穴的高度复合，对更高的光催化活性的需求仍然存在。本研究的目的是使二氧化钛具有更高的抗菌性能，并揭示其杀菌作用的机理。在本研究中，我们用水热法合成了具有高度取向结构的二氧化钛纳米片(NS)。根据原料中氟/钛的比例，将样品分为五组，即NS1.0、NS1.2、NS1.5、NS1.8和NS2.0。随着氟钛比的增加，晶面比和纳米片尺寸增大。通过产生ROS来评价纳米二氧化钛的光催化活性。NS1.5和NS1.0分别在紫外光照射下有效地产生了羟基自由基和超氧阴离子。在存在和不存在紫外线照射的情况下，对变形链球菌的抗菌活性进行了评估；NS1.0在这两种条件下，由于细胞内成分和细胞膜的氧化，显示出比商业上可获得的二氧化钛纳米颗粒更好的抗菌性能。这些结果表明，二氧化钛纳米片通过氧化诱导细菌细胞死亡，二氧化钛表面工程导致了二氧化钛的光催化和抗菌活性的提高。
Titania (TiO2) has attracted much attention recently for reducing bacterial diseases by the generation of reactive oxygen species (ROS) under UV irradiation. However, demand for higher photocatalytic activity due to higher recombination of electron and hole remains. The aims of this study were to make titania with higher antibacterial property and show the mechanisms of the bactericidal effect. In this study, we hydrothermally synthesized TiO2 nanosheets (NS) with highly-oriented structures. Samples were divided into five groups, depending on the fluorine/titanium ratio in the raw material, namely NS1.0, NS1.2, NS1.5, NS1.8, and NS2.0. Facet ratio and nanosheet size increased with an increase of fluorine/titanium ratio. The photocatalytic activity of TiO2 nanosheet was assessed by the generation of ROS. Hydroxyl radicals and superoxides were generated efficiently by ultraviolet light irradiation on NS1.5 and NS1.0, respectively. Antibacterial activity against Streptococcus mutans was assessed in the presence and absence of UV irradiation; NS1.0 showed superior antibacterial properties compared to commercially available TiO2 nanoparticles, under both conditions, due to the oxidation of intracellular components and cell membrane. These results together suggested TiO2 nanosheet induced bacterial cell death by oxidation, and TiO2 facet engineering resulted in enhancement of both photocatalytic and antibacterial activities of TiO2.