Canillas M, Chinarro E, Pêgo A P, Moreno B
Ceramic and Glass Institute (ICV), Spanish National Research Council (CSIC), C/ Kelsen 5, Campus de Cantoblanco, 28049, Madrid, Spain.
Chem Commun (Camb). 2017 Sep 21;53(76):10580-10583. doi: 10.1039/c7cc05862d.
TiO is able to scavenge reactive oxygen and nitrogen species (ROS and RNS) in the absence of light. The scavenging mechanism has been related to the chemistry of defects (oxygen vacancy reduced oxidation states of Ti) but it is still unknown. This study describes the ROS scavenging activity of different titanium oxide phases and relates their scavenging activities with the Ti/Ti molar ratio as well as the band gap value. The TiO phase, with a mixture of both oxidation states, presented a substantially higher percentage of 2,2-diphenyl-1-picrylhydracyl radicals (DPPH˙) eliminated per m of specific surface area in comparison to phases with predominant oxidation states Ti or Ti such as TiO and TiO, respectively. The obtained results indicate that the DPPH˙ scavenging mechanism corresponds to a catalytic process on the TiO surface which is facilitated by the presence of charges that can easily move through the material. The mobility of charges and electrons in the semiconductor surface, related to the presence of oxidation states Ti and Ti and a small band gap, could create an attractive surface for radical species such as DPPH˙. This puts forward TiO as a promising candidate coating for implantable biomedical devices, as an electrode, since it can cushion inflammatory processes which could lead to device encapsulation and, consequently, failure.
二氧化钛（TiO）能够在无光条件下清除活性氧和氮物种（ROS和RNS）。清除机制与缺陷化学（氧空位降低了Ti的氧化态）有关，但仍不清楚。本研究描述了不同氧化钛相的ROS清除活性，并将它们的清除活性与Ti³⁺/Ti⁴⁺摩尔比以及带隙值联系起来。与分别具有主要氧化态Ti³⁺或Ti⁴⁺的相（如TiO₂和TiO）相比，具有两种氧化态混合物的TiO相每平方米比表面积消除的2,2-二苯基-1-苦基肼自由基（DPPH˙）百分比要高得多。所得结果表明，DPPH˙清除机制对应于TiO表面的催化过程，这一过程因材料中易于移动的电荷的存在而得到促进。半导体表面电荷和电子的迁移率与Ti³⁺和Ti⁴⁺氧化态的存在以及小带隙有关，这可能为DPPH˙等自由基物种创造一个有吸引力的表面。这使TiO成为植入式生物医学设备（如电极）的一种有前景的候选涂层，因为它可以缓解可能导致设备封装并最终导致故障的炎症过程。
