Chinese handmade mulberry paper: Generation of reactive oxygen species and sensitivity to photodegradation
Chinese handmade mulberry paper: Generation of reactive oxygen species and sensitivity to photodegradation
复制标题
中国手工桑皮纸：活性氧的产生和光降解敏感性
DOI：
10.1016/j.culher.2017.06.004
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发表时间：
2017-11-01
影响因子：
3.1
通讯作者：
Kong, Xue
中科院分区：
文献类型：
--
作者：
Tang, Ying;Smith, Gerald J.;Kong, Xue
手工制作的桑树纸是一种传统的中国树皮纸，可追溯到近两千年，并且是今天用于保存和恢复亚洲纸张手工艺品的流行媒介。在本研究中，来自不同传统制造商的现代中国桑树纸的样品是通过暴露于UVA辐射的人为老化的。它们的降解模式以及相关的超氧化物阴离子和氢过氧化氢的产生是通过我们先前方法遵循各种光谱技术来确定的。此外，采用5,5-二甲基-1-吡咯氨酸-N-氧化物（DMPO）作为自旋诱饵剂的电子自旋共振（ESR）光谱法被用于检测羟基激素辐照纸，并为光降解提供其他信息机制。像Xuan纸一样，中国手工制作的桑纸纸也表现出蓝色荧光（lambda ex = 340-400 nm; lambda em = 450-480 nm），与它一致，源于许多天然溶解的羟基 - 羟基蛋白。 UVA对不同起源的论文的辐照导致荧光特性的变化变化，这些变化与可见区域吸收的发色团的水解或形成，导致纸张的光泽或光蛋白色。不同论文的光觉范围与它们的相对产生活性氧（ROS）的相对速率，包括过氧化物，超氧化物阴离子和羟基自由基。 SEM-EDS分析表明，在工作中研究的中国桑树纸具有高水平的钙和磷，加上钾，铁和铜的量较低，这可能起源于其制造方法中的细节。含有高浓度的这些金属离子的论文也表现出更高的ROS产量，这有助于更高水平的氧化应激，从而影响其光稳定性。中国桑caper纸的光降解的主要机制是通过形成活化的ROS的敏化氧化的，该氧化是由于过渡金属离子（尤其是铁和铜）的存在而催化的，并由其他因素加速。这项研究为中国桑树纸的光降解过程提供了详细的知识，该纸张旨在帮助开发有效的治疗方法，以恢复重要的纸文化遗产对象。 （c）2017 Elsevier Masson SAS。版权所有。
Handmade mulberry paper is a traditional bark paper of China dating back nearly two millennia and is stilla popular medium used today for preserving and restoring Asian paper artefacts. In the present study, samples of modern Chinese mulberry paper from different traditional manufacturers were artificially aged by exposure to UVA radiation. Their degradation patterns and associated generation of superoxide anions and hydrogen peroxides were determined by means of various spectroscopic techniques following our previous approach. Furthermore, electron spin resonance (ESR) spectroscopy using 5,5-dimethyl-1-pyrroline-N-oxide ( DMPO) as a spin-trapping agent was employed to detect hydroxyl radicalsin irradiated paper as well as to provide additional information for the photodegradation mechanism. Like Xuan paper, Chinese handmade mulberry paper exhibited blue fluorescence (lambda ex = 340 - 400 nm; lambda em = 450 - 480 nm) consistent with it originating from a number of naturally-occurring hydroxyl-coumarins. UVA irradiation of papers of different origins resulted in varying changes to the fluorescentspecies, which, together with the hydrolysis or formation of chromophores absorbing in the visible region, leads to the photobleaching or photoyellowing of paper. The extent of photodiscolouration of different papers correlate with their relative rates of the production of reactive oxygen species (ROS), includinghydrogen peroxides, superoxide anions and hydroxyl radicals. SEM-EDS analyses revealed that the Chinese mulberry paper studied in the work had high levels of calcium and phosphorous, together with a much lesser amount of potassium, iron and copper, which probably originate from details in their manufacturing methods. Papers containing high concentrations of these metal ions also exhibited higher yields of ROS, which contribute to a higher level of oxidative stress and thereby affects their photostability. The main mechanism for the photodegradation of Chinese mulberry paper is proposed to be a sensitised oxidation via the formation of activated ROS, catalysed by the presence of transition metal ions, particularly ferric and cupric, and was accelerated by other factors such as moisture. This study has provided detailed knowledge for the photodegradation process of Chinese mulberry paper, which aims to assist the development of effective treatments for the restoration of important paper cultural heritage objects. (C) 2017 Elsevier Masson SAS. All rights reserved.