pH纳米传感器的构建及纸张表面酸度的原位测定方法研究

【作者】 屈颖娟；

【导师】 郑行望；

【作者基本信息】 陕西师范大学 ， 分析化学， 2015， 博士

【摘要】 纸质文物的保存、修复和保护等方面都与纸张表面的酸度息息相关,纸张表面酸度是决定纸张寿命的重要因素之一。纸质图书、档案、字画等酸化是一个世界性问题,各个国家的馆藏图书资料均面临不同程度的酸侵蚀,我们国家纸质文物酸化的形势更为严峻。面对纸质文物的酸化问题,各个国家都纷纷开展了纸质文物脱酸的研究工作,大量的脱酸方法不断涌现,脱酸效果的表征最直接的方法就是脱酸前后纸质pH的变化。因此,在纸质文物的脱酸、保护和修复等研究工作中,纸质文物表面pH的测定占据着重要的地位。纳米传感器的尺寸在纳米级,与被检测物质之间的距离也在纳米尺寸,它能获得原子尺度上的数据,并且该数据能作为宏观世界里可被分析的数据。基于纳米传感器的尺寸优势,它能扩散至纸质纤维表面,灵敏地传感纸张纤维孔道的化学信息,为文物分析、文物保护及文物修复工作者提供更加精细的原位信息。本论文共分为五章,第1章为引言,介绍了常见的荧光纳米材料,并对5种荧光纳米材料在细胞和活体分析中的应用进展做了评述,同时对纳米材料在纸质文物保护中的应用研究方面己经取得的一些重要研究成果进行了评述,此基础上提出了本论文的研究设想。第2章主要研究了基于SiO2/壳聚糖复合纳米材料构建pH纳米传感器检测纸张表面pH的分析方法,通过反相微乳液法制备了包埋有参比染料-钌联吡啶(Rubpy)并掺杂了壳聚糖的二氧化硅荧光纳米粒子,利用壳聚糖的氨基将异硫氰酸荧光素(FITC)固定在复合纳米粒子表面,制备了能对纸张表面pH响应的比率型纳米pH传感器。该pH纳米传感器凭借其约100 nm的粒径很容易进入纸质纤维表面,传感纤维表面的氢离子,且比较容易从纸张表面洗脱,洗脱效率约85%。残余在纸质表面的纳米pH传感器对纸张性能的影响也进行了研究,结果表明,残余的少量纳米pH传感器对纸张性能基本无影响,建立了一种原位、无损测定纸张表面pH的新方法。第3章基于DNA纳米结构构建了一种纸张表面pH纳米荧光探针,其可以非破坏性、原位检测纸张表面pH。将pH敏感荧光指示剂羧基荧光素(FAM)修饰在不同结构和不同长度的DNA单链上,选择了 DNA链的碱基类型、长短和排列顺序,DNA进行杂交反应后,将修饰有FAM的双链DNA滴加在纸张表面,连接在DNA双链上的FAM对纸张表面的氢离子就会响应,继而通过FAM的荧光强度变化进行纸张表面pH的测定。该DNA纳米pH探针制备简单,对纸张pH响应灵敏,在纸张表面的洗脱效率达到92%,建立了一种新型、无损、原位、简单检测纸张表面pH的方法。第4章利用四面体结构DNA纳米技术构建了 一种纸张表面pH纳米荧光探针,羧基荧光素(FAM)固定在DNA单链的链端上,四面体结构形成后,FAM位于四面体结构的顶点,据此构筑了基于四面体DNA纳米结构的pH纳米荧光探针。将四面体结构DNA纳米pH荧光探针滴加在不同pH纸张表面,在紫外灯的照射下即可看到不同强度的荧光斑点,根据发荧光的强度可目视检测纸张表面pH。测定完后,用纯水简单冲洗即可除去约90%的四面体结构DNA纳米pH荧光探针,据此基于四面体DNA纳米结构建立了一种新型、原位、无损、简单检测纸张表面pH的方法。第5章对本论文的研究工作进行了整体总结,概括了本论文的创新性,并对研究工作的进一步深入探究提出了设想。本论文研究工作将荧光纳米材料引入纸张表面pH传感器的设计中,拓展了荧光纳米材料在文物分析中的应用,为纸张和纸质文物表面的酸度测定建立了新方法,同时也为纸张表面化学成分的测定提供了一种新思路。更多还原

【Abstract】 Acidity(pH) is one of the most important factors for the stability of paper,which can damage the paper during production and upon prolonged by the atmospheric pollutants.In fact,paper with low acidity is highly desirable to assure permanence of valuable paper materials.The deacidification of value books,archives,calligraphy and painting is a worldwide problem.In the face of acidification,there is a lot of deacidification methods emerged in endlessly.The result of acidification is directly characterized by the changes of paper treated with deacidification before and after.Therefore,in the deacidification,protection and repairing work of paper relics,it is important for determination of surface pH of paper relics.The size of nanosensor is in nanometer,and the distance between the detected.substances and nanosensor is also in nanosize.The data at the atomic scale is obtained by nanosensor,and the data can be used in the macro world.Based on the small size of nanosensor,it can be distributed to the cellulose fiber of paper and supply more precise information of cellulose fiber to the protection of cultural relics.This paper is divided into five chapters.In chapter 1,the common on fluorescent nanomaterials is introduced and the application of five kinds of fluorescent nano materials in cells and in vivo are reviewed.At the same time,the comment on the application of nanomaterials in the paper conservation of cultural relics has made.Last,the purpose of this research work was presented.In chapter 2,a new fluorescent nanosensor was developed for measurement surface pH of paper.The nanosensor is based on the chitosan-modified silica nanoparticles,where Ru(bpy)32+(bpy=2l 2’-bipyridyl)was doped in the nanoparticles as reference dye and pH sensitive fluorescein isothiocyanate(FITC)were used as pH indicator.The nanocomposite was prepared by the modified reverse microemulsion method and charterized by TEM.The dynamic performances of the nanosensor on the paper fiber showed the nanosensor was suitable for sensing in-situ surface pH of paper fiber because it could actively infiltrate into the surface of paper fiber.We demonstrated one practical application of the nanosensor for detection of surface pH in the precious art sample by integrating our nanosensor into the paper fiber.Simply washing by water,the nanosensor could be easily removed from the measured precious art sample without any damage after measurement.Taken together,this work established a modular approach to pH nansensor design for detection of surface pH in precious art sample.In chapter 3,a visual fluorescence method was developed for non-destructive detection of surface pH of paper using deoxyribonucleic acid(DNA)nanoprobe.The nanometer scale of the nanoprobe showed it was suitable for sensing in-situ surface pH of paper because it could actively infiltrate into the surface of paper fiber.We demonstrated one practical application of the nanoprobe for detection of surface pH in the precious art sample by visual colorimetry.The pH nanoprobe could be easily removed from the measured precious art sample by water without any damage after measurement.Taken together,a new approach to pH nanoprobe design for in-situ detection of surface pH in precious art sample was established in this work.In chapter 4,a fluorescent nanoprobe was constructed using DNA tetrahedron structure to sensing surface pH of paper.Carboxyfluorescein(FAM)was modified on the single stranded DNA.After the formation of DNA tetrahedron structure,FAM is located on the vertex of tetrahedral structure.Thus,a fluorescent nanoprobe based on DNA tetrahedron structure was fabricated.When this fluorescent nanoprobe was dropped on paper surface with different pH,under the irradiation of UV lamp it can be seen fluorescent spots with different intensity.According to the fluorescence intensity,a visual detecting of surface pH of paper was developed.After the determination of sample,the fluorescent nanoprobe was removed by simple washing from the surface of paper and the removed ration was about 90%.Thus,a new method for in-situ detecting of surface pH of paper was developed based on the DNA tetrahedron structure.The fifth chapter is the overall summary of the research work of this thesis,and further research work is put forward.In this thesis,fluorescent nanomaterials were introduced into the design of pH nanosensor for detecting surface pH of paper.The application of fluorescent nanomaterials was expanded in the area of cultural heritage.And also a new idea for the determination of surface acidity of paper and cultural relics was provided.更多还原