【作者】 王莹；

【导师】 钱卫平；

【作者基本信息】 东南大学 ， 生物医学工程， 2017， 博士

【摘要】 表面增强拉曼散射(surface-enhanced Raman scattering,SERS)光谱作为一种光谱分析技术,在生物、医学、物理、化学、环境监测等领域都得到了相应关注。SERS应用的前提,是制备具有增强能力强、均一性好等特点的活性基底。设计和合成拥有SERS活性的纳米结构用于进行定量或半定量的检测是目前极为活跃的研究领域之一。金纳米花(GNFs)是具有尖锐边缘和多枝角的新型纳米材料,尖锐枝角的“热点”极大增强了周围电磁场的强度。研究报道金-硫(Au-S)之间可产生强作用力,同时又可以通过巯基来介导Au-S键的置换,该Au-S键置换行为在分子生物学、分析化学、表面科学以及材料科学的研究中广泛涉及。本论文基于金纳米花构筑SERS活性基底,开展金纳米花表面Au-S键置换行为的SERS研究。具体开展工作如下:1.采用种子介导生长法,通过调节反应体系中对苯二酚、氯金酸以及金种子溶液的比例,调控金纳米花粒径和表面粗糙度,制备出GNFs形貌均一,单分散性好,具有优异SERS增强性能的GNFs。2.系统研究了谷胱甘肽(GSH)介导的金纳米花界面上Au-S键置换行为,以5,5’-二硫代-(2-硝基苯甲酸)(DTNB)作为拉曼信号分子,检测GSH浓度与SERS信号强弱关系,指示GSH对DTNB的置换过程,从而构建基于Au-S键置换行为的GSH的SERS检测方法。3.选用6-巯基嘌呤(6-MP)作为拉曼信号分子,通过Au-S键连接到金纳米花表面,研究金纳米花表面GSH对6-MP的置换行为,研究谷胱甘肽-s-转移酶(GST)在低浓度GSH下,对GSH置换6-MP的影响。基于GST可以加速GSH对6-MP置换行为,建立GST的高灵敏SERS检测方法。4.利用静电自组装法将金纳米花组装到导电玻璃表面,形成均一、稳定的大面积SERS固相活性基底,检测了血清和组织匀浆液对SERS固相活性基底信号的影响,评价了不同浓度四氯化碳诱导的小鼠肝损伤情况。5.构建了微型SERS固相基底,以拉伸成针状结构的玻璃毛细管为载体,利用静电自组装的方法将金纳米花组装到玻璃针表面,修饰好的玻璃针具有良好的SERS增强效果,初步实现了活细胞检测。更多还原

【Abstract】 Surface-enhanced Raman scattering(SERS)has potential in biological,medical,physical,chemical and environmental monitoring applications.As a spectual analytical method,the preparation of an active substrate with the characteristics of strong enhancement and uniformity is principal.Quantitative or semi-quantitative detection can be realized through the design and synthesis of SERS-active nanostructures.Sharp edges and corners make the nanoparticles more sensitive to the changes in the local dielectric environment and thus greatly enhance the intensity of the surrounding electric field.Therefore,coronal nanostructures such as gold nanostar and gold nanoflower can be better applied to ultra-sensitive sensing such as LSPR sensing,surface enhancement Raman scattering(SERS)etc..Researches show that gold-sulfur bond(Au-S)can generate strong interaction and that the displacement of Au-S bond can be mediated by sulfhydryl groups.The behavior of Au-S bond displacement is wildly involved in the research of molecular biology,analytical chemistry,surface science and materials science.Based on the SERS-active substrate constructed by gold nanoflower,the SERS study of the Au-S bond displacement on the surface of gold nanoflower was carried out.The details are as follows:1.Using seeds-mediated method,gold chloride acid(HAuCl4)was reduced by ascorbic acid(AA)with cetyl ammonium chloride(CTAB),and cetylpyridinium chloride(CPC)which acted as surfactants.By adjusting the ratio of hydroquinone,chloroauric acid and gold seed in the system,the roughness and particle size of gold nanoflower surface were regulated.The fabricated gold nanoflowers(GNFs)holds the advantages of high yield,excellent monodispersity and good stability.Optical properties from visible light to near infrared can be controlled.The results show that the surface of gold nanoflower has rich"hot spots" which owns excellent SERS enhancement performance that meets the needs of SERS testing.2.The behavior of glutathione(GSH)-mediated Au-S bond diaplacement was studied systematically.5N-nitrobenzoic acid(DTNB)was used as Raman signal molecule to detect the relation between the intensity of SERS signal and the concentration of GSH,indicating the influence of GSH on the displacement of Au-S bond,and thus constructed the SERS detection method based on Au-S bond displacement through glutathione.3.Use 6-mercaptopurine(6-MP)as a Raman signal molecule to help construct a gold nanoprobe with SERS function.6-MP was connected to GNFs surface through Au-S bond.Study of the displacement of high concentration of GSH to 6-MP on GNFs was conducted.The effect of glutathione-s-transferase(GST)on GSH-substituted 6-MP at low concentration of GSH was further studied.Based on the discovery that GST can accelerate the 6-MP displacement,a highly sensitive SERS detection method was established.4.The method of using liquid phase nanoparticles was improved by using a uniform and stable solid substrate through the electrostatic self-assembly of GNFs on the surface of the conductive glass.The effects of serum and tissue homogenate on the signal of solid-phase SERS active substrate were investigated.The effects of different concentrations of carbon tetrachloride-induced liver injury in mice were evaluated.5.The micro-SERS solid-phase substrate was constructed and the glass capillary was drawn into a needle-like structure.The GNFs were assembled on the surface of the glass needle by electrostatic self-assembly method and the modified needle shows excellent effect of SERS enhancement and the highly sensitive detection of intracellular was achieved.更多还原