【作者】 王怡红；

【导师】 顾宁；

【作者基本信息】 东南大学 ， 生物医学工程， 2006， 博士

【摘要】 在活细胞研究中,因光子对细胞和生物分子损害最小、所获结果可信,光学方法备受关注。要实现对单细胞的光学检测,需容积小、光学收集效率高、低噪声的检测器和低的背景光。作为生物光学检测的传感器,光纤探针的尺寸形状对提高光学收集效率至关重要。本文根据生物光学检测对光纤探针的要求,应用静态刻蚀法,通过选择覆盖液种类、控制刻蚀时间和等方法,制备了形状尺寸可控的笔状光纤探针;通过在光纤探针表面修饰3-巯丙基-三甲氧基硅烷(HS(CH2)3Si(OCH3)3, 3-MPT)自组装单层膜(Self-Assemblied Monolayers,SAMs)、采用超声处理等手段,制备了顶部具有金属孔洞的银膜包覆光纤探针。考虑探针表面银镀层由于氧化导致的探针使用寿命短和探针的生物相容性等,采用3-MPT和长链有机硫醇(正十八硫醇,C18H37SH),在银表面构筑了3-MPT SAMs和两种分子在银表面的混合自组装单层膜(Self-Assemblied Mixed Monolayers,SAMM),并进一步采用甲基丙烯酸—乙烯基咔唑共聚物修饰,形成有机聚合物复合自组装膜(Complex Self-Assemblied Film,CSAF)。由于硫醇中的巯基可与贵金属之间产生强的结合力,硅羟基(硅甲氧基易水解形成硅羟基,-Si(OH)3)可与羟基化的氧化硅表面进行化学键合,当银金属化光纤探针在上述两种溶液或它们的混合溶液中浸泡组装时,在Ag表面将形成以巯基为头基,硅甲氧基-Si(OCH3)3或甲基-CH3为尾基的单分子层。而在经预处理的光纤探针的SiO2表面,则会形成以硅氧键相连的、巯基为尾基的3-MPT的单分子层组装膜,该单分子层组装膜的存在,将有效阻止共聚物分子在针尖顶部的缩合沉积。利用分子中两种基团与不同表面上的作用的特点,可得到针尖顶部无聚合物沉积而其余银镀层表面形成惰性聚合物复合(Complex Self-Assemblied Film,CSAF)修饰层的Ag包覆光纤探针。CSAF的厚度在一定范围内可通过调节表面-Si(OH)3的量来控制。论文共分以下几个章节:1.液体界面性质对光纤探针形状的影响:选择几种覆盖液对静态刻蚀法制备的光纤探针进行了较为系统的研究。首先根据溶剂的表面张力、分子体积、溶解度和体积大小等因素对覆盖液进行比对,并考虑极性对界面性质的影响,选择正辛烷、对二甲苯、油酸和邻二甲苯为覆盖液,研究探针形状随覆盖液和时间变化的规律;其次,考虑覆盖溶剂的表面张力不同于该覆盖液与HF水溶液界面的界面张力,采用Fu-Ju-Fu方法计算覆盖溶剂/HF水溶液的界面张力,用界面张力代替表面张力计算了探针锥高;最后考虑HF水溶液在不同有机相中的溶解度以及可能发生的两相间的相互扩散对探针形状和针尖顶角的影响,通过比较探针锥高理论估算值、实验值和加入表面活性剂后的实验值,得出了两相溶液之间的相互扩散是影响探针形状的重要因素的结论。2.顶部具有金属孔洞的银膜包覆光纤探针的制备:考虑分子的组装性能和细胞毒性,选择金属更多还原

【Abstract】 Significant attention is focused on the optics application in the studies of alive cell for its smaller injury on cell and credible result. To achieve the optic detection in individual cell, it is prerequisite for optical detector to be tiny volume, highly optical collection- efficiency, low noise and light background. As the biosensor of optic transfer and measurement, suitable profile of fiber probe is essential for improvement of optical collection- efficiency.Pencil-like fiber probes with controllable profile were prepared by the choice of coverlayers and etching time at etchant /coverlaye. Diffusion theory was applied in explaining the effect of diffusion on the size and profile of probe. Ag-coating-probe with aperture at its apex has been obtained by means of （3-mercaptopropy） trimethoxysilane （HSC₃H₆Si（OCH₃）₃,3-MPT） SAMs assembled on fiber probe surface and chemical plating silver under ultrasonic condition. Considering the shorter hold time due to oxidation of silver coating and cytocompatibility of probe, 3-MPT and 1-octadecanethiol (C₁₈H₃₇SH) were used to construct the Self- Assembled Mixed Monolayers （SAMM） and moreover, co-polymers composed of N-vinylcarbazole（VCz）and Methyl methacrylate（MMA）were deposited on 3-MPT SAMs or SAMM to form inert multilayer polymer films—Complex Self-Assembled Films （CSAF） on silver. 3-MPT SAMs can also be formed on fiber surface by means of hydrolyzed Si（OCH₃）₃ group on hydroxyl- SiO2, which prevents the apex of tips from the deposition of co-polymer. The thickness of co-polymer can be controlled by augment or diminishment of -Si（OH）3 on Ag to some extent. The dissertation is composed by following chapters:1. Effect of the Interface Properties on Profile of Fiber Probes: In this chapter, the profiles and their changes of pencil-like fiber tips in static chemical etching process had been studied with several coverlayer-etchant systematically. Octane, paraxylene, oleic acid and n-xylene were chosen as coverlayer according to their natures such as surface tension, solubility, molecular volume and polarities. The interface tensions of coverlayer /HF aqueous solution were then calculated by Fu-Ju-Fu Method because the interface tensions of coverlayer /HF aqueous solution is different from that of air /HF aqueous solution, and the cone heights of the probes were also calculated with the interface tension. Compare to the calculation value and experiment value about cone length, whether added surfactant or not, we found that the solubility of HF aqueous in different organic phases and diffusion in two phases play a very important role in tip’s profile. It has been concluded that Diffusion is another important factor working on the profile of probes.2. Preparation of Silvering Probe with Silver Aperture at the Top of Probe: Considering the cytocompatibility and bonding ability with some groups of compounds, metal silver, in this chapter, was used as the coating material of probe. In order to avoid the light leakage and meet the need of individual cell detection, probes with silver coating and aperture at the top were fabricated with the help of chemical plating and ultrasonic. According to the yield of silvering probe with aperture at the top and the size of aperture, we filtered better process out in different techniques. The probes prepared in this way have higher luminous flux and the leaking of light was also solved preferably.3. SA Studies on Silvering Probe Surface （I）—Control and Quantitative Measurement of Two Molecules in SAMM on silver: Considering the oxidation and cytocompatibility of silver coating probe, it is necessary for some appropriate modification on silvering probe surface. In this chapter, SAMM consisted of 3-MPT and C₁₈H₃₇SH was fabricated by means of exchange and competitive absorption on Ag at given concentrations更多还原