【作者】 李凯伟；

【导师】 宣明； 吴一辉；

【作者基本信息】 中国科学院研究生院(长春光学精密机械与物理研究所) ， 机械制造及其自动化， 2014， 博士

【摘要】 在过去的十年中生物传感技术发展迅速，各种高灵敏度传感方法和器件不断涌现，然而高灵敏度也导致其易受非特异性因素干扰，从而影响了生物传感的实用化进程。本文针对双锥型光纤生物传感器的原理、制作工艺、灵敏度增强、金纳米粒子标记等技术开展了深入细致的理论和实验研究，揭示了双锥光纤无标生物传感器重复性差的内在原因，提出了可同时获得该传感器高灵敏度、重复性和特异性的方法。（1）通过研究微纳光纤的传导特性，特别是纳米粒子在光纤消逝场中的散射和吸收特性，建立了微纳米粒子对微纳光纤消逝场功率损耗的理论模型，证明了采用纳米光纤可实现单个金、银纳米粒子以及细菌的检测，并通过50nm的金纳米粒子的单粒子探测实验对其进行了验证；（2）通过系列实验和仿真分析研究，揭示了双锥型光纤无标生物传感器高灵敏度和高重复性之间的矛盾。研究表明，其高灵敏度得益于锥腰中的模式干涉，但模式干涉所引起的光纤对折射率的不规则震荡又导致了传感器的重复性较差；该发现对从根本上解决高灵敏光纤消逝场生物传感的实用化问题有重要意义；（3）研究了金纳米粒子对微纳光纤消逝场传感器的折射率探测及其生物探测灵敏度增强效应；相比传统光纤LSPR传感器，本文构造的金纳米粒子修饰的微纳光纤LSPR传感器，具有单模传输和表面场增强特性，对折射率灵敏度达到20A/RIU，对亲和素检出限达到1pg/mL；由于该传感器在测试范围内具有较好的线性，因此也具有较好重复性；该方法较成功地解决了光纤传感器灵敏度和重复性间的矛盾；（4）采用金纳米粒子标记方法对双锥型光纤生物传感器的特异性、灵敏度及重复使用特性进行了研究，实现了对癌症标志物AFP血清样品的高灵敏度检测，检出限达到2ng/mL，最小解离再生次数可达9次。更多还原

【Abstract】 Biosensing technology has advanced rapidly and dramatically in the last decadeand various highly sensitive sensing methods and devices are constantly emerging.However, high sensitivity also makes these devices vulnerable to nonspecificinterferences, which hindered the application process for biosensors. In thisdissertation, biconical optical fiber sensors were systematically studied in the aspectof sensing mechanism, manufacturing technology, sensitive enhancement, andlabeling technique. The underlying mechanism of poor reproducibility for biconicaloptical fiber sensors was revealed and several methods to enhance the sensitivity,reproducibility and specificity were proposed.(1) By combining the optical guiding property of optical micro/nanofibers andthe scattering and absorbance property of nanospheres, a model for calculating theoptical losses caused by nano spheres in the evanescent field of an optical fiber wasbuilt. Theoretical calculations suggested the possibility of single particle detection forgold nanoparticles, silver nanoparticles and bacterial using optical nanofibers. Singlegold nanoparticles of40were detected using a500nm thick nanofiber in experiments,which demonstrated the reliability of the model.(2) The underlying contradiction between sensitivity and reproducibility wererevealed through systematically experimental and simulation studies. The study shows that the high sensitivity is mainly caused by the modes coupling and this in turncaused the poor reusability of biconical fiber biosensors. This finding is of greatimportance for promoting the application process of highly sensitive optical fiberbiosensors.(3) The enhanced sensitivity of optical micro/nanofiber sensors modified withgold nanoparticles for refractive index detection and biodetection was carefullystudied both theoretically and experimentally. By introducing gold nanoparticles tothe surface of optical micro/nanofibers, the sensitivity and reproducibility can begreatly improved. A RI sensitivity of20A/RIU and detection limit of1pg/mL wasarchived in the experiments.(4) The selectivity enchantment of using gold nanoparticles as labels for opticalmicrofiber biosensors was evaluated. This sensor utilizes both the unique opticalproperty of ultrathin optical microfibers and the strong optical absorption property ofgold nanoparticles. Bio-functionalized gold nanoparticles are used as signal amplifiersin a sandwich assay to enhance both sensitivity and selectivity. In immunoassay, AFPwas detected in bovine serum with limits of detection of2ng/mL. This biosensor canbe regenerated for9times.更多还原