纳颗粒-纳结构复合SERS基底的生化辅助可控制造及性能增强方法研究

Biochemistry sensing technology of high sensitivity and high reliability has been widely applied in many areas such as defending biochemistry warfare agents, diagnosing major diseases, monitoring environmental pollution and detecting food safety. Surface-enhanced Raman scattering (SERS) is a very prospective biochemistry sensing technology which has the advantages of high detection sensitivity, high molecular specificity and multiplex detection. However, SERS active substrates have many problems such as limited enhancement factor (EF), bad repeatability and poor controllability of manufacturing process. Therefore, this project proposes some new high-performance nanoparticles-nanostructure composite SERS substrate and realizes the controllable fabrication and performance-enhancing of the substrates based on biochemistry-assisted processes such as crystogen or DNA linking. The research contents are listed as following: firstly, fulfilling the optimal design and mechanism research of the composite SERS substrate based on FDTD method; secondly, accomplishing the research of micro-nano fundamental processes relating to the fabrication of nanostructure and nanoparticles; thirdly, finishing the research of manufacturing method and performance evaluating of the composite SERS substrate based on chemistry-assisted manufacturing processes; lastly, completing the research of manufacturing method and performance evaluating of the composite SERS substrate with adjustable nanogapes based on biology-assisted manufacturing processes. The results will provide new theoretical and key technical support for the research and practical application of high-performance biochemistry sensing technology based on SERS.

高灵敏、高可靠的生化传感技术在生化战剂防护、重大疾病诊断、环境污染监测、食品安全检测等领域存在迫切需求。表面增强拉曼散射（SERS）是一种极具发展前景的新兴生化传感技术，具有检测灵敏度高、分子特异性好、可实现高通量等优点。但目前的SERS基底存在增强因子较低、均匀性与重复性较差、制备工艺可控性不好等问题。对此，本项目提出了若干种纳颗粒-纳结构复合的高性能SERS基底构型，并基于胱胺、DNA连接等生化辅助工艺方法实现复合基底的可控制备与SERS性能增强。主要研究内容包括：基于时域有限差分算法的复合SERS基底的优化设计与性能增强机理；纳结构与纳颗粒制备的相关微纳基础工艺；基于化学辅助制造工艺的复合SERS基底构筑方法与性能评价；基于生物制造工艺的纳间隙可调复合SERS基底构筑方法与性能评价。项目的研究成果将为我国基于SERS的高灵敏生化传感技术的研究与实际应用提供基础理论和关键技术支撑。

基于纳米结构的表面增强拉曼光谱（Surface-enhanced Raman Spectroscopy）是一种在现场快速检测领域极具发展前景的新兴技术。高性能SERS基底的制造是将SERS技术应用于生化传感领域并实现超灵敏检测的关键。针对此问题，本项目提出多种纳颗粒-纳结构复合SERS基底构型，通过理论分析研究SERS基底的性能调控与提升方法，结合MEMS工艺、化学辅助制造以及生物辅助制造等技术实现其可控制备。主要研究内容与获得的研究成果如下：.1、理论分析：基于时域有限差分算法分析了电磁场在复合基底表面的分布和耦合，仿真结果表明纳颗粒-纳结构复合可以有效调节表面电磁场耦合，提高基底增强因子。.2、纳结构固态基底的制备：系统研究了尺寸范围从200nm到1300nm的聚苯乙烯纳米球旋涂工艺参数，实现了其大面积可控制备；构建了聚苯乙烯纳米球氧刻蚀模型，掌握了其形貌随氧刻蚀时间的变化规律。基于纳米球光刻与MEMS微纳融合工艺，分别AuFON及Ag纳米柱结构的可控制备，拉曼增强因子达到1.12×〖10〗^7，对R6G的检测限为〖10〗^(-8) M。.3、纳颗粒胶体的制备：实现了多种粒径Au@AgNPs溶胶的可控制备，利用支链型聚醚酰亚胺PEI作为中间层的“种子生长法”制备了银壳磁珠，利用超声辅助羟胺种子生长法制备了金壳磁珠。.4、基于化学辅助制造工艺构筑复合SERS基底：分别采用胱氨、PATP等化学小分子及PEI多聚物实现了Au@AgNPs溶胶与AuFON结构之间的可靠连接，证明了PEI结合效率最优，该复合基底对R6G的检测限为〖10〗^(-10) M，优于AuFON和Au@AgNPs的检测限两个数量级；分别采用聚多巴胺、PEI和聚2-乙烯吡啶P2VPy实现了Au@AgNPs溶胶与AgNRs结构之间的可靠连接，证明了P2VPy能有效解决颗粒在银纳米柱表面的均匀分散问题，该复合基底对BPE的检测限为〖10〗^(-8) M，比银纳米柱结构灵敏度提高了2个数量级。.5、基于生物制造工艺构筑间隙可调复合SERS基底：以AuFON结构作为基底，Ag@PATP@SiO2作为SERS标记物，在纳结构表面通过DNA杂交实现了复合SERS基底的构筑，该结构既可以直接检测DNA的SERS光谱，检测限为1nM，也可作为夹心结构检测其他生物分子。