Well-designed shape anisotropical bi-metallic nanoparticles for optical bioanalytics

解决现代医学、生物技术和环境科学的紧迫问题，如掌握新的和多重耐药的病原体、个性化医学或开发可持续的生物技术进程，都需要在单细胞水平上进行诊断。因此，需要新颖而强大的传感方法，这种方法将选择性识别与普遍适用的转换原理和高转换率相结合，并且也适用于小分子系综甚至单分子。基于纳米尺度换能器的光学传感(LSPR局域表面等离子体共振)与已建立的SPR(传播表面等离子体共振)相比，具有显著的优势(如更简单的检测、小型化、并行化)，在生物分析中具有广泛的应用潜力。为了利用这一潜力，拟议的项目基于两种灵敏度提升效应的组合，即各向异性(使用银棱镜)和双金属成分，开发出新型、更灵敏的等离子体纳米颗粒。各向异性粒子在某些位置(如角落)表现出电磁场的增强，通过分析物结合在那里导致对折射率变化的更高敏感性。这种效应将首次与最近观察到的等离子体纳米结构上由于薄的二次金属层而引起的灵敏度增强结合在一起[1]。为了充分利用这种颗粒的优点，需要在尺寸上的窄分布(从而在所产生的光谱特性中)，这将通过发展微流控合成颗粒来实现。除了在较小的液室中形成更均匀的化学和热种子条件外，这一过程还受到合成种子阶段初级金属团簇自组装成生长颗粒的强烈影响。除了增加一次种子形成，这种微流控合成方法能够独立于种子形成影响簇排列，这将允许形成具有显著改善的生物传感性能的新型双金属粒子。利用形态各向异性等离子体纳米粒子，拟议的项目将展示微反应技术如何应用于新型功能纳米材料的系统组装。

Addressing pressing problems of modern medicine, biotechnology and environmental science, such as mastering of new and multiresistant pathogens, personalized medicine, or the development of sustainable biotechnological processes requires a diagnostic at the single cell level. Therefore novel and powerful sensoric approaches are needed, which combine a selective recognition with a general applicable transducing principle and a high transduction rate, and which are also applicable for small molecular ensembles or even single molecules. Optical sensing based on nanoscale transducer (LSPR localized surface plasmon resonance) shows a high potential for a broad application in bioanalytics with significant advantages (like simpler detection, miniaturization, parallelization) compared to the established SPR (propagating surface plasmon resonance). In order to utilize this potential, the proposed project develops novel, more sensitive plasmonic nanoparticles based on a combination of two sensitivity boosting effects, namely anisotropy (using silver prisms) and bi-metal composition. Anisotropic particles show an enhancement of the electromagnetic field in certain locations (like corners) leading to a higher sensitivity for refractive index changes by analytes binding there. This effect will be, for the first time, combined with the recently observed sensitivity enhancement due to thin secondary metal layer on plasmonic nanostructures [1].In order to utilize the advantages of such particles fully, a narrow distribution in size (and thereby in the resulting spectroscopic properties) is required, what will be realized by the development of a microfluidic synthesis of the particles. Beside more homogenous chemical and thermal seed formation conditions in small liquid compartments, this process is strongly influenced by the self-assembly of primary metal clusters into growing particle during the seed phase of the synthesis. Beyond increased primary seed formation, this microfludic synthetic approach enables to influence cluster arrangement independently from seed formation, what will allow the formation of novel bi-metallic particles with significantly improved biosensoric properties. Using form-anisotrope plasmonic nanoparticles, the proposed project will demonstrate how micro reaction technology can be applied for a systematic assembly of novel functional nanomaterials.