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病原体、个性化医疗或可持续生物技术过程的发展，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，将选择性识别与普遍适用的转导原理和高转导率结合起来，并且也适用于小分子集成甚至单分子。基于纳米级传感器的光学传感（LSPR局部表面等离子体共振）与现有的SPR（传播表面等离子体共振）相比，具有检测简单、小型化、并行化等显著优势，在生物分析领域具有广阔的应用前景。为了利用这一潜力，提出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，开发出新颖、更敏感的等离子体纳米粒子。各向异性粒子在某些位置（如角落）显示出电磁场的增强，导致对分析物在那里结合的折射率变化具有更高的灵敏度。这种效应将首次与最近观测到的等离子体纳米结构[1]上的薄二次金属层引起的灵敏度增强相结合。为了充分利用这些颗粒的优点，需要在尺寸上（从而在所得的光谱特性上）有一个狭窄的分布，这将通过开发微流控合成颗粒来实现。除了更均匀的化学和热种子形成条件在小的液体隔间，这一过程受到强烈的影响，自组装成生长颗粒的原生金属簇在合成的种子阶段。除了增加原始种子的形成，这种微流体合成方法能够独立于种子的形成影响簇的排列，这将允许形成具有显着改善的生物传感性能的新型双金属颗粒。利用各向异性等离子体纳米粒子，该项目将展示如何将微反应技术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.