Nanoplating of functional plasmonic gold and silver films

金属纳米粒子因其独特的光学性质而广为人知，例如，由于局域表面等离子激子的激发，它们与可见光或近红外辐射相互作用。等离子体激元共振条件强烈依赖于纳米粒子的局部化学环境。例如，分子在纳米颗粒表面的吸附可以改变其周围介质的折射率，导致纳米颗粒与光的相互作用发生变化，从而能够对这种过程进行光学检测。基于这一原理，可以制备出能够快速、选择性、痕量检测生物分子的光学传感器。因此，等离子体检测元件是下一代高效生物传感器的重要组成部分，对医学诊断具有重要意义。本研究计划旨在展示化学镀技术在合成用于光学生物传感的金和银纳米粒子涂层方面的潜力。制备具有局域表面等离子体共振特性的纳米颗粒薄膜的新方法越来越受到人们的重视，化学镀显示出了一种很有前途的湿化学方法：该方法简单、易扩展、对衬底形状和材料具有灵活性，并且可以广泛地调节沉积材料的功能特性。在概述的项目中，将加强对化学镀金和镀银的纳米级控制，以生产定义明确的纳米颗粒涂层。为此，涉及到的播种反应和电镀反应将相互优化。基于对反应参数的系统评估，将制定策略来控制所产生的纳米颗粒的密度、大小和形状。除了非原位的形态和成分表征外，薄膜的等离子体共振将在其生长过程中通过原位光谱进行分析。结构和光学演化之间的相关性将被用来开发针对等离子体生物传感的特定功能需求的纳米颗粒薄膜的实时可控电镀工艺。最后，根据钥匙锁原理，选定的纳米颗粒涂层将被装饰上受体分子，以选择性结合生物分析物。这种相互作用将被用来研究优化系统的生物传感性能。

Metal nanoparticles are known for their unique optical properties, such as their interaction with visible light or near-infrared radiation due to the excitation of localized surface plasmons. The plasmon resonance conditions strongly depend on the local chemical environment of the nanoparticles. For instance, the adsorption of molecules on the surface of a nanoparticle can alter the refractive index of its surrounding medium, causing a change in the nanoparticle-light interaction, which enables the optical detection of such processes. Based on this principle, optical sensors can be prepared, which can detect biomolecules rapidly, selectively and in trace amounts. Accordingly, plasmonic detection elements are promising components for a next generation of efficient biosensors, with important implications for medical diagnostics.This research proposal aims at demonstrating the potential of the electroless plating technique to synthesize gold and silver nanoparticle coatings for optical biosensing. Novel facile and versatile strategies for the deposition of nanoparticle films exhibiting localized surface plasmon resonance are in high demand, and electroless plating displays a promising wet-chemical option for this task: The method is simple, easily scalable, flexible regarding the substrate shape and material, and allows to widely adjust the functional properties of the deposited material.Traditionally, electroless plating is employed to fabricate closed metal films. Within the outlined project, the nanoscale control of electroless gold and silver plating will be enhanced to enable the production of well-defined nanoparticulate coatings. To this end, the involved seeding and plating reactions will be mutually optimized. Based on a systematic evaluation of the reaction parameters, strategies will be developed to control the density, size and shape of the resulting nanoparticles. Aside from ex situ morphological and compositional characterization, the plasmon resonance of the films will be analyzed by in situ spectroscopy in the course of their growth. The correlation between structural and optical evolution will be utilized to develop real-time controlled plating processes for nanoparticle films tailored toward the specific functional needs of plasmonic biosensing. Finally, selected nanoparticle coatings will be decorated with receptor molecules for the selective binding of biological analytes according to the key-lock-principle. This interaction will be used to investigate the biosensing performance of optimized systems.