EAGER: Plasmonic Sensing in Liquid with Metal-Insulator-Metal Nanosensors Embedded in Soft Matrices

水是维持生命的重要资源，获得清洁水是保持健康的根本。全球有超过20亿人受到严重的水资源压力和污染的影响，因此开发一个高效、具有成本效益和可获得的水资源监测系统成为当务之急。现有的水监测技术，包括气相色谱法、质谱法和浊度测量，通常过于昂贵，需要高技能人员操作，因此不适合在最需要的地区广泛部署。此外，这些技术通常缺乏即时或现场监测的能力。本项目旨在探索用于即时和现场水质监测的纳米级传感器设计。该系统可以为社区，特别是资源受限地区的社区，提供现场实时水质评估所需的工具，从而可能带来革命性的变化。该检测系统的核心由金属-绝缘体-金属（MIM） Au-SiO2-Au纳米结构和介孔海藻酸盐水凝胶薄膜组成。该项目的目标将通过三个研究活动来实现：(1)利用有限元分析（FEA）开发Au-SiO2-Au MIM纳米传感器。COMSOL的有限元模拟将探讨形状、尺寸等方面对传感器性能的影响，并研究等离子体增强因素，如内外金纳米颗粒的形式、中央硅壳的厚度以及外部金纳米颗粒之间的间距。(2)各种Au-SiO2-Au - MIM纳米传感器等离子体增强的合成、测试和对比分析，并给出数值模拟结果。(3)将Au-SiO2-Au - MIM纳米传感器嵌入ZnO纳米棒修饰的海藻酸盐水凝胶薄膜中，根据厚度、孔径和光吸收效率等因素进行定制。这一阶段的目的是将Au-SiO2-Au - MIM纳米传感器安全地附着在固定的底座上，而不是让它们在样品溶液中自由漂浮。该项目旨在提供新的技术和信息，以应对在理解和监督全球水危机方面的困难。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Water is a vital life-sustaining resource, with access to clean water being fundamental to maintaining health. Over 2 billion individuals globally are affected by significant water stress and pollution, making the development of an efficient, cost-effective, and accessible water monitoring system a top priority. Existing water monitoring technologies, including gas chromatography, mass spectrometry, and turbidity measurement, are often too costly and necessitate the operation by highly skilled personnel, rendering them unfit for broad deployment in the most needing areas. Additionally, these technologies usually lack the capability for immediate or on-site monitoring. This project aims to explore nanoscale sensor designs for immediate and on-site water quality monitoring. This system could potentially bring about transformative changes by providing communities, especially those in resource-constrained areas, with the tools needed for on-the-spot, real-time water quality assessments. The core of the detection system comprises a metal-insulator-metal (MIM) Au-SiO2-Au nanostructures and mesoporous alginate hydrogel thin films. The project's objectives will be met through three research activities: (1) Utilizing finite element analysis (FEA) to develop Au-SiO2-Au MIM nanosensors. The FEA modelling on COMSOL will probe the influences of aspects such as shape, size, and others on sensor performance, as well as study the plasmonic enhancement factors, such as the form of inner and outer Au nanoparticles, the thickness of the central silica shell, and the space between the exterior Au nanoparticles. (2) Synthesis, testing and comparative analysis of plasmonic enhancement of various Au-SiO2-Au MIM nanosensors with numerical simulation results. (3) Embedding Au-SiO2-Au MIM nanosensors into a thin alginate hydrogel film decorated with ZnO nanorods, tailored for factors like thickness, pore size, and light absorption effectiveness. The purpose of this stage is to securely attach the Au-SiO2-Au MIM nanosensors onto a fixed base, as opposed to having them floating freely in the sample solution. This project is set to offer new techniques and information to confront the difficulties in comprehending and overseeing the global water crisis.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.