Red Shifted Nanomaterials for Security Applications

表面增强拉曼散射是一种非常灵敏和选择性的技术，正迅速成为超灵敏分析的一种有效方法。它提供了比正常拉曼散射增加的增强，因此是检测痕量分析物的理想选择，并且由于获得的分子特异性光谱，它是检测混合物中的分析物的理想选择。SERS的灵敏度也使其能够经得起检测，因为可以从特殊合成的标签以及商业上可用的标签中获得强烈的信号。这些标签与纳米颗粒结合使用，由于其独特的振动光谱，可以在饮料市场等品牌保护领域对产品进行标签。该项目建议开发在恶劣（工业）环境下使用785 nm以上的激发波长（例如1064 nm或1280 nm）进行编码纳米粒子检测所需的技术和标签。这将需要合成不同类型的金属纳米颗粒，这些纳米颗粒在电磁波谱的红外区域具有消光剖面，并为纳米颗粒开发涂层，以保护它们免受恶劣环境（如强酸）的影响，同时仍然能够提供强大的SERS响应。目的是开发一种使用SERS主动标签的标记系统，该系统将允许在红外中检测SERS信号。它还将涉及SERS标签的开发，这些标签对它们作为标签的环境是稳定的。这将涉及探索标记纳米粒子的封装，例如不同的聚合物或清漆。目的(1)探索具有红移吸光度的金属纳米颗粒的合成方法。这将涉及合成不同尺寸、形状和外壳结构的纳米粒子，包括金和银。(2)评估可用于1064 nm和1280 nm激光激发合成纳米颗粒的可能标签，以获得最大的SERS增强。(3)评估可用于保护或封装标记纳米颗粒并保护其免受环境影响的基质，并研究编码纳米颗粒在恶劣环境中随时间的稳定性。(4)开发一种编码方案，该方案将允许使用独特的光谱特征来识别SERS编码纳米粒子。这将涉及编码纳米粒子的不同组合的多路复用。

Surface enhanced Raman scattering is an extremely sensitive and selective technique that is rapidly emerging as an effective method for ultrasensitive analysis. It offers an increased enhancement over normal Raman scattering therefore is ideal for the detection of trace amounts of analyte and because of the molecularly specific spectra obtained it is ideal for detecting analytes in mixtures. The sensitivity of SERS also lends itself to stand off detection due to the intense signals which can be obtained from specially synthesised labels as well as ones which are commercially available. These labels, in combination with nanoparticles, can be used as coded labels due to their unique vibrational spectra allowing labelling of products in areas such as brand protection for example in the beverage market.This project proposes to develop the technique and labels required to carry out detection of coded nanoparticles using excitation wavelengths above 785 nm e.g.1064 nm or 1280 nm in harsh (industrial) environments. This will require synthesising different types of metal nanoparticles which have extinction profiles towards the infrared region of the electromagnetic spectrum and developing coatings for the nanoparticles that would protect them from harsh environments such as strong acid, while still being able to give a strong SERS response.The aim is to develop a tagging system using SERS active labels which will allow SERS signals to be detected in the infrared. It will also involve the development of SERS labels which are stable to the environment in which they will act as a label. This will involve exploring the encapsulation of labelled nanoparticles in for example different polymers or varnishes.Objectives(1) To explore the synthesis of metal nanoparticles with red shifted absorbances. This will involve synthesising nanoparticles with different sizes, shapes and shell structures including gold and silver.(2) To evaluate possible labels, both commercially available and synthesised in-house for use with 1064 nm and 1280 nm nm laser excitation with the synthesised nanoparticles to give maximum SERS enhancement.(3) Evaluate matrices which can be used to protect or encapsulate the labelled nanoparticles and protect them from the environment and investigate the stability of the coded nanoparticles over time in harsh environments.(4) To develop a coding scheme which will allow unique spectral signatures to be used to identify the SERS coded nanoparticles. This will involve multiplexing of different combinations of coded nanoparticles.