School of Physics and Astronomy, University of Exeter, Exeter EX4 4QL, UK.
Molecules. 2022 Jan 28;27(3):892. doi: 10.3390/molecules27030892.
Noble metal nanoparticles (NP) such as gold (AuNPs) and silver nanoparticles (AgNPs) can produce ultrasensitive surface-enhanced Raman scattering (SERS) signals owing to their plasmonic properties. AuNPs have been widely investigated for their biocompatibility and potential to be used in clinical diagnostics and therapeutics or combined for theranostics. In this work, labeled AuNPs in suspension were characterized in terms of size dependency of their localized surface plasmon resonance (LSPR), dynamic light scattering (DLS), and SERS activity. The study was conducted using a set of four Raman labels or reporters, i.e., small molecules with large scattering cross-section and a thiol moiety for chemisorption on the AuNP, namely 4-mercaptobenzoic acid (4-MBA), 2-naphthalenethiol (2-NT), 4-acetamidothiophenol (4-AATP), and biphenyl-4-thiol (BPT), to investigate their viability for SERS tagging of spherical AuNPs of different size in the range 5 nm to 100 nm. The results showed that, when using 785 nm laser excitation, the SERS signal increases with the increasing size of AuNP up to 60 or 80 nm. The signal is highest for BPT labelled 80 nm AuNPs followed by 4-AATP labeled 60 nm AuNPs, making BPT and 4-AATP the preferred candidates for Raman labelling of spherical gold within the range of 5 nm to 100 nm in diameter.
贵金属纳米粒子（NP），如金（AuNPs）和银纳米粒子（AgNPs），由于其等离子体特性，可产生超灵敏的表面增强拉曼散射（SERS）信号。AuNPs 因其生物相容性和在临床诊断和治疗中的潜在应用，或与其他物质结合用于治疗诊断而得到了广泛的研究。在这项工作中，悬浮液中的标记 AuNPs 的尺寸依赖性，通过其局域表面等离子体共振（LSPR）、动态光散射（DLS）和 SERS 活性进行了表征。该研究使用了一组四个拉曼标记物或报告分子，即具有大散射截面和硫醇部分的小分子，用于化学吸附在 AuNP 上，即 4-巯基苯甲酸（4-MBA）、2-萘硫醇（2-NT）、4-乙酰氨基硫酚（4-AATP）和联苯-4-硫醇（BPT），以研究它们在 SERS 标记不同尺寸（5nm 至 100nm）的球形 AuNPs 中的可行性。结果表明，当使用 785nm 激光激发时，SERS 信号随 AuNP 尺寸的增加而增加，直到 60 或 80nm。对于 BPT 标记的 80nm AuNPs，SERS 信号最高，其次是 4-AATP 标记的 60nm AuNPs，这使得 BPT 和 4-AATP 成为直径为 5nm 至 100nm 的球形金的拉曼标记的首选候选物。
