Boca Sanda, Farcau Cosmin, Baia Monica, Astilean Simion
Nanobiophotonics and Laser Microspectroscopy Center, Interdisciplinary Research Institute on Bio-Nano-Sciences, Babes-Bolyai University, 42 Treboniu Laurian, 400271, Cluj-Napoca, Romania.
Biomolecular Physics Department, Faculty of Physics, Babes-Bolyai University, 1 M. Kogalniceanu, 400084, Cluj-Napoca, Romania.
Biomed Microdevices. 2016 Feb;18(1):12. doi: 10.1007/s10544-016-0037-3.
Neuroendocrine tumors, such as pheochromocytoma or paraganglioma, are dangerous tumors that constitute a potential threat for a large number of patients. Currently, the biochemical diagnosis of neuroendocrine tumors is based on measurement of the direct secretory products of the adrenomedullary-sympathetic system or of their metabolites, such as catecholamines or their metanephrine derivatives, from plasma or urine. The techniques used for analysis of plasma free metanephrines, i.e. high-performance liquid chromatography or high-performance liquid chromatography coupled with mass-spectrometry are technically-demanding and time consuming, which limit their availability. Here we demonstrate a simple, fast and low-cost method for detecting metanephrine by Surface Enhanced Raman Scattering (SERS). The protocol consists in using evaporation-induced self-assembly of gold (Au) nanoparticles incubated with the analyte, on planar gold films. The assembly process produces regions with a dense distribution of both inter-particle gaps and particle-film gaps. Finite-difference time-domain simulations confirm that both kinds of gaps are locations of enhanced electromagnetic fields resulting from inter-particle and particle-film plasmonic coupling, useful for SERS amplification. Metanephrine vibrational bands assignment was performed according to density functional theory calculations. Metanephrine metabolite was detected in liquid at concentration levels lower than previously reported for other similar metabolites. The obtained results demonstrate that the Au nanoparticle/Au film exhibits noticeable SERS amplification of the adsorbed metabolite and can be used in the design of efficient, stable SERS-active substrates for the detection and identification of specific tumor markers.
神经内分泌肿瘤，如嗜铬细胞瘤或副神经节瘤，是危险的肿瘤，对大量患者构成潜在威胁。目前，神经内分泌肿瘤的生化诊断基于对肾上腺髓质 - 交感神经系统的直接分泌产物或其代谢物的测量，例如来自血浆或尿液中的儿茶酚胺或其甲氧基肾上腺素衍生物。用于分析血浆游离甲氧基肾上腺素的技术，即高效液相色谱法或与质谱联用的高效液相色谱法，技术要求高且耗时，这限制了它们的可用性。在此，我们展示了一种通过表面增强拉曼散射（SERS）检测甲氧基肾上腺素的简单、快速且低成本的方法。该方案包括在平面金膜上使用与分析物孵育的金（Au）纳米颗粒的蒸发诱导自组装。组装过程产生了颗粒间间隙和颗粒 - 膜间隙密集分布的区域。时域有限差分模拟证实，这两种间隙都是由颗粒间和颗粒 - 膜等离子体耦合产生的增强电磁场的位置，可用于SERS放大。根据密度泛函理论计算对甲氧基肾上腺素的振动带进行了归属。在液体中检测到甲氧基肾上腺素代谢物的浓度水平低于先前报道的其他类似代谢物。所得结果表明，金纳米颗粒/金膜对吸附的代谢物表现出明显的SERS放大作用，可用于设计高效、稳定的SERS活性底物，用于检测和鉴定特定肿瘤标志物。
