de la O-Cuevas Emmanuel, Badillo-Ramírez Isidro, Islas Selene R, Araujo-Andrade C, Saniger José M
Unidad Académica de Física de La Universidad Autónoma de Zacatecas 98068 Zacatecas Mexico.
Instituto de Ciencias Aplicadas y Tecnología, Universidad Nacional Autónoma de México Circuito Externo S/N, Cd. Universitaria 04510 Ciudad de México Mexico
RSC Adv. 2019 Apr 17;9(22):12269-12275. doi: 10.1039/c9ra01396b.
Recombinant human interleukin-6 (IL-6) is a key cytokine that plays an important role in the immune system and inflammatory response, explaining why any modification of its concentration in biological fluids is considered a signal of a pathological condition. Therefore, it is important to develop alternative, highly sensitive and reliable analytical methodologies to detect and identify this analyte in biological fluids. Herein, we present a proof of concept for the development of a new analytical hybrid platform for IL-6 detection that is based on the combination of drop-coating deposition Raman (DCDR) spectroscopy and graphene-enhanced Raman spectroscopy (GERS) effects. The sensitivity limits for IL-6 detection were found to be a function of the type of substrate used. When a 1 μL droplet of IL-6 solution is deposited and dried on an Si substrate, a DCDR effect occurs, and a detection limit below 1 ng mL is obtained; however, when the same is performed using a hybrid substrate of reduced graphene oxide and silicon (rGO/Si), the joint action of DCDR and GERS effects results in a detection limit well below 1 pg mL. It is important to note that this result implies the absolute mass detection of 1 fg of IL-6. In summary, the Raman spectroscopy DCDR/GERS analytical platform proposed here allows the reliable identification of, as well as the very sensitive detection of, IL-6 and promises to improve the performance of clinical evaluations of this biomarker that are currently in use. In this study, the Raman spectra of IL-6 in powder and solution, together with the corresponding band assignment, are presented for the first time in the literature.
重组人白细胞介素-6（IL-6）是一种关键细胞因子，在免疫系统和炎症反应中发挥重要作用，这解释了为何生物体液中其浓度的任何改变都被视为病理状态的信号。因此，开发替代的、高灵敏度且可靠的分析方法以检测和识别生物体液中的这种分析物非常重要。在此，我们展示了一种基于滴涂沉积拉曼（DCDR）光谱和石墨烯增强拉曼光谱（GERS）效应相结合的用于IL-6检测的新型分析混合平台的概念验证。发现IL-6检测的灵敏度极限是所用基底类型的函数。当将1 μL的IL-6溶液液滴滴加并干燥在硅基底上时，会出现DCDR效应，并且获得低于1 ng/mL的检测限；然而，当使用还原氧化石墨烯和硅的混合基底（rGO/Si）进行同样操作时，DCDR和GERS效应的联合作用导致检测限远低于1 pg/mL。需要注意的是，这一结果意味着能够绝对检测到1 fg的IL-6。总之，本文提出的拉曼光谱DCDR/GERS分析平台能够可靠地识别IL-6，并对其进行非常灵敏的检测，有望提高目前正在使用的该生物标志物临床评估的性能。在本研究中，首次在文献中呈现了IL-6粉末和溶液的拉曼光谱以及相应的谱带归属。
