Wu Jindan, Chen Kaixin, Pan Junming, Li Dehua, Ma Ying, Li Nan
Key Laboratory of Biomaterials of Guangdong Higher Education Institutes, Department of Biomedical Engineering, Jinan University, Guangzhou 510632, China.
School of Chemistry and Chemical Engineering, South China University of Technology, Guangzhou 510632, China.
Anal Chem. 2024 Dec 17;96(50):19981-19987. doi: 10.1021/acs.analchem.4c04544. Epub 2024 Dec 5.
Surface-enhanced Raman scattering spectroscopy (SERS) has been widely applied to screen biomarkers and biological species due to its high sensitivity; however, severe background noise signals significantly limit its practical application. In this study, we develop an ultrasensitive SERS sensor to determine cellular oxidative stress based on the HO-induced enzymatic amplification and a silent-range Raman fingerprint. In the presence of horseradish peroxidase, HO could trigger the coupling reaction of 4-hydroxythiophenol (4-MTP) with phenol-d5 to form a new compound, which can bind to the SERS substrate via the Au-S bond and generate the stable SERS signal with nearly zero background signals owing to the Raman-silent fingerprint of phenol-d5 at 2125 cm. The high-performance enzymatic reaction and the silent-range Raman fingerprint enable the ultrasensitive determination of HO with a broad linear range of 5 × 10 to 1 × 10 M and a limit of detection as low as 1.6 nM. Taking advantage of its excellent sensitivity and anti-interference capability, the as-developed SERS sensor is employed to profile the triggered dynamic change of the intracellular HO release, and further to testify the cancerous cells exhibiting a significantly higher level of intracellular oxidative stress than the healthy cells, and the different cell populations possessing the susceptible difference to additional oxidative stimulation. This study paves the way for improving SERS sensing capability through the silent-range fingerprint and signal amplification via an enzymatic reaction and reveals SERS as an effective tool for monitoring the endogenous oxidative behavior of living cells.
表面增强拉曼散射光谱（SERS）因其高灵敏度已被广泛应用于筛选生物标志物和生物物种；然而，严重的背景噪声信号显著限制了其实际应用。在本研究中，我们基于HO诱导的酶促放大和无拉曼信号范围的拉曼指纹开发了一种超灵敏的SERS传感器来测定细胞氧化应激。在辣根过氧化物酶存在的情况下，HO可触发4-羟基硫酚（4-MTP）与苯酚-d5的偶联反应形成一种新化合物，该化合物可通过Au-S键与SERS底物结合，并由于苯酚-d5在2125 cm处的无拉曼信号指纹而产生背景信号几乎为零的稳定SERS信号。高性能的酶促反应和无拉曼信号范围的拉曼指纹使得能够超灵敏地测定HO，其线性范围宽达5×10至1×10 M，检测限低至1.6 nM。利用其优异的灵敏度和抗干扰能力，所开发的SERS传感器用于描绘细胞内HO释放触发的动态变化，并进一步证明癌细胞表现出比健康细胞显著更高水平的细胞内氧化应激，以及不同细胞群体对额外氧化刺激具有敏感性差异。本研究通过无拉曼信号范围的指纹和酶促反应信号放大为提高SERS传感能力铺平了道路，并揭示了SERS作为监测活细胞内源性氧化行为的有效工具。
