Here, a single-drop paper-based surface-enhanced Raman spectroscopy (SERS) immunoassay was developed to pave the way for monitoring exosome numbers for the early diagnosis of prostate cancer. Exosomes are nano-sized (40-150 nm) membrane vesicles that provide intercellular communication. In our work, we offer a new paper SERS substrate for exosome detection in urine. We initially electrochemically deposited nanostar-shaped gold nanoparticles (AuNPs) on the working electrode to crate the paper SERS substrates. Then we functionalized them with 11-mercaptoundecanoic acid (11-MUA) and conjugated them with anti-CD9 antibodies. After capturing exosomes, the sandwich immunoassay structure was created by using gold nanorods (AuNRs) modified with 5,5-dithiobis (2-nitrobenzoic acid) (DTNB) as a Raman tag. The SERS signal intensities of DTNB molecules at 1330 cm⁻¹ were monitored to determine the exosome concentration. Each step occurred in only one drop of solution or sample. The developed single-drop paper-based SERS immunoassay exhibited a linear range from 1.0×10³ to 1.0×10⁹ exosome particles/mL with correlation coefficients (R²) of 0.9903. The limit of detection (LOD) was found as 9.9×10¹ exosome particles/mL. The developed system was tested with clinical urine samples from patients with benign prostatic hyperplasia, prostatitis, prostate cancer, and healthy individuals. The obtained results were compared with the exosome particle numbers in these samples determined by an enzyme-linked immunosorbent assay (ELISA) method and the accuracy of the system was evaluated with an average recovery value of 96.7%. The developed biosensor system enables highly sensitive detection of exosomes in low-volume urine samples. The usage of a paper membrane as a SERS substrate, combined with the electrochemical deposition of gold nanoparticles, provides an eco-friendly and cost-effective solution, enabling wider use and applications.

中文翻译：

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用于检测尿液样品中外泌体的电化学生成纸 SERS 底物


在这里，开发了一种基于单滴纸的表面增强拉曼光谱 （SERS） 免疫测定法，为监测外泌体数量以早期诊断前列腺癌铺平了道路。外泌体是纳米级 （40-150nm） 膜囊泡，可提供细胞间通讯。在我们的工作中，我们提供了一种用于尿液中外泌体检测的新论文 SERS 底物。我们最初在工作电极上电化学沉积纳米星形金纳米颗粒 （AuNPs），以将纸 SERS 衬底装箱。然后，我们用 11-巯基十一酸 （11-MUA） 对它们进行功能化，并将它们与抗 CD9 抗体偶联。捕获外泌体后，通过使用用 5,5-二硫双（2-硝基苯甲酸）（DTNB）修饰的金纳米棒 （AuNR） 作为拉曼标签来创建夹心免疫测定结构。监测 DTNB 分子在 1330cm-1 处的 SERS 信号强度以确定外泌体浓度。每个步骤仅发生在一滴溶液或样品中。开发的单滴纸质 SERS 免疫测定法的线性范围为 1.0×10³ 至 1.0×10^{9 个}外泌体颗粒/mL，相关系数 （R²） 为 0.9903。检测限 （LOD） 为 9.9×10¹ 个外泌体颗粒/mL。开发的系统使用良性前列腺增生、前列腺炎、前列腺癌患者和健康个体的临床尿液样本进行了测试。将获得的结果与通过酶联免疫吸附测定 （ELISA） 方法测定的这些样品中的外泌体颗粒数进行比较，并以 96.7% 的平均回收率评估系统的准确性。开发的生物传感器系统能够对低容量尿液样本中的外泌体进行高灵敏度检测。 使用纸膜作为 SERS 基材，结合金纳米颗粒的电化学沉积，提供了一种环保且具有成本效益的解决方案，可实现更广泛的使用和应用。