Gold Nanoparticle-Decorated Ag@SiO₂ Nanocomposite-Based Plasmonic Affinity Sandwich Assay of Circulating MicroRNAs in Human Serum

Abstract

Circulating microRNAs (miRNAs) hold great value in the diagnostics of cancer diseases. Ultrasensitive detection schemes are essential for the determination of circulating miRNAs, due to the limited levels of miRNAs in human serum. To this end, surface enhanced Raman scattering (SERS), which relies on plasmonic nanomaterials to amplify the Raman signal, has evolved as a promising tool. However, plasmonic nanomaterials that allow for fast and ultrasensitive SERS detection are still much needed. Herein, we proposed a fast and ultrasensitive strategy for the determination of circulating miRNAs in human serum, called gold nanoparticle (AuNP)-decorated Ag@SiO 2 nanocomposite-based plasmonic affinity sandwich assay (PASA). We first theoretically verified the presence of multiple hot-spots around the nanocomposite and then experimentally demonstrated the improved detection sensitivity generated by the AuNP-decorated Ag@ SiO 2 nanocomposite. The PASA approach exhibited several significant advantages including ultrahigh sensitivity (the limit of quantification was 10 fM), fast speed (the total analysis time was only 3 h), and very low sample volume requirement (only 5 μL). Quantification of miR-21 in human serum was achieved by the method, which allowed for differentiation of a breast cancer patient from a healthy individual. The AuNP-decorated Ag@SiO 2 nanocomposite and the PASA method can be easily extended for other microRNAs and circulating tumor DNA. Therefore, the PASA method holds great promise for cancer diagnosis.

New Promises of Advanced Molecular Recognition: Bioassays, Single Cell Analysis, Cancer Therapy, and Beyond

“…To further improve the detection sensitivity of PASA, AuNP‐decorated Ag@SiO 2 nanocomposites, which are core− satellites‐like construction, were developed as the labeling probes. [ 55 ] Under the radiation of incident laser, multiple hotspots formed around the nanocomposites generate significantly enhanced Raman signal. Such labeling nanocomposite‐based PASA has been demonstrated to be capable of apparently improving the detection sensitivity as compared with PASA using only silver Raman nanotags, yielding an ultrahigh sensitivity (LOQ, 10 −14 mol·L –1 ).…”

Advances in Protein Biomarker Assay via the Combination of Molecular Imprinting and Surface-enhanced Raman Scattering

“…此外, PISA 技术还可以用于植物果实中单糖的空间分布分 析 [144] . 基于此种原理结合核酸序列杂交亲和识别作用 还可构建等离激元亲和夹心法(PASA)用于单细胞和血 清中的 microRNA 的检测 [145][146] . 结合适配体识别 PASA 可用于血清和活体动物中蛋白质疾病标志物的检测 [147] .…”

Green Synthesis of Luminescent Gold-Zinc Oxide Nanocomposites: Cell Imaging and Visible Light–Induced Dye Degradation

“…Wang et al, 2018b;Wu et al, 2019). In addition to imaging applications, deposition of gold nanoclusters or nanoparticles was successfully attempted on Ag@SiO 2 or covalent organic framework for important functional activities such as circulating miRNA in human serum (Zhang Q. et al, 2019) or surface-enhanced Raman scattering (He et al, 2017), respectively. Building upon this past research, the present study developed a method to deposit luminescent AuNP with 5-6 nm diameter on the surface of Au-ZnO nanocomposites.…”