High Uniformity and Enhancement Au@AgNS 3D Substrates for the Diagnosis of Breast Cancer

Abstract

Breast cancer appears to be one of the leading causes of cancer-related morbidity and mortality for women worldwide. The accurate and rapid diagnosis of breast cancer is hence critical for the treatment and prognosis of patients. With the vibrational fingerprint information and high detection sensitivity, surface-enhanced Raman spectroscopy (SERS) has been extensively applied in biomedicine. Here, an optimized bimetallic nanosphere (Au@Ag NS) 3D substrate was fabricated for the aim of the diagnosis of breast cancer based on the SERS analysis of the extracellular metabolites. The unique stacking mode of 3D Au@Ag NSs provided multiple plasmonic hot spots according to the theoretical calculations of the electromagnetic field distribution. The low relative standard deviation (RSD = 2.7%) and high enhancement factor (EF = 1.42 × 10 5 ) proved the uniformity and high sensitivity. More importantly, the normal breast cells and breast cancer cells could be readily distinguished from the corresponding SERS spectra based on the extracellular metabolites. Furthermore, the clear clusters of SERS spectra from MCF-7 and MDA-MB-231 extracellular metabolites in the orthogonal partial least-squares discriminant analysis plot indicate the distinct metabolic fingerprint between breast cancer cells, which imply their potential clinical application in the diagnosis of breast cancer.

Surface-Enhanced Raman Spectroscopy Sensor Integrated with Ag@ZIF-8@Au Core–Shell–Shell Nanowire Membrane for Enrichment, Ultrasensitive Detection, and Inactivation of Bacteria in the Environment

“…The purity and crystal structure of ZIF-8, A-NW, and AZA-NW are characterized by X-ray diffraction (XRD) (Figure h). XRD patterns of ZIF-8 are consistent with the literature, suggesting the successful synthesis of ZIF-8. , Similarly, XRD patterns of A-NW are consistent with those of the standard card (JCPDS NO.04–0783). The (1 1 1), (2 0 0), and (2 2 0) crystal planes correspond to diffraction peaks at 38.1, 44.3, and 64.5°, respectively, suggesting that the synthesized A-NW exhibits a face-centered cubic structure. , No impurity peaks in the XRD pattern indicate that the A-NW has a high purity.…”

“…XRD patterns of ZIF-8 are consistent with the literature, suggesting the successful synthesis of ZIF-8. 16 , 60 Similarly, XRD patterns of A-NW are consistent with those of the standard card (JCPDS NO.04–0783). The (1 1 1), (2 0 0), and (2 2 0) crystal planes correspond to diffraction peaks at 38.1, 44.3, and 64.5°, respectively, suggesting that the synthesized A-NW exhibits a face-centered cubic structure.…”

“…Surface-enhanced Raman spectroscopy (SERS) is a powerful analytical technique providing fingerprint spectra to detect and distinguish bacterial species with high sensitivity. − However, due to the complexity of bacterial composition, it must be located at the hotspot region (the region with a dense noble metal structure) in the SERS substrate to realize higher detection sensitivity. Moreover, trace bacteria should also be enriched to detect them efficiently.…”

Recent Trends in SERS-Based Plasmonic Sensors for Disease Diagnostics, Biomolecules Detection, and Machine Learning Techniques

“…There are many reports of researchers using exosomes as biomarkers for the identification of cancer, using SERS [ 186 ]. A highly sensitive (EF ~10 5 ) and reproducible (2.7%) method was developed using Au@Ag nanospheres for the detection of breast-cancer-based extracellular metabolites [ 187 ]. Systematic experiments were performed to understand the effects of laser power and acquisition time on the reproducibility in immune-SERS microscopy and found that a longer acquisition time and higher laser power lead to poor reproducibility [ 188 ].…”