Recent advances of Au@Ag core–shell SERS‐based biosensors

Abstract

The methodological advancements in surface-enhanced Raman scattering (SERS) technique with nanoscale materials based on noble metals, Au, Ag, and their bimetallic alloy Au-Ag, has enabled the highly efficient sensing of chemical and biological molecules at very low concentration values. By employing the innovative various type of Au, Ag nanoparticles and especially, high efficiency Au@Ag alloy nanomaterials as substrate in SERS based biosensors have revolutionized the detection of biological components including; proteins, antigens antibodies complex, circulating tumor cells, DNA, and RNA (miRNA), etc. This review is about SERS-based Au/Ag bimetallic biosensors and their Raman enhanced activity by focusing on different factors related to them. The emphasis of this research is to describe the recent developments in this field and conceptual advancements behind them. Furthermore, in this article we apex the understanding of impact by variation in basic features like effects of size, shape varying lengths, thickness of core-shell and their influence of large-scale magnitude and morphology. Moreover, the detailed information about recent biological applications based on these core-shell noble metals, importantly detection of receptor binding domain (RBD) protein of COVID-19 is provided.

Carbon dots-mediated synthesis of gold nanodendrites with extended absorption into NIR-II window for in vivo photothermal therapy

“…As shown in Fig. 3 i, the electric field results confirmed the existence of hot spots, which was likely attributed to the abundant plasmon coupling occurred between the closely spaced branches [ 37 , 38 ]. Such enhancement of electric field resulted in strong NIR-II absorption and localized plasmon heating, which could be considered as a good candidate for NIR-II photoacoustic and photothermal agents.…”

Highly uniform core/shell structures AuR/Ag and AuR/Ag@BSA with various shell thicknesses for surface-enhanced Raman scattering

“…For AuR/Ag core/shell structures of the same core size, the thickness of the Ag shell affects the SERS results. To understand and explain this influence more deeply, we use the simulation results of the near electromagnetic (EM) field distribution of the FDTD method which is based on Mie theory and uses an excitation wavelength of 785 nm [7,42]. The results of this method show that the proximal electromagnetic near-field distribution increases as the length and width of the core/shell structures increase.…”

Lectin-conjugated nanotags with high SERS stability: selective probes for glycans

“…Surface-enhanced Raman spectroscopy (SERS) is a powerful analytical technique that has received tremendous attention and consideration in the design of biosensors and optical probes for biological studies. [1][2][3][4] SERS nanotags are plasmonic metal nanoparticles (for example Au, Ag, etc.) coated with Raman molecules with a specific Raman signature.…”