A monolayer of hierarchical silver hemi-mesoparticles with tunable surface topographies for highly sensitive surface-enhanced Raman spectroscopy

Trends in Application of SERS Substrates beyond Ag and Au, and Their Role in Bioanalysis

This article compares the applications of traditional gold and silver-based SERS substrates and less conventional (Pd/Pt, Cu, Al, Si-based) SERS substrates, focusing on sensing, biosensing, and clinical analysis. In recent decades plethora of new biosensing and clinical SERS applications have fueled the search for more cost-effective, scalable, and stable substrates since traditional gold and silver-based substrates are quite expensive, prone to corrosion, contamination and non-specific binding, particularly by S-containing compounds. Following that, we briefly described our experimental experience with Si and Al-based SERS substrates and systematically analyzed the literature on SERS on substrate materials such as Pd/Pt, Cu, Al, and Si. We tabulated and discussed figures of merit such as enhancement factor (EF) and limit of detection (LOD) from analytical applications of these substrates. The results of the comparison showed that Pd/Pt substrates are not practical due to their high cost; Cu-based substrates are less stable and produce lower signal enhancement. Si and Al-based substrates showed promising results, particularly in combination with gold and silver nanostructures since they could produce comparable EFs and LODs as conventional substrates. In addition, their stability and relatively low cost make them viable alternatives for gold and silver-based substrates. Finally, this review highlighted and compared the clinical performance of non-traditional SERS substrates and traditional gold and silver SERS substrates. We discovered that if we take the average sensitivity, specificity, and accuracy of clinical SERS assays reported in the literature, those parameters, particularly accuracy (93-94%), are similar for SERS bioassays on AgNP@Al, Si-based, Au-based, and Ag-based substrates. We hope that this review will encourage research into SERS biosensing on aluminum, silicon, and some other substrates. These Al and Si based substrates may respond efficiently to the major challenges to the SERS practical application. For instance, they may be not only less expensive, e.g., Al foil, but also in some cases more selective and sometimes more reproducible, when compared to gold-only or silver-only based SERS substrates. Overall, it may result in a greater diversity of applicable SERS substrates, allowing for better optimization and selection of the SERS substrate for a specific sensing/biosensing or clinical application.

The surface-enhanced Raman scattering of all-inorganic perovskite quantum dots of CsPbBr3 encapsulated in a ZIF-8 metal–organic framework

We used a one-pot method to synthesize CsPbBr₃@ZIF-8 and found that it has strong surface-enhanced Raman scattering performance and stability at room temperature.

In situ SERS monitoring of plasmonic nano-dopants during photopolymerization

The motion of the plasmonic nano-dopant in photopolymers was monitored in situ and in real time using the surface-enhanced Raman scattering (SERS) technique. Here an Au@MBA@Ag (core-molecule-shell) nanoparticle colloid was synthesized to act as the nano-dopant and adsorbed 4-mercaptobenzoic acid (MBA) between the Au cells and Ag shells as the internal standard. The changes of the MBA signal closely reflect the motion of nanoparticles, since the MBA signal itself has time stability. Experimental data indicate that the optimized concentration of the nano-dopant can be obtained based on the peak intensity change of MBA at 1583  cm^-1. This Letter provides a novel way for in situ monitoring of photophysicial and photochemical processes.