A hybrid plasmonic nanoprobe using polyvinylpyrrolidone-capped bimetallic silver–gold nanostars for highly sensitive and reproducible solution-based SERS sensing

Abstract

Practical solution-based assays using surface-enhanced Raman spectroscopy (SERS) with portable instrumentation are currently of particular interest for rapid, efficient, and low-cost detection of analytes. However, current assays still have limited...

Rapid Solution-Based SERS Detection of Pesticides Using Graphene Oxide-Coated Silver–Gold Nanostars

“…Silver-coated gold nanoparticles can produce a much stronger SERS signal than gold nanoparticles because of the high scattering silver enhancing the overall electromagnetic field. ,,,, In addition, to achieve ultrahigh SERS sensitivity, controlled assembly of gold–silver nanoparticles over GO nanosheets can further enhance the SERS signal because of the synergetic effect of both the electromagnetic enhancement induced by plasmonic SGNS nanoparticles and the chemical enhancement induced by GO . Moreover, GO can produce a large contact area, create more “hot spots”, and protect the internal silver layer from oxidation.…”

“…EDS images indicate that the Ag layer is preferentially deposited on the core of GNS, which agrees with previous reports. 27,55 The silver thickness of SGNS′, SGNS″, and SGNS was determined from the TEM images (Figure S2), where the core radius of GNS increased from SGNS′ to SGNS. The average silver thickness was 8, 16, and 30 nm for SGNS′, SGNS″, and SGNS respectively, which is consistent with the previously reported silver coated gold nanostars.…”

“…To improve the SERS sensitivity and stability, extensive studies have focused on optimizing plasmonic noble metal nanoparticles. Anisotropic bimetallic gold–silver nanostructures have attracted significant attention in recent years to take the advantage of both the metal gold and silver, where silver facilitates higher enhancement factors in comparison to gold, and gold has better chemical stability and fine-tunability of the morphology with a broader localized surface plasmon resonance (LSPR). ,− Various approaches have been devoted to developing gold–silver nanostructures with a variety of different shape morphologies, including spheres, cubes, rods, and stars, to achieve ultrahigh SERS sensitivity. ,− Among them, bimetallic gold–silver nanostars have attracted interest in the research community because of their unique morphology and optical properties. − There is great interest in improving the properties and performance of bimetallic gold–silver nanostars such as improved stability in real-world conditions.…”

Artificial Intelligence for Surface‐Enhanced Raman Spectroscopy

“…ResNet, [ 115] ANN, [ 116] CNN, [117][118][119][120][121] PCA [ 122] Quantify the abundance of certain molecules RF, [44] PCA+LR, [123] ANN, [ 47,[123][124][125][126] CNN, [127][128][129][130] PCA+SVM, [ 131] PLS, [124,125] SVR, [124] PLS+GA, [132] SVM [ 133] Discover the multiplexed variation in the whole profile PCA, [ 134] Autoencoder, [ 135] CNN, [ 136,137] PCA+LDA [138] Early disease diagnosis ResNet, [ 115] RF, [139] KNN, [ 139] naïve Bayes, [ 139] PLS+SVM [140] SERS spectrum with microRNAs Early disease diagnosis RF, [ 141] LR, [141] naïve Bayes [ 141] Covariance matrices of SERS spectrum…”

“…Algorithms have been applied such as MCR [268] to decompose the mixed spectra with pure components (standard spectra of a certain kind of nanoparticles) through iterative optimization, indicating the existence of certain nanoparticles by the coefficients corresponding to each component (nanoparticle) if above a predetermined threshold. While for the label-free strategy with high uncertainty in the molecular composition, apart from MCR, [44,281] ANNs can also determine the composition based on the concept of classification even if with only minor differentiations, [115] succeeding in qualitatively identifying antibacterial agents, [116] bacterial pathogens, [117,118] disease-related exosomes, [115] water pollutants, [119,120,122] food adulterations, [121] etc. with high accuracy simply with Ag and/or Au nanospheres and their related SERS substrates of more complex structures (Figure 6b).…”