Aluminum Plasmonic Nanoclusters for Paper-Based Surface-Enhanced Raman Spectroscopy

Abstract

Although surface-enhanced Raman spectroscopy (SERS) can rapidly identify molecular fingerprints and has great potential for analysis, the need for delicate plasmonic substrates and complex laboratory instruments seriously limits its applicability for on-site detection. This paper describes the development of an inexpensive aluminum nanoparticle (AlNP)-decorated paper that functions as a facile SERS-based detection platform (Al-PSERS). Polydopamine-protected AlNPs were chemically synthesized and then simply drop-cast onto a hydrophobic cellulose paper, forming a monolayer AlNP cluster array. Because of the abundance of hot spots arising from the plasmonic clusters, the inherent quasi-three-dimensional structure of the cellulose fibers, and the concentration effect of the hydrophobic surface, the Al-PSERS provided significant enhancements to the signal of various analytes, measured using a portable 785 nm Raman spectrometer. Near-field optical simulations and experimental spectroscopic results revealed that the local electric fields and corresponding SERS signal intensities of the AlNP array exhibited clear particle-length and cluster-size dependencies. Therefore, the Al-PSERS could be optimized to provide high sensitivity (enhancement factor: 2 × 103) and excellent reproducibility (variation: 8.72%). Moreover, the optimal Al-PSERS was capable of detecting colorants and environmental pollutants; for example, the detection limits of allura red and benzo[a]pyrene reached as low as 3.5 and 0.15 ppm, respectively. Furthermore, the Al-PSERS could rapidly identify illegal (rhodamine B) and edible (allura red, erythrosine) colorants from a mixture of multiple colorants or from adulterated candies. Because it facilitates rapid detection, is of low cost, and has minimal technical requirements, Al-PSERS should be applicable to on-site detection in, for example, food inspection and environmental monitoring.

Practical Considerations for Simulating the Plasmonic Properties of Metal Nanoparticles

“…Such details are already known to greatly impact near-field effects central to surface-enhanced Raman spectroscopy. That is, the electric field enhancement is greatly impacted by fine structural features as discussed previously for Au nanostars, as well as for many other nanostructures. ,− Simulations must accurately represent these features (and an appropriate mesh size must be selected) because small volume changes can lead to large changes in the electric field enhancement, ultimately affecting the use of a given nanostructure as a SERS substrate. These constraints again highlight the importance of accurate modeling for systems with fine structural features.…”

The Convenience of Polydopamine in Designing SERS Biosensors with a Sustainable Prospect for Medical Application

“…The PDA layer can protect the highly oxidizable metal matrix [ 128 ]. Renard et al synthesized octahedral aluminum nanocrystals coated with a 5–7 nm PDA layer binding to Al 2 O 3 by catechol groups.…”

A high-density Ag nanoneedle forest array by using a nano-peeling technique for near-infrared SERS detection

“…Surface-enhanced Raman scattering (SERS) is a wellestablished non-destructive detection technique that has been intensely studied in various applications, including molecule detection, analytical chemistry, electrochemistry, medical diagnostics and bio-sensing. [1][2][3][4][5][6][7][8] However, the use of intense laser power in the ultraviolet and visible region often leads to the destruction of molecular structures, resulting in decreased sensitivity and selectivity. Additionally, the presence of water in biological tissues can cause imprecise detection.…”