Reproducible fabrication of gold nanostar monolayers for surface‐enhanced Raman spectroscopy‐based trace detection

Abstract

Rapid, simple, and reliable detection of toxics at trace level is of great significance for public health. Surface‐enhanced Raman spectroscopy (SERS) as a powerful vibrational spectroscopic technique for molecules probing provides great advantages in trace detection; however, the low reproducibility of SERS signals from spot to spot and substrate to substrate remains a great challenge restricting its real applications. Here, we report a facile method for reproducibly preparing highly uniform self‐assembled monolayers of gold nanostars (Au NSs SAM) as SERS substrates using the classic Langmuir–Blodgett technique and introduced a statistical method to explore the signal reproducibility by t test. Our results show that the Au NSs SAM substrates fabricated in the same batch and different batches generated constant SERS signals without statistical differences and could detect dye molecules CV, R6G, and RhB in solution at concentrations as low as 10−8, 10−8, and 10−7 M, respectively. We then applied the Au NSs SAM for trace detection of Tetracycline (TC), one of the most widespread antibiotics entering the food chain and threatening the ecological balance. A detection limit of 0.05 μg/ml was achieved, with a linear response between SERS signal and TC concentration in the range of 0.05–10 μg/ml. Overall, this uniform Au NSs SAM could be reproducibly fabricated to provide a reliable platform for trace detection of TC residues or other toxics in water and is expected to have broad applications in different fields including environmental monitoring, food security, and so on.

Silver nanostar films for surface-enhanced Raman spectroscopy (SERS) of the pesticide imidacloprid

“…AgNs films were prepared on silicon and glass surfaces using a self-assembly technique based on films formed at a colloidal aqueous-toluene interface as reported by the Zhang group [ 23 ]. To assemble AgNs on the solid surface, the monolayer film was prepared by mixing 12.0 ml colloidal AgNs and 6.0 ml toluene into a watch glass with diameter of 8.0 cm and 1.3 cm height.…”

A review of metal nanoparticle‐based surface‐enhanced Raman scattering substrates for severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) detection

“…This approach has been used both with and without a template to promote the metal nanostructures' adhesion on the solid surfaces. [16,64] The coverage and nanoparticles arrangement on the solid surface can be easily controlled which can help to generate homogenous SERS enhancement of the analyte molecules. Hydrothermal growth [65] and seed-mediated growth of nanoparticles [66] on the solid surface are alternative approaches that offer good controllable distribution of the active species on the SERS platform.…”

Au Nanostars Coated with a Thin Film of MIL-100 (Fe) for SERS-Based Sensing of Volatile Organic Compound Indicators in Saliva

“…38 Stable and uniform Au-star can be obtained conveniently through a simple and fast synthesis method. 36,39 Thus, we designed the SERS sensor with a Au star as the core. The thin film of MIL-100 (Fe) primarily functions through adsorption, whereas the core of Au-star serves to enhance signals.…”

“…Besides, Au-star have a stronger SERS effect and larger surface area, making them more suitable for SERS gas sensing compared to ordinary Au nanospheres and Au nanorods . Stable and uniform Au-star can be obtained conveniently through a simple and fast synthesis method. , Thus, we designed the SERS sensor with a Au star as the core. The thin film of MIL-100 (Fe) primarily functions through adsorption, whereas the core of Au-star serves to enhance signals.…”

“…Although, the SERS effect of Ag-based nanoparticles is typically stronger than that of Au when the nanoparticles have similar size and morphology . Ag-based nanoparticles have lower chemical stability and are more susceptible to oxidation, especially in environments with high humidity, such as saliva. − So in order to maintain the sensing performance, we employed Au-based nanoparticles that are stable in air as the core material for this research. Besides, Au-star have a stronger SERS effect and larger surface area, making them more suitable for SERS gas sensing compared to ordinary Au nanospheres and Au nanorods .…”