Salmonella typhimurium (S. typhimurium) and Staphylococcus aureus (S. aureus) are the two most important foodborne pathogens which can easily cause disease infections. Here, the aptamer-facilitated gold/silver nanodimer SERS probes were built for the simultaneous detection of the two bacteria with the help of magnetic separation enrichment. First, two nanodimer SERS signal probes and two magnetic capture probes each connected with the specific aptamer were fabricated. The distance between gold and silver nanoparticles in the dimer can amplify the Raman signal (Cy3 and Rox) at the junction but modified in the aptamer sequence. Then, after the addition of S. typhimurium and S. aureus, the sandwich-like composite structures "SERS signal probes-target-magnetic capture probes" formed because of the high affinity between aptamer sequences and their target bacteria. Under the optimal experimental conditions, the linear correlations between Raman intensity and the logarithm of the concentration of bacteria were y = 876.95x-67.84 (R = 0.9865) for S. typhimurium and y = 1280.43x-1752.6 (R = 0.9883) for S. aureus. The SERS detection showed the nanodimer probe had high selectivity. Besides, the recovery experiment in milk sample indicated good accuracy compared with the traditional plate counting method.
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http://dx.doi.org/10.1007/s00604-021-04791-4 | DOI Listing |
Anal Chem
January 2024
Institute of Health and Medical Technology, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei 230031, China.
Interface interaction between aromatic molecules and noble metals plays a prominent role in fundamental science and technological applications. However, probing π-metal interactions under ambient conditions remains challenging, as it requires characterization techniques to have high sensitivity and molecular specificity without any restrictions on the sample. Herein, the interactions between polycyclic aromatic hydrocarbon (PAH) molecules and Au nanodimers with a subnanometer gap are investigated by surface-enhanced Raman spectroscopy (SERS).
View Article and Find Full Text PDFNanotechnology
December 2022
Jihua Laboratory, Foshan 528000, People's Republic of China.
The suspended metallic nanostructures with tiny gaps have certain advantages in surface-enhanced Raman scattering (SERS) due to the coaction of the tiny metallic nanogaps and the substrate-decoupled electromagnetism resonant modes. In this study, we used the lithographic HSQ/PMMA electron-beam bilayer resist exposure combined with a deposition-induced nanogap-narrowing process to define elevated suspended metallic nanodimers with tiny gaps for surface-enhanced Raman spectroscopy detection. By adjusting the deposited metal thickness, the metallic dimers with sub-10 nm gaps can be reliably obtained.
View Article and Find Full Text PDFFront Chem
May 2021
Department of Chemistry, Humboldt-Universität zu Berlin, Berlin, Germany.
Surface enhanced hyper Raman scattering (SEHRS) can provide many advantages to probing of biological samples due to unique surface sensitivity and vibrational information complementary to surface-enhanced Raman scattering (SERS). To explore the conditions for an optimum electromagnetic enhancement of SEHRS by dimers of biocompatible gold nanospheres and gold nanorods, finite-difference time-domain (FDTD) simulations were carried out for a broad range of excitation wavelengths from the visible through the short-wave infrared (SWIR). The results confirm an important contribution by the enhancement of the intensity of the laser field, due to the two-photon, non-linear excitation of the effect.
View Article and Find Full Text PDFMikrochim Acta
May 2021
State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, 214122, People's Republic of China.
Salmonella typhimurium (S. typhimurium) and Staphylococcus aureus (S. aureus) are the two most important foodborne pathogens which can easily cause disease infections.
View Article and Find Full Text PDFBiosens Bioelectron
May 2021
Advanced Photonics Center, School of Electronic Science and Engineering, Southeast University, Nanjing, 210096, Jiangsu, China.
Accurate quantitative detection of dopamine (DA) in blood is essential for the early diagnosis and the pathogenesis analysis of dopaminergic dysfunction, which still remains a great challenge because of the extremely low concentration in patients. Using our previously reported DNA-assisted synthesis of ortho-nanodimers (DaSON) strategy, a microfluidic surface enhanced Raman spectroscopy (SERS) biosensor for the ultrasensitive and reliable detection of DA in serum was demonstrated by modifying SERS probes with DA aptamers in a specific orientation to form zipper-like ortho-nanodimers. The uniform 1-nm gap in zipper-like ortho-nanodimers endows the SERS sensor with ultrahigh sensitivity and high accuracy for the detection of DA.
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