Quantitative Analysis of Salmonella typhimurium Based on Elemental-Tags Laser-Induced Breakdown Spectroscopy

Abstract

Current rapid bacterial detection methods are dedicated to the classification and identification of bacteria. However, there is still a lack of a method for specific quantitative analysis of certain bacteria. In this work, a method based on elemental-tags laser-induced breakdown spectroscopy (ETLIBS) was developed for the rapid and specific quantitative analysis of Salmonella typhimurium (S. ty). Elemental tags were first synthesized by assembling copper nanoparticles (CuNPs) with poly­(thymine) (poly-T) template that linked with the aptamer sequence. Under the specific recognition of the aptamer, S. ty can be fully combined with the elemental tags within 30 min to achieve labeling. Afterward, the silicon nanowires (SiNWs) array modified with Au@Ag nanoparticles (SiNWs–Au@Ag) was employed to capture S. ty in 30 min. Attributed to the rapid analysis superiority of ETLIBS mapping, 100 spectra of SiNWs–Au@Ag/S. ty/CuNPs can be obtained in 5 min. It was found that the peak area of the Cu­(I) atomic emission line at 324.75 nm fitted by the Voigt profile was linearly related to the bacterial concentration in the range of 102–106 CFU/mL­(R 2 = 0.978). Furthermore, ETLIBS mapping achieved a low limit of detection (LOD) of 61 CFU/mL and showed good selectivity to S. ty compared with other bacteria. Besides, the method exhibited preeminent detection performance in spiked samples with the recoveries of 87–113%. With the advantages of rapidity, high efficiency, and specificity, the proposed method is expected to be a powerful tool for bacterial detection.

An enzyme-mediated universal fluorescent biosensor template for pathogen detection based on a three-dimensional DNA walker and catalyzed hairpin assembly

“…The detection limit of the PolyA 10 -DNA system for S. ty is one to four orders of magnitude lower than that of the previously reported methods (Table S2a †) and this PolyA 10 -DNA detection system has the advantages of being fast and low-cost compared with the cultured bacterial sample 43 and laser-induced breakdown spectroscopy (LIBS). 44 In addition, there are some methods that reach a lower LOD than this work (Table S2b †). For example, the reported PCR, 7 immunology-based assays 45 and surfaceenhanced Raman scattering (SERS) 46 methods have realized the sensitive detection of S. ty, and their LODs have reached 7-9, 10 and 4 CFU mL −1 , respectively.…”

T-Shaped Aptamer-Based LSPR Biosensor Using Ω-Shaped Fiber Optic for Rapid Detection of SARS-CoV-2

“…The results demonstrate the preparation of apt-Ag@AuNPs. 25 , 33 Further, the stability of apt-Ag@AuNPs was explored. After apt-Ag@AuNPs were mixed with the binding buffer for 2 h, their silver layer retained an ignorable change in thickness with original apt-Ag@AuNPs ( Figure S10 ), indicating the stability of apt-Ag@AuNPs for the sandwich assay.…”

Recent Advances and Applications of Rapid Microbial Assessment from a Food Safety Perspective

“…The method achieved S. Typhimurium recoveries >87% and relative standard deviations (RSD) <11.56% at spiked samples, in all cases. In conclusion, it should be mentioned that this method could possibly integrate other pathogens with different aptamers for simultaneous identification and quantification; however, it was not yet tested with food samples that were naturally containing S. Typhimurium but with food samples’ dilutions (made with ultra-pure water for 12 h) that were artificially spiked [ 45 ].…”