Sensitive colorimetric detection of Salmonella enteric serovar typhimurium based on a gold nanoparticle conjugated bifunctional oligonucleotide probe and aptamer

Abstract

A rapid, specific and visible detection method for Salmonella enteric serovar typhimurium (S. typhimurium) was developed based on a gold nanoparticle (AuNP) conjugated bifunctional oligonucleotide probe and aptamer. AuNPs were conjugated with bifunctional oligonucleotide probes and aptamer, then the target bacteria S. typhimurium cells were incubated with the conjugated AuNP. Since the aptamer had a higher affinity and specificity on binding with the cells and its configurations was therefore changed, AuNPs particles were released. These AuNPs particles would aggregate with NaCl and the color of the solution would turn blue from red. Under the optimal conditions, the correlation between the concentration of S. typhimurium and the intensity of the signals was observed to be linear within the range of 1.0 × 101∼1.0 × 106 cfu/ml (R2 = 0.9952), and the detection limit of the proposed method was observed to be 10 cfu/ml. This developed method offers the potential for rapid, sensitive, and visible detection of S. typhimurium in milk and shrimp samples. Practical applications The developed method in this study can be used for the detection of S. typhimurium in food samples such as milk and shrimp. Furthermore, the developed method can be easily modified for the simultaneous detection of S. typhimurium and other bacteria.

Functionalized Inorganic Nanoparticles for the Detection of Food and Waterborne Bacterial Pathogens

“…Direct infestation, transmission and spread of these contaminated products by bacteria, biotoxins and other materials had consistently been reported in many countries [115,116]. Shrimps spiked with S. aureus, V. parahemolyticus and S. typhimurium were detected with AuNPs and MNPs-UCNPs functionalized with aptamers [67,109]. The co-existence of the three samples were reported to be efficiently and simultaneously detected in the samples.…”

“…It was found to increase electron transfer, electrochemical signal and ascertain detection within a short period (20-60 minutes). Few studies evaluated the bi-functional approaches of aptamer with other bio-receptors such as 4-mercaptobenzoic acid (4-MBA) [66], oligonucleotide probe [67], chitosan [68], 4-MBA and citrate [69]. Each complementing bio-receptors reported showed fast, sensitive, specificity and accurate SERS based sensors towards the detection of pathogens in samples.…”

Noble Metal Nanoparticles Applications: Recent Trends in Food Control

“…This method was able to detect Escherichia coli in water and milk samples as low as 7.8 × 10 5 and 3 × 10 6 CFU/mL (colony-forming unit/volume), respectively, and as low as 3 × 10 8 and 3 × 10 7 CFU/mL in water and milk samples, respectively, for Salmonella typhi . Other papers were found based on a colorimetric assay for sensing Salmonella in milk and shrimp [49], Listeria in lettuce [50] and Escherichia coli and Salmonella in water and milk [51]. All these sensing methods gave good results and their application in food control is easy, due to the simple colour change of the solution after the AuNP interaction.…”

Synthesis and application of peptidoglycan oligomers as metabolic labeling agents for bacteria

“…[96][97] Recognition from these molecules were commonly associated with high specificity, being selective for limited species or strains. 88,[98][99] In contrast, PGOs have demonstrated recognition and uptake in a broad spectrum of bacterial species as shown in Chapter 3. Hence, after the composition of PGO-AuNP conjugates had been optimized, its sensitivity was subject to test against S. aureus and E. coli, one bacterial specie each from both Gram-positive and Gram-negative distinctions.…”