Journal
MICROCHIMICA ACTA
Volume 185, Issue 7, Pages -Publisher
SPRINGER WIEN
DOI: 10.1007/s00604-018-2852-0
Keywords
Pathogenic bacteria; Raman spectroscopy; Foodborne pathogen; DNA; Nanoparticles
Categories
Funding
- Key Research and Development Program of Jiangsu Province [BE2017623]
- national first-class discipline program of Food Science and Technology [JUFSTR20180303]
- Distinguished Professor Program of Jiangsu Province and Synergetic Innovation Center of Food Safety and quality control of Jiangsu Province
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The authors describe a surface-enhanced Raman scattering (SERS) based aptasensor for Salmonella typhimurium (S. typhimurium). Gold nanoparticles (AuNPs; 35 nm i.d.) were functionalized with the aptamer (ssDNA 1) and used as the capture probe, while smaller (15 nm) AuNPs were modified with a Cy3-labeled complementary sequence (ssDNA 2) and used as the signalling probe. The asymmetric gold nanodimers (AuNDs) were assemblied with the Raman signal probe and the capture probe via hybridization of the complementary ssDNAs. The gap between two nanoparticles is a hot spot in which the Raman reporter Cy3 is localized. It experiences a strong enhancement of the electromagnetic field around the particle. After addition of S. typhimurium, it will be bound by the aptamer which therefore is partially dehybridized from its complementary sequence. Hence, Raman intensity drops. Under the optimal experimental conditions, the SERS signal at 1203 cm(-1) increases linearly with the logarithm of the number of colonies in the 10(2) to 10(7) cfu.mL(-1) concentration range, and the limit of detection is 35 cfu.mL(-1). The method can be performed within 1 h and was successfully applied to the analysis of spiked milk samples and performed very well and with high specificity.
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