title: A novel aptasensor for the colorimetric detection of S. typhimurium based on gold nanoparticles.
abstract: A simple, fast and convenient colorimetric aptasensor was fabricated for the detection of Salmonella typhimurium (S. typhimurium) which was based on the color change effect of gold nanoparticles (GNPs). S. typhimurium is one of the most common causes of food-associated disease. Aptamers with specific recognition toward S. typhimurium was modified to the surface of prepared GNPs. They play a role for the protection of GNPs from aggregation toward high concentrations of NaCl. With the addition of S. typhimurium, aptamers preferably combined to S. typhimurium and the protection effect was broken. With more S. typhimurium, more aptamers detached from GNPs. In such a situation, the exposed GNPs would aggregated to some extent with the addition of NaCl. The color changed from red, purple to blue which could be characterized by UV-Vis spectrophotometer. The absorbance spectra of GNPs redshifted constantly and the intensity ratio of A700/A521 changed regularly. This could be calculated for the basis of quantitative detection of S. typhimurium from 102cfu/mL to 107cfu/mL. The obtained linear correlation equation was y=0.1946x-0.2800 (R2=0.9939) with a detection limit as low as 56cfu/mL. This method is simple and rapid, results in high sensitivity and specificity, and can be used to detect actual samples.
authors.affiliation: State Key Laboratory of Food Science and Technology, School of Food Science and Technology, Jiangnan University, Wuxi 214122, PR China; Synergetic Innovation Center of Food Safety and Nutrition, Jiangnan University, Wuxi 214122, PR China.
authors.forename: Xiaoyuan
authors.initials: X
authors.lastname: Ma
authors.affiliation: State Key Laboratory of Food Science and Technology, School of Food Science and Technology, Jiangnan University, Wuxi 214122, PR China.
authors.forename: Liangjing
authors.initials: L
authors.lastname: Song
authors.affiliation: Department of Health Management and Basic Education, Jiangsu Jiankang Vocational College, Nanjing 211800, PR China.
authors.forename: Nixin
authors.initials: N
authors.lastname: Zhou
authors.affiliation: State Key Laboratory of Food Science and Technology, School of Food Science and Technology, Jiangnan University, Wuxi 214122, PR China; Synergetic Innovation Center of Food Safety and Nutrition, Jiangnan University, Wuxi 214122, PR China.
authors.forename: Yu
authors.initials: Y
authors.lastname: Xia
authors.affiliation: State Key Laboratory of Food Science and Technology, School of Food Science and Technology, Jiangnan University, Wuxi 214122, PR China; Synergetic Innovation Center of Food Safety and Nutrition, Jiangnan University, Wuxi 214122, PR China. Electronic address: wangzp@jiangnan.edu.cn.
authors.forename: Zhouping
authors.initials: Z
authors.lastname: Wang
mesh_terms: D052157:Aptamers, Nucleotide / Q000737:chemistry*; D003116:Color; D003124:Colorimetry / Q000379:methods*; D005506:Food Contamination; D005516:Food Microbiology / Q000379:methods; D006046:Gold; D057230:Limit of Detection; D053768:Metal Nanoparticles / Q000737:chemistry*; D046529:Microscopy, Electron, Transmission; D015203:Reproducibility of Results; D012486:Salmonella typhimurium / Q000302:isolation & purification*; D012965:Sodium Chloride / Q000737:chemistry; D013056:Spectrophotometry, Ultraviolet
chemical_list: D052157:Aptamers, Nucleotide; D012965:Sodium Chloride; D006046:Gold
keywords: Aptamer; Colorimetric detection; Gold nanoparticles; S. typhimurium