1. Research background and content
Escherichia coli O157∶H7 is a major foodborne pathogen, which often leads to severe diseases such as hemolytic uremic syndrome, bloody diarrhea and even death. Infection with very low doses of live E. coli O157∶H7 can cause disease and further outbreaks. Rapid and sensitive detection methods can help clinical management and prevent transmission. In this paper, immunomagnetic beads and fluorescent quantum dots were used to detect E. coli O157∶H7.
2.Methods
The principle of reaction is shown in Fig.1. Using FeCl3·6H2O as the iron source, anhydrous sodium acetate as the precipitant, and polyethylene glycol 2000 as the surfactant, reacted in a mixed solution of ethylene glycol and diethylene glycol as the reducing agent at 200 ℃ for 12 h to prepare the monomer Fe3O4 nanoparticles with good dispersibility and uniform particle size. Fe3O4 was dispersed in deionized water, and then ammonia water and isopropyl alcohol solution were added uniformly, followed by the addition of ethyl teosilicate drop by drop. After 20 h of continuous reaction at 35 ℃ under the protection of nitrogen, Fe3O4@SiO2 was obtained. Then, coreshell immunomagnetic beads Fe3O4@SiO2@Ab1 were obtained by carboxyl binding antibodies against E. coli O157∶H7, and then the fluorescent probe Qds@Ab2 was obtained by using fluorescent quantum dots to label the resistance regime of E. coli O157∶H7. Subsequently the free E. coli O157∶H7 was first combined with the immune magnetic beads, and then the antibody labeled by quantum dots was combined with E. coli O157∶H7 to form a sandwich structure. Finally, the complex of “immune nano magnetic beads - bacteria - immune quantum dots” was detected by fluorescence (excitation/emission wavelength was 370/472 nm).
3.Conclusion
The introduction of silica shell structure reduces the non-specific adsorption of traditional immune magnetic beads, improves the selectivity of target bacteria, and effectively prevents the fluorescence quenching caused by electron transfer to ferric oxide in the sandwich structure of quantum dots, ensuring the feasibility of the analysis method. The dynamic range of the immunoassay was 10-108 CFU/mL, and the detection limit was 10 CFU/mL. The average recoveries of E. coli O157∶H7 in beef, milk and honey samples were 95%-104%, 90%-94% and 90%-110% respectively; and the relative standard deviations were 2.1%-3.8%, 3.2%-7.8% and 5.8%-6.3% respectively.
WEN Xiangjun
,
TENG Xin
,
DING Xingyu
,
SHE Zhuxin
,
LI Yi
,
XIONG Xiaohui
. Preparation and application of a novel immunomagnetic beads-quantum dot nanoparticles for the detection of Escherichia coli O157∶H7[J]. Food and Fermentation Industries, 2022
, 48(13)
: 48
-54
.
DOI: 10.13995/j.cnki.11-1802/ts.029734
[1] KING T, COLE M, FARBER J M, et al.Food safety for food security:Relationship between global megatrends and developments in food safety[J].Trends in Food Science & Technology, 2017, 68:160-175.
[2] CHEN J, PARK B.Label-free screening of foodborne Salmonella using surface plasmon resonance imaging[J].Analytical and Bioanalytical Chemistry, 2018, 410(22):5 455-5 464.
[3] JIANG T, SONG Y, WEI T X, et al.Sensitive detection of Escherichia coli O157:H7 using Pt-Au bimetal nanoparticles with peroxidase-like amplification[J].Biosensors and Bioelectronics, 2016, 77:687-694.
[4] NGUYEN Y, SPERANDIO V.Enterohemorrhagic E.coli (EHEC) pathogenesis[J].Frontiers in Cellular and Infection Microbiology, 2012, 2:90.
[5] GRIFFIN P M, TAUXE R V.The epidemiology of infections caused by Escherichia coli O157:H7, other enterohemorrhagic E.coli, and the associated hemolytic uremic syndrome[J].Epidemiologic Reviews, 1991, 13(1):60-98.
[6] RANGEL J M, SPARLING P H, CROWE C, et al.Epidemiology of Escherichia coli O157:H7 outbreaks, United States, 1 982-2002[J].Emerging Infectious Diseases, 2005, 11(4):603-609.
[7] SANCAK Y C, SANCAK H, ISLEYICI O.Presence of Escherichia coli O157 and O157:H7 in raw milk and Van herby cheese[J].Bulletin of the Veterinary Institute in Pulawy, 2015, 59(4):511-514.
[8] KARMALI M A.Infection by verocytotoxin-producing Escherichia coli[J].Clinical Microbiology Reviews, 1989, 2(1):15-38.
[9] VERHAEGEN B, DE REU K, HEYNDRICKX M, et al.Comparison of six chromogenic agar media for the isolation of a broad variety of non-O157 shigatoxin-producing Escherichia coli (STEC) serogroups[J].International Journal of Environmental Research and Public Health, 2015, 12(6):6 965-6 978.
[10] SUAIFAN G A R Y, ALHOGAIL S, ZOUROB M.Paper-based magnetic nanoparticle-peptide probe for rapid and quantitative colorimetric detection of Escherichia coli O157:H7[J].Biosensors and Bioelectronics, 2017, 92:702-708.
[11] WU X L, WANG W B, LIU L Q, et al.Monoclonal antibody-based cross-reactive sandwich ELISA for the detection of Salmonella spp.in milk samples[J].Analytical Methods, 2015, 7(21):9 047-9 053.
[12] FENG M, YONG Q Q, WANG W B, et al.Development of a monoclonal antibody-based ELISA to detect Escherichia coli O157:H7[J].Food and Agricultural Immunology, 2013, 24(4):481-487.
[13] YU H, BRUNO J G.Immunomagnetic-electrochemiluminescent detection of Escherichia coli O157 and Salmonella typhimurium in foods and environmental water samples[J].Applied and Environmental Microbiology, 1996, 62(2):587-592.
[14] ZHOU C, ZOU H M, LI M, et al.Fiber optic surface plasmon resonance sensor for detection of E.coli O157:H7 based on antimicrobial peptides and AgNPs-rGO[J].Biosensors and Bioelectronics, 2018, 117:347-353.
[15] YU X J, LU H D, WU D.Development of deep learning method for predicting firmness and soluble solid content of postharvest Korla fragrant pear using Vis/NIR hyperspectral reflectance imaging[J].Postharvest Biology and Technology, 2018, 141:39-49.
[16] BURRIS K P, STEWART C N Jr.Fluorescent nanoparticles:Sensing pathogens and toxins in foods and crops[J].Trends in Food Science & Technology, 2012, 28(2):143-152.
[17] ESTEVE-TURRILLAS F A, ABAD-FUENTES A.Applications of quantum dots as probes in immunosensing of small-sized analytes[J].Biosensors and Bioelectronics, 2013, 41:12-29.
[18] VINAYAKA A C, THAKUR M S.Focus on quantum dots as potential fluorescent probes for monitoring food toxicants and foodborne pathogens[J].Analytical and Bioanalytical Chemistry, 2010, 397(4):1 445-1 455.
[19] YANG L J, LI Y B.Simultaneous detection of Escherichia coli O157:H7 and Salmonella Typhimurium using quantum dots as fluorescence labels[J].The Analyst, 2006, 131(3):394-401.
[20] STÖBER W, FINK A, BOHN E.Controlled growth of monodisperse silica spheres in the micron size range[J].Journal of Colloid and Interface Science, 1968, 26(1):62-69.
[21] 苏鹏飞, 陈国, 赵珺.表面羧基化Fe3O4磁性纳米粒子的快捷制备及表征[J].高等学校化学学报, 2011, 32(7):1 472-1 477.
SU P F, CHEN G, ZHAO J.Convenient preparation and characterization of surface carboxyl-functioned Fe3O4 magnetic nanoparticles[J].Chemical Journal of Chinese Universities, 2011, 32(7):1 472-1 477.
[22] AI L H, ZHANG C Y, LIAO F, et al.Removal of methylene blue from aqueous solution with magnetite loaded multi-wall carbon nanotube:Kinetic, isotherm and mechanism analysis[J].Journal of Hazardous Materials, 2011, 198:282-290.
[23] HUANG L, ZHU P L, LI G, et al.Core–shell SiO2@RGO hybrids for epoxy composites with low percolation threshold and enhanced thermo-mechanical properties[J].Journal of Materials Chemistry A, 2014, 2(43):18 246-18 255.
[24] ZHU W T, PENG H L, LUO M, et al.Zipper-like magnetic molecularly imprinted microspheres for on/off-switchable recognition and extraction of 17β-estradiol from food samples[J].Food Chemistry, 2018, 261:87-95.
[25] XIE X W, MA X G, GUO L H, et al.Novel magnetic multi-templates molecularly imprinted polymer for selective and rapid removal and detection of alkylphenols in water[J].Chemical Engineering Journal, 2019, 357:56-65.
