scholarly journals A Microfluidic Biosensor Based on Magnetic Nanoparticle Separation, Quantum Dots Labeling and MnO2 Nanoflower Amplification for Rapid and Sensitive Detection of Salmonella Typhimurium

Micromachines ◽  
2020 ◽  
Vol 11 (3) ◽  
pp. 281 ◽  
Author(s):  
Li Hao ◽  
Li Xue ◽  
Fengchun Huang ◽  
Gaozhe Cai ◽  
Wuzhen Qi ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Salmonella Typhimurium ◽  
Foodborne Pathogens ◽  
Polyclonal Antibodies ◽  
Food Poisoning ◽  
Sensitive Detection ◽  
Fluorescent Intensity ◽  
Practical Applications ◽  
Nanoparticle Separation ◽  
Microfluidic Biosensor

Screening of foodborne pathogens is an effective way to prevent microbial food poisoning. A microfluidic biosensor was developed for rapid and sensitive detection of Salmonella Typhimurium using quantum dots (QDs) as fluorescent probes for sensor readout and manganese dioxide nanoflowers (MnO2 NFs) and as QDs nanocarriers for signal amplification. Prior to testing, amino-modified MnO2 nanoflowers (MnO2-NH2 NFs) were conjugated with carboxyl-modified QDs through EDC/NHSS method to form MnO2-QD NFs, and MnO2-QD NFs were functionalized with polyclonal antibodies (pAbs) to form MnO2-QD-pAb NFs. First, the mixture of target Salmonella Typhimurium cells and magnetic nanoparticles (MNPs) modified with monoclonal antibodies (mAbs) was injected with MnO2-QD-pAb NFs into a microfluidic chip to form MNP-bacteria-QD-MnO2 complexes. Then, glutathione (GSH) was injected to dissolve MnO2 on the complexes into Mn2+, resulting in the release of QDs. Finally, fluorescent intensity of the released QDs was measured using the fluorescent detector to determine the amount of Salmonella. A linear relationship between fluorescent intensity and bacterial concentration from 1.0 × 102 to 1.0 × 107 CFU/mL was found with a low detection limit of 43 CFU/mL and mean recovery of 99.7% for Salmonella in spiked chicken meats, indicating the feasibility of this biosensor for practical applications.

Automatic and multi-channel detection of bacteria on a slidable centrifugal disc based on FTA card nucleic acid extraction and recombinase aided amplification

Lab on a Chip ◽  
2021 ◽  
Author(s):  
Siyuan Wang ◽  
Gaozhe Cai ◽  
Hong Duan ◽  
Wuzhen Qi ◽  
Jianhan Lin
Keyword(s):  
Nucleic Acid ◽  
Salmonella Typhimurium ◽  
Foodborne Pathogens ◽  
Food Poisoning ◽  
Rapid Screening ◽  
Acid Extraction ◽  
Nucleic Acid Extraction ◽  
Channel Detection

Rapid screening of foodborne pathogens is the key to prevent food poisoning. In this study, a slidable centrifugal disc was developed for automatic and multi-channel detection of Salmonella typhimurium using...

Tryptamine-functionalized magnetic nanoparticles for highly sensitive detection of Salmonella Typhimurium

The Analyst ◽  
2021 ◽  
Author(s):  
Seonyeong Lee ◽  
Feixiong Chen ◽  
Tae Yoon Lee
Keyword(s):  
Magnetic Nanoparticles ◽  
Nucleic Acid ◽  
Salmonella Typhimurium ◽  
Food Poisoning ◽  
Nucleic Acid Amplification ◽  
Sensitive Detection ◽  
Nucleic Acid Amplification Tests ◽  
Functionalized Magnetic Nanoparticles ◽  
Highly Sensitive ◽  
Highly Sensitive Detection

There is significant demand for the development of rapid, sensitive, and specific methods for detecting bacterial pathogens in order to identify the causes of food poisoning. Nucleic acid amplification tests...

Immunofluorescence Assay Using Monoclonal and Polyclonal Antibodies for Detection of Staphylococcal Enterotoxins A in Milk

2019 ◽  
Vol 13 (1) ◽  
pp. 137-145 ◽  
Author(s):  
Tzonka Godjevargova ◽  
Zlatina Becheva ◽  
Yavor Ivanov ◽  
Andrey Tchorbanov
Keyword(s):  
Monoclonal Antibody ◽  
Magnetic Nanoparticles ◽  
Polyclonal Antibody ◽  
Polyclonal Antibodies ◽  
Food Poisoning ◽  
Staphylococcal Enterotoxin ◽  
Staphylococcal Enterotoxin A ◽  
Fluorescence Immunoassay ◽  
Magnetic Separator ◽  
Milk Samples

Objectives: Staphylococcus aureus is a Gram-positive microorganism. S. aureus can grow in various foods and cause food poisoning by secreting enterotoxins. The most common enterotoxins involved in food poisoning are staphylococcal enterotoxin A and staphylococcal enterotoxin B, but Staphylococcal Enterotoxin A (SEA) is predominant. The main types of food contaminated with SEs are meat and meat products, poultry and eggs, milk and dairy products. The aim of this study was to develop a rapid and sensitive fluorescence immunoassay for detection of staphylococcal enterotoxin A in milk. Methods: Monoclonal and polyclonal antibodies for SEA were produced and characterized. Competitive fluorescence immunoassay based on Magnetic Nanoparticles (MNPs) was performed and optimized. MNPs were used as a solid carrier of the antibodies. The first step of the assay was immunoreaction between the immobilized antibody onto MNPs and SEA in milk sample. Then the fluorescein-SEA conjugate was added to the sample. Thus, competitive immunoreaction between MNP-mAb/MNP-pAb with SEA and SEA-FITC was performed. These immuno-complexes were separated by a magnetic separator and the obtained supernatants were analyzed. The fluorescent signal from the excess of conjugated SEA was proportional to the SEA contained in the milk. The assay duration was only 30 min. Results: The fluorescence immunoassays performed with polyclonal antibody had linear ranges from 5 pg/mL to 100 ng/mL SEA in a buffer, and from 50 pg/mL to 50 ng/mL SEA in spiked milk samples. While the same assays performed with monoclonal antibody had linear ranges from 1 pg/mL to 20 ng/mL SEA in buffer, and from 10 pg/mL to 10 ng/mL SEA in spiked milk samples. The detection limits of the developed immunoassays performed in milk were: 48 pg/mL with polyclonal antibody and 9 pg/mL with monoclonal antibody. Conclusion: A rapid and sensitive fluorescence immunoassay based on magnetic nanoparticles with a polyclonal and monoclonal antibody for determination of staphylococcal enterotoxin A in milk was developed.

Highly Fluorescent Nitrogen and Boron Doped Carbon Quantum Dots for Selective and Sensitive Detection of Fe3+

2021 ◽  
Author(s):  
Yunhao Zhang ◽  
Hongxin Qin ◽  
Yuting Huang ◽  
Feng Zhang ◽  
Hairong Liu ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Environmental Protection ◽  
Essential Role ◽  
Disease Diagnosis ◽  
Carbon Quantum Dots ◽  
Sensitive Detection ◽  
Boron Doped

Due to the essential role of Fe3+ in physiological and pathological processes, the detection of Fe3+ has drawn an increasing attention in the field of disease diagnosis and environmental protection....

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