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He S, Chen Y, Wang J, Sun J, Zhang X, Chen Q. Rapid and Sensitive Quantification of Bacterial Viability Using Ratiometric Fluorescence Sensing. Anal Chem 2024; 96:11018-11025. [PMID: 38934709 DOI: 10.1021/acs.analchem.4c01737] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/28/2024]
Abstract
Bacterial viability assessment plays an important role in food-borne pathogen detection and antimicrobial drug development. Here, we first used GelRed as a DNA-binding stain for a bacterial viability assessment. It was found that live bacteria were able to exclude GelRed, which however could easily penetrate dead ones and be absorbed nonspecifically on the bacterial periplasm. Cations were used to reduce the nonspecific adsorption and greatly increase the red fluorescence ratio of dead to live bacteria. Combined with SYTO 9 (a membrane-permeable dye) for double-staining, a ratiometric fluorescent method was established. Using Escherichia coli O157:H7 as a bacteria model, the ratiometric fluorescent method can probe dead bacteria as low as 0.1%. A linear correlation between the ratiometric fluorescence and the theoretical ratio of dead bacteria was acquired, with a correlation coefficient R2 of 0.97. Advantages in sensitivity, accuracy, and safety of the GelRed/SYTO9-based ratiometric fluorescent method against traditional methods were demonstrated. The established method was successfully applied to the assessment of germicidal efficacy of different heat treatments. It was found that even 50 °C treatment could lead to the death of minor bacteria. The as-developed method has many potential applications in microbial researches, and we believe it could be expanded to the viability assessment of mammalian cells.
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Affiliation(s)
- Shengbin He
- Key Laboratory of Longevity and Aging-related Diseases of Chinese Ministry of Education, Guangxi Colleges and Universities Key Laboratory of Biological Molecular Medicine Research, School of Basic Medical Sciences, Guangxi Medical University, Nanning, Guangxi 530021, P. R. China
| | - Yajing Chen
- Key Laboratory of Longevity and Aging-related Diseases of Chinese Ministry of Education, Guangxi Colleges and Universities Key Laboratory of Biological Molecular Medicine Research, School of Basic Medical Sciences, Guangxi Medical University, Nanning, Guangxi 530021, P. R. China
| | - Jingtong Wang
- Key Laboratory of Longevity and Aging-related Diseases of Chinese Ministry of Education, Guangxi Colleges and Universities Key Laboratory of Biological Molecular Medicine Research, School of Basic Medical Sciences, Guangxi Medical University, Nanning, Guangxi 530021, P. R. China
| | - Jian Sun
- Key Laboratory of Longevity and Aging-related Diseases of Chinese Ministry of Education, Guangxi Colleges and Universities Key Laboratory of Biological Molecular Medicine Research, School of Basic Medical Sciences, Guangxi Medical University, Nanning, Guangxi 530021, P. R. China
| | - Xinyi Zhang
- Key Laboratory of Longevity and Aging-related Diseases of Chinese Ministry of Education, Guangxi Colleges and Universities Key Laboratory of Biological Molecular Medicine Research, School of Basic Medical Sciences, Guangxi Medical University, Nanning, Guangxi 530021, P. R. China
| | - Quanzhi Chen
- Key Laboratory of Longevity and Aging-related Diseases of Chinese Ministry of Education, Guangxi Colleges and Universities Key Laboratory of Biological Molecular Medicine Research, School of Basic Medical Sciences, Guangxi Medical University, Nanning, Guangxi 530021, P. R. China
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Sun J, Ning X, Cui L, Qin W, Wang W, He S. Sensitive detection of aflatoxin B1 in foods by aptasensing-based qPCR. Food Chem 2024; 432:137240. [PMID: 37639887 DOI: 10.1016/j.foodchem.2023.137240] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2023] [Revised: 08/02/2023] [Accepted: 08/21/2023] [Indexed: 08/31/2023]
Abstract
In this study, a reproductive switch DNA template was designed using aptasensing principles for the accurate quantification of aflatoxins. The template transformed the aflatoxin molecule into linear DNA of 102 nt. The linear DNA was subjected to a quantitative polymerase chain reaction (qPCR) to determine its initial copy number, which was positively correlated with the aflatoxin concentration. Using aflatoxin B1 (AFB1) as a model, the established method could quantify AFB1 within the range of 10-16-10-11 Mol/mL (detection limit equals 0.03 pg/mL), with a linear correlation coefficient R2 of 0.974. Good anti-interference abilities against common food ingredients and high specificity towards other mycotoxins were demonstrated. The established method was successfully applied for the quantification of AFB1 in complex foods such as soy sauce, milk, yellow wine, and peanut butter. The design of a reproductive switch template introduces a novel approach for the sensitive detection of small-molecule toxicants in foods.
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Affiliation(s)
- Jian Sun
- Key Laboratory of Longevity and Aging-related Diseases of Chinese Ministry of Education, Guangxi Colleges and Universities Key Laboratory of Biological Molecular Medicine Research, School of Basic Medical Sciences, Guangxi Medical University, Nanning, Guangxi 530021, PR China
| | - Xueping Ning
- Key Laboratory of Longevity and Aging-related Diseases of Chinese Ministry of Education, Guangxi Colleges and Universities Key Laboratory of Biological Molecular Medicine Research, School of Basic Medical Sciences, Guangxi Medical University, Nanning, Guangxi 530021, PR China
| | - Lanyu Cui
- Key Laboratory of Longevity and Aging-related Diseases of Chinese Ministry of Education, Guangxi Colleges and Universities Key Laboratory of Biological Molecular Medicine Research, School of Basic Medical Sciences, Guangxi Medical University, Nanning, Guangxi 530021, PR China
| | - Wenhui Qin
- Key Laboratory of Longevity and Aging-related Diseases of Chinese Ministry of Education, Guangxi Colleges and Universities Key Laboratory of Biological Molecular Medicine Research, School of Basic Medical Sciences, Guangxi Medical University, Nanning, Guangxi 530021, PR China
| | - Wenxu Wang
- Key Laboratory of Longevity and Aging-related Diseases of Chinese Ministry of Education, Guangxi Colleges and Universities Key Laboratory of Biological Molecular Medicine Research, School of Basic Medical Sciences, Guangxi Medical University, Nanning, Guangxi 530021, PR China
| | - Shengbin He
- Key Laboratory of Longevity and Aging-related Diseases of Chinese Ministry of Education, Guangxi Colleges and Universities Key Laboratory of Biological Molecular Medicine Research, School of Basic Medical Sciences, Guangxi Medical University, Nanning, Guangxi 530021, PR China.
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Li Z, Fu J, Wang L, Zhou Y, Li J, He S. Transformation of proteins into reproductive DNA templates for sensitive quantification of PSA. Talanta 2024; 267:125206. [PMID: 37716239 DOI: 10.1016/j.talanta.2023.125206] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2023] [Revised: 09/06/2023] [Accepted: 09/11/2023] [Indexed: 09/18/2023]
Abstract
A switch DNA template was designed to transform proteins into linear DNA strands of 97 nt. The linear DNA was subjected to quantitative polymerase chain reaction (qPCR) to determine the initial copy number, which correlated positively with the protein concentration. A restriction endonuclease was used to remove background amplification. Using prostate-specific antigen (PSA) as a protein model, the established method quantified PSA in the range of 10-18-10-13 mol/mL (detection limit = 0.034 pg/mL) with an R2 of 0.974. Good repeatability and specificity of the method were demonstrated. The established method was successfully applied for the quantification of serum PSA levels in women. Significant differences in PSA levels were observed between healthy participants and polycystic ovary syndrome patients.
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Affiliation(s)
- Zhao Li
- Key Laboratory of Longevity and Aging-related Diseases of Chinese Ministry of Education, Guangxi Colleges and Universities Key Laboratory of Biological Molecular Medicine Research, School of Basic Medical Sciences, Guangxi Medical University, Nanning, Guangxi, 530021, PR China
| | - Jingjing Fu
- Guangxi Medical College, Nanning, Guangxi, 530021, PR China
| | - Lijuan Wang
- The First Affiliated Hospital of Guangxi Medical College, Guangxi Medical College, Nanning, Guangxi, 530021, PR China
| | - Yingzhu Zhou
- Key Laboratory of Longevity and Aging-related Diseases of Chinese Ministry of Education, Guangxi Colleges and Universities Key Laboratory of Biological Molecular Medicine Research, School of Basic Medical Sciences, Guangxi Medical University, Nanning, Guangxi, 530021, PR China
| | - Jinyan Li
- Key Laboratory of Longevity and Aging-related Diseases of Chinese Ministry of Education, Guangxi Colleges and Universities Key Laboratory of Biological Molecular Medicine Research, School of Basic Medical Sciences, Guangxi Medical University, Nanning, Guangxi, 530021, PR China
| | - Shengbin He
- Key Laboratory of Longevity and Aging-related Diseases of Chinese Ministry of Education, Guangxi Colleges and Universities Key Laboratory of Biological Molecular Medicine Research, School of Basic Medical Sciences, Guangxi Medical University, Nanning, Guangxi, 530021, PR China.
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He S. No-cost ballpoint pen dispenser for lateral flow assays. Talanta 2023; 263:124742. [PMID: 37257236 DOI: 10.1016/j.talanta.2023.124742] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2023] [Revised: 05/21/2023] [Accepted: 05/24/2023] [Indexed: 06/02/2023]
Abstract
We have developed a no-cost, lightweight, human-powered dispenser using an empty ballpoint pen. Used in lateral flow assays, this dispenser restricts antibody deposition to narrow zones, allowing freehand drawing of test and control lines. The lines can be drawn in widths ranging from 0.15 to 1.00 mm. Naphthol green B, a compatible stain, was used to label antibody solutions and certify handwriting traces. Using human chorionic gonadotropin (HCG) as a model antigen, we demonstrated that the pen dispenser can imprint antibodies on nitrocellulose membranes without affecting their microstructure and chromatographic function. A lateral flow assay using the pen dispenser detected HCG at 0.1 μg/mL, comparable to the sensitivity of standard tests using traditional benchtop dispensers.
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Affiliation(s)
- Shengbin He
- Key Laboratory of Longevity and Aging-related Diseases of Chinese Ministry of Education, Guangxi Colleges and Universities Key Laboratory of Biological Molecular Medicine Research, School of Basic Medical Sciences, Guangxi Medical University, Nanning, Guangxi, 530021, PR China.
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