Escherichia coli (E. coli) O157:H7 is a foodborne pathogen that causes symptoms in humans. Its rapid identification should be considered to avoid toxic effects of the pathogen. In this study, systematic evolution of ligands by exponential enrichment using whole cells (Cell-SELEX) method was used for recognizing E. coli strain, O157 by single-stranded DNA library of aptamer. Nine rounds of cell-selex procedure were applied using O157, as a whole-cell target, with O42, K12, Top10, DH5α E. coli cells, Shigella flexneri and Salmonella typhi as counterparts. The specific interaction between selected DNA aptamers and targeted cell was assessed. After applying six rounds of SELEX for selection of DNA aptamers, the candidate sequences were obtained. Finally, specific aptamer was selected as an ideal aptamer for detection and capturing of E. coli O157. Dissociation constant of the selected aptamer were calculated (107.6 ± 67.8 pM). In addition, the secondary structure prediction and cross reactivity assays were performed. The isolated aptamer efficiency was confirmed and it was shown that the new DNA aptamer sequence has the ability to use for detection. This specific O157:H7 aptamer have the potential for application as a diagnostic ligand and could be used for detection of the related food borne diseases.
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http://dx.doi.org/10.1016/j.ab.2017.08.005 | DOI Listing |
Biosensors (Basel)
January 2025
Key Laboratory of Interfacial Reaction & Sensing Analysis in Universities of Shandong, School of Chemistry and Chemical Engineering, University of Jinan, Jinan 250022, China.
Rapid, effective, and cost-effective methods for large-scale screening of pesticide residues in the environment and agricultural products are important for assessing potential environmental risks and safeguarding human health. Here, we constructed a novel aggregation-induced emission (AIE) electrochemical aptamer (Apt) sensor based on red-emissive sulfur quantum dots (SQDs), which aimed at the rapid screening and quantitative detection of malathion. SQDs were prepared using a two-step oxidation method with good electrochemiluminescence (ECL) optical properties.
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January 2025
Chair of Medical Biotechnology, Faculty of Chemistry, Warsaw University of Technology, Noakowskiego 3, 00-664 Warsaw, Poland.
Since lead can cause severe effects on living organisms' health and life, the regular monitoring of Pb levels in water and soil is of particular significance. Recently, it was shown that lead ions can also be detected using affinity-based biosensors, namely, using aptamers as recognition elements. In most cases, thrombin binding aptamer (TBA) was utilized; however, there are more examples of DNA aptamers which could also serve that purpose.
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January 2025
Department of Bioscience and Biotechnology, Konkuk University, Seoul 05029, Republic of Korea.
Lateral flow immunoassays (LFIAs) are widely used for their low cost, simplicity, and rapid results; however, enhancing their reliability requires the meticulous selection of ligands and nanoparticles (NPs). SiO@QD@SiO (QD) nanoparticles, which consist of quantum dots (QDs) embedded in a silica (SiO) core and surrounded by an outer SiO shell, exhibit significantly higher fluorescence intensity (FI) compared to single QDs. In this study, we prepared QD@PEG@Aptamer, an aptamer conjugated with QD using succinimidyl-[(N-maleimidopropionamido)-hexaethyleneglycol]ester, which is 130 times brighter than single QDs, for detecting carbohydrate antigen (CA) 19-9 through LFIA.
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January 2025
Graduate School of Interdisciplinary Science and Engineering in Health Systems, Okayama University, Okayama 700-8530, Japan.
In this study, we utilized a terahertz chemical microscope (TCM) to map surface potential changes induced by molecular interactions on silicon-on-sapphire (SOS) substrates. By functionalizing the SOS substrate with DNA aptamers and an ion-selective membrane, we successfully detected and visualized aptamer-neurochemical complexes through the terahertz amplitude. Additionally, comparative studies of DNA aptamers in PBS buffer and artificial cerebrospinal fluid (aCSF) were performed by computational structure modeling and terahertz measurements.
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January 2025
Department of Bioengineering, Faculty of Engineering, Ege University, 35040 Izmir, Türkiye.
Drug abuse is a major public problem in the workplace, traffic, and forensic issues, which requires a standardized test device to monitor on-site drug use. For field testing, the most important requirements are portability, sensitivity, non-invasiveness, and quick results. Motivated by this problem, a point of care (POC) test based on lateral flow assay (LFA) was developed for the detection of cocaine (COC) and methamphetamine (MET) in saliva which has been selected as the matrix for this study due to its rapid and non-invasive collection process.
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