Electrochemical quantification of Ag2S quantum dots: evaluation of different surface coating ligands for bacteria determination
| Autor: | Alba Iglesias-Mayor, Francisco Parra, Agustín Costa-García, Ana Podadera, Ana Soldado, Alfredo de la Escosura-Muñiz, José M. Costa-Fernández, Pablo Llano-Suárez, Olaya Amor-Gutiérrez |
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| Jazyk: | angličtina |
| Rok vydání: | 2020 |
| Předmět: |
Detection limit
Chemistry Inorganic chemistry Nanochemistry 02 engineering and technology engineering.material 010402 general chemistry 021001 nanoscience & nanotechnology Electrochemistry 01 natural sciences 0104 chemical sciences Analytical Chemistry Surface coating chemistry.chemical_compound Anodic stripping voltammetry Coating engineering 0210 nano-technology Biosensor Boronic acid |
| Zdroj: | Scopus RUO. Repositorio Institucional de la Universidad de Oviedo instname |
| Popis: | In this work, novel silver sulphide quantum dots (Ag2S QD) are electrochemically quantified for the first time. The method is based on the electrochemical reduction of Ag+ to Ag0 at −0.3 V on screen-printed carbon electrodes (SPCEs), followed by anodic stripping voltammetric oxidation that gives a peak of currents at +0.06 V which represents the analytical signal. The optimized methodology allows the quantification of water-stabilized Ag2S QD in the range of approximately 2 × 109–2 × 1012 QD·mL−1 with a good reproducibility (RSD: 5%). Moreover, as proof-of-concept of relevant biosensing application, Ag2S QD are evaluated as tags for Escherichia coli (E. coli) bacteria determination. Bacteria tagged with QD are separated by centrifugation from the sample solution and placed on the SPCE surface for quantitative analysis. The effect of two different Ag2S QD surface coating/stabilizing agents on both the voltammetric response and the bacteria sensing is also evaluated. 3-mercaptopropionic acid (3-MPA) is studied as model of short length coating ligand with no affinity for the bacteria, while boronic acid (BA) is evaluated as longer length ligand with chemical affinity for the polysaccharides present in the peptidoglycan layer on the bacteria cells surface. The biosensing system allows to detect bacteria in the range 10−1-103 bacteria·mL−1 with a limit of detection as low as 1 bacteria·mL−1. This methodology is a promising proof-of-concept alternative to traditional laboratory-based tests, with good sensitivity and short time and low cost of analysis. |
| Databáze: | OpenAIRE |
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