Relative efficiency of zinc sulfide (ZnS) quantum dots (QDs) based electrochemical and fluorescence immunoassay for the detection of Staphylococcal enterotoxin B (SEB)

Abstract

In this paper an attempt was made to detect Staphylococcal enterotoxin B (SEB) both by electrochemical and fluorescence immunoassay methods using zinc sulphide (ZnS) QDs. Wet-chemical method was adopted for the preparation of fluorescent ZnS QDs (diameter ∼ 5–10 nm). These QDs were bioconjugated with monoclonal antibodies and then characterized by various method. A detection limit of 0.02 ng mL−1 by fluorescence assay and 1.0 ng mL−1 by electrochemical assay for SEB was achieved. While by sandwich ELISA it is possible to detect 0.24 ng mL−1 only. The sensitivity of all techniques is very good, since the LD50 of SEB is 20 ng kg−1. Electrochemical assay is faster, need low-cost instrument, independent to the size of QDs and found to be one of the best alternative methods as compared to the other existing methods studied herein. The presented method could be expanded to the development of electrochemical and fluorescence biosensors for various agents for field and laboratory use.

A Group of Complexes Based on PAMAM and Quantum Dots Used in Clinical Immunoassays

“…In this study, we used core/shell CdSe/ZnS water-soluble quantum dots stabilized with carboxyl ligands and the carbodiimide coupling reaction using EDC (1-ethyl-3-(3-dimethylaminopropyl)-carbodiimide hydrochloride). This method is one of the most popular methods for conjugating an antibody to the surface of QDs [15][16][17]. The CdSe/ZnS QDs' micelles were first incubated in the presence of EDC and sulfo-NHS in borate buffer (5 mM BS, pH 7.2).…”

Rapid detection of staphylococcal enterotoxin B in milk samples based on fluorescence hybridization chain reaction amplification

“…At present, numerous immunoassay methods including ELISA, 6 electrochemical, 7,8 chemiluminescence, 9,10 immunopolymerase chain reaction (PCR), 11 POCT, 12 piezoelectric crystal immunosensor, 13 magnetoelastic immunosensor, 14 lateral ow assay, 15 and LC-LC/MS 16 have been established to detect SEB. The methods described above manifest low sensitivity and high specicity based on the antigen-antibody interactions.…”

“…To date, this signal amplication has been applied in various biosensor platforms, including color, 28,29 uorescence, 7,[30][31][32] chemiluminescence, [33][34][35] and electrochemical. 8,[36][37][38][39] Mostly traditional HCR-based aptasensor need to wash unbound probes and long incubation period.…”

Microbead QD-ELISA: Microbead ELISA Using Biocatalytic Formation of Quantum Dots for Ultra High Sensitive Optical and Electrochemical Detection

“…27 While the exploitation of the optical properties of QDs is usually a key parameter in the design of such ultra sensitive assays, there is still little knowledge about the practical exploitation of a pure electrochemical (without the need of any light source and optical detector) quantification of enzymatically generated QDs. Usually, the metal ions (Cd 2+ , Pb 2+ , Zn 2+ ) of semiconductor NPs possess different oxidation potentials yielding well-resolved voltammetric signals with a nicely low detection limit, [28][29][30][31][32] and works by Bard et al showed that in particular CdS QDs exhibit the requested inherent electrochemical properties which are necessary for an electrochemical detection. 33,34 In recent years, several voltammetric techniques such as linear sweep, differential pulse voltammetry (DPV) and square-wave voltammetry (SWV) have been the most widely employed electrochemical methods for characterization and quantification of QDs.…”

“…35,36 SWV became the most employed methodology due to its high selectivity and sensitivity. [28][29][30][31][32] The inexpensive, commercially available, disposable screen-printed electrodes (SPEs) with their versatility, miniaturization and ease of handling 37,38 significantly diminish assay times and volume samples, being therefore increasingly used.…”