Impedimetric determination of Staphylococcal enterotoxin B using electrochemical switching with DNA triangular pyramid frustum nanostructure

Abstract

An electrochemical switching strategy is presented for the sensitive determination of Staphylococcus enterotoxin B (SEB). It is based on the use of DNA triangular pyramid frustum nanostructure (TPF) consisting of (a) three thiolated probes, (b) one auxiliary probe, and (c) an aptamer against SEB. The TPF was assembled on the gold electrode, with the SEB aptamer designed on top of the TPF. The electron transfer to hexacyanoferrate acting as an electrochemical probe is strongly inhibited in the TPF-modified electrode. This is assumed to be due to the formation of a 3D TPF structure that limits access of hexacyanoferrate to the electrode. Therefore, the Faradaic impedance is large. However, in the presence of SEB, it will bind to the aptamer and dehybridize the hybrid formed between aptamer and its complementary sequence. As a result, the TPF nanostructure changes to an equilateral triangle DNA nanostructure. This results in a more efficient electron transfer and a smaller Faradaic impedance. The method has a detection limit of 0.17 ng mL of SEB (at an S/N of 3) and a dynamic range that covers the 0.2-1000 ng mL concentration range. The applicability and reliability of the method was demonstrated by anayzing (spiked) milk samples, and the results were compared to those obtained with an ELISA kit. The relative standard deviations between the two methods range between -6.59 and 9.33%. Graphical abstract An electrochemical switching strategy is presented for the sensitive detection of Staphylococcus enterotoxin B based on 3D DNA structure conversion of nanostructure from triangular pyramid frustum to equilateral triangle.

Self-Assembling Nucleic Acid Nanostructures Functionalized with Aptamers

“…Inspired by this approach, Xiong's group developed an electrochemical biosensor to detect staphylococcal enterotoxin B (SEB), a leading cause of foodborne illnesses, in milk samples. 266 TPF−ET transformation occurred in the presence of SEB and was made observable by changes in Faradaic impedance.…”

“…The authors found a linear relation between Faradaic impedance response and cocaine concentration for concentrations between 1.0 nM and 2.0 μM. Inspired by this approach, Xiong’s group developed an electrochemical biosensor to detect staphylococcal enterotoxin B (SEB), a leading cause of foodborne illnesses, in milk samples . TPF–ET transformation occurred in the presence of SEB and was made observable by changes in Faradaic impedance.…”

Reagentless detection of staphylococcal enterotoxin B via electrochemical interrogation of conformational changes

“…Our previous work has been done on electrochemical detection of SEB based on DNA nanostructured probe. [26][27][28][29] DNA nanomaterials have excellent structural properties, but assembly is complex. [26][27][28] Impedance method is simple and convenient, but it is greatly disturbed by food substrate.…”

“…[26][27][28][29] DNA nanomaterials have excellent structural properties, but assembly is complex. [26][27][28] Impedance method is simple and convenient, but it is greatly disturbed by food substrate. 29 Thus, the purpose of this work is to develop a sensitive and easy aptamer-based electrochemical sensor, capable of reagentless detection of SEB with high sensitivity, selectivity, and extremely broad dynamic ranges.…”

Nanobodies Based on a Sandwich Immunoassay for the Detection of Staphylococcal Enterotoxin B Free from Interference by Protein A

“…Until now, various analytical methods have been employed for the detection and quantification of SE content in food, water, and even bodily fluids, such as serum. These techniques include enzyme-linked immunosorbent assays (ELISAs), , lateral flow platforms, polymerase chain reactions (PCRs), chemiluminescent assays, colorimetric sensors, , electrochemical assays, , and surface-enhanced Raman scattering assays . Most of these detection strategies demand complicated instruments, strict laboratory conditions, and trained personnel.…”