A novel biosensor regulated by the rotator of F₀F₁-ATPase to detect deoxynivalenol rapidly

Progress and challenges in sensing of mycotoxins using molecularly imprinted polymers

Mycotoxin is toxic secondary metabolite formed by certain filamentous fungi. This toxic compound can enter the food chain through contamination of food (e.g., by colonization of toxigenic fungi on food). In light of the growing concerns on the health hazards posed by mycotoxins, it is desirable to develop reliable analytical tools for their detection in food products in both sensitive and efficient manner. For this purpose, the potential utility of molecularly imprinted polymers (MIPs) has been explored due to their meritful properties (e.g., large number of tailor-made binding sites, sensitive template molecules, high recognition specificity, and structure predictability). This review addresses the recent advances in the application of MIPs toward the sensing of various mycotoxins (e.g., aflatoxins and patulin) along with their fabrication strategies. Then, performance evaluation is made for various types of MIP- and non-MIP-based sensing platforms built for the listed target mycotoxins in terms of quality assurance such as limit of detection (LOD). Further, the present challenges in the MIP-based sensing application of mycotoxins are discussed along with the future outlook in this research field.

Fluorometric determination of Vibrio parahaemolyticus using an F0F1-ATPase-based aptamer and labeled chromatophores

An F₀F₁-ATPase-based aptasensor is described for the fluorometric determination of Vibrio parahaemolyticus. Chromatophores containing F₀F₁-ATPases were first prepared from Rhodospirillum rubrum cells. Then, an aptamer-functionalized chromatophore acts as the capture probe, and a chromatophore labeled with the pH probe fluorescein acts as the signalling probe. In the presence of V. parahaemolyticus, the rotation rate of F₀F₁-ATPase is decreased due to the formation of the aptamer-chromatophore complex. This leads to a retarded proton flux out of the chromatophores. As a result, the pH value inside the chromatophores is reduced, and the fluorescence of the pH probe F1300 is accordingly decreased. The relative fluorescence varies linearly over the 15 to 1.5 × 10⁶ cfu·mL^-1 Vibrio parahaemolyticus concentration range, and the limit of detection is 15 cfu·mL^-1. The method was applied to analyze artificially contaminated salmon samples where it showed excellent perfomance. Graphical abstract In this assay, aptamer functionalized chromatophores act as a capture probe, and the fluoresce in labeled chromatophores as signalling probe. The formation of aptamer-chromatophore complex leads to a retarded proton flux out of the chromatophores. As a result, the pH value inside the chromatophores is reduced, and fluorescence intensity is accordingly decreased.

Application of F0F1‑ATPase immuno‑biosensors for detecting Escherichia coli O157:H7

Escherichia coli (E. coli) O157:H7 is an important food‑borne pathogen with a low infective threshold and high resistance to treatment. There are currently a number of detection methods available, however, the majority are time‑consuming, complex and expensive, thus it is hard for these methods to be applied in routine detection. Therefore, there is urgent requirement to develop more sensitive, rapid and specific detective techniques. In the present study, an immuno‑biosensor based on the interference of load to the F0F1‑ATPase rotation, indicated by the fluorescence fluctuation, was constructed to detect O157:H7. The results demonstrated a good linear relationship (R2=0.9818) between antigen concentration (range, 102 cfu to 104 cfu) and the fluorescence intensity. The detection signals of the samples containing 102 cfu/well and 104 cfu/well E. coli O157:H7 were significantly stronger than the signal produced by the control sample (P<0.01). Due to its higher sensibility and simplicity when compared with the current methods applied, the results of the present study indicate a promising future for the application of this technique in detecting food source pathogens.

Advances in Biosensors, Chemosensors and Assays for the Determination of Fusarium Mycotoxins

The contaminations of Fusarium mycotoxins in grains and related products, and the exposure in human body are considerable concerns in food safety and human health worldwide. The common Fusarium mycotoxins include fumonisins, T-2 toxin, deoxynivalenol and zearalenone. For this reason, simple, fast and sensitive analytical techniques are particularly important for the screening and determination of Fusarium mycotoxins. In this review, we outlined the related advances in biosensors, chemosensors and assays based on the classical and novel recognition elements such as antibodies, aptamers and molecularly imprinted polymers. Application to food/feed commodities, limit and time of detection were also discussed.