High-sensitivity chemiluminescent immunoassay investigation and application for the detection of T-2 toxin and major metabolite HT-2 toxin

Upconversion nanoparticles-modified aptasensors for highly sensitive mycotoxin detection for food quality and safety

Mycotoxins, highly toxic and carcinogenic secondary metabolites produced by certain fungi, pose significant health risks as they contaminate food and feed products globally. Current mycotoxin detection methods have limitations in real-time detection capabilities. Aptasensors, incorporating aptamers as specific recognition elements, are crucial for mycotoxin detection due to their remarkable sensitivity and selectivity in identifying target mycotoxins. The sensitivity of aptasensors can be improved by using upconversion nanoparticles (UCNPs). UCNPs consist of lanthanide ions in ceramic host, and their ladder-like energy levels at f-orbitals have unique photophysical properties, including converting low-energy photons to high-energy emissions by a series of complex processes and offering sharp, low-noise, and sensitive near-infrared to visible detection strategy to enhance the efficacy of aptasensors for novel mycotoxin detection. This article aims to review recent reports on the scope of the potential of UCNPs in mycotoxin detection, focusing on their integration with aptasensors to give readers clear insight. We briefly describe the upconversion photoluminescence (UCPL) mechanism and relevant energy transfer processes influencing UCNP design and optimization. Furthermore, recent studies and advancements in UCNP-based aptasensors will be reviewed. We then discuss the potential impact of UCNP-modified aptasensors on food safety and present an outlook on future directions and challenges in this field. This review article comprehensively explains the current state-of-the-art UCNP-based aptasensors for mycotoxin detection. It provides insights into potential applications by addressing technical and practical challenges for practical implementation.

Mn2+-Triggered Swing-Arm Robot Strategy Using Anemone-Like Thi@AuPd@Cu-MOFs as Signaling Probes for the Detection of T-2 Toxin

Herein, we synthesized anemone-like copper-based metal-organic frameworks (MOFs) loaded with gold-palladium nanoparticles (AuPd@Cu-MOFs) and polyethylenimine-reduced graphene oxide/gold-silver nanosheet composites (PEI-rGO/AuAg NSs) for the first time to construct the sensor and to detect T-2 toxin (T-2) using triple helix molecular switch (THMS) and signal amplification by swing-arm robot. The aptasensor used PEI-rGO/hexagonal AuAg NSs as the electrode modification materials and anemone-like AuPd@Cu-MOFs as the signal materials. The prepared PEI-rGO/hexagonal AuAg NSs had a large specific surface area, excellent electrical conductivity, and good stability, which successfully improved the electrochemical performance of the sensors. The AuPd@Cu-MOFs with high porosity provided a great deal of attachment sites for the signaling molecule thionine (Thi), thereby increasing the signal response. The aptasensor developed in this study demonstrated a remarkable detection limit of 0.054 fg mL-1 under optimized conditions. Furthermore, the successful detection of T-2 in real samples was achieved using the fabricated sensor. The simplicity of the THMS-based method, which entails modifying the aptamer sequence, allows for easy adaptation to different target analytes. Thus, the sensor holds immense potential for applications in quality supervision and food safety.

T-2 and HT-2 Toxins: Toxicity, Occurrence and Analysis: A Review

One of the major classes of mycotoxins posing serious hazards to humans and animals and potentially causing severe economic impact to the cereal industry are the trichothecenes, produced by many fungal genera. As such, indicative limits for the sum of T-2 and HT-2 were introduced in the European Union in 2013 and discussions are ongoing as to the establishment of maximum levels. This review provides a concise assessment of the existing understanding concerning the toxicological effects of T-2 and HT-2 in humans and animals, their biosynthetic pathways, occurrence, impact of climate change on their production and an evaluation of the analytical methods applied to their detection. This study highlights that the ecology of F. sporotrichioides and F. langsethiae as well as the influence of interacting environmental factors on their growth and activation of biosynthetic genes are still not fully understood. Predictive models of Fusarium growth and subsequent mycotoxin production would be beneficial in predicting the risk of contamination and thus aid early mitigation. With the likelihood of regulatory maximum limits being introduced, increased surveillance using rapid, on-site tests in addition to confirmatory methods will be required. allowing the industry to be proactive rather than reactive.

Advances in immunoassay-based strategies for mycotoxin detection in food: From single-mode immunosensors to dual-mode immunosensors

Mycotoxin contamination in foods and other goods has become a broad issue owing to serious toxicity, tremendous threat to public safety, and terrible loss of resources. Herein, it is necessary to develop simple, sensitive, inexpensive, and rapid platforms for the detection of mycotoxins. Currently, the limitation of instrumental and chemical methods cannot be massively applied in practice. Immunoassays are considered one of the best candidates for toxin detection due to their simplicity, rapidness, and cost-effectiveness. Especially, the field of dual-mode immunosensors and corresponding assays is rapidly developing as an advanced and intersected technology. So, this review summarized the types and detection principles of single-mode immunosensors including optical and electrical immunosensors in recent years, then focused on developing dual-mode immunosensors including integrated immunosensors and combined immunosensors to detect mycotoxins, as well as the combination of dual-mode immunosensors with a portable device for point-of-care test. The remaining challenges were discussed with the aim of stimulating future development of dual-mode immunosensors to accelerate the transformation of scientific laboratory technologies into easy-to-operate and rapid detection platforms.

Gene expression in farm poultry under the influence of T-2 toxin and the use of biological preparations

Background. Feed-borne T-2 toxin may inhibit innate immune system function in birds.The aim. To evaluate the effect of T-2 toxin, artificially introduced with feed, on the expression level of a number of immunity-related genes in the tissues of the broiler digestive system.Materials and methods. The experiments were carried out in the vivarium of the FSC “VNITIP” RAS broilers of the Smena 8 cross from 33 to 47-day old. Experimental contamination of feed T-2 toxin was performed. The birds were divided into 4 groups of 5 animals each: I – control, receiving a diet without the introduction of T-2 toxin, II experimental – receiving a diet with the addition of T-2 toxin, III experimental – receiving a diet with the addition of T-2 toxin and the sorbent Zaslon2+, IV experimental – receiving a diet with the addition of T-2 toxin, the same sorbent Zaslon2+and Axtra Pro enzyme. The level of mRNA expression was analyzed by quantitative reverse transcription PCR.Results. The data obtained indicated the impact of T-2 toxin contamination of broiler feed on the modulation of the level of expression of genes associated with the functioning of the immune system in the cecum and pancreas. Exposure to T-2 toxin (group II) led to an increase in the expression of the pro-inflammatory gene IL-6 in the tissues of the caecum by 10.8 times and IL-8 in the pancreas by 3.89 times (p ≤ 0.05) compared with control group I. The effect of the sorbent, as well as the complex, including the sorbent and the enzyme, on the expression of broiler genes was positive. The sorbent without the enzyme showed greater efficiency than with the additional introduction of the enzyme.

An Automated and Highly Sensitive Chemiluminescence Immunoassay for Diagnosing Mushroom Poisoning

Mushrooms containing Amanita peptide toxins are the major cause of mushroom poisoning, and lead to approximately 90% of deaths. Phallotoxins are the fastest toxin causing poisoning among Amanita peptide toxins. Thus, it is imperative to construct a highly sensitive quantification method for the rapid diagnosis of mushroom poisoning. In this study, we established a highly sensitive and automated magnetic bead (MB)-based chemiluminescence immunoassay (CLIA) for the early, rapid diagnosis of mushroom poisoning. The limits of detection (LODs) for phallotoxins were 0.010 ng/ml in human serum and 0.009 ng/ml in human urine. Recoveries ranged from 81.6 to 95.6% with a coefficient of variation <12.9%. Analysis of Amanita phalloides samples by the automated MB-based CLIA was in accordance with that of HPLC-MS/MS. The advantages the MB-based CLIA, high sensitivity, repeatability, and stability, were due to the use of MBs as immune carriers, chemiluminescence as a detection signal, and an integrated device to automate the whole process. Therefore, the proposed automated MB-based CLIA is a promising option for the early and rapid clinical diagnosis of mushroom poisoning.

A fluorescence aptasensor for the sensitive detection of T-2 toxin based on FRET by adjusting the surface electric potentials of UCNPs and MIL-101

T-2 toxin is a class A trichothecene mycotoxin produced by Fusarium, which exhibits genotoxic, cytotoxic, and immunotoxic effects in animals and humans. In this study, we developed an aptasensor for the sensitive detection of T-2 toxin, which was based on fluorescence resonance energy transfer (FRET), and acted by adjusting the electric potential on the surface of upconversion nanoparticles (UCNPs) and MIL-101(Cr). In addition, it combined the excellent spectral properties of UCNPs with the good adsorption quenching abilities of metal organic frameworks (MOFs). Under the action of π-π stacking interactions, the UCNPs-aptamer was adsorbed onto the surface of MIL-101, leading to fluorescence quenching due to the occurrence of FRET. After the addition of T-2 toxin, owing to its selective binding to the UCNPs-aptamer, the UCNPs-aptamer moved away from MIL-101(Cr), resulting in fluorescence recovery. Moreover, the extent of fluorescence recovery was positively correlated with the concentration of T-2 toxin. The limit of detection (LOD) of this sensor was 0.087 ng mL^-1 (S/N = 3), and a good linear correlation was observed between the fluorescence intensity and the T-2 toxin concentration in the range of 0.1-100 ng mL^-1. Moreover, the recovery of this method was 97.52-109.53% for corn meal samples (relative standard deviation, RSD = 1.7-2.4%) and 90.81-100.02% for beer samples (RSD = 2.4-2.7%). By adjusting the surface electric potentials, the efficient fluorescence aptasensor combined the advantages of UCNPs and MIL-101(Cr) and allowed the first application of such a system in toxin detection, thereby indicating its potential food sample analysis and biochemical sensing.

Novel colorimetric aptasensor based on unmodified gold nanoparticle and ssDNA for rapid and sensitive detection of T-2 toxin

A novel colorimetric aptasensor based on unmodified gold nanoparticle (AuNPs) and single-strand DNA (ssDNA) aptamer was developed for the rapid and sensitive detection of T-2 toxin. In the absence of T-2, the AuNPs were wrapped by the aptamer to avoid the salt-induced aggregation and the solution remains red. In the presence of T-2, the aptamer was bound with T-2 and released from the surface of AuNPs, resulting in the aggregation of AuNPs under proper salt solution and the color change from red to purple-blue. The aptasensor exhibited a high sensitivity and selectivity for the detection of T-2. The range of linearity and detection limit were 0.1 ng/mL-5000 ng/mL (0.21435 nM-10717.5 nM) and 57.8 pg/mL (0.124 nM), respectively. The aptasensor developed here was applicable to assay T-2 in wheat and corn samples. These results implied that the colorimetric aptasensor was potentially useful in food detection.

A competitive immunoassay based on engineered magnetic/fluorescent nanoparticles and biolayer interferometry-based assay for T-2 toxin determination

For the first time a competitive immunoassay was developed by employing T-2 antibody-functionalized magnetite nanoparticles and T-2 toxin-conjugated fluorescent quantum dots (QDs). Free T-2 and the T-2-modified QDs compete for binding to antibody-modified magnetic beads; the magnetic beads collected by magnetic separation were subjected to fluorescence intensity analysis (with excitation/emission wavelengths at 460/616 nm). This competitive immunoassay for T-2 toxin determination was applied both in a microcentrifuge tube and on a 96-well plate. The dynamic range of the immunoassay is 1-100 ng mL^-1, the limit of detection (LOD) is 0.1 ng mL^-1, and determination was completed in about 40 min and 30 min in the microcentrifuge tube and 96-well plate, respectively. Moreover, the biolayer interferometry (BLI) technique was employed for T-2 determination for the first time, in which the conjugate of T-2 toxin and bovine serum albumin (BSA) was immobilized on the sensors before detection. Its average recovery of T-2 toxin from barley sample ranged from 82.00 to 123.33%, and the relative standard deviation (RSD) was between 9.42 and 15.73%. The LOD of the BLI-based assay is 5 ng mL^-1, and it only takes 10 min to finish the determination. Graphical abstract.

T-2 Toxin Induces Oxidative Stress, Apoptosis and Cytoprotective Autophagy in Chicken Hepatocytes

T-2 toxin is type A trichothecenes mycotoxin, which produced by fusarium species in cereal grains. T-2 toxin has been shown to induce a series of toxic effects on the health of human and animal, such as immunosuppression and carcinogenesis. Previous study has proven that T-2 toxin caused hepatotoxicity in chicken, but the regulatory mechanism is unclear. In the present study, we assessed the toxicological effect of T-2 toxin on apoptosis and autophagy in hepatocytes. The total of 120 1-day-old healthy broilers were allocated randomly into four groups and reared for 21 day with complete feed containing 0 mg/kg, 0.5 mg/kg, 1 mg/kg or 2 mg/kg T-2 toxin, respectively. The results showed that the apoptosis rate and pathological changes degree hepatocytes were aggravated with the increase of T-2 toxin. At the molecular mechanism level, T-2 toxin induced mitochondria-mediated apoptosis by producing reactive oxygen species, promoting cytochrome c translocation between the mitochondria and cytoplasm, and thus promoting apoptosomes formation. Meanwhile, the expression of the autophagy-related protein, ATG5, ATG7 and Beclin-1, and the LC3-II/LC3-I ratio were increased, while p62 was downregulated, suggesting T-2 toxin caused autophagy in hepatocytes. Further experiments demonstrated that the PI3K/AKT/mTOR signal may be participated in autophagy induced by T-2 toxin in chicken hepatocytes. These data suggest a possible underlying molecular mechanism for T-2 toxin that induces apoptosis and autophagy in chicken hepatocytes.

Occurrence of mycotoxins in rice consumed by Iranians: a probabilistic assessment of risk to health

Risks based on cancer and non-cancer endpoints, to Iranians from exposure to several mycotoxins (aflatoxin B1, ochratoxin, deoxynivalenol and T-2 toxin) following consumption of rice were evaluated. Point estimates of hazard were made for each mycotoxin and a hazard index (HI) and probabilistic estimates were based on results of Monte Carlo Simulations (MCS). All known 17 peer-reviewed studies, published in databases included in Science Direct, PubMed, Scopus and Web of Science, as well as grey literature published in Google Scholar from 2008 to 2017 were considered. The 95^th and 50^th centiles of Hazard Index (HI) in Iranians due to ingestion of rice were estimated to be 2.5 and 0.5, respectively. The 95^th and 50^th centiles of people with positive surface antigens for hepatitis B (HBsAg+) risk characterisation for AFB₁ in Iranian consumers of rice were 81 and 79.1, respectively. The 95^th and 50^th centiles for risks of Iranians negative for the surface antigen of hepatitis B HBsAg (HBsAg-) were 4.4 and 2.6, respectively. Based on results of the MCS for risks to cancer effects, the 95^th and 50^th centiles of margins of exposure (MOE) were 233 and 231, respectively. Therefore, it is recommended to update agricultural approaches and storage methods and implement monitoring and regulations based on risks to health posed by consumption of rice by the Iranian population.

Construction of Electrochemical Immunosensor Based on Gold-Nanoparticles/Carbon Nanotubes/Chitosan for Sensitive Determination of T-2 Toxin in Feed and Swine Meat

T-2 toxin (T-2) is one of major concern mycotoxins acknowledged as an unavoidable contaminant in human foods, animal feeds and also agriculture products. Thus, a facile and sensitive method is essential for accurate T-2 toxin detection. In our work, a specific electrochemical immunosensor based on gold nanoparticles/carboxylic group-functionalized single-walled carbon nanotubes/chitosan (AuNPs/cSWNTs/CS) composite was established. The mechanism of the electrochemical immunosensor was an indirect competitive binding to a given amount of anti-T-2 between free T-2 and T-2-bovine serum albumin, which was conjugated on covalently functionalized cSWNTs decorated on the glass carbon electrode. Afterwards, the alkaline phosphatase labeled anti-mouse secondary antibody was bound to the electrode surface by reacting with the primary antibody. Lastly, alkaline phosphatase catalyzed the hydrolysis of the substrate α-naphthyl phosphate, which produced an electrochemical signal. Compared with conventional methods, the established immunosensor was more sensitive and simpler. Under optimal conditions, this method could quantitatively detect T-2 from 0.01 to 100 μg·L-1 with a detection limit of 0.13 μg·L-1 and favorable recovery 91.42⁻102.49%. Moreover, the immunosensor was successfully applied to assay T-2 in feed and swine meat, which showed good correlation with the results obtained from liquid chromatography-tandem mass spectrometry (LC-MS/MS).

T-2 mycotoxin: toxicological effects and decontamination strategies

Mycotoxins are highly diverse secondary metabolites produced in nature by a wide variety of fungus which causes food contamination, resulting in mycotoxicosis in animals and humans. In particular, trichothecenes mycotoxin produced by genus fusarium is agriculturally more important worldwide due to the potential health hazards they pose. It is mainly metabolized and eliminated after ingestion, yielding more than 20 metabolites with the hydroxy trichothecenes-2 toxin being the major metabolite. Trichothecene is hazardously intoxicating due to their additional potential to be topically absorbed, and their metabolites affect the gastrointestinal tract, skin, kidney, liver, and immune and hematopoietic progenitor cellular systems. Sensitivity to this type of toxin varying from dairy cattle to pigs, with the most sensitive endpoints being neural, reproductive, immunological and hematological effects. The mechanism of action mainly consists of the inhibition of protein synthesis and oxidative damage to cells followed by the disruption of nucleic acid synthesis and ensuing apoptosis. In this review, the possible hazards, historical significance, toxicokinetics, and the genotoxic and cytotoxic effects along with regulatory guidelines and recommendations pertaining to the trichothecene mycotoxin are discussed. Furthermore, various techniques utilized for toxin determination, pathophysiology, prophylaxis and treatment using herbal antioxidant compounds and regulatory guidelines and recommendations are reviewed. The prospects of the trichothecene as potential hazardous agents, decontamination strategies and future perspectives along with plausible therapeutic uses are comprehensively described.