Detection Of Toxins Research Articles

An Update of DNA Hydrogel Application in Biosensing

AbstractDNA gel not only uses the skeleton function of hydrogel but also the biological function of DNA to realize the unified fusion of the structure and function of hydrogel material. By introducing specific small molecules into the DNA gel, it can respond to pH, temperature, ultraviolet, infrared, metal ions, and drug small molecules. To further realize the detection and loading of various small molecules in the biomedical field, the specific recognition and detection of heavy metal ions and toxins in the environment are done. In this paper, the preparation of pure DNA gel and hybrid DNA gel, their detection in the biomedical and environmental fields are reviewed, and their prospects and further development directions are discussed.

Multiplex strategy electrochemical platform based on self-assembly dual-site DNA tetrahedral scaffold for one-step detection of diazinon and profenofos

In the work, based on self-assembly dual-site DNA tetrahedral scaffold (DTS), thionine (Thi), and 6-(Ferrocenyl)hexanethiol (Fc6S), a multiplex strategy electrochemical platform was fabricated for the simultaneous detection of profenofos (PFF) and diazinon (DZN). Thi and Fc6S were used to label aptamers for the synthesis of probes respectively. Notably, Thi and Fc6S engendered recognizable DPV peaks at different potentials to achieve simultaneous detection of PFF and DZN. In addition to increasing the conductivity of the electrode, the combination of carboxylic acid functionalized multi-walled carbon nanotubes and ferroferric oxide nanoparticles could also increase its higher specific surface area of the electrode interface to adsorb more DTS. Because of the mechanical rigidity of the DTS, the DTS could keep a complementary chain upright and provide more binding sites for aptamers, the binding efficiency between the complementary chain and 2 binding aptamers could be improved. Comparing the aptasensors performance of single-strand DNA with that of the DTS with complementary strands, the benefits of the DTS were highlighted in this system. Under optimal conditions, the detection limits of PFF and DZN were both 3.33 pg/mL and the detection ranges were both 1.00 × 101–1.00 × 107 pg/mL. Meanwhile, the recoveries of PFF and DZN were 87.15%–117.34% and 91.20%–114.19%, respectively. The aptasensor could realize the simultaneous detection of PFF and DZN in vegetables. Furthermore, the aptasensor also had good stability and selectivity. This strategy could provide a good reference for developing effective aptasensors for the simultaneous detection of other small molecules and toxins.

Direct Electrical Sensing of Iodine Gas by a Covalent Organic Framework-Based Sensor

Rapid and highly sensitive detection of iodine gaseous species is crucial as the first response in case of nuclear accidents and nuclear waste clean-up. A robust and user-friendly sensor-based technology that allows online monitoring is highly desirable. Herein, we report the success of using a covalent organic framework (AQ-COF)-based sensor for real-time iodine gas adsorption and detection by the electrochemical impedance spectroscopy (EIS) technique. The sensor exhibits a high sensitivity and a pronounced electrical response to trace amounts of iodine vapor. Gaseous iodine was readily detected with a significant change in resistance (104×) at 70 °C within 5 min exposure to air. Notably, the EIS response is quite chemoselective to iodine over other common species such as air, methanol, ethanol, and water, with a selectivity of 320, 14, 49, and 1030, respectively. A mechanical study shows that the adsorption of iodine can reduce the optical bandgap of the AQ-COF, causing the impedance to drop significantly. This study demonstrates how the adsorption enrichment effect of selective I2 adsorption by a covalent organic framework can be leveraged to create a highly selective sensor for the direct online electrical detection of radioactive gaseous toxins.

Reshaping de Novo Protein Switches into Bioresponsive Materials for Biomarker, Toxin, and Viral Detection.

De novo designed protein switches are powerful tools to specifically and sensitively detect diverse targets with simple chemiluminescent readouts. Finding an appropriate material host for de novo designed protein switches without altering their thermodynamics while preserving their intrinsic stability over time would enable the development of a variety of sensing formats to monitor exposure to pathogens, toxins, and for disease diagnosis. Here, a de novo protein-biopolymer hybrid that maintains the detection capabilities induced by the conformational change of the incorporated proteinsin response to analytes of interest is generated in multiple, shelf-stable material formats without the need of refrigerated storage conditions. A set of functional demonstrator devices including personal protective equipment such as masks and laboratory gloves, free-standing films, air quality monitors, and wearable devices is presented to illustrate the versatility of the approach. Such formats are designed to be responsive to human epidermal growth factor receptor (HER2), anti-hepatitis B (HBV) antibodies, Botulinum neurotoxin B (BoNT/B), and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). This combination of form and function offers wide opportunities for ubiquitous sensing in multiple environments by enabling a large class of bio-responsive interfaces of broad utility.

Carbon dots applications for development of sustainable technologies for food safety: A comprehensive review

This review describes the application of carbon dots in the development of sustainable technologies for food safety and quality. Carbon dots (CDs) are surface-functionalized and minuscule in size, with controlled fluorescence, high environmental sensitivity, and a range of remarkable photochemical properties. Green CDs are now the subject of extensive study due to their potential applications in a wide range of fields, such as nano sensing, bio imaging, and photo catalysis. Synthesizing CDs involves the top-down strategy, which includes splitting the bigger carbon molecule into nanoscale particles, and the bottom-up methodology, which involves producing CDs from small carbon units. The problems in the food supply chain are very prominent, from farm to fork that include chemical, microbiological and human hygiene. CDs have recently garnered interest because of the straightforward synthesis method, high biocompatibility, and potential for a variety of innovative applications. CDs were prepared from any carbon source, such as food, food waste, plants, chemicals, and graphene. CDs may be extracted naturally from some foods, such as honey, caramels, and sugar beet molasses. The rapid detection of dietary nutrients and toxins has sparked considerable attention, and nanomaterials-based fluorescence sensing has great promise for establishing exceptionally selective and sensitive identification procedures for food safety testing. Carbon dots have a promising future in fluorescence detection of contaminants due to their significant properties. Carbon dot sensors have capacity in the food sensing sector, since food samples include a variety of components that might create interferences, more innovative approaches to bind with CDs are necessary to develop specific sensing probes.

Aptamer-Based Technologies for Parasite Detection.

Centuries of scientific breakthroughs have brought us closer to understanding and managing the spread of parasitic diseases. Despite ongoing technological advancements in the detection, treatment, and control of parasitic illnesses, their effects on animal and human health remain a major concern worldwide. Aptamers are single-stranded oligonucleotides whose unique three-dimensional structures enable them to interact with high specificity and affinity to a wide range of targets. In recent decades, aptamers have emerged as attractive alternatives to antibodies as therapeutic and diagnostic agents. Due to their superior stability, reusability, and modifiability, aptamers have proven to be effective bioreceptors for the detection of toxins, contaminants, biomarkers, whole cells, pathogens, and others. As such, they have been integrated into a variety of electrochemical, fluorescence, and optical biosensors to effectively detect whole parasites and their proteins. This review offers a summary of the various types of parasite-specific aptamer-based biosensors, their general mechanisms and their performance.

Mushrooms to live or die: toxicity of some Basidiomycota using Artemia franciscana.

Consumption of wild mushrooms has increased in recent years; however, not all of them are edible and there is no precise information on those that may cause poisoning. Therefore, studies to obtain data about their toxicity are needed. For this purpose, we used the brine shrimp Artemia franciscana, a crustacean employed in toxicity tests and with wide application in the toxin detection, including mycotoxins. Mushrooms were collected in the state of Jalisco, Mexico, with which aqueous extracts were prepared. Dilutions of the stock solution of each extract were made to final concentrations of 50, 100, 250, 500, and 1000 µg/mL. Potassium dichromate (PD) was used as positive control and artificial seawater as negative control. The median lethal dose (LD50) of extracts on nauplii of A. franciscana was calculated. The aqueous extracts obtained from Amanita amerivirosa, A. muscaria, Chlorophyllum molybdites, and Leucopaxillus amarus showed a LD50 < 70 µg/mL, similar to PD (LD50 = 37 µg/mL). This is the first indication of the probable toxicity of Leucopaxillus amarus in humans. Cantharellus cibarius and Scleroderma texense caused the lower toxicity to the nauplii. The brine shrimp bioassay was effective in evaluating the toxicity of Basidiomycota. Scleroderma texense has been reported to be toxic, but it was not for this crustacean nauplii, and probably not to humans either, as recent literature has reported.

Microbial ecology between Clostridioides difficile and gut microbiota.

Clostridioides difficile colonizes a polymicrobial environment in the intestine and is a causative agent for antibiotic-associated diarrhea (AAD) and pseudomembranous colitis (PMC). The most important virulence factors of C. difficile are bacterial toxins, and three toxins (toxin A, toxin B, and binary toxin) are produced by toxigenic strains. Other virulence factors include spores, flagella, capsules, biofilms, hydrolytic enzymes and adhesins. C. difficile infection (CDI) is specifically diagnosed by anaerobic culture and toxin detection by either nucleic acid amplification test (NAAT) or enzyme-linked immunosorbent assay (ELISA). For treatment of CDI, metronidazole, vancomycin and fidaxomicin are used based on the severity of CDI. Mutual interaction between C. difficile and gut microbiota is associated with pathogenesis of CDI, and decreased microbial diversity with altered gut microbiome was detected in CDI patients. Restoration of certain gut microbiota is considered to be potentially effective for the prevention and treatment of CDI, and an ideal goal for CDI patients is restoration of the gut microbiota to a healthy state. Fecal microbiota transplantation (FMT) is a highly successful method of microbiome restoration and has been reported to be effective for the prevention of recurrent CDI. In addition, approaches to restoring the gut microbiota by using probioitcs and live biotherapeutic products (LBPs) are currently being studied to examine the effect on CDI. Further microbial ecological research on C. difficile and gut microbiota could lead to a better understanding of the pathogenesis and treatment of CDI.

A review of various methods for the detection of foodborne pathogens and toxins

A review of various methods for the detection of foodborne pathogens and toxins

Detection of Environmental Toxins in Mixed Matrices of Tap Water, Soil, Food Waste, Serum and Milk Using Hememics Biosensor

Detection of Environmental Toxins in Mixed Matrices of Tap Water, Soil, Food Waste, Serum and Milk Using Hememics Biosensor

Challenges and future solutions for detection of Clostridioides difficile in adults.

There are no established standards for the diagnosis of Clostridioides difficile infection (CDI), even though the importance of this infection in humans is well known. The effectiveness of the commercially available techniques, which are all standardized for use with human feces, is also limited in terms of the accuracy of the tests. Furthermore, the current approach lacks a point-of-care diagnosis with an acceptable range of sensitivity and specificity. This article reviews the challenges and possible future solutions for the detection of CDI in adults. Existing diagnostic methods, such as enzyme-linked immunoassays and microbial culturing for the detection of toxins A and B, appear to work poorly in samples but exhibit great sensitivity for glutamate dehydrogenase. Real-time polymerase chain reaction and nucleic acid amplification tests have been investigated in a few studies on human samples, but so far have shown poor turnaround times. Thus, developing a multiplex point-of-care test assay with high sensitivity and specificity is required as a bedside approach for diagnosing this emerging infection.

A competitive, bead-based assay combined with microfluidics for multiplexed toxin detection.

The requirement for rapid, in-field detection of cyanotoxins in water resources necessitates the developing of an easy-to-use and miniaturized system for their detection. We present a novel bead-based, competitive fluorescence assay for multiplexed detection of two types of toxins: microcystin-LR (MC-LR) and okadaic acid (OA). To automate the detection process, a reusable microfluidic device, termed toxin-chip, was designed and validated. The toxin-chip consists of a micromixer where the target toxins were efficiently mixed with a reagent solution, and a detection chamber for magnetic retainment of beads for downstream analysis. Quantum dots (QDs) were used as the reporter molecules to enhance the sensitivity of the assay and the emitted fluorescence signal from QDs was reversely proportional to the amount of toxins in the solution. An image analysis program was also developed to further automate the detection and analysis steps. Two toxins were simultaneously analyzed on a single microfluidic chip, and the device exhibited a low detection limit of 10-4 μg ml-1 for MC-LR and 4 × 10-5 μg ml-1 for OA detection. The bead-based, competitive assay also showed remarkable chemical specificity against potential interfering toxins. We also validated the device performance using natural lake water samples from Sunfish Lake of Waterloo. The toxin-chip holds promise as a versatile and simple quantification tool for cyanotoxin detection, with the potential of detecting more toxins.

Detection of diarrheal shellfish toxins

Abstract Seafood poisoning outbreaks are often caused by biotoxins generated by harmful algal blooms. Shellfish toxins, mainly derived from phytoplankton, cause diarrhea and poisoning in humans who consume contaminated seafood. Many studies suggest that diarrheal shellfish toxins cause functional changes in various cells. In order to protect shellfish products, it is becoming increasingly important to remove these contaminants from the ocean. Public attention plays a crucial role in reducing the risk of acute intoxication caused by contaminated seafood. Monitoring algal toxins is the best way to ensure that seafood is safe and clean. In order to attain these objectives, a variety of technologies were developed and constructed for the purpose of detecting and decontaminating algal toxins in aquatic environments. A review of the current literature regarding the detection and detoxification of diarrheal shellfish toxins is presented in this article.

A microfluidic immunosensor based on magnetic separation for rapid detection of okadaic acid in marine shellfish

Okadaic acid (OA) is a marine biotoxin that accumulates in seafood and can cause diarrheic shellfish poisoning if consumed. Accordingly, many countries have established regulatory limits for the content of OA in shellfish. At present, methods used for the detection of marine toxins are time-consuming and labor-intensive. In order to realize rapid, simple, and accurate detection of OA, we developed a novel microfluidic immunosensor based on magnetic beads modified with a highly specific and sensitive monoclonal antibody (mAb) against OA that is used in conjunction with smartphone imaging to realize the rapid detection of OA in shellfish. The method achieves on-site detection results within 1 h with an IC50 value of 3.30 ng/mL for OA and a limit of detection (LOD) of 0.49 ng/mL. In addition, the analysis of real samples showed that the recoveries for spiked shellfish samples ranged from 84.91% to 95.18%, and the results were confirmed by indirect competitive enzyme-linked immunosorbent assay (icELISA), indicating that the method has good accuracy and precision. Furthermore, the results are reported in a specially designed smartphone app. The microfluidic immunosensor has the advantages of simple operation, rapid detection, and high sensitivity, providing a reliable technical solution for detecting OA residues in shellfish.

Magnetic Nanoseparation Technology for Efficient Control of Microorganisms and Toxins in Foods: A Review.

Outbreaks of foodborne diseases mediated by food microorganisms and toxins remain one of the leading causes of disease and death worldwide. It not only poses a serious threat to human health and safety but also imposes a huge burden on health care and socioeconomics. Traditional methods for the removal and detection of pathogenic bacteria and toxins in various samples such as food and drinking water have certain limitations, requiring a rapid and sensitive strategy for the enrichment and separation of target analytes. Magnetic nanoparticles (MNPs) exhibit excellent performance in this field due to their fascinating properties. The strategy of combining biorecognition elements with MNPs can be used for fast and efficient enrichment and isolation of pathogens. In this review, we describe new trends and practical applications of magnetic nanoseparation technology in the detection of foodborne microorganisms and toxins. We mainly summarize the biochemical modification and functionalization methods of commonly used magnetic nanomaterial carriers and discuss the application of magnetic separation combined with other instrumental analysis techniques. Combined with various detection techniques, it will increase the efficiency of detection and identification of microorganisms and toxins in rapid assays.

Targeted Proteomics Analysis of Staphylococcal Superantigenic Toxins in Menstrual Fluid from Women with Menstrual Toxic Shock Syndrome (mTSS).

Menstrual toxic shock syndrome (mTSS) is a rare life-threatening febrile illness that occurs in women using intravaginal menstrual protection. It is caused by toxic shock syndrome toxin 1 (TSST-1) produced by Staphylococcus aureus, triggering a sudden onset of rash and hypotension, subsequently leading to multiple organ failure. Detecting TSST-1 and S. aureus virulence factors in menstrual fluid could accelerate the diagnosis and improve therapeutic management of mTSS. However, menstrual fluid is a highly complex matrix, making detection of bacterial toxins challenging. Here, we present a mass-spectrometry-based proteomics workflow for the targeted, quantitative analysis of four S. aureus superantigenic toxins in menstrual fluids (TSST-1, SEA, SEC, and SED). This method was applied to characterize toxin levels in menstrual fluids collected from patients with mTSS and healthy women. Toxins were detectable in samples from patients with mTSS and one healthy donor at concentrations ranging from 0 to 0.46 µg/mL for TSST-1, and 0 to 1.07 µg/mL for SEC. SEA and SED were never detected in clinical specimens, even though many S. aureus strains were positive for the corresponding genes. The method presented here could be used to explore toxin production in vivo in users of intravaginal devices to improve the diagnosis, understanding, and prevention of mTSS.

In silico selection of aptamers for bacterial toxins detection

The most commonly used toxins in biological warfare are staphylococcal enterotoxin B (3SEB), cholera toxin (1XTC), and botulinum toxin (3BTA). Uncovering novel strategies for identifying these toxins is paramount; therefore, aptamers are used for this purpose. Aptamers are single-stranded DNA or RNA oligonucleotides selected via Systematic Evolution of Ligands by Exponential Enrichment (SELEX) with high binding affinity and specificity against target molecules. However, SELEX in vitro is tedious; hence, adopting alternative in silico molecular docking approaches is necessary. We aimed to conduct molecular docking with accessible tools and obtain RNA aptamers. First, 4,820,095 sequences obtained from an initial library of 9.5 × 109 Python script sequences were used. The GraphClust program was used to create representative groups or clusters, and the DoGSiteScorer (https://proteins.plus/) was used to conduct binding site detection of the proteins: 5DO4 (thrombin), 3SEB, 1XTC, and 3BTA. rDock, HDock, and PatchDock were adopted, combining different docking program results (consensus scoring), to improve receptor–ligand prediction. An analysis of the poses and root mean square deviation (RMSD) was performed, and 468 structurally different aptamers were obtained. The DoGSiteScorer program predicted the binding site of each protein to direct the interaction with the aptamer. Candidate aptamers for 3SEB, 1XTC, and 3BTA were selected according to the pose value considering the closeness of the interaction with a lower mean of 45.923 Å, 45.854 Å, and 72.490 Å, respectively. Communicated by Ramaswamy H. Sarma

Microbial toxins in fermented foods: health implications and analytical techniques for detection.

Recently, demand for fermented foods has increased due to their improved nutritional value, taste, and health-promoting properties. Worldwide consumption of these products is increasing. Fermented foods are generally safe for human consumption. However, some toxins, primarily biogenic amines (putrescine, phenylethylamine, histamine, tyramine, and cadaverine), mycotoxins (fumonisins, aflatoxins, ochratoxin A, zearalenone, and trichothecenes), and bacterial toxins (endotoxins, enterotoxins, and emetic toxins) can be produced as a result of using an inappropriate starter culture, processing conditions, and improper storage. These toxins can cause a multitude of foodborne illnesses and can lead to cardiovascular aberration and adverse gastrointestinal symptoms. Analytical techniques are in use for the detection of toxins in fermented foods for monitoring and control purposes. These include culture, chromatographic, immunoassays, and nano sensor-based techniques. These detection techniques can be used during the production process and along the food chain. On an industrial scale, HPLC is widely used for sensitive quantification of toxins in fermented foods. Recently, biosensor and nano sensor-based techniques have gained popularity due to accuracy, time efficiency, and simultaneous detection of multiple toxins. Other strategic methods being investigated for the removal of toxins from fermented foods include the use of specific starter cultures for bio-preservation, aflatoxin-binding, and biogenic amine-degradation agents that may help to appropriately manage the food safety concerns associated with fermented foods.

Detection, occurrence, influencing factors and environmental risks of paralytic shellfish toxins in seawater in a typical mariculture bay

Paralytic shellfish toxins (PSTs) producing algae are widely distributed in the global coastal aquatic environment, posing a threat to coastal ecosystem health and mariculture safety. However, the levels and potential environmental risks of PSTs frequently detected in shellfish remain largely unexplored in seawater of mariculture zones. In this study, a new method for trace detection of 13 common PSTs (<1.0 ng/L) in seawater was established based on off-line solid phase extraction (SPE) and on-line SPE-liquid chromatography-tandem mass spectrometry (on-line SPE-LC-MS/MS), and a systematic investigation of PSTs in seawater of the Laizhou Bay, a typical aquaculture bay in China, was conducted to understand their pollution status, environmental impact factors and ecological risks for the first time. Eleven PSTs were detected in the seawater of Laizhou Bay with total concentrations ranging from 0.75 to 349.47 ng/L (mean, 176.27 ng/L), which indicates the rich diversity of PSTs in the mariculture bay and demonstrates the reliability of the proposed analytical method. C1, C2, GTX2, GTX3, dcGTX2, and dcGTX3 were found to be the predominant PSTs, which refreshed the knowledge of PST contamination in the coastal aquatic environment. PST levels in seawater exhibited the highest levels in the southeastern mouth of Laizhou Bay and decreased toward the inner bay. Correlation analyses showed that climatic factors, nutrient status and hydrological conditions had significant effects on the distribution of PST in mariculture bay. Preliminary environmental risk assessments revealed that aquatic organisms throughout the waters of Laizhou Bay are at risk of chronic PST toxicity. These findings imply that the risk of PST in seawater of mariculture bay has previously been grossly underestimated, and that the coastal aquatic environment in North China and even the world may be at more serious risk of PST pollution, which should be taken seriously.

Modification of amphiphilic block copolymers for responsive and biologically active surfactants in complex droplets

Concerns regarding the speed and portability of sensing devices have spurred development of numerous novel platforms. Complex emulsions with responsive surfactants have emerged as a promising class of materials for the detection of various pathogens and environmental toxins. Herein, we report a study of the amphiphilic block copolymer surfactant (BCP), polystyrene-block-poly(acrylic acid), and its use as a functional surfactant. We observe that the composition and molecular weight of BCPs affect the interfacial properties, specifically, more amphiphilic BCPs lead to greater reductions in interfacial tension at the water/oil interface. We further demonstrate that conformational change of poly(acrylic acid) leads to changes in the interfacial tension reductions at these interfaces. Next, we present modification of BCPs with trypsin through carbodiimide mediated amidation to produce functional BCP-trypsin. The modified polymers retain their surfactant capabilities, as well as the functionality of the initial trypsin. Furthermore, we successfully demonstrate the use of the modified polymers within the active complex emulsion framework and the ability of the emulsion framework to turn “on” and “off” functionality through shielding of the active compounds. These responses to chemical changes in their surrounding environment illustrate the potential use of amphiphilic block copolymers as the key component of a complex emulsion systems for sensing device that is rapid, portable, and produces results in real-time.