Detection Of Toxins Research Articles

Detection of Epsilon Toxin in Goats Affected with Acute Enterotoxaemia and the Haemato-biochemical Alterations

Background: The principal cause of caprine enterotoxaemia is Clostridium perfringens type D which is normally resident in digestive tract and soil in fairly low numbers. Overeating of carbohydrate rich diet or sudden change in diet leads to proliferation of the bacteria and release of lethal toxins in intestine of the host. It causes sudden death in affected ruminants of different ages, though lambs of 3 to 10 weeks of age are highly susceptible. It causes sever enterocolitis with or without haemorrhagic diarrhoea and encephalitis resulting in acute nervous signs with a fatal outcome. Methods: Thirty goats of different breeds under 1-4 years age and both sex were presented to Veterinary Clinical Complex, Veterinary College and Research Institute, Tirunelveli with the neurological signs and diarrhoea were the subject of study. Faecal samples were collected from all these cases and tested on spot by immunochromatographic test kit to identify the Clostridium perfringens Epsilon toxin (ETX). Blood and serum samples were collected and subjected haemato-biochemical analysis. Peripheral blood smears were also collected to rule out haemoprotozoan infections in all the cases. Result: Epsilon toxin was detected from faecal samples of 36.6 per cent of the goats. Diarrhoea was the most consistent finding which is due to enterocolitis in acute cases. A significant increase (P less than 0.001) in the neutrophils and leukocytes count and a significant increase (P less than 0.05) in the levels of BUN, creatinine, glucose, ALP and chloride levels were observed. All the cases were treated with sulphadimidine at recommended dose with supportive therapy but no response was reported due to the fatal encephalitis.

Electrochemical Characterization of Silicon-Based Gold Microband Electrode Array and its Application for Labelless T-2/HT-2 Toxin Immunosensing

Microelectrode arrays (MEAs) are gaining interest in electroanalysis owing to its distinctive voltammetry properties compared to its macro counterparts. Among the MEAs widely fabricated and studied are microdisc array and microband array. We report here the microfabrication of 10 μm microband array (number of band in an array, N=17) and its application in labelless impedimetric sensing of T-2/HT-2 toxin. The microband array has recess depth (i.e. Si3N4 passivation thickness) of 200 nm. Upon fabrication, the device was first characterized via visual inspection and electrochemical analysis. Cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) studies were performed in 1 mM ferrocenecarboxylic acid (FCA) in 0.01 M PBS, pH 7.4. At scan rate of 100 mv s-1, cyclic voltammogram for the microband array exhibited a slight peak-shaped CV; and was found to be scan-rate dependent. Experimental limiting current of the microband array (529±7 nA) was slightly lower compared to the calculated theoretical current (632 nA) indicating mixed diffusion profile of the microband array. The device was then employed in immunosensor construction for T-2/HT-2 toxins detection. T-2 mycotoxin and its metabolite (HT-2), are target of concern in the biosensing application due to its lethal toxicity and prominent presence in EU grains industry. Surface functionalization for anti-T-2 monoclonal antibody (mAb) immobilization was first achieved via surface hydroxylation with plasma cleaning and piranha solution treatment, followed by (3-Aminopropyl) triethoxysilane (APTES) silanization and 15 minutes pre-incubation with various concentrations of anti-T-2 toxin mAb in EDC/NHS mixture. The optimal concentrations for anti-T-2 toxin mAb immobilization on the microband array surface was determined at 0.75 mg mL-1. Based on the calibration curve developed in buffer solution system, the functionalized microband array was proven sensitive as it was able to detect T-2/HT-2 toxin at low dynamic working range (0-25 ppb) and limit of quantitation (LOQ) achieved at 4.89 ppb.

Inside Back Cover: Cover Image, Volume 21, Issue 2

The cover image is based on the Original Article Phage?based technologies for highly sensitive luminescent detection of foodborne pathogens and microbial toxins: A review by Yane Luo et al., https://doi.org/10.1111/1541-4337.12908.

Tethered Bilayer Membrane Formation on Silanized Fluorine Doped Tin Oxide Surface

Silane compound was synthesized via click chemistry and a mixture of synthesis products without purification was used to form the self-assembled monolayers on metal oxide conducting films of fluorine doped tin oxide (FTO). Silanized FTO surfaces triggered rupture of multilamellar vesicles and formed electrically insulating tethered bilayer membranes (tBLMs). In contrast to well-known hybrid bilayer membranes on silane monolayers such as ones formed from octadecyltrichlorosilane, tBLMs on FTO contained water-ion reservoir between solid surface and phospholipid bilayer sheet. They demonstrated biological relevance and ability to reconstitute the pore-forming protein channels such as α-hemolysin from Staphylococcus aureus and melittin. The addition of cholesterol to tBLMs decreased the membrane-damaging effect of melittin, while the opposite was observed in the case of α-hemolysin. The tBLMs can be regenerated multiple times without losing their functionality. The described methodology (both synthesis and formation of anchor monolayer) can be extended to any oxide film surface by properly adjusting chemical composition of molecular anchor and silanization conditions. This makes the proposed biomimetic membrane system attractive for various applications including biomedical sensors for the detection of pore-forming toxins.

Metal-organic framework-based sensors for the detection of toxins and foodborne pathogens

Toxins and foodborne pathogens contamination induce adverse effects on human health and cause enormous economic losses. Therefore, reliable analysis methods are essential. Recently, with the achievements of nanoscience, metal-organic frameworks (MOFs), a novel class of porous crystalline materials, have received increasing interest in preparing sensors for toxins and pathogens analysis because of their intriguing properties, such as large surface area, high porosity, and diverse functionality. In this article, first, typical methods for MOF synthesis are presented. Then a brief introduction of some typical toxin and pathogens is given. Furthermore, recent progress in MOF-based sensors for the measurement of toxins and pathogens are summarized. Different electrochemical and optical sensors are outlined according to the roles of MOFs in sensor development and some typical examples are presented. Finally, challenges and future perspectives are discussed. • MOFs and MOF composites emerge as promising materials in sensing. • Recent developments of MOF-based sensors are summarized for toxins and pathogens detection. • Challenges and prospects of MOF-based sensors in toxins and pathogens analysis are proposed.

Lateral Flow Immunoassay for Rapid Identification of the Diphtheria Agent

<h3>Purpose</h3> Recent reports from several EU countries indicate circulation of toxigenic <i>Corynebacterium diphtheriae</i> among refugees from Asia and Africa as well as children's deaths among indigenous populations. Toxigenic <i>C. diphtheriae</i> carriers pose a serious risk for unvaccinated persons and ones with low level of immunological protection, the number of which in Europe has increased. The International system of quality control revealed the poor state of laboratory diagnosis of diphtheria in EU. This is mostly due to the absence of simple, standard and reliable method of the diphtheria toxin (DT) detection. The common method for detecting the production of DT by corynebacteria, gel immunoprecipitation or Elek test is vulnerable, time consuming and laborious. PCR for DT gene detection cannot be used instead of the Elek test, since non-toxigenic toxin gene-bearing (NTTB) <i>C. diphtheriae</i> and <i>C. ulcerans</i> circulate worldwide. The aim of this study was development and evaluation of rapid immunochemical test for the detection of DT. <h3>Methods & Materials</h3> Lateral Flow Immunoassay (LFIA) strips were designed using monoclonal antibodies against DT. Two hundred and fifty of toxigenic, non-toxigenic <i>C. diphtheriae, C. ulcerans</i> and other corynebacteria isolated in Germany in 2019-2021 were tested for DT after 6 hours of growth on the WHO-recommended liquid nutrient medium. <h3>Results</h3> A complete convergence of the conventional method of DT detection - Elek test and the LFIA for all 250 isolates of diphtheria and non-diphtheria corynebacteria was observed. The use of the LFIA makes it possible to significantly simplify DT detection and reduce the time of analysis from 24-48 to 4-6 hours. Thus, the possibility of replacing the Elek test with the LFIA appears real. <h3>Conclusion</h3> The availability of such a simple and reliable method for DT detection will speed up and increase the accuracy of diphtheria diagnosis globally. The efficient diphtheria laboratory diagnosis will enable timely initiation of anti-diphtheritic treatment that will save lives, prevent the development of complications, as well as stop the spread of the disease through early initiation of preventive measures.

“From Protein Toxins to Applied Toxicological Testing” virtual workshop identifies the need for a bioinformatic framework to assess novel food protein safety

On October 21–22, 2020 the HESI (Health and Environmental Sciences Institute) Protein Allergens, Toxins, and Bioinformatics Committee, and the Society of Toxicology Food Safety Specialty Section co-hosted a virtual workshop titled “From Protein Toxins to Applied Toxicological Testing”. The workshop focused on the safety assessment of novel proteins contained in foods and feeds, was globally represented by over 200 stakeholder attendees, and featured contributions from experts in academia, government and non-government organizations, and agricultural biotechnology developers from the private sector. A range of topics relevant to novel protein safety were discussed, including: the state of protein toxin biology, modes and mechanisms of action, structures and activity, use of bioinformatic analyses to assess the safety of a protein, and ways to leverage computational biology with in silico approaches for protein toxin identification/characterization. Key outcomes of the workshop included the appreciation of the complexity of developing a definition for a protein toxin when viewed from the perspective of food and feed safety, confirming the need for a case-by-case hypothesis-driven interpretation of bioinformatic results that leverages additional metadata rather than an alignment threshold-driven interpretation, and agreement that a “toxin protein database” is not necessary, as the bioinformatic needs for toxin detection may be accomplished by existing databases such as Pfam and UniProtKB/Swiss-Prot. In this paper, a path forward is proposed.

Analytical documentation of an Arabian horse fatality related to Oenanthe crocata poisoning

Analytical detection of Oenanthe crocata toxins in biological samples is challenging because of their instability, the lack of commercially available standards and the exceptionally low detection of these molecules using mass spectrometry. This work aims to report the used analytical methods that allowed identification of the main plant toxins in biological samples from an equid (an Arabian horse) fatality related to hemlock water dropwort (Oenanthe crocata Linnaeus) intake. Using both LC-DAD and LC-HRMS methods allowed identification (i) of oenanthotoxin in roots found on the site, root fragments found in the stomach, stomach content, kidney, and liver, and (ii) of the hydrogenated metabolite of oenanthotoxin (2,3-dihydro-oenanthotoxin) in roots found on the site, root fragments found in the stomach, stomach content, kidney, liver and spleen. Reported analytical data about Oenanthe crocata toxins can be useful for identification of the ingested plant and for supporting a poisoning diagnosis in such cases.

A comparative study of “turn-off” mode and “turn-on” mode lateral flow immunoassay for T-2 toxin detection

The “turn-off” mode lateral flow immunoassay (LFA) based on the conventional competitive format and “turn-on” mode LFA mainly determined by inner filter effect (IFE-LFA) were objectively compared using T-2 toxin as a model molecule and T-2-BSA and anti-T-2 monoclonal antibody as immunocomplex pairs to improve the sensitivity of the LFA. First, Au nanoparticles (Au NPs), amorphous carbon nanoparticles (ACNPs), quantum dots nanospheres (QDs), and time-resolved fluorescent microspheres (TRFMs) were selected as labels for developing the “turn-off” mode LFAs (Au NPs-LFA, ACNPs-LFA, QDs-LFA, and TRFMs-LFA, respectively). Thereafter, Au NPs and ACNPs were used as absorbers, and QDs and TRFMs were selected as fluorescers, for preparing the “turn-on” mode IFE-LFAs (IFE-LFA based on Au NPs as absorbers and QDs as fluorescers [Au NPs-mAb-QDs-BSA], IFE-LFA based on Au NPs as absorbers and TRFMs as fluorescers [Au NPs-mAb-TRFMs-BSA], IFE-LFA based on ACNPs as absorbers and QDs as fluorescers [ACNPs-mAb-QDs-BSA], and IFE-LFA based on ACNPs as absorbers and TRFMs as fluorescers [ACNPs-mAb-TRFMs-BSA]). Under optimized conditions, the naked-eye observation cut-off values for the aforementioned eight LFAs were 4, 2, 2, 2, 3, 2, 1.5, and 1 ng/mL, with quantitative limit of detection values of 0.50, 0.23, 0.24, 0.23, 0.47, 0.45, 0.27, and 0.22 ng/mL, respectively. Among all LFAs, ACNPs-mAb-TRFMs-BSA showed the highest sensitivity. The results of this study provide a perspective for improving the sensitivity of the LFAs to meet the requirements of on-site screening for trace substances.

Phage-based technologies for highly sensitive luminescent detection of foodborne pathogens and microbial toxins: A review.

Foodborne pathogens and microbial toxins are the main causes of foodborne illness. However, trace pathogens and toxins in foods are difficult to detect. Thus, techniques for their rapid and sensitive identification and quantification are urgently needed. Phages can specifically recognize and adhere to certain species of microbes or toxins due to molecular complementation between capsid proteins of phages and receptors on the host cell wall or toxins, and thus they have been successfully developed into a detection platform for pathogens and toxins. This review presents an update on phage-based luminescent detection technologies as well as their working principles and characteristics. Based on phage display techniques of temperate phages, reporter gene detection assays have been designed to sensitively detect trace pathogens by luminous intensity. By the host-specific lytic effects of virulent phages, enzyme-catalyzed chemiluminescent detection technologies for pathogens have been exploited. Notably, these phage-based luminescent detection technologies can discriminate viable versus dead microbes. Further, highly selective and sensitive immune-based assays have been developed to detect trace toxins qualitatively and quantitatively via antibody analogs displayed by phages, such as phage-ELISA (enzyme-linked immunosorbent assay) and phage-IPCR (immuno-polymerase chain reaction). This literature research may lead to novel and innocuous phage-based rapid detection technologies to ensure food safety.

Detection of Clostridioides difficile toxin B gene: benefits of identifying gastrointestinal pathogens by mPCR assay in the diagnosis of diarrhea in pediatric patients

BackgroundIn the pediatric population, severe Clostridioides difficile infection (CDI) sometimes occurs, but most cases are asymptomatic. The asymptomatic carriage rate in pediatric populations is reportedly higher than in the adult population. It is difficult to diagnose CDI, even if C. difficile is detected in children with diarrhea. This study aimed to evaluate the positivity rate of toxigenic C. difficile in the pediatric population with diarrhea.MethodsWe collected and retrospectively analyzed gastrointestinal pathogen multiplex PCR results of 960 patients to estimate the positivity rate of toxigenic C. difficile in pediatric populations aged between 0 and 18 years.ResultsThe overall rate of C. difficile toxin B positivity was 10.1% in the stool samples. The positivity rate peaked in 1-year-old infants (29/153, 19.0%) and continually decreased thereafter. The positivity rate we observed was lower than the rates described in the literature. Remarkably, no C. difficile was detected in neonates. Antibiotic usage was inversely related to the positivity rate, especially in infants < 2 years of age. The odds ratio of antibiotics was 0.44 (95% confidence interval (CI) 0.28–0.68; P < 0.001). The presence of concomitant gastrointestinal pathogens was not associated with toxigenic C. difficile positivity.ConclusionsEven though toxigenic C. difficile infection is neither an important nor a common cause of pediatric diarrhea, children can spread it to adults at risk of developing CDI. The pediatric population can act as hidden reservoirs for pathogenic strains in the community.

Development of Fc-specific multi-biotinylated antibodies via photoreactive tandem AviTag repeats for the ultrasensitive determination of ochratoxin A

Ochratoxin A (OTA) is a common food contaminant that seriously threatens the safety and health of consumers. Here, an indirect competitive biotin-streptavidin-amplified enzyme-linked immunosorbent assay (icBA-ELISA) was developed for the sensitive detection of OTA by employing Fc-specific multi-biotinylated antibodies. An Fc-binding protein (Z-domain) carrying a photo-cross-linker ( p -benzoylphenylalanine, Bpa) fused with tandem AviTag repeats, viz. Z Bpa -(AviTag) n , was first constructed using the aminoacyl-tRNA synthetase/suppressor tRNA technique. Biotin molecules were covalently conjugated to antibodies mediated by the photoreactive biotinylated Z Bpa -(AviTag) n , resulting in the Fc-specific multi-biotinylated antibodies (IgG−*Z-B n conjugates) that were used to establish icBA-ELISA. Among the IgG−*Z-B n -based icBA-ELISA, the IgG−*Z-B 5 conjugates exhibited a half-maximal inhibitory concentration of 0.0519 ng mL −1 and a limit of detection of 0.00944 ng mL −1 for OTA. The sensitivity was improved 4.8 and 4.7 times compared with that of the chemical-coupled IgG−biotin conjugates. Thus, the proposed icBA-ELISA for the sensitive detection of OTA has remarkable potential applications for the detection of various toxins in food.

Metallic Nanoparticles in the Food Sector: A Mini-Review.

Nanomaterials, and in particular metallic nanoparticles (MNPs), have significantly contributed to the production of healthier, safer, and higher-quality foods and food packaging with special properties, such as greater mechanical strength, improved gas barrier capacity, increased water repellency and ability to inhibit microbial contamination, ensuring higher quality and longer product shelf life. MNPs can also be incorporated into chemical and biological sensors, enabling the design of fast and sensitive monitoring devices to assess food quality, from freshness to detection of allergens, food-borne pathogens or toxins. This review summarizes recent developments in the use of MNPs in the field of food science and technology. Additionally, a brief overview of MNP synthesis and characterization techniques is provided, as well as of the toxicity, biosafety and regulatory issues of MNPs in the agricultural, feed and food sectors.

Polimeric Immunoglobulin Diagnosticum for Detection of Cholera Toxin and Assessing the Level of Its Production by Vibrios

A marker of the epidemic significance of Vibrio cholerae is their toxigenicity. Therefore, much attention is currently paid to the creation of diagnostic preparations for the detection of cholera toxin and assessment of the level of its production. The volumetric immunosuspension agglomeration reaction, carried out with the help of latex diagnosticums, is an analogue of the indirect hemagglutination reaction, an affordable and technically simple method, since it does not require special equipment and can be used when conducting research in the field. The aim of the study was to design a polymeric immunoglobulin diagnosticum for determining cholera toxin and the level of its production by vibrio strains. Materials and methods. Cholera toxin was obtained from the producer strain Vibrio cholerae Classical 569 B. Rabbit serum to the toxin was obtained according to the method selected by the authors. A polymeric diagnostic immunoglobulin antitoxic drug was obtained through sensitizing immunoglobulins from cholera antitoxic rabbit serum on the surface of polyacrolein microspheres with a size of (1±0.1) μm. Results and discussion. The analytical sensitivity of the developed diagnostic preparation with control cholera toxin is 100 ng/ml. It detects cholera toxin in toxigenic strains of Vibrio cholerae in a titer of 1:16 – 1:512, gives negative results with non-toxigenic strains of V. cholerae O1, V. Cholerae nonO1/nonO139, with samples of heterologous cultures, LPS preparations, liquid nutrient medium used for the cultivation of V. cholerae. Thus, a polymeric immunoglobulin diagnosticum has been constructed to detect and quantify the production of cholera toxin by vibrio strains, and its analytical sensitivity and specificity have been established.

Fluorescence of nanodiamond cocktails: pH-induced effects through interactions with comestible liquids

Fluorescent nanodiamonds with nitrogen-vacancy centers have become important nanoscale probes for sensing and imaging. The surface chemistry of the nanodiamonds influences their emission, interactions, and quantum properties. In this work, we propose to utilize fluorescent nanodiamonds as photostable markers for investigation of comestible liquids. We prepared nanodiamond/comestibles suspensions/cocktails with a wide range of pH levels and studied the samples via fluorescence, wettability, and zeta potential. The composition of the created cocktails revealed a strong impact on the properties of the nanodiamond and its surface chemistry, mainly induced by pH but also tuned by specific quenching compounds. Moreover, the stability of the nanodiamonds in the cocktail media was studied, along with various nature-originated compounds influencing their surface termination, polarity, and charge states. Thanks to the stability and biocompatibility of the nanodiamond, it can be applied in monitoring the condition of foodstuffs, and in the detection of toxins and pathogens in them.

Biocompatible Nanomaterials in Food Science, Technology, and Nutrient Drug Delivery: Recent Developments and Applications.

Nanomaterials exist as potential biocompatible materials in nature and are being synthesized to provide extraordinary characteristics in various food industry sectors. Synthesis of biocompatible nanomaterials requires modification in the shape, density, and size of nanomaterials. Biocompatible nanomaterials are synthesized to reduce toxicity, decrease adverse effects in the gastrointestinal tract, and enhance immune response. Nanomaterials can target organs and tissues. Nanomaterials are found to be effectively compatible by interacting with functional foods and nutraceuticals. Applications of these nanomaterials are novel strategies in food industries such as food safety, food processing, food quality, food packaging, and food labeling. Various functions like detection of toxins and pathogens; production of biocompatible packaging; enhancement in color, flavor, and aroma; processing edible film, and sensing authenticity of food product are being accomplished with no toxicity. This review provides a systematic study on the biocompatibility of nanomaterials. It highlights the synthesis of biocompatible nanomaterials and advanced functions of these nanomaterials in the production area, processing industry, safety improvement, quality control, edible packaging films, biocompatibility, current developments, legislations and regulations for Nano-products, health and safety concerns, toxicity and public perceptions for use of nanomaterials.

Construction and Characterization of a Single-Chain Variable Fragment (scFv) for the Detection of Cry1Ab and Cry1Ac Toxins from the Anti-Cry1Ab Monoclonal Antibody

Construction and Characterization of a Single-Chain Variable Fragment (scFv) for the Detection of Cry1Ab and Cry1Ac Toxins from the Anti-Cry1Ab Monoclonal Antibody

Highly sensitive detection of three protein toxins via SERS-lateral flow immunoassay based on SiO2@Au nanoparticles

We developed surface-enhanced Raman scattering–lateral flow immunoassay (SERS–LFIA) biosensor strips based on SiO2@Au nanoparticles (NPs) for the specific and highly sensitive detection of ricin, staphylococcal enterotoxin B (SEB), and botulinum neurotoxin type A (BoNT/A). SiO2@Au NPs were used to prepare SERS tags with useful properties, such as light weight, uniform particle size, good dispersion, and high SERS performance. The detection limit of the SERS–LFIA strips developed herein for ricin, SEB, and BoNT/A was 0.1, 0.05, and 0.1 ng/mL. Their sensitivity was 100-fold higher than that of colloidal gold–LFIA strips, and the same batch of strips had good repeatability. Moreover, the test was completed within 15 min, indicating that the strips are suitable for the rapid and on-site detection of the said toxins. The SERS–LFIA strips based on SiO2@Au NPs developed herein for the detection of toxins are important to the prevention of bioterrorism attacks.

Electrochemical sensing and photocatalytic degradation of 2,4-dinitrophenol via bismuth (III) oxide nanowires

A user-friendly detection of toxins is extremely required in order to ensure a sustainable environment. In this study, we have performed the electrochemical sensing of 2,4-Dinitrophenol (2,4-DNP) and for this purpose, one-dimensional Bismuth (III) oxide (Bi2O3) nanostructures have been investigated as selective materials. The Bi2O3 nanowires were fabricated at 90 °C through a straightforward heating technique. The standard characterization techniques such as X-ray diffraction (XRD), Scanning electron microscopy (SEM), Energy-dispersive X-ray spectroscopy (EDS), and X-ray photoelectron spectroscopy (XPS) were used to study the morphological, structural and optical properties of the synthesized Bi2O3 nanowires while Cyclic voltammetry (CV) and Differential pulse voltammetry (DPV) electrochemical methods were employed for observing the electrochemical reaction of the original and modified electrode for 2,4-DNP determination. Additionally, the degradation of 2,4-DNP was studied with the addition of Bi2O3 nanowires. The results showed that the Bi2O3 nanowires successfully degrades 2,4-DNP in 600 min under visible light. This study provides an economical, facile and low-temperature method for the application of Bi2O3 nanowires in integration devices.

A robust colorimetric aptasensor for the label-free detection of marine toxins based on tyrosine-capped gold nanoparticles.

PbTx-2 and okadaic acid (OA) are two typical marine toxins that are highly toxic and harmful to human health. The approach based on citrate-capped gold nanoparticles (Cit-AuNPs) and specific aptamers to construct label-free colorimetric sensors is a widely used method for marine toxin detection. However, the potential interactions between Cit-AuNPs and target molecules have always been ignored, which may result in wrong analytical results due to shortcomings in the Cit-AuNPs. To overcome these shortfalls, in this work, AuNPs were synthesized using tyrosine as a reducing and capping agent, and a robust colorimetric aptasensor based on tyrosine-capped AuNPs (Tyr-AuNPs) was constructed for the label-free detection of marine toxins. Tyr-AuNPs presented better stability compared to Cit-AuNPs due to the stronger binding of amine groups on tyrosine to AuNPs through the Au-N bond. Interactions between Tyr-AuNPs and PbTx-2 were analyzed through UV-vis and isothermal titration calorimetry methods and the results validated the robustness of the Tyr-AuNPs. Colorimetric aptasensors were established for PbTx-2 and OA detection with a linear range of 0.05-4 ppm and limits of detection of 2.25 ppb and 5.19 ppb, respectively. These results demonstrate that the developed colorimetric aptasensor can be a robust and promising method for marine toxin detection.