Highly sensitive fluorescence sensing of zearalenone using a novel aptasensor based on upconverting nanoparticles

Electrochemical determination of zearalenone using a label-free competitive aptasensor

An electrochemical aptasensor is described for determination of the phytohormone of zearalenone (ZEA). The gold electrode was modified with ZEA via covalent attachment using cysteamine-hydrochloride and 1,4-phenylene diisocyanate linker. A truncated ZEA aptamer with a dissociation constant of 13.4 ± 2.1 nM was used in an aptasensor. The electrochemical property was investigated using square wave voltammetry for monitoring the change in the electron transfer using the ferro/ferricyanide system as redox probe. Under optimal experimental conditions, the response was best measured at a potential of 0.20 V (vs. Ag/AgCl). The signals depended on the competitive mechanism between the immobilised ZEA and free ZEA for the aptamer binding site. The aptasensor works in the range 0.01 to 1000 ng·mL^-1 ZEA concentration, with a detection limit of 0.017 ng·mL^-1. High degree of cross-reactivity with the other analogues of ZEA was observed, whereas none towards other mycotoxins. The aptasensor was further applied for the determination of ZEA in the extract of maize grain and showed good recovery percentages between 87 and 110%. Graphical abstract Schematic representation of the electrochemical determination of zearalenone based on indirect competitive assay. Step a Immobilisation of ZEA on the surface of gold electrode via covalent attachment, b competition for the ZEA aptamer binding site between immobilised and free ZEA, and c current signal of the binding event based on SWV technique.

Quantification of zearalenone in mildewing cereal crops using an innovative photoelectrochemical aptamer sensing strategy based on ZnO-NGQDs composites

Zearalenone (ZEN) is highly toxic to humans, and therefore, development of sensitive and effective methods for ZEN quantification in cereal crops is particularly important. Here, an innovative photoelectrochemical (PEC) aptasensor based on simply in-situ conjugated composites of zinc oxide-nitrogen doped graphene quantum dots (ZnO-NGQDs) was constructed. On addition of NGQDs, the composites displayed higher PEC signal with 8.8-fold enhancement than pure ZnO nanoparticles. A sensitive and selective PEC aptasensor was fabricated by combining the composites with ZEN aptamer, which yielded an excellent analytical performance for ZEN detection, with a wide linear range of 1.0 × 10^-13-1.0 × 10^-7 g mL^-1 and a low detection limit of 3.3 × 10^-14 g mL^-1. Good recoveries were obtained using the PEC aptasensor, which were consistent with those obtained using the national standard method (HPLC-MS). Finally, ZEN in mildewing cereal crops was monitored with the PEC aptasensor, exhibiting good potential for application in cereal crops for early diagnosis.

A fluorometric method for aptamer-based simultaneous determination of two kinds of the fusarium mycotoxins zearalenone and fumonisin B1 making use of gold nanorods and upconversion nanoparticles

An aptamer-based assay for the determination of two different kinds of fusarium mycotoxins, i.e., zearalenone (ZEN) and fumonisin B₁ (FB₁), is presented. Based on the inner filter effect (IFE) strategy, the contents of ZEN and FB₁ can be simultaneously quantified. It is making use of 65-nm gold nanorods (AuNRs), 20-nm upconversion nanoparticles (UCNPs), fluorescence dyes, and DNA sequences. In the absence of ZEN and FB₁, the UCNPs and AuNRs associate through DNA sequences. Due to IFE effect, weak fluorescence signals are collected. In the presence of ZEN or FB₁, UCNPs and AuNRs become unstable and partially separate from each other. This results in the recovery of fluorescence signals. Under 980-nm laser excitation, the logarithmic values of fluorescence signal intensities at 606 nm and 753 nm gradually increase with the concentration of ZEN and FB₁ in the ranges 0.05-100 μg L^-1 (the coefficient of determination is 0.997) and 0.01-100 ng L^-1 (the coefficient of determination is 0.986), respectively. The limits of detection (LOD) of the fabricated assay for ZEN and FB1 are 0.01 μg L^-1 and 0.003 ng L^-1, respectively. The proposed method has a high selectivity over other competitive mycotoxins, including aflatoxin B1, ochratoxin A, patulin and ochratoxin B. The applicability of the assay was evaluated in the determination of ZEN and FB1 contents in spiked corn samples. The average recoveries ranged from 89.9 to 106.6%. This result confirms the practicality of this method. Graphical abstract Schematic representation of an aptamer-based fluorometric method for simultaneous determination of two kinds of the fusarium mycotoxins zearalenone and fumonisin B₁.

Detection of zearalenone in an aptamer assay using attenuated internal reflection ellipsometry and it's cereal sample applications

Mycotoxins are toxic compounds produced by the metabolism of certain fungi that threaten the food and agricultural industry. Over hundreds of mycotoxins, one of the most common toxins, zearalenone (ZEN), has toxic effects on human and animal health due to its mutagenicity, treatogenicity, carcinogenicity, nephrotoxicity, immunotoxicity, and genotoxicity. In this work, attenuated internal reflection spectroscopic ellipsometry (AIR-SE) combined with the signal amplification via surface plasmon resonance conditions that were proved to be a highly sensitive analytical tool in bio-sensing was developed for the sensitive and selective ZEN detection in cereal products such as corn, wheat, rice, and oat. Combined with the oligonucleotide aptamer for ZEN recognition, our proposed method showed good performance with yielding 0.08 ng/mL LOD and 0.01-1000 ng/mL detection range. A mini-review was also introduced in, to compare various methods for ZEN detection.

A review on recent developments in optical and electrochemical aptamer-based assays for mycotoxins using advanced nanomaterials

This review (with 163 refs) covers the recent developments of nanomaterial-based optical and electrochemical sensors for mycotoxins. The review starts with a brief discussion on occurrence, distribution, toxicity of mycotoxins and the legislations in monitoring their levels. It further outlines the research methods, various recognition matrices and the strategies involved in the development of highly sensitive and selective sensor systems. It also points out the salient features and importance of aptasensors in the detection of mycotoxins along with the different immobilization methods of aptamers. The review meticulously discusses the performance of different optical and electrochemical sensors fabricated using aptamers coupled with nanomaterials (CNT, graphene, metal nanoparticles and metal oxide nanoparticles). The review addresses the limitations in the current developments as well as the future challenges involved in the successful construction of aptasensors with the functionalized nanomaterials. Graphical abstract Recent developments in nanomaterial based aptasensors for mycotoxins are summarized. Specifically, the efficiency of the nanomaterial coupled aptasensors (such as CNT, graphene, metal nanoparticles and metal oxide nanoparticles) in optical and electrochemical methods are discussed.

Optical-Based (Bio) Sensing Systems Using Magnetic Nanoparticles

In recent years, various reports related to sensing application research have suggested that combining the synergistic impacts of optical, electrical or magnetic properties in a single technique can lead to a new multitasking platform. Owing to their unique features of the magnetic moment, biocompatibility, ease of surface modification, chemical stability, high surface area, high mass transference, magnetic nanoparticles have found a wide range of applications in various fields, especially in sensing systems. The present review is comprehensive information about magnetic nanoparticles utilized in the optical sensing platform, broadly categorized into four types: surface plasmon resonance (SPR), surface-enhanced Raman spectroscopy (SERS), fluorescence spectroscopy and near-infrared spectroscopy and imaging (NIRS) that are commonly used in various (bio) analytical applications. The review also includes some conclusions on the state of the art in this field and future aspects.

Electrochemiluminescent competitive immunoassay for zearalenone based on the use of a mimotope peptide, Ru(II)(bpy)3-loaded NiFe2O4 nanotubes and TiO2 mesocrystals

An ultrasensitive competitive-type electrochemiluminescence immunoassay for the mycotoxin zearalenone is described. The method is based on the use of (a) a mimotope peptide that was selected from a phage displayed peptide library and used to substitute ZEN for designing the competitive assay; (b) NiFe₂O₄ nanotubes with large specific surface area loaded with the ECL probe Ru(bpy)₃²⁺; and (c) poly(vinylpyrrolidone) (PVP)-assisted synthesis of TiO₂ mesocrystals that acts as the sensing platform and support for antibody immobilization. Under the optimized conditions and at an ECL working potential of 1.1 V, a linear response is found for ZEN in the 0.1 to 1.0 × 10^-5 ng·mL^-1 concentration range with a detection limit as low as 3.3 fg·mL^-1. Graphical abstract An ultrasensitive competitive-type electrochemiluminescence (ECL) immunosensor based on mimotope peptide was constructed for the detection of Zearalenone.

A "turnon" aptasensor for simultaneous and time-resolved fluorometric determination of zearalenone, trichothecenes A and aflatoxin B1 using WS2 as a quencher

A "turn on" time-resolved fluorometric aptasensor is described for the simultaneous detection of zearalenone (ZEN), trichothecenes A (T-2), and aflatoxin B₁ (AFB₁). Multicolor-emissive nanoparticles doped with lanthanide ions (Dy³⁺, Tb³⁺, Eu³⁺) were functionalized with respective aptamers and applied as a bioprobe, and tungsten disulfide (WS₂) nanosheets are used as a quencher of time-resolved fluorescence. The assay exploits the quenching efficiency of WS₂ and the interactions between WS₂ and the respective DNA aptamers. The simultaneous recognition of the three mycotoxins can be performed in a single solution. In the absence of targets, WS₂ is easily adsorbed by the mixed bioprobes via van der Waals forces between nucleobases and the WS₂ basal plane. This brings the bioprobe and WS₂ into close proximity and results in quenched fluorescence. In the presence of targets, the fluorescence of the bioprobes is restored because the analytes react with DNA probe and modify their molecular conformation to weaken the interaction between the DNAs and WS₂. Under the optimum conditions and at an excitation wavelength of 273 nm, the time-resolved fluorescence intensities (peaking at 488, 544 and 618 nm and corresponding to emissions of Dy³⁺, Tb³⁺ and Eu³⁺) were used to quantify ZEN, T-2 and AFB₁, respectively, with detection limits of 0.51, 0.33 and 0.40 pg mL^-1 and a linear range from 0.001 to 100 ng mL^-1. The three mycotoxins can be detected simultaneously without mutual interference. The assay was applied to the quantification of ZEN, T-2 and AFB₁ in (spiked) maize samples. This homogeneous aptamer based assay can be performed within 1 h. Conceivably, it can become an alternative to other heterogeneous methods such as the respective enzyme-linked immunosorbent assays. Graphical abstract Schematic presentation of an aptasensor for simultaneous detection of zearalenone, trichothecenes A and aflatoxin B₁ using aptamer modified time-resolved fluorescence nanoparticles as signalling probes and tungsten disulfide as the quencher. This assay shows lower detection limit and requires no washing steps.

Monitoring zearalenone in corn flour utilizing novel self-enhanced electrochemiluminescence aptasensor based on NGQDs-NH2-Ru@SiO2 luminophore

Accurate and early diagnosis of mycotoxin is particularly significant to the food and agricultural product safety. In the present work, a sensitive and effective monitoring method for zearalenone (ZEN) was exploited based on a novel self-enhanced electrochemiluminescence (ECL) aptasensor. The self-enhanced lumonophore was compounded by electrostatically combining amine-functionalized Ru(bpy)₃²⁺-doped silica nanoparticles (NH₂-Ru@SiO₂ NPs) and nitrogen doped graphene quantum dots (NGQDs) together. Since the emitter and co-reactant simultaneously existed in the same nanoparticle, shortened electron-transfer distance and decreased energy loss was obtained. Therefore, self-enhanced ECL aptasensor based on the novel complex expressed the widest linear range of 10 fg mL^-1-10 ng mL^-1 and the lowest detection limit of 1 fg mL^-1 for ZEN detection. More importantly, ZEN produced during the mildew process of corn flour was monitored by the developed aptasensor, which exhibited superior determination and potential application in real samples.

Fabrication of methyl acrylate and tetraethylenepentamine grafted magnetic chitosan microparticles for capture of Cd(II) from aqueous solutions

MCS-MA-TEPA microparticles, with 251.22 mg g^-1 of adsorption capacity for Cd(II), higher than most of the counterparts, were first fabricated by chemical coprecipitation, spray drying, and Michael addition reaction, without any cross-linker participation. These Fe₃O₄-nanoparticle-embedded microparticles of 5.95 μm in size, derived from modifications by methyl acrylate (MA) and tetraethylenepentamine (TEPA) on magnetic chitosan (MCS) microparticles, were of plum-pudding-like and wrinkle-like topography portrayed by TEM and SEM. Such features were beneficial to adsorbent recycling and Cd(II) capture. BET examinations illustrated 6.084 m² g^-1 of specific surface area, 0.015 mL g^-1 of pore volume, and 6.536 nm of pore diameter. FTIR, VSM, XRD, TEM-SAED, TG, and DTG characterizations were indicative of successful synthesis, satisfactory magnetism, well-defined architecture, and good thermostability. Optimal adsorption parameters for Cd(II) were determined via batch experiments. Thermodynamic parameters and adsorption data fitting implied an exothermic, spontaneous, monolayer, and chemisorption process. XPS analyses confirmed a potential adsorption mechanism that N and O atoms on microparticles chelated with Cd(II) ions in solutions. Additionally, MCS-MA-TEPA-Cd(II) microparticles were magnetically separated easily and had outstanding reusability even after five-time recycling, with a slight adsorption capability loss (< 12%). Altogether, MCS-MA-TEPA microparticles might serve as a promising adsorbent for contaminated water scavenging.

Quantitative assessment of zearalenone in maize using multivariate algorithms coupled to Raman spectroscopy

Zearalenone is a contaminant in food and feed products which are hazardous to humans and animals. This study explored the feasibility of the Raman rapid screening technique for zearalenone in contaminated maize. For representative Raman spectra acquisition, the ground maize samples were collected by extended sample area to avoid the adverse effect of heterogeneous component. Regression models were built with partial least squares (PLS) and compared with those built with other variable selection algorithms such as synergy interval PLS (siPLS), ant colony optimization PLS (ACO-PLS) and siPLS-ACO. SiPLS-ACO algorithm was superior to others in terms of predictive power performance for zearalenone analysis. The best model based on siPLS-ACO achieved coefficients of correlation (R_p) of 0.9260 and RMSEP of 87.9132 μg/kg in the prediction set, respectively. Raman spectroscopy combined multivariate calibration showed promising results for the rapid screening large numbers of zearalenone maize contaminations in bulk quantities without sample-extraction steps.

A novel coumarin-based fluorescent probe for sensitive detection of copper(II) in wine

A novel coumarin-based fluorescent probe (probe 1) for the detection of copper(II) was developed. The fluorescence intensity of probe 1 showed a linear relationship with the concentration of copper(II) in the range 0-16 μM (0-1.02 mg/L) and the limit of detection was 62 nM (3.94 µg/L). The luminescence of probe 1 at the maximum allowable amounts of copper(II) in wine and water could be observed with the naked eye under a 365-nm ultraviolet lamp. Moreover, probe 1 was successfully used for the qualitative and quantitative detection of copper(II) in wine.

Enzyme-free amplified and ultrafast detection of aflatoxin B1 using dual-terminal proximity aptamer probes

Aptamer probes provide an opportunity for achieving rapid and on-site detection of food contaminants. Herein, we proposed a general design strategy for aptamer probes enabling enzyme-free amplified, ultrafast and one-test tube homogeneous detection of aflatoxin B₁ (AFB₁). The key feature of the aptamer probe is designed with dual-terminal proximity structures, allowing the binding of one molecule to light up two fluorophores, leading to enzyme-free amplification and a remarkable improvement of signal to background ratio and sensitivity for AFB₁ detection. This aptamer probe could accommodate quick response to AFB₁, and the detection process could be finished within 1 min, ranking one of the quickest assays for AFB₁. AFB₁ detection of broad bean paste and peanut oil conferred satisfactory recoveries ranging from 90.3% to 114.8%. Contributed to the generality and simplicity of the design strategy, this structure-switching probe could potentially act as a general platform of on-site detection for food safety.

A mimotope peptide-based dual-signal readout competitive enzyme-linked immunoassay for non-toxic detection of zearalenone

In this study, a mimotope peptide-based non-toxic photoelectrochemical (PEC) competitive enzyme-linked immunoassay (ELISA) was established for ultrasensitive detection of zearalenone (ZEN) with dual-signal readout.

Selection of a DNA Aptamer against Zearalenone and Docking Analysis for Highly Sensitive Rapid Visual Detection with Label-Free Aptasensor

Contamination of feed with zearalenone (ZEN) presents a significant risk to animal health. Here, a visible, rapid, and cost-effective aptamer-based method is described for the detection of ZEN. After 8 rounds of SELEX (systematic evolution of ligands by exponential enrichment) with an affinity-based monitor and counter-screening process, the ssDNA aptamer Z100 was obtained, which had high affinity (dissociation constant = 15.2 ± 3.4 nM) and good specificity. Docking analysis of Z100 indicated that noncovalent bonds (π-π interactions, hydrogen bonds, and hydrophobic interactions) helped ZEN to anchor in the binding sites. Finally, a label-free detection method based on gold nanoparticles and Z100 at 0.25 μM was developed for ZEN determination. Excellent linearity was achieved, and the lowest detection limit was 12.5 nM. This rapid and simple method for ZEN analysis has high sensitivity and can be applied for on-site detection of ZEN in animal feeds.

A novel SERS-based aptasensor for ultrasensitive sensing of microcystin-LR

We developed a novel aptasensor based on surface enhanced Raman spectroscopy (SERS) and applied it for highly sensitive detection of microcystin-LR (MC-LR). In this work, MC-LR aptamer and its corresponding complementary DNA fragments (cDNA) were conjugated to gold nanoparticles (AuNPs) and magnetic nanoparticles (MNPs), respectively. Then, MC-LR aptamer-AuNPs and cDNA-MNPs conjugates were used as signal probes and capture probes, respectively. The proposed assay exhibited a linearity range from 0.01 to 200 ng/mL with the limit of detection (LOD) of 0.002 ng/mL. In addition, the reliability of the novel approach was validated by detecting different levels of MC-LR spiked in tap water samples. Overall, the novel aptasensor paves a new way for rapid and accurate determination of MC-LR and can be referred to detect other hazardous substances in water products.

Colorimetric zearalenone assay based on the use of an aptamer and of gold nanoparticles with peroxidase-like activity

An aptamer based colorimetric assay is described for the determination of zearalenone (ZEN). It is based on the inhibition of the peroxidase-mimicking activity of gold nanoparticles (AuNPs) by the ZEN aptamer. However, in the presence of ZEN, the aptamer is bound by ZEN and can no longer inhibit the peroxidase-mimicking activity of AuNPs. The color change of solution is related to ZEN concentration and observed with bare eyes. Under optimal conditions, the absorbance (at 630 nm) increases linearly in the ZEN concentration range of 10-250 ng·mL^-1, and the limit of detection is 10 ng·mL^-1. The specificity of the assay was verified by studying the effect of potential interferents. The recoveries from ZEN spiked corn and corn oil range from 92 to 110%, and the relative standard deviations are between 2.4 and 6.4%. The results are in good agreement with those obtained by an ELISA. Graphical abstract Schematic presentation of colorimetric assay for rapid and sensitive determination of zearalenone (ZEN) based on the inhibition of ZEN aptamer on the the peroxidase-like activity of gold nanoparticle (AuNPs).

Lanthanide Doped Near Infrared Active Upconversion Nanophosphors: Fundamental Concepts, Synthesis Strategies, and Technological Applications

Near infrared (NIR) light utilization in a range of current technologies has gained huge significance due to its abundance in nature and nondestructive properties. NIR active lanthanide (Ln) doped upconversion nanomaterials synthesized in controlled shape, size, and surface functionality can be combined with various pertinent materials for extensive applications in diverse fields. Upconversion nanophosphors (UCNP) possess unique abilities, such as deep tissue penetration, enhanced photostability, low toxicity, sharp emission peaks, long anti-Stokes shift, etc., which have bestowed them with prodigious advantages over other conventional luminescent materials. As new generation fluorophores, UCNP have found a wide range of applications in various fields. In this Review, a comprehensive overview of lanthanide doped NIR active UCNP is provided by discussing the fundamental concepts including the different mechanisms proposed for explaining the upconversion processes, followed by the different strategies employed for the synthesis of these materials, and finally the technological applications of UCNP, mainly in the fields of bioimaging, drug delivery, sensing, and photocatalysis by highlighting the recent works in these areas. In addition, a brief note on the applications of UCNP in other fields is also provided along with the summary and future perspectives of these materials.

A smartphone-based quantitative detection platform of mycotoxins based on multiple-color upconversion nanoparticles

The detection of mycotoxins in food is urgently needed because they pose a significant threat to public health. In this study, we developed a quantitative detection platform for mycotoxins by integrating multicolor upconversion nanoparticle barcode technology with fluorescence image processing using a smartphone-based portable device. The multi-colored upconversion nanoparticle encoded microspheres (UCNMs) were used as encoded signals for detecting different mycotoxins simultaneously. After indirect competitive immunoassays using UCNMs, images could be captured by the portable device and the camera of a smartphone. Then, a self-written Android application, which is an HSV-based image recognition program installed on a smartphone, analyzed images and offered a reliable and accurate result in less than 1 min. The quantitative detection platform of mycotoxins proved to be feasible and reliable, and the limit of detection (LOD) was 1 ng, which was lower than that obtained from standard assays. This study demonstrates a method for detecting mycotoxins in food and other point of care analysis.

Rapid and sensitive double-label based immunochromatographic assay for zearalenone detection in cereals

A double-label immunochromatographic based assay (DL-ICA) was developed to monitor zearalenone (ZEN) levels in cereals, based on Eu3+ nanoparticles (EuNP). The DL-ICA exhibited excellent sensitivity, reliability and selectivity in real samples. It showed low limits of detection (0.21-0.25 μg/kg) and broad analytical ranges (up to 120 μg/kg). The total analytical time, including sample preparation and DL-ICA execution, was reduced by 15 min compared with HPLC. The recovery rates ranged from 95.0-118.4%, with relative standard deviations (RSD) <11.6%. Inter- and intra-day validations were assessed, recovery rates of 89.3-106.9% and RSD of 2.3-9.7% were obtained, suggesting considerable stability and reliability for the assay. An excellent correlation was observed between DL-ICA and a reference HPLC method (R2 = 0.9899). Compared to current immunoassays, the current DL-ICA is inexpensive, highly sensitive, and rapid. Therefore, DL-ICA constitutes a novel tool for monitoring mycotoxins in food and feed to ensure safety.

A novel bioassay based on aptamer-functionalized magnetic nanoparticle for the detection of zearalenone using time resolved-fluorescence NaYF4: Ce/Tb nanoparticles as signal probe

Zearalenone (ZEN) is a non-steroidal estrogenic mycotoxin produced by fungi on stored grains. The earlier detection methods used for ZEN rely on expensive equipment, time-consuming sample preparation and temperature sensitive antibodies. The current work, proposed a novel strategy based on ZEN aptamer labeled with amine-functionalized magnetic nanoparticle (MNPs) as a capture probe and time-resolved fluorescence (TRFL) nanoparticles labeled with complementary DNA (cDNA) as a signal probe. Under the optimized conditions, TRFL intensity at 544 nm was used to measure ZEN (R² = 0.9920) in the range of 0.001-10 ng mL^-1 and limits of detection (LOD) for proposed method was 0.21 pg mL^-1. The specificity of bioassay was also determined by using other mycotoxins (OTA, AFB₂, DON and Patulin) and results showed that the aptamer are specific to recognize only ZEN. The analytical applications of the present bioassay in maize and wheat samples were also examined and results were compared with existing methods. Based on these findings, it is suggested to use current rapid and simple bioassay for the determination of ZEN in food and agricultural products.

Developments in mycotoxin analysis: an update for 2016-2017

This review summarises developments in the determination of mycotoxins over a period between mid-2016 and mid-2017. Analytical methods to determine aflatoxins, Alternaria toxins, ergot alkaloids, fumonisins, ochratoxins, patulin, trichothecenes and zearalenone are covered in individual sections. Advances in proper sampling strategies are discussed in a dedicated section, as are methods used to analyse botanicals and spices and newly developed LC-MS based multi-mycotoxin methods. This critical review aims to briefly discuss the most important recent developments and trends in mycotoxin determination as well as to address limitations of the presented methodologies.

An ultrasensitive aptasensor based on fluorescent resonant energy transfer and exonuclease-assisted target recycling for patulin detection

Patulin (PAT) is a type of mycotoxin which can compromise both food quality and human health. Due to its harmful effects, strict monitoring of PAT contents in food systems is necessary. A novel kind of bioassay was proposed for determining PAT based on the fluorescent resonant energy transfer (FRET) strategy. The exonuclease-catalyzed target recycling strategy was employed to improve the sensitivity of the FRET system. The results showed that the linear range extends from 0.01 ng/mL to 100 ng/mL. Furthermore, the average recoveries ranged from 93.33% to 105.21%, confirming the reliability of this method. The total analysis time for our assay developed is about 50 min. Compared to traditional analytical methods, the developed assay is more stable and has a significantly lower detection of limit (0.003 ng/mL). We believe the approach developed in this study would be useful for high-throughput screening of PAT in food industry and government laboratory.

Homogeneous electrochemical aptasensor based on a dual amplification strategy for sensitive detection of profenofos residues

A homogeneous type of electrochemical aptasensor was designed based upon the principle of target-induced and tool enzyme-assisted signal amplification, which was employed for the detection of profenofos residues.

Nano-Aptasensing in Mycotoxin Analysis: Recent Updates and Progress

Recent years have witnessed an overwhelming integration of nanomaterials in the fabrication of biosensors. Nanomaterials have been incorporated with the objective to achieve better analytical figures of merit in terms of limit of detection, linear range, assays stability, low production cost, etc. Nanomaterials can act as immobilization support, signal amplifier, mediator and artificial enzyme label in the construction of aptasensors. We aim in this work to review the recent progress in mycotoxin analysis. This review emphasizes on the function of the different nanomaterials in aptasensors architecture. We subsequently relate their features to the analytical performance of the given aptasensor towards mycotoxins monitoring. In the same context, a critically analysis and level of success for each nano-aptasensing design will be discussed. Finally, current challenges in nano-aptasensing design for mycotoxin analysis will be highlighted.

Bimodal counterpropagating-responsive sensing material for the detection of histamine

A dual-mode system for simultaneous fluorescence and SERS sensing of histamine.

How to make nanobiosensors: surface modification and characterisation of nanomaterials for biosensing applications

This report aims to provide the audience with a guideline for construction and characterisation of nanobiosensors that are based on widely used affinity probes including antibodies and aptamers.