Development of a biomimetic enzyme-linked immunosorbent assay method for the determination of estrone in environmental water using novel molecularly imprinted films of controlled thickness as artificial antibodies

A comprehensive review of mycotoxins: Toxicology, detection, and effective mitigation approaches

Mycotoxins, harmful compounds produced by fungal pathogens, pose a severe threat to food safety and consumer health. Some commonly produced mycotoxins such as aflatoxins, ochratoxin A, fumonisins, trichothecenes, zearalenone, and patulin have serious health implications in humans and animals. Mycotoxin contamination is particularly concerning in regions heavily reliant on staple foods like grains, cereals, and nuts. Preventing mycotoxin contamination is crucial for a sustainable food supply. Chromatographic methods like thin layer chromatography (TLC), gas chromatography (GC), high-performance liquid chromatography (HPLC), and liquid chromatography coupled with a mass spectrometer (LC/MS), are commonly used to detect mycotoxins; however, there is a need for on-site, rapid, and cost-effective detection methods. Currently, enzyme-linked immunosorbent assays (ELISA), lateral flow assays (LFAs), and biosensors are becoming popular analytical tools for rapid detection. Meanwhile, preventing mycotoxin contamination is crucial for food safety and a sustainable food supply. Physical, chemical, and biological approaches have been used to inhibit fungal growth and mycotoxin production. However, new strains resistant to conventional methods have led to the exploration of novel strategies like cold atmospheric plasma (CAP) technology, polyphenols and flavonoids, magnetic materials and nanoparticles, and natural essential oils (NEOs). This paper reviews recent scientific research on mycotoxin toxicity, explores advancements in detecting mycotoxins in various foods, and evaluates the effectiveness of innovative mitigation strategies for controlling and detoxifying mycotoxins.

Recent Progress in Rapid Determination of Mycotoxins Based on Emerging Biorecognition Molecules: A Review

Mycotoxins are secondary metabolites produced by fungal species, which pose significant risk to humans and livestock. The mycotoxins which are produced from Aspergillus, Penicillium, and Fusarium are considered most important and therefore regulated in food- and feedstuffs. Analyses are predominantly performed by official laboratory methods in centralized labs by expert technicians. There is an urgent demand for new low-cost, easy-to-use, and portable analytical devices for rapid on-site determination. Most significant advances were realized in the field bioanalytical techniques based on molecular recognition. This review aims to discuss recent progress in the generation of native biomolecules and new bioinspired materials towards mycotoxins for the development of reliable bioreceptor-based analytical methods. After brief presentation of basic knowledge regarding characteristics of most important mycotoxins, the generation, benefits, and limitations of present and emerging biorecognition molecules, such as polyclonal (pAb), monoclonal (mAb), recombinant antibodies (rAb), aptamers, short peptides, and molecularly imprinted polymers (MIPs), are discussed. Hereinafter, the use of binders in different areas of application, including sample preparation, microplate- and tube-based assays, lateral flow devices, and biosensors, is highlighted. Special focus, on a global scale, is placed on commercial availability of single receptor molecules, test-kits, and biosensor platforms using multiplexed bead-based suspension assays and planar biochip arrays. Future outlook is given with special emphasis on new challenges, such as increasing use of rAb based on synthetic and naïve antibody libraries to renounce animal immunization, multiple-analyte test-kits and high-throughput multiplexing, and determination of masked mycotoxins, including stereoisomeric degradation products.

A biomimetic enzyme-linked immunosorbent assay (BELISA) for the analysis of gonadorelin by using molecularly imprinted polymer-coated microplates

An original biomimetic enzyme-linked immunoassay (BELISA) to target the small peptide hormone gonadorelin is presented. This peptide has been recently listed among the substances banned in sports by the World Antidoping Agency (WADA) since its misuse by male athletes triggers testosterone increase. Hence, in response to this emerging issue in anti-doping controls, we proposed BELISA which involves the growth of a polynorepinephrine (PNE)–based molecularly imprinted polymer (MIP) directly on microwells. PNE, a polydopamine (PDA) analog, has recently displayed impressive performances when it was exploited for MIP preparation, giving even better results than PDA. Gonadorelin quantification was accomplished via a colorimetric indirect competitive bioassay involving the competition between biotinylated gonadorelin linked to the signal reporter and the unlabeled analyte. These compete for the same MIP binding sites resulting in an inverse correlation between gonadorelin concentration and the output color signal (λ = 450 nm). A detection limit of 277 pmol L⁻¹ was achieved with very good reproducibility in standard solutions (_avCV% = 4.07%) and in urine samples (_avCV% = 5.24%). The selectivity of the assay resulted adequate for biological specimens and non-specific control peptides. In addition, the analytical figures of merit were successfully validated by mass spectrometry, the reference anti-doping benchtop platform for the analyte. BELISA was aimed to open real perspectives for PNE-based MIPs as alternatives to antibodies, especially when the target analyte is a poorly or non-immunogenic small molecule, such as gonadorelin.

Monitoring pharmaceuticals in the aquatic environment using enzyme-linked immunosorbent assay (ELISA)-a practical overview

The presence of pharmaceuticals, which are considered as contaminants of emerging concern, in natural waters is currently recognized as a widespread problem. Monitoring these contaminants in the environment has been an important field of research since their presence can affect the ecosystems even at very low levels. Several analytical techniques have been developed to detect and quantify trace concentrations of these contaminants in the aquatic environment, namely high-performance liquid chromatography, gas chromatography, and capillary electrophoresis, usually coupled to different types of detectors, which need to be complemented with time-consuming and costly sample cleaning and pre-concentration procedures. Generally, the enzyme-linked immunosorbent assay (ELISA), as other immunoassay methodologies, is mostly used in biological samples (most frequently urine and blood). However, during the last years, the number of studies referring the use of ELISA for the analysis of pharmaceuticals in complex environmental samples has been growing. Therefore, this work aims to present an overview of the application of ELISA for screening and quantification of pharmaceuticals in the aquatic environment, namely in water samples and biological tissues. The experimental procedures together with the main advantages and limitations of the assay are addressed, as well as new incomes related with the application of molecular imprinted polymers to mimic antibodies in similar, but alternative, approaches. Graphical Abstract.

Development of fluorescent lateral flow test strips based on an electrospun molecularly imprinted membrane for detection of triazophos residues in tap water

Herein, a molecularly imprinted membrane chromatography strip using a combination of electrospinning, molecular imprinting, and fluorescent lateral flow test strips (LFTS) was developed for specific recognition of triazophos residues in tap water.

Doping of transition metal dichalcogenides in molecularly imprinted conductive polymers for the ultrasensitive determination of 17β-estradiol in eel serum

Molecularly imprinted polymers (MIPs) have been developed to replace antibodies for the recognition of target molecules (such as antigens), and have been integrated into electrochemical sensing approaches by polymerization onto an electrode. Electrochemical sensing is inexpensive and flexible, and has demonstrated utility in point-of-care devices. In this work, several 2D (conductive) materials were employed to improve the performance of MIP sensors. Screen-printed electrodes were coated by the electropolymerization of aniline and metanilic acid, commingled with target molecules and various 2D materials. Tungsten disulfide (WS₂) with an average particle size of 2 μm was found to increase the sensitivity of detection of molecularly imprinted conductive polymer-coated electrodes to 17β-estradiol. As estradiol concentrations are important to eel aquaculture, we screened eel serum samples to determine their 17β-estradiol concentrations, which were found to be in the range 28.2 ± 3.6 to 73.0 ± 11.6 pg/mL after dilution. These results were in agreement with measurements using commercial immunoanalysis.

Integrating ionic liquids with molecular imprinting technology for biorecognition and biosensing: A review

As promising alternatives to natural receptors, artificial molecularly imprinted polymers (MIPs) have received great attention in biotechnology. Nevertheless, some bottlenecks limit their further development, including low adsorption capacity, poor recognition efficiency, slow response, and insipid aqueous compatibility. Ionic liquids (ILs) show the features of tailored structures and properties, high conductivity, good solubility, and excellent stability. Because of these advantages, they have found intensive use in MIPs by remedying the latter's shortcomings. In this review, we summarize the integration of ILs and MIPs for biorecognition and biosensing. The versatile roles of ILs in improving the performance of MIPs are firstly summarized, including serving as solvents, porogens, functional monomers, organic surface modifiers, dummy templates, and cross-linkers. Then, specific applications of IL-based MIPs in peptide recognition, protein sensing, and food safety analysis are discussed. Finally, future trends and challenges for the design and development of IL-based MIPs and their applications in the biorecognition and biosensing are proposed.

Advancements of molecularly imprinted polymers in the food safety field

Molecularly imprinted technology (MIT) has been widely employed to produce stable, robust and cheap molecularly imprinted polymer (MIP) materials that possess selective binding sites for recognition of target analytes in food, such as pesticides, veterinary drugs, mycotoxins, illegal drugs and so on. Because of high selectivity and specificity, MIPs have drawn great attention in the food safety field. In this review, the recent developments of MIPs in various applications for food safety, including sample preparation, chromatographic separation, sensing, immunoassay etc., have been summarized. We particularly discuss the advancements and limitations in these applications, as well as attempts carried out for their improvement.

Probing and Quantifying the Food-Borne Pathogens and Toxins: From In Vitro to In Vivo

Development of real-time and in situ analytical methods for determination of food-borne pathogens and toxins ingested into the human body would be a promising research direction in the food-safety area. The present perspective starts with summarization of the up-to-date progress of the nanomaterial-assisted in vitro detection methods for pathogens and toxins and finally focuses on application of animal bioimaging to in vivo study, including prospective strategies for in vivo quantification of target pathogens or toxins and in vivo investigation of their behaviors inside the living body, with the assistance of real-time and non-invasive optical bioimaging. This perspective provides the advisory direction for food-safety research, from in vitro to in vivo, along with a prospective discussion of the further development roadmap of the food-safety detection techniques, especially the bioimaging-guided methods for investigation and mediation of the food contamination effect to human health.

Biomimetic enzyme-linked immunoassay based on a molecularly imprinted 96-well plate for the determination of triazophos residues in real samples

In this study, a direct competitive biomimetic enzyme-linked immune-sorbent assay (BELISA) based on a molecularly imprinted nanomembrane as an artificial antibody was developed for the determination of triazophos in real samples. The imprinted film was directly synthesized on the well surface of a 96-well plate using a dummy molecular template under the conditions of thermal polymerization. The developed BELISA using a hapten of triazophos as an enzyme-labeled probe is much more sensitive, simple, quick, steady and inexpensive than the other instrumental and immuno assay methods. Under optimal conditions, the linear range of the method was 0.001–10 000 μg L⁻¹ with a good regression coefficient of 0.977. The sensitivity (IC₅₀) and the limit of detection (LOD) of BELISA were 428 μg L⁻¹ and 0.001 μg L⁻¹, respectively. This method was performed to detect triazophos in cabbage and apple samples, and showed excellent recovery and relative standard deviations (RSDs) ranging from 70.5 to 119.8% and from 5.2 to 19.7%, respectively. The results correlated well with those obtained using high performance liquid chromatography-tandem mass spectrometry.

In this study, a direct competitive biomimetic enzyme-linked immune-sorbent assay (BELISA) based on a molecularly imprinted nanomembrane as an artificial antibody was developed for the determination of triazophos in real samples.

Analytical applications of MIPs in diagnostic assays: future perspectives

Many efforts have been made to produce artificial materials with biomimetic properties for applications in binding assays. Among these efforts, the technique of molecular imprinting has received much attention because of the high selectivity obtainable for molecules of interest, robustness of the produced polymers, simple and short synthesis, and excellent cost efficiency. In this review, progress in the field of molecularly imprinted sorbent assays is discussed-with a focus on work conducted from 2005 to date.

Does size matter? Study of performance of pseudo-ELISAs based on molecularly imprinted polymer nanoparticles prepared for analytes of different sizes

Here we evaluate whether the size of the template used to produce molecularly imprinted nanoparticles can affect their performance in pseudo-ELISAs.

Molecularly imprinted polymeric micro- and nano-particles for the targeted delivery of active molecules

Molecular imprinting (MI) represents a strategy to introduce a 'molecular memory' in a polymeric system obtaining materials with specific recognition properties. MI particles can be used as drug delivery systems providing a targeted release and thus reducing the side effects. The introduction of molecular recognition properties on a polymeric drug carrier represents a challenge in the development of targeted delivery systems to increase their efficiency. This review will summarize the limited number of drug delivery MI particles described in the literature along with an overview of potential solutions for a larger exploitation of MI particles as targeted drug delivery carriers. Molecularly imprinted drug carriers can be considered interesting candidates to significantly improve the efficiency of a controlled drug treatment.

Molecular imprinting science and technology: a survey of the literature for the years 2004-2011

Herein, we present a survey of the literature covering the development of molecular imprinting science and technology over the years 2004-2011. In total, 3779 references to the original papers, reviews, edited volumes and monographs from this period are included, along with recently identified uncited materials from prior to 2004, which were omitted in the first instalment of this series covering the years 1930-2003. In the presentation of the assembled references, a section presenting reviews and monographs covering the area is followed by sections describing fundamental aspects of molecular imprinting including the development of novel polymer formats. Thereafter, literature describing efforts to apply these polymeric materials to a range of application areas is presented. Current trends and areas of rapid development are discussed.

Direct replacement of antibodies with molecularly imprinted polymer nanoparticles in ELISA--development of a novel assay for vancomycin

A simple and straightforward technique for coating microplate wells with molecularly imprinted polymer nanoparticles (nanoMIPs) to develop assays similar to the enzyme-linked immunosorbent assay (ELISA) is presented here for the first time. NanoMIPs were synthesized by a solid-phase approach with an immobilized vancomycin (template) and characterized using Biacore 3000, dynamic light scattering, and electron microscopy. Immobilization, blocking, and washing conditions were optimized in microplate format. The detection of vancomycin was achieved in competitive binding experiments with a horseradish peroxidase-vancomycin conjugate. The assay was capable of measuring vancomycin in buffer and in blood plasma within the range of 0.001-70 nM with a detection limit of 0.0025 nM (2.5 pM). The sensitivity of the assay was 3 orders of magnitude better than a previously described ELISA based on antibodies. In these experiments, nanoMIPs have shown high affinity and minimal interference from blood plasma components. Immobilized nanoMIPs were stored for 1 month at room temperature without any detrimental effects to their binding properties. The high affinity of nanoMIPs and the lack of a requirement for cold chain logistics make them an attractive alternative to traditional antibodies used in ELISA.

Development of a biomimetic enzyme-linked immunosorbent assay method based on a hydrophilic molecularly imprinted polymer film for determination of olaquindox in chick feed samples

In this study, a new way to substitute the biology antibody was introduced by using a hydrophilic molecularly imprinted film, which was directly prepared on the well surface of MaxiSorp polystyrene 96-well plate by the bulk polymerization technique. This imprinted film exhibited good recognition and fast adsorption-desorption dynamics toward olaquindox. Using it as the recognition element, a fast and new direct competitive biomimetic enzyme-linked immunosorbent assay (BELISA) method for the determination of olaquindox in chick feed was developed. This BELISA method had low cross-reactivities of 6.2% and 12% for two analogues. Under the optimal conditions, the sensitivity (IC50) and the limit of detection (IC15) were 700 ± 60 µg L(-1) and 17.0 ± 1.6 µg L(-1), respectively. The blank chick feed samples spiked with olaquindox at three levels were determined by this developed method with recoveries ranging from 82.0-96.0%.

Development of an on-line molecularly imprinted chemiluminescence sensor for determination of trace olaquindox in chick feeds

BACKGROUND

Olaquindox, as one of the antimicrobial growth accelerants, is usually used in livestock production to improve feed efficiency. Due to health concerns over possible carcinogenic, mutagenic and photoallergenic effects of olaquindox on animals, the development of simple, rapid and sensitive analytical method for determination of olaquindox is crucial and necessary.

RESULTS

In this study, a surface molecularly imprinted polymer was prepared by a molecular imprinting technique in combination with a sol-gel process using activated silica gel as a support material. This imprinted material exhibited with good recognition and selective ability, and fast adsorption-desorption dynamics toward olaquindox. Using it as the recognition element, a new on-line molecularly imprinted solid phase extraction coupled with chemiluminescence sensor for the determination of olaquindox was developed. The factors affecting preconcentration of the analytes and sensitivity of the method were all investigated. Under the optimal condition, the linear range of the calibration graph was between 2 × 10(-8) and 1 × 10(-6) g mL(-1) , and the detection limit of this method was 7 × 10(-9) g mL(-1) . The blank chick feed samples spiked with olaquindox at 0.3, 0.9 and 1.5 µg g(-1) levels were extracted and determined by this presented method with recoveries ranging from 87% to 94%. This method was validated by high-performance liquid chromatography and the results correlated well with those obtained by both methods. Moreover, this method was quantitatively analysed with two contaminated chick feed samples.

CONCLUSION

This study will provide a sensitive and fast method for the monitoring of olaquindox residues in foods.

The biomimetic immunoassay based on molecularly imprinted polymer: a comprehensive review of recent progress and future prospects

Immunoassay, based on a selective affinity of the biological antibody for its antigen, is one of the most usual analytical methods in food safety and environmental chemistry. However, it presents several drawbacks because of the nature of the antibody. Molecular imprinting technique, due to its high selectivity and stability, ease of preparation and low cost, has shown great potential in producing artificial antibodies in biomimetic immunoassays. This article focuses on the recent states, advantages, current problems and outlooks of molecularly imprinted radio, fluoro, enzyme-linked and chemiluminescent immunoassays, and biomimetic immunosensor, with special emphasis on the challenges in developing biomimetic enzyme-linked immunosorbent assays (BELISAs). The biomimetic immunoassay method will provide an important new analysis platform in food safety, although the sensitivity and specificity is relatively low.

PRACTICAL APPLICATION

As a new simple analysis method, the biomimetic immunoassay has attractive prospect, although some limitations were existed in real-sample assay. In this critical review, some promising solutions for overcoming its drawbacks were put forward, which may promote the more quick development and extensive application of this method in food safety.

Immuno-like assays and biomimetic microchips

Biomimetic assays with molecularly imprinted polymers (MIPs) are bound to be an alternative to the traditional immuno-analytical methods based on antibodies. This is due to the unique combination of advantages displayed by the artificial materials including the absence of animal inoculation and sacrifice, unnecessary hapten conjugation to a carrier protein for stimulated production, the possibility of manufacturing MIPs against toxic substances, excellent physicochemical stability, reusability, ease of storage, and recognition in organic media. If the selectivity and affinity of MIPs are increased, many more immuno-like assays will be developed using radioactive, enzymatic, colorimetric, fluorescent, chemiluminescent, or electrochemical interrogation methods. This chapter provides a comprehensive comparison between the bio- and biomimetic entities and their usage.