A sensitive sandwich ELISA using a modified biotin-streptavidin amplified system for histamine detection in fish, prawn and crab

Rapid, Sensitive, and Specific Microbial Whole-Cell Biosensor for the Detection of Histamine: A Potential Food Toxin

Histamine is a biogenic amine; its level indicates food quality, as elevated levels cause food poisoning. Therefore, monitoring food at each step during processing until it reaches the consumer is crucial, but current techniques are complicated and time-consuming. Here, we designed a Pseudomonas putida whole-cell biosensor using a histamine-responsive genetic element expressing a fluorescent protein in the presence of the cognate target. We improved the performance of the proposed biosensor by optimizing the chassis, genetic regulatory element, and reporter gene. A sensitive and rapid biosensor variant was obtained with a limit of detection (LOD) of 0.39 ppm, manifesting a linear response (R2 = 0.98) from 0.28 to 18 ppm in 90 min. The biosensor showed minimal cross-reactivity with other biogenic amines and amino acids prevalent in food, making it highly specific. The biosensor effectively quantified histamine in spiked fish, prawn, and wine samples with a satisfactory recovery. Additionally, a colorimetric sensor variant PAlacZ was developed enabling histamine quantification in seafood via a smartphone application, with an LODgray of 0.23 ppm, exhibiting a linear response from 0 to 2.24 ppm. Overall, this study reports an efficient, specific, and highly sensitive biosensor with strong potential for the on-site detection of histamine, ensuring food safety.

Sensitive detection of histamine utilizing the SERS platform combined with an azo coupling reaction and a composite hydrophobic layer

Herein, the surface-enhanced Raman scattering (SERS) platform was combined with an azo coupling reaction and an aluminum alloy covered with a hydrophobic layer of praseodymium oxide and stearic acid complexes for the detection of histamine. The praseodymium oxide on aluminum alloy was successfully synthesized by the rare-earth-salt-solution boiling bath method and modified by stearic acid. Its surface exhibits a water contact angle (WCA) of 125.0°. Through the azo derivatization reaction with 3-amino-5-mercapto-1,2,4-triazole (AMTA) diazonium salts, histamine can be converted into the derivatization product with higher Raman activity. The mixture of the derivatization product and β-cyclodextrin-modified Ag nanoparticles (β-CD-AgNPs) were dropped onto the surface of an aluminum alloy covered with a hydrophobic layer of praseodymium oxide and stearic acid complexes, and dried for SERS measurement. The intensity ratio between the SERS peaks at 1246 cm-1 and 1104 cm-1 (I1246/I1104) of the derivatization product was used for the quantification of histamine. Under the selected conditions, the limit of detection (LOD) and the limit of quantification (LOQ) for this method were 7.2 nM (S/N = 3) and 24 nM (S/N = 10), respectively. The relative standard deviation (RSD) of this method for the determination of 1 μM histamine was 6.1 % (n = 20). The method was also successfully used for the determination of histamine in fish samples with recoveries ranging from 92 % to 111 %. The present method is simple, sensitive, reliable, and may provide a new approach for preparing the composite hydrophobic layer that can enhance SERS signals through hydrophobic condensation effect. Meanwhile, it may have a promising future in the determination of small molecular compounds containing an imidazole ring.

Highly sensitive biosensors for real-time monitoring of histamine at acupoint PC6 in rats based on graphene-modified acupuncture needles

Acupoints are the local initial response sites of acupuncture therapeutic effects. As a biomarker, histamine is released into the acupoint region and plays its role concurrently as acupuncture needles are inserted into acupoints. Hence, real-time monitoring of histamine at acupoints is important to elucidate the effectiveness of the acupoint-activation process in acupuncture. Therefore, we developed highly sensitive acupuncture/Au particles/graphene biosensors by electrodeposition, brushing, and annealing methods based on bare acupuncture needles. We achieved a histamine detection limit of approximately 4.352 (±3.419) × 10-12 mol L-1 and good sensitivity of approximately 6.296 (±3.873) μA μM-1, with satisfactory specificity, repeatability, and stability in vitro, rendering them more competitive and suitable for real-time monitoring in vivo without causing additional damage. Subsequently, we conducted real-time histamine monitoring at non-acupoint and acupoint PC6 in rats, respectively. Our results showed minimal changes at the non-acupoint, whereas a trend of initial increase followed by a decrease was observed at acupoint PC6. The change in histamine concentration at acupoint PC6 reflected its involvement in the acupoint-activation procedure. Moreover, its peak position at ∼18 min could provide guidance for optimizing needle retaining time for maximum therapeutic effect. This work presents the first real-time in vivo monitoring of histamine at acupoints with high sensitivity and underscores the specificity of histamine release between non-acupoint and acupoint PC6, demonstrating great potential for elucidating the acupoint-activation mechanisms in acupuncture. Additionally, this work expands the application of nanomaterials in the integration of medicine and engineering, which is an important aspect of the future development of materials science.

Rapid Microfluidic Immuno-Biosensor Detection System for the Point-of-Care Determination of High-Sensitivity Urinary C-Reactive Protein

A microfluidic immuno-biosensor detection system consisting of a microfluidic spectrum chip and a micro-spectrometer detection device is presented for the rapid point-of-care (POC) detection and quantification of high-sensitivity C-reactive protein (hs-CRP) in urine. The detection process utilizes a highly specific enzyme-linked immunosorbent assay (ELISA) method, in which capture antibodies and detection antibodies are pre-deposited on the substrate of the microchip and used to form an immune complex with the target antigen. Horseradish peroxidase (HRP) is added as a marker enzyme, followed by a colorimetric reaction using 3,3',5,5'-tetramethylbenzidine (TMB). The absorbance values (a.u.) of the colorimetric reaction compounds are measured using a micro-spectrometer device and used to measure the corresponding hs-CRP concentration according to the pre-established calibration curve. It is shown that the hs-CRP concentration can be determined within 50 min. In addition, the system achieves recovery rates of 93.8-106.2% in blind water samples and 94.5-104.6% in artificial urine. The results showed that the CRP detection results of 41 urine samples from patients with chronic kidney disease (CKD) were highly consistent with the conventional homogeneous particle-enhanced turbidimetric immunoassay (PETIA) method's detection results (R2 = 0.9910). The experimental results showed its applicability in the detection of CRP in both urine and serum. Overall, the results indicate that the current microfluidic ELISA detection system provides an accurate and reliable method for monitoring the hs-CRP concentration in point-of-care applications.

Progress in Procalcitonin Detection Based on Immunoassay

Procalcitonin (PCT) serves as a crucial biomarker utilized in diverse clinical contexts, including sepsis diagnosis and emergency departments. Its applications extend to identifying pathogens, assessing infection severity, guiding drug administration, and implementing theranostic strategies. However, current clinical deployed methods cannot meet the needs for accurate or real-time quantitative monitoring of PCT. This review aims to introduce these emerging PCT immunoassay technologies, focusing on analyzing their advantages in improving detection performances, such as easy operation and high precision. The fundamental principles and characteristics of state-of-the-art methods are first introduced, including chemiluminescence, immunofluorescence, latex-enhanced turbidity, enzyme-linked immunosorbent, colloidal gold immunochromatography, and radioimmunoassay. Then, improved methods using new materials and new technologies are briefly described, for instance, the combination with responsive nanomaterials, Raman spectroscopy, and digital microfluidics. Finally, the detection performance parameters of these methods and the clinical importance of PCT detection are also discussed.

Au@Ag Core-Shell Nanoparticles for Colorimetric and Surface-Enhanced Raman-Scattering-Based Multiplex Competitive Lateral Flow Immunoassay for the Simultaneous Detection of Histamine and Parvalbumin in Fish

Foodborne allergies and illnesses represent a major global health concern. In particular, fish can trigger life-threatening food allergic reactions and poisoning effects, mainly caused by the ingestion of parvalbumin toxin. Additionally, preformed histamine in less-than-fresh fish serves as a toxicological alert. Consequently, the analytical assessment of parvalbumin and histamine levels in fish becomes a critical public health safety measure. The multiplex detection of both analytes has emerged as an important issue. The analytical detection of parvalbumin and histamine requires different assays; while the determination of parvalbumin is commonly carried out by enzyme-linked immunosorbent assay, histamine is analyzed by high-performance liquid chromatography. In this study, we present an approach for multiplexing detection and quantification of trace amounts of parvalbumin and histamine in canned fish. This is achieved through a colorimetric and surface-enhanced Raman-scattering-based competitive lateral flow assay (SERS-LFIA) employing plasmonic nanoparticles. Two distinct SERS nanotags tailored for histamine or β-parvalbumin detection were synthesized. Initially, spherical 50 nm Au@Ag core-shell nanoparticles (Au@Ag NPs) were encoded with either rhodamine B isothiocyanate (RBITC) or malachite green isothiocyanate (MGITC). Subsequently, these nanoparticles were bioconjugated with anti-β-parvalbumin and antihistamine, forming the basis for our detection and quantification methodology. Additionally, our approach demonstrates the use of SERS-LFIA for the sensitive and multiplexed detection of parvalbumin and histamine on a single test line, paving the way for on-site detection employing portable Raman instruments.

Recent advances in inspection technologies of food safety health hazards for fish and fish products

The development of reliable and sensitive detection methods is essential for addressing the escalating concerns surrounding fish and fish products, driven by increasing market demands. This comprehensive review presents recent advances in detection approaches, specifically focusing on microplastic, biological, and chemical hazards associated with these products. The overview encompasses 21 distinct detection methods, categorized based on the type of hazard they target. For microplastic hazards, six methods are visual, spectroscopic, and thermal analyses. Biological hazard identification relies on six approaches employing nucleic-acid sequence, immunological, and biosensor technologies. The investigation of chemical hazards encompasses ten methods, including chromatography, spectroscopy, mass spectrometry, immunological, biosensor, and electrochemical techniques. The review provides in-depth insights into the basic principles, general characteristics, and the recognized advantages and disadvantages of each method. Moreover, it elaborates on recent advancements within these methodologies. The concluding section of the review discusses current challenges and outlines future perspectives for these detection methods. Overall, this comprehensive summary not only serves as a guide for researchers involved in fish safety and quality control but also emphasizes the significance of staying abreast of evolving detection technologies to ensure the continued safety of fish and fish products in response to emerging food safety hazards.

Spectro-Electrochemical Properties of A New Non-Enzymatic Modified Working Electrode Used for Histamine Assessment in the Diagnosis of Food Poisoning

We successfully prepared a non-enzymatic sensor based on a graphene-thiophene composite for histamine detection. The self-assembling properties of the thiophene onto Au support and the high electrical conductivity of graphene encouraged the choice of this type of composite. The composite was deposited via electrochemical polymerization onto the Au layer of a screen-printed microelectrode. The electropolymerization and electrochemical detection of histamine were both achieved by cyclic voltammetry. Two types of electrolytes were used for the electrochemical detection: (a) phosphate buffer solution (PBS), which showed low-intensity redox peaks for histamine; and (b) trichloroacetic acid (TCA) 0.01 M, which showed improved results over PBS and did not damage the microelectrode. For the concentration range of 100-200 mg/kg, the sensor shows a linear regression pattern for the oxidation peak fitted on the equation Ipa = 123.412 + 0.49933 ×x, with R2 = 0.94178. The lowest limit of detection was calculated to be 13.8 mg/kg and the limit of quantification was calculated at 46 mg/kg. These results are important since by monitoring the amount of histamine in a food product, early onset of spoilage can be easily detected, thus reducing foodborne poisoning and food waste (by recycling products that are still edible).

Integrated one-dimensional CuO-nanowire arrays/Cu-foam nanoarchitecture for ultrahigh sensitive and non-enzymatic electrochemical determination of histamine levels in different-bacteria fermented mandarin fish

Integrated one-dimensional CuO-nanowire arrays/Cu-foam (CuO-NWAs/Cu-foam) nanostructure, which was fabricated by oxidation and calcination, has been newly utilized as non-enzymatic electrocatalytic electrode for exploring histamine level. Under optimal condition of pH at 13 and potential at 0.55 V (vs Ag/Ag/Cl), the sensitivity of CuO-NWAs/Cu-foam electrode towards non-enzymatic electrochemical histamine determination presented as high as 12.94 mA mM^-1 cm^-2, linear range spanned between 0.5 and 1046 μM, a detection limit (S/N = 3) was about 44 nM. The unprecedented causes of ultrahigh sensitivity were physically contributed to enhancing active surface area and declining charge transfer resistance. More crucially, the outstanding selectivity, stability and reproducibility facilitated its practical capacity on evaluating histamine levels in different-bacteria fermented mandarin fish, which triggered the potential feasibility for commercializing non-enzymatic electrochemical determination of histamine with high sensitivity, reliable precision and low expenditure.

Glucometer-based biosensor for the determination of ractopamine in animal-derived foods using rolling circle amplification

Screening for persistent organic pollutants (POPs) in food is a complex and challenging process, as POPs can be present in very low levels and can be difficult to detect. Herein, we developed an ultrasensitive biosensor based on a rolling circle amplification (RCA) platform using a glucometer to determine POP. The biosensor was constructed using gold nanoparticle probes modified with antibodies and dozens of primers, magnetic microparticle probes conjugated with haptens, and targets. After competition, RCA reactions are triggered, numerous RCA products hybridize with the ssDNA-invertase, and the target is successfully transformed into glucose. Using ractopamine as a model analyte, this strategy obtained a linear detection range of 0.038-5.00 ng mL^-1 and a detection limit of 0.0158 ng mL^-1, which was preliminarily verified by screening in real samples. Compared with conventional immunoassays, this biosensor utilizes the high efficiency of RCA and the portable properties of a glucometer, which effectively improves the sensitivity and simplifies the procedures using magnetic separation technology. Moreover, it has been successfully applied to ractopamine determination in animal-derived foods, revealing its potential as a promising tool for POP screening.

Rapid, Convenient, and Ultrasensitive Point-of-Care sensing of histamine from fish: A Portable chromatographic platform based on derivatization reaction

Food poisoning caused by histamine ingestion is one of the prevalent allergies associated with fish consumption in the world. Reliable detection of histamine from fish by a portable platform was of urgent importance to food safety. A portable technology for on-site monitoring of histamine in tuna was established through combined azo-derivatized thin-layer chromatography (TLC) with surface-enhanced Raman scattering (SERS) spectroscopy. The real tuna meat sample was directly applied onto the portable sensor for the separation of histamine and azo-derivatizing of histamine was reacted on the TLC plate. The colorless histamine was visualized by azo-derivatization after spraying Pauly reagent onto the diatomite TLC plate. The molecule information and concentration of the histamine was measured and calculated by SERS spectra. Diatomite TLC plate was capable of separating histamine with 1.32 × 10^-7 M of Au colloid for the SERS enhancement. Accordingly, the limit of detection of histamine from mixture sample could achieve 2.8 × 10^-4 ppm. These results indicated that the portable azo-derivatized TLC-SERS sensor not only visualizes the histamine but also improves the intensity of the Raman spectra. The azo-derivatized TLC-SERS sensor could be applied for rapid, convenient, and ultrasensitive point-of-care sensing of histamine in fish.

Supersensitive detection of single-histamine molecule on nanoplates by turn-on small molecule fluorescence sandwich immunoassay

We develop a supersensitive "turn-on format" fluorescence sandwich immunoassay for detecting small single molecules. Gold nanoplate-based biotin antibodies and streptavidin-fluorophores were used instead of streptavidin-horseradish peroxidase reacting with a biotin tracer in a microplate-based competitive enzyme-linked immunosorbent assay (ELISA). Our platform showed a low detection limit of 5 zeptomolar (5 × 10^-21 M), 5.4 × 10¹⁰ times higher detection sensitivity than the conventional tune-off format ELISA.

Enzyme-modulated photothermal immunoassay of chloramphenicol residues in milk and egg using a self-calibrated thermal imager

Highly sensitive and accurate detection of chloramphenicol is of paramount importance for food safety. Herein, an enzyme-modulated photothermal immunosensor that uses a self-calibrated thermal imaging system (SCTIS) as signal read-out was developed for detecting chloramphenicol. In this immunosensor, alkaline phosphatase was used as a modulator of the photothermal conversion. It could hydrolyze the substrate into ascorbic acid, thereby reducing oxidized 3,3',5,5'-tetramethylbenzidine, which exhibited a near-infrared laser-driven photothermal effect. For precise temperature measurement, the SCTIS was designed by using the temperature compensation of a ceramic chip to enable real-time self-calibration of the temperature. This SCTIS-based immunosensor could detect chloramphenicol with a LOD of 9 pg/mL in 2 h, and relative standard derivations from 3.95% to 13.58%. The average recoveries in milk and egg samples ranged from 76% to 114%. This versatile sensing strategy can detect various targets by altering recognition elements, thus has wide applicability in food safety testing and monitoring.

A Highly Sensitive Fluorescence and Screen-Printed Electrodes—Electrochemiluminescence Immunosensor for Ricin Detection Based on CdSe/ZnS QDs with Dual Signal

A sensitive dual-readout immunosensor for fluorescence and electrochemiluminescence (ECL) detection of ricin was established, which was combined with a streptavidin–biotin signal amplification system. CdSe/ZnS quantum dots with fine fluorescence and ECL properties were used as the dual-signal function probes of the sandwich immunocomplex. Under the optimum experimental conditions, the dual signal intensity increased significantly with the rise in ricin concentration. The fluorescence intensity of the senor exhibited a good liner relationship toward the ricin concentrations with 0.1~100 ng/mL and the limit of detection (LOD) was 81.7 pg/mL; taking ECL as the detection signal, the sensor showed a linear relationship with the ricin concentrations ranging from 0.01 ng/mL to 100 ng/mL and the LOD was 5.5 pg/mL. The constructed sensor with high sensitivity had been successfully applied to the detection of ricin in complex matrices with satisfactory recoveries. The proposed immunosensor model can be extended to the analysis and detection of others target proteins.

Rapid and Wash-Free Time-Gated FRET Histamine Assays Using Antibodies and Aptamers

Histamine (HA) is an indicator of food freshness and quality. However, high concentrations of HA can cause food poisoning. Simple, rapid, sensitive, and specific quantification can enable efficient screening of HA in food and beverages. However, conventional assays are complicated and time-consuming, as they require multiple incubation, washing, and separation steps. Here, we demonstrate that time-gated Förster resonance energy transfer (TG-FRET) between terbium (Tb) complexes and organic dyes can be implemented in both immunosensors and aptasensors for simple HA quantification using a rapid, single-step, mix-and-measure assay format. Both biosensors could quantify HA at concentrations relevant in food poisoning with limits of detection of 0.19 μg/mL and 0.03 μg/mL, respectively. Excellent specificity was documented against the structurally similar food components tryptamine and l-histidine. Direct applicability of the TG-FRET assays was demonstrated by quantifying HA in spiked fish and wine samples with both excellent concentration recovery and agreement with conventional multistep enzyme-linked immunosorbent assays (ELISAs). Our results show that the simplicity and rapidity of TG-FRET assays do not compromise sensitivity, specificity, and reliability, and both immunosensors and aptasensors have a strong potential for their implementation in advanced food safety screening.

G-quadruplex based biosensors for the detection of food contaminants

G-quadruplex (G4) is a very interesting DNA structure, commonly associated with cancer and its treatment. With flexible binding ability, G4 has been extended as a significant component in biosensors. On account of its simple operation, high sensitivity and low cost, G4-based biosensors have attracted considerable interest for the detection of food contaminants. In this review, research published in recent 5 years is collated from a principle perspective, that is target recognition and signal transduction. Contaminants with G4 binding capacity are illustrated, emerging G4-based biosensors including colorimetric, electrochemical and fluorescent sensors are also elaborated. The current review indicates that G4 has provided an efficient and effective solution for the rapid detection of food contaminants. A distinctive feature of G4 as recognition unit is the simple composition, but the selectivity is still unsatisfactory. As signal reporter, G4/hemin DNAzyme has not only achieved amplified signals, but also enabled visualized detection, which offers great potential for on-site measurement. With improved selectivity and visualized signal, the combination of aptamer and G4 seems to be an ideal strategy. This promising combination should be developed for the real-time monitor of multiple contaminants in food matrix.

Immunoassay technology: Research progress in microcystin-LR detection in water samples

Increasing global warming and eutrophication have led to frequent outbreaks of cyanobacteria blooms in freshwater. Cyanobacteria blooms cause the death of aquatic and terrestrial organisms and have attracted considerable attention since the 19th century. Microcystin-LR (MC-LR) is one of the most typical cyanobacterial toxins. Therefore, the fast, sensitive, and accurate determination of MC-LR plays an important role in the health of humans and animals. Immunoassay refers to a method that uses the principle of immunology to determine the content of the tested substance in a sample using the tested substance as an antigen or antibody. In analytical applications, the immunoassay technology could use the specific recognition of antibodies for MC-LR detection. In this review, we firstly highlight the immunoassay detection of MC-LR over the past two decades, including classical enzyme-link immunosorbent assay (ELISA), modern immunoassay with optical signal, and modern immunoassay with electrical signal. Among these detection methods, the water environment was used as the main detection system. The advantages and disadvantages of the different detection methods were compared and analyzed, and the principles and applications of immunoassays in water samples were elaborated. Furthermore, the current challenges and developmental trends in immunoassay were systematically introduced to enhance MC-LR detection performance, and some critical points were given to deal with current challenges. This review provides novel insight into MC-LR detection based on immunoassay method.

Gold-based immunochromatographic assay strip for the detection of quinclorac in foods

In this study, a highly specific and sensitive monoclonal antibody (mAb) against quinclorac (Qui) was prepared. Based on the selected mAb, 2G3, an indirect competitive enzyme-linked immunosorbent assay (ic-ELISA) and an immunochromatographic strip assay were established for the detection of Qui in actual samples. The 50%-inhibitory concentration of mAb 2G3 against Qui was 48.763 ng mL^-1. No cross-reaction with other quinolines indicated that mAb 2G3 had high specificity. The recovery of the established ic-ELISA method was in the range of 85.6% to 98.9%. The cut-off value of Qui in cucumber and tomato by immunochromatographic strip was 200 ng g^-1. The analysis results of ic-ELISA and immunochromatographic strip assay were consistent with the results of LC-MS/MS, which further proved that the established ic-ELISA and immunochromatographic strip assay could provide valuable tools for the rapid detection of Qui residues in cucumber and tomato samples.

An immunochromatographic sensor for ultrasensitive and direct detection of histamine in fish

To ensure food quality and prevent histamine (HA) toxicity, a rapid and direct method of detecting HA is required. In this work, we prepared a monoclonal antibody (mAb) against HA using a hapten produced by the introduction of a phenyl-containing linker. The novel mAb exhibited high sensitivity against HA as determined by ELISA, with a half-maximal inhibitory concentration of 21.51 ng/mL. A gold nanoparticle-based immunosensor was fabricated for rapid detection of HA in fish samples. After optimizing the immunosensor, a visual limit of detection (LOD) and a calculated LOD were 0.25 mg/kg and 10.48 μg/kg for HA, respectively. Recovery rates from the spiked fish samples ranged from 87.33% to 104.67% with the coefficient of variation below 10.82%. Concurrently, the whole process in testing real sample was completed within 15 min, and all results were well confirmed and comparable by liquid chromatography-mass spectrometry and the commercial test strip. These data revealed that the proposed immunosensor could be used as a monitoring tool for the rapid and direct detection of HA in fish samples.