Diazinon (DAZ) is an important organophosphorus pesticide, widely retained in the environmental and food samples, badly affecting the ecological environment and human health. The rapid screening and accurate quantitative detection of DAZ are of great significance for environmental and food safety. This study proposed a novel hapten and evaluated its design rationale based on computer simulation analysis of molecular structural similarity, matching degree, and energetic state. Then, a sensitive monoclonal antibody (mAb) was successfully prepared, with a semi-inhibitory concentration (IC50) of 0.40 ng/mL for DAZ in an indirect competitive enzymelinked immunosorbent assay (ic-ELISA). We analyzed the relationship between the similarity of haptens and antibody performance, providing new possibilities and methods for developing antibodies against other small molecule compounds. Moreover, we successfully developed colloidal gold immunochromatographic assay (CGICA) strips for on-site and visual detection of DAZ in water and food samples, and visual limit of detection (vLOD) was 0.2 mu g/L in lake water, and 0.5 mu g/kg in fruits and vegetables. The recovery rates were 87.35-106.20 % and coefficients of variation were 1.37-7.60 %. And the accuracy of the method was further demonstrated by the liquid chromatography-tandem mass spectrometry method. This study is a new exploration in the DAZ detection method, providing ideas for rapid screening and accurate quantitative analysis of typical and new environmental pollutants.

Hen egg-white lysozyme (HEWL) is commonly used in food preservation and as a substitute for sulfur dioxide in wine production and to prevent late blowing defects in cheese production. However, HEWL is an egg allergen that can cause severe allergic reactions in allergic individuals after accidental ingestion. Therefore, in order to prevent life-threatening health problems caused by consumer allergies, we developed an extremely specific gold immunochromatographic assay (GICA) tolerant to matrix effects for the qualification and quantification of HEWL in food products. First, we prepared a monoclonal antibody (mAb) specific for HEWL. By optimizing the parameters of the sandwich enzyme-linked immunosorbent assay, we performed mAb interaction analysis. We developed GICA strips for the determination of HEWL in foods by combining mAb with colloidal gold. Additionally, considering the complex matrix of foods, standard curves for HEWL-negative milk, cheese, and grape wine samples were established to minimize matrix effects. The calculated limits of detection for the determination of HEWL in milk, cheese, and grape wine were 21.12 ng/mL, 0.89 mu g/kg, and 1.61 ng/mL, respectively. The recovery rates of the HEWL-spiked samples were 99.16 %-102.25 %, which were comparable to the HPLC results. Thus, we have successfully developed a rapid, sensitive and specific GICA method for the qualification and quantification of HEWL in milk, cheese and grape wine.

A gold nanoparticle-based immunochromatographic test strip for the detection of avian leukosis virus P27 antigen in egg white samples.

Flubendiamide (FLU), a widely used diamide insecticide, has been observed to potentiate adipogenesis in 3T3-L1 preadipocytes in vitro. Whether exposure to FLU disrupts hepatic lipid homeostasis in mammals and induces visceral obesity, however, remains unclear. The aim of this study was to assess the effects of FLU when administered orally to male C57BL/6J mice under normal diet (ND) and high-fat diet (HFD) conditions. FLU accumulated at higher levels in the tissues of the HFD group than those of the ND group, indicating that an HFD contributed to the accumulation of lipophilic pesticides in vivo. Notably, FLU (logP = 4.14) is highly lipophilic and easily accumulates in fat. Exposure to FLU had opposing effects on the lipid metabolism of the liver in the ND and HFD groups. Liver triacylglycerol levels in the ND group were reduced, while those in the HFD group were increased, resulting in more severe hepatic steatosis. More lipid accumulation was also observed in HepG2 cells exposed to FLU. Changes in hepatic lipid deposition in vivo occurred as the enhanced transcriptional regulation of the genes involved in lipid uptake, de novo lipogenesis, and fatty acid β-oxidation (FAO). Moreover, an excessive increase in FAO caused oxidative stress, which in turn exacerbated the inflammation of the liver. This study revealed the disruptive effect of FLU exposure on hepatic lipid homeostasis, which may facilitate the triggering of nonalcoholic fatty liver disease in HFD-fed mice.

Pyriftalid (Pyr) is one of the most commonly used herbicides and due to its widespread and improper use, it has led to serious pollution of groundwater, soil and other ecosystems, threatening human health. A rapid method to detect Pyr was urgently needed. A high specific monoclonal antibody (mAb) against Pyr with IC50 values of 4.7 ng/mL was obtained by mAb screening technique and method with enhanced matrix effect. The study firstly proposed colloidal gold immunochromatographic test strips (CGIA) for Pyr, which enables rapid qualitative and quantitative determination of a large number of samples anytime and anywhere, so as to effectively monitor Pyr in environment and grain samples. Based on the properties of the desired Pyr antibody, the hapten Pyr-hapten-4 with high structural similarity to Pyr molecule, similar electrostatic potential distribution, and the ability to expose Pyr functional groups was screened out from five different Pyr haptens, which was consistent with mouse antiserum test. The CGIA quickly analyze the Pyr content in positive samples such as water samples, soil samples, paddy samples, brown rice samples within 10 min, the LOD for Pyr by CGIA as low as 1.84 ng/g, the v LOD value as low as 6 ng/g, and the extinction value as low as 25 ng/g. The content of positive samples detected by CGIA was consistent with the quantitative results of LC-MS/MS, the relative accuracy was within the range of 97 -103 %. The recovery rate range for Pyr by CGIA was 92.0 -99.7 %, and the coefficient of variation was between

Bupirimate (BPM) is a high-efficiency and low-toxicity fungicide used to combat powdery mildew in crops. To mitigate potential health risks to consumers resulting from improper BPM usage, we prepared a monoclonal antibody against BPM based on novel hapten synthesis, which has high sensitivity and strong specificity, and then successfully designed a colloidal gold-based immunochromatographic (ICG) strip. The newly designed ICG strip was then employed for detecting BPM residues in peach, orange, and carrot. The results show that for the peach, orange, and carrot samples, the calculated detection limits of the ICG strip are 9.36, 0.79, and 0.57 ng/g, respectively, and that it is resistant to the matrix effect and meets the maximum residue limit requirements of European Commission for BPM. Therefore, this developed ICG strip is expected to enable swift detection of BPM residues on the spot.

Bacillus cereus is a foodborne opportunistic pathogen commonly found in humans and animals. It produces various toxins, causing frequent food safety incidents. Therefore, establishing a fast and accurate method for detecting B. cereus enterotoxin is crucial for disease diagnosis and food safety. In this study, Haemolysin BL comprising Hbl B and L2 was obtained from a prokaryotic expression system and then used to immunize mice for antibody preparation. Paired antibodies 2A10-5C7 against Hbl B and 1E2-10A4 against Hbl L2 were screened using the chessboard method and then used to construct a double-antibody sandwich detection method and a lateral flow immunochromatographic assay (LFIA) to quantify the concentrations of Hbl B and L2 in PBS and milk. The limits of detection for Hbl B and L2 in milk were 0.74 ng mL(-1) and 1 ng mL(-1) with detection ranges of 1.48-645.5 ng mL(-1) and 2.33-391.5 ng mL(-1). The spiked recoveries ranged from 82.2% to 105.67% and there was no cross-reactivity with common microbial toxins. The established LFIA was low in cost and rapid and was comparable with commercially available detection kits for food samples.

Sartans, as a class of antihypertensive drugs, pose a threat to human health when illegally added to herbal beverages. It is crucial to detect sartans in herbal beverages. We have developed a highly sensitive monoclonal antibody against candesartan (CAN), olmesartan medoxomil (OLM), and irbesartan (IRB), with 50% inhibitory concentrations (IC50) that were obtained via indirect enzyme-linked immunosorbent assay (ic-ELISA) as 0.178 ng mL-1, 0.185 ng mL-1, and 0.262 ng mL-1 against CAN, OLM, and IRB, respectively. Based on this monoclonal antibody, we developed a rapid screening method for CAN, OLM, and IRB in herbal beverage samples using an immunochromatographic assay (ICA) strip. Test for 15 minutes after simple and rapid sample pre-treatment and the results of this method can be obtained through naked eye observation. The detection limits (LODs) of the ICA strip for CAN, OLM, and IRB in herbal beverage samples are lower than 0.15 ng mL-1, and the results of the ICA strip and ic-ELISA are consistent in spiked samples and recovery experiments. Therefore, this method can quickly, efficiently, and reliably achieve high-throughput on-site rapid detection of illegally added CAN, OLM, and IRB in herbal beverages. Sartans, as a class of antihypertensive drugs, pose a threat to human health when illegally added to herbal beverages.

The residue of fungicides in food packaging paper materials is one of the important factors leading to food safety problems, which poses a serious threat to public health. (2-benzothiazolylthio) methyl thiocyanate (TCMTB) is an important anti-mildew fungicide, which is widely used in wood and paper industry. In order to ensure the health of consumers, it is of great significance to establish an efficient and sensitive rapid detection method for TCMTB in food packaging materials. In this study, we prepared monoclonal antibody (mAb) against TCMTB with the IC50 value of 7.60 ng/mL, and subsequently developed an immunochromatographic assay (ICA) strip based on the mAb for the rapid detection of TCMTB residues. The calculated detection limit of the ICA strip in food packaging paper was 3.20 ng/g, and the recovery rate was within an acceptable range, ranging from 97.7% to 102.7%. Therefore, the developed ICA is expected to realize the rapid screening of TCMTB residues in food packaging paper.

Herein, four haptens of niacin (Vitamin B3, VB3) were designed, and after a series of experiments, it was concluded that hapten D had the best immune effect. To avoid false positives in the detection of real samples, a monoclonal antibody (mAb) against VB3 was prepared by a matrix effect-enhanced mAb screening method. The concentration of the inhibition rate reaching 50% (IC50) was 603.41 ng mL-1 and the limit of detection (LOD) using an indirect enzyme-linked immunosorbent assay (ic-ELISA) was 54.89 ng mL-1. A lateral flow immunochromatographic assay (LFIA) based on gold nanoparticles was established to detect the concentration of VB3 in compound vitamin B tablets and infant formulas, with a visual LOD of 5 μg mL-1. Using a handheld reader, the quantitative LOD was calculated to be 0.60 μg mL-1. The contents of the compound vitamin B tablets and infant formulas were also verified by liquid chromatography. Therefore, the LFIA developed in this study can be applied to the specific identification and rapid detection of niacin in nutritional dietary supplements, thus meeting the market's demand for efficient niacin detection methods.

Due to the characteristics of long-term persistence, leading to extensive temporal and spatial distribution of the environmental pollutant dibutyl phthalate (DBP), analyzing of a large number of food and environment samples over a long period and at a high frequency must be necessary. It is of great significance to construct a simple, rapid, sensitive and high-throughput immunoassay method. For the first time, 8 different DBP hapten molecules were designed using computer simulation to provide DBP epitope informations from both conformation and electrostatic aspects for the target molecule. This approach helped to establish a reasonable hapten design strategy while reducing the cost and increasing the success rate of producing the required high-specificity and high-sensitivity DBP antibodies. Hapten DBP-1 was proposed, and the effectiveness of computer-aided hapten DBP-1 design was further verified by mouse antiserum experiments. A highly-specific monoclonal antibody (mAb) against DBP with an IC50 value of 19.8 ng/mL was obtained by mAb screening with enhanced matrix effect. A colloidal gold immunochromatographic test strip (CIS) which can be used to detect DBP in environmental, food and human urine samples was further prepared, and the DBP content in positive samples such as water, soil, and liquor samples could be rapidly analyzed within 15 min, which were basically consistent with the data by Gas Chromatography-Mass Spectrometry (GC-MS). In summary, our study proposed a detection method that can be directly used to detect DBP in environmental water, soil, liquor and human urine samples, which is ready for application in environmental monitoring, food safety control and clinical use.

Chloridazon (CLZ) is a selective herbicide used in the control of annual broadleaf weeds. The misuse or abuse of CLZ may result in the accumulation of CLZ in crops and water, which can pose a risk to human health. In this study, a hapten of CLZ with three carbon spacer arms was designed and a highly sensitive and specific antibody against CLZ was prepared with a half-maximal inhibitory concentration of 0.630 ng mL-1 and a linear range of 0.181-2.195 ng mL-1.Based on this antibody, we developed an immunochromatographic assay (ICA) strip for the detection of CLZ in oranges and celery. Under optimized conditions, the visual limit of detection was 2 ng mL-1 and 10 ng mL-1 in oranges and celery, respectively, and the cut-off value was 50 ng mL-1. In CLZ-spiked samples and the recovery test, the results of the ICA strip were consistent with those of indirect competitive enzyme-linked immunosorbent assay (ic-ELISA). Therefore, the ICA strip developed in our study represents an efficient and reliable method for the rapid screening of CLZ in oranges and celery.

Due to the complexity and diversity of infectious diseases, diagnosis based solely on symptoms and imaging manifestations is associated with a high rate of misdiagnosis, so it is particularly important to find reliable and accurate biomarkers. Four inflammatory biomarkers (CRP, IL-6, PCT and SAA) have different manifestations and roles in different infectious diseases and stages of infection, and the diagnosis and identification of infectious diseases can be realized through quantitative analysis of these four biomarkers simultaneously. In this study, we developed a colloidal gold nanoparticle (AuNP)-based multiplex LFA strip using eight highly-sensitive monoclonal antibodies that simultaneously detected CRP, IL-6, PCT and SAA in serum within 15 min. And quantitative analysis was achieved with a portable strip reader, the LODs were 2.5 mu g/mL, 25.3 pg/mL 0.87 ng/mL and 8.8 mu g/mL for CRP, IL-6, PCT and SAA, while detection ranges were 2.5-200 mu g/mL, 25.3-8000 pg/mL 0.87-100 ng/mL and 8.8-200 mu g/mL. Moreover, the quantitative colloidal gold assay correlated well with the results of a chemiluminescence immunoassay when testing clinical serum samples. Our developed method was reliable and accurate according to the recovery test results. Therefore, the strip can be used as an alternative method for the simultaneous monitoring of CRP, IL-6, PCT and SAA in serum samples.

Asarum plants containing many functional substances are widely used in traditional prescriptions and tonics. DNA barcoding is a relatively short specific gene segment in the genome which can be used for species identification purposes. The present work selected RNA transcriber type II intron shear enzyme gene (matK) as the target and developed a novel fluorescence and surface enhanced Raman scattering (SERS) dual-model PCR for the detection of Asarum heterotropoides (AH) in plants. The dual-model method achieved specific AH DNA detection with a limit of detection (LOD) of 10 - 3 ng/������L for the fluorescence signal and 10- 4 ng/������L for the SERS signal in the range of 10 - 4-10 ng/������ L. Agarose gel electrophoresis results and qPCR results showed the novel method was highly specific for AH detection and only the AH was successfully amplified.

In the study, we discovered zoxamide hapten (ZOX-hapten) by introducing a carboxyl extension chain, combined it with protein to make a complete antigen to immunize mice, and generated a monoclonal antibody (mAb) against ZOX. To identify ZOX residues in grape, tomato, and cucumber samples, we used our anti-ZOX mAb to develop a lateral flow immunoassay (LFIA) strip. In grape, tomato, and cucumber samples, the calculated detection limit of the LFIA strip in grape, tomato and cucumber samples was 3.44, 4.78 and 3.53 ng/g, respectively. Using the LFIA strip, the recovery rate from grape samples was 96.4-106.8%, and that from tomato samples was 98.4-107.5%, while the recovery from cucumber samples was 99.4-111.3%. These results showed that our LFIA strip could be expected to achieve rapid screening of ZOX residues in fruits and vegetables.

In the study, a hapten was designed to preserve the molecular structure of tolfenpyrad while introducing a carboxyl group and was coupled with a carrier protein to synthesize an immunogen and coating antigen. A monoclonal antibody was fabricated against tolfenpyrad and its performance was assessed by indirect competitive enzyme-linked immunosorbent assay. Finally, we developed a colloidal gold nanoparticle immunochromatographic test strip (CGN-ICTS) for the detection of tolfenpyrad in kale, Chinese cabbage, and eggplant samples. The results shows that CGN-ICTS was sensitive, with calculated detection limits of 0.49 ng/g for kale and Chinese cabbage and 0.99 ng/g for eggplant. Subsequently, CGN-ICTS and LC-MS were used to analyze the tolfenpyrad-spiked samples. The recovery rate of the CGN-ICTS for kale samples was 97.1-103.0%, for Chinese cabbage samples was 93.7-103.4%, and for eggplant samples was 92.7-105.7%. Recovery rates were similar between CGN-ICTS and LC-MS. Therefore, CGN-ICTS can be used to quickly screen tolfenpyrad residues in foods.

In this study, we prepared a highly sensitive monoclonal antibody (mAb) against Cyhalofop-butyl (Cyh) by indirect competitive enzyme-linked immunosorbent assay (ic-ELISA). Based on this mAb, an immunochromatographic strip (ICA) was established to detect Cyh in corn and brown rice samples. Through screening different coating antigens and antibodies, the half-maximum inhibitory concentration (IC50) of the highly specific Cyh mAb 1A3 was 2.2 ng/mL, and the detection linear range (IC20-IC80) was 0.5-5.2 ng/mL. When Cyh in corn samples was detected by ICA, the detection limit of the T line elimination value was 100 & mu;g/kg, and the detection limit for colorimetric value was 25 & mu;g/kg. When the detection sample was brown rice, the detection limit of the T line elimination value was 100 & mu;g/kg, and the detection limit for colorimetric value was 12 & mu;g/kg. The results of recovery experiments for both ic-ELISA and LC-MS/MS were consistent with those of the test results when using the ICA. The ICA test strip met the requirements for on-site rapid detection of Cyh in corn and brown rice samples. Therefore, this method is suitable for real-time detection and monitoring of agricultural products as well as during plant growth, harvesting, transportation, storage, and sales, thereby guaranteeing the safety of consumers.

To screen for fenhexamid in cucumber and grape samples, a monoclonal antibody (mAb) was prepared and a gold nanoparticle-based immunochromatographic strip (GNP-ICS) was developed. In the GNP-ICS, the visible detection limit (vLOD) and calculated detection limit (cLOD) of GNP-ICS in cucumber samples were 5 ng/g and 0.92 ng/g, respectively, and in grape samples were 10 ng/g and 1.19 ng/g, respectively. The GNP-ICS gave recovery rates of 97-105 % of cucumber samples, and 94-100 % of grape samples. Moreover, the results obtained using GNP-ICS were highly consistent with those obtained using an indirect competitive enzyme-linked immunosorbent assay (ic-ELISA). Therefore, the GNP-ICS achieved rapid screening of fenhexamid residues in fruits and vegetables.

We report the development of a sensitive, fast, and simple method for the detection of prometryn (PRO) in potato and celery using a lateral flow immunochromatographic assay (LFIA). A monoclonal antibody (mAb) against PRO was prepared under optimized conditions, and the 50% inhibition concentration (IC 50 ) for use in ELISA was determined to be 0.6 ng mL −1 . Moreover, the cut-off value for use in an LFIA was 50 ng mL −1 . To validate the reliability of the developed LFIA strip, real samples were used, and the recovery rate was found to be 99.3–104.3%. The assays were completed within 8 min, demonstrating the suitability of our developed methods for the detection of PRO in potato and celery.

Imidacloprid (IMP) is toxic and a potential carcinogen that is most widely used as an insecticide for pest control and seed treatment. It is important to produce a rapid and sensitive assay for on-site monitoring. We have developed a novel lateral flow assay (LFA) using a sensitive monoclonal antibody (mAb) for monitoring IMP residues on fruits and vegetables. The 50% inhibition concentration result that was found when using the ELISA method was 0.247 ng mL−1, with the cut-off limits using the LFA method the result was 10 ng mL−1 (0.01 M PBS), and in the samples it was 20 ng mL−1 (with a recovery rate of 96–104.7% for Chinese cabbage, cowpea, apple, and pear samples, respectively). All of the results can be determined within seven minutes. The proposed LFA method is a valid, quick, and stable assay for the on-site detection of IMP in large numbers of samples.