Fluopyram (FPR), a widely used succinate dehydrogenase inhibitor fungicide, has raised potential concerns regarding residue risks, highlighting the importance of developing rapid on-site detection methods. In this study, a novel and unique hapten was designed through computer-assisted simulation, leading to the production of a highly sensitive and specific antibody with a half-maximal inhibitory concentration value of 0.09 ng mL-1. Based on this antibody, a colloidal gold immunochromatographic assay strip method applicable to potato and soybean samples was successfully developed, with a visual limit of detection of 10 μg kg-1. In the analysis of real samples, potato sample No. 9 and soybean samples No. 1 and No. 5 were identified as positive samples. These results corresponded closely to those obtained using the instrument detection method, thereby confirming the reliability of the strips.

To address the residue risk of pencycuron in vegetable matrices, this study rationally designed and synthesized a hapten with high structural similarity via computer-aided molecular design. Subsequently, a monoclonal antibody (mAb) 4B6 with high affinity and specificity was successfully generated. Leveraging this antibody, two detection platforms were constructed: an indirect competitive enzyme-linked immunosorbent assay (ic-ELISA) and a colloidal gold immunoassay (CGIA). The half-maximal inhibitory concentration (IC50) of the developed icELISA was determined to be 1.87 ng/mL (95% CI: 1.83 similar to 1.91 ng/mL). For the CGIA, the visual limit of detection (vLOD) ranged from 2 to 20 ng/g in phosphate-buffered saline and various vegetable matrices. Spiked recovery tests on real samples yielded recoveries between 92.32% and 114.86%, which were in good agreement with results obtained from LC-MS/MS. This study provides a reliable dual-mode immunoanalytical solution for both precise laboratory quantification and rapid on-site screening of pencycuron residues, thereby offering technical support for the surveillance of pencycuron contamination in vegetable matrices.

Organophosphorus pesticides pose significant risks to the ecosystem and human health due to their environmental persistence and potential accumulation in medicinal herbs. This study aimed to develop rapid immunoassays for detecting four phosphorothioate organophosphorus pesticides isofenphos-methyl (Fen), isocarbophos (Car), isofenphos (Phe), and isofenphos-oxon (Oxon) in complex Codonopsis pilosula and Angelica sinensis matrices. Five novel haptens (H1-H5) were synthesized. Among them, a broad-spectrum hapten (H1) was rationally designed through computer-aided modeling, which optimized its spatial conformation, electrostatic potential, and electronic structure for maximum similarity to those of the target pesticides. This hapten yielded a high-affinity monoclonal antibody (mAb 2B1) with excellent sensitivity (IC50 values of 0.78, 1.53, 6.89, and 8.36 ng/mL for Fen, Car, Phe, and Oxon, respectively) and specificity. Homology modeling and molecular docking revealed the structural basis for the mAb's differential affinity; amino acid GLY-99(A), TYR-36(B), and TRP-106(A) play a central role in and could be a key target for subsequent antibody affinity maturation to broaden its cross-reactivity profile against structural analogs. GLY-99(A) and TYR-36(B) are responsible for polar complementarity and precise positioning, while TRP-106(A) contributes to hydrophobic stabilization and energy gain. Based on mAb 2B1, a high-throughput ic-ELISA and a rapid dual-test-line immunochromatographic strip (AuNP-LFIA) were developed; it enabled on-site, visual detection within 15 min, with detection limits compliant with regulatory standards. The liquid chromatography-mass spectrometry (LC-MS/MS) analysis of the positive samples was consistent with the results of the AuNP-LFIA method, further validating the reliability, accuracy, and practical applicability of the developed assay in this study for monitoring phosphorothioate organophosphorus pesticide residues in environmental and agricultural products.

Alkaline phosphatase (ALP) in milk serves as an important indicator for evaluating the effectiveness of pasteurization. To ensure food safety, there is an urgent need to develop rapid and accurate methods for detecting ALP in milk. In this research, monoclonal antibodies with high sensitivity and specificity against ALP were screened. The limit of detection for ALP in milk was 1.17 ng/mL, with a detection range of 2.39-238.17 ng/ mL. Subsequently, a lateral flow immunoassay (LFIA) platform based on monoclonal antibodies was developed, which could provide results within 12 min. The established LFIA strip enables the effective identification and quantification of ALP in milk without cross-reacting with other common milk proteins. In addition, the strip accurately distinguished raw milk from pasteurized milk. The established LFIA platform is low-cost and rapid, demonstrating significant market potential.

Quinoxyfen (QXY), a persistent and bioaccumulative fungicide, raises mounting concerns for food safety and environmental health, yet field-deployable detection methods remain lacking. Here we report a rationally designed hapten (QXY-1) guided by computer-assisted molecular simulation that retains the core structural and electrostatic features of QXY, eliciting a high-quality immune response. A highly specific monoclonal antibody (mAb 4E10) was generated, exhibiting an IC50 of 45.67 ng/mL and negligible cross-reactivity with structurally related analogues. Using this antibody, we developed the first colloidal gold-based immunochromatographic assay (CG-ICA) for QXY, enabling both visual semi-quantitative and instrument-based quantitative readout within 10 min. The assay achieved a visual limit of detection of 20 ng/mL in buffer, 0.10 mg/kg in grapes and 0.05 mg/kg in lettuce, with cut-off values of 5 mg/kg and 2 mg/kg, respectively. Recoveries from spiked samples ranged from 86.1% to 109.3%, and results correlated well with LC-MS/MS in blind market samples. Beyond delivering a practical tool for on-site QXY monitoring, this work establishes a computer-aided rational hapten design strategy that is generalizable to developing sensitive immunoassays for other challenging small-molecule contaminants.

Improper application of anilinopyrimidine (AP) fungicides on fruits and vegetables may lead to residues that threaten human health through the food chain. Developing rapid detection methods for AP fungicides is therefore critical for food safety supervision. Herein, a computer-aided hapten design strategy was employed to design broad-spectrum haptens against cyprodinil (Cyp), mepanipyrim (Mep), and pyrimethanil (Pyr), enabling the generation of broad-spectrum anti-AP monoclonal antibodies. An immunochromatographic assay (ICA) was further developed for simultaneous rapid detection of Cyp, Mep, and Pyr residues in grapes, strawberries, and tomatoes, with calculated limits of detection of 0.02-0.07 μg/kg. The ICA exhibited sufficient sensitivity for routine detection, and matrix spike recoveries ranged from 84.7%-94.7%. GC-MS/MS and authentic sample analysis confirmed its high accuracy and reliability, making it suitable for on-site screening.

Given concerns over Triflusulfuron-methyl (Tri) residues and their risks to food safety and ecosystems, we developed a rapid detection method. Using computer-aided technology based on electrostatic potential and charge distribution of Tri, we designed a novel hapten (H2) that induced a favorable immune response. This approach maximally simulated the immune recognition features of the target molecule. The precise structural retention combined with optimized physical and chemical properties effectively enhanced the specificity of antibody recognition. It enabled the generation of a high-performance monoclonal antibody (mAb) 4C6 with a half-maximal inhibitory concentration (IC50) of 1.25 ng/mL. The lateral flow immunoassay (LFIA) achieved visual detection limits of 5, 5, 10 and 5 ng/g in cabbage, apple, sugar beet, and lake water samples, with recoveries of 93.7%-102.3% and coefficients of variation below 8%. And the determined results of positive samples were highly consistent with the results of LC-MS/MS. The LFIA method developed in this study has the advantages of simple operation, low cost and good stability, successfully meeting the need for on-site rapid detection of Tri and providing reliable technical support for the supervision of food and ecological safety.

Triclosan (TCS), triclocarban (TCC), and chlorophene (CP) are widely used antimicrobial agents with persistent environmental residues, posing potential ecological and health risks. Thus, developing a sensitive, rapid on-site screening method is highly significant. In this study, computer simulation was first employed to screen the haptens of TCS, TCC and CP to prepare highly specific and high affinity monoclonal antibodies with half-maximal inhibitory concentrations of 1.044, 0.964, and 1.704 ng/mL, respectively. Based on this, a multi-immunochromatography assay (MICA) was established to simultaneously and rapidly detect TCS, TCC, and CP in lake water, wastewater and sludge, with calculated limits of detection of 1.138, 1.090, and 2.525 μg/kg in lake water; 1.147, 1.093, and 2.511 μg/kg in wastewater; and 1.668, 1.493, and 3.106 μg/kg in sludge, respectively. Analysis of real samples confirmed strong consistency between MICA and HPLC-MS/MS results, with high accuracy, stability, and reliability, supporting its application for on-site screening of large batches of samples.

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.

Carmoisine (CMS) is a synthetic azo colorant that can be used as a food colorant in products such as candy. However, due to potential health risks associated with carcinogenic, child development and allergic reactions, its use is strictly regulated. We have developed a colloidal gold immunochromatographic assay (CG-ICA) based on a highly sensitive monoclonal antibody (mAb) for the rapid and sensitive detection of CMS in food products. This study proposes a novel hapten and evaluates its structure through computer-aided analysis based on molecular structural similarity. Then, a mAb was successfully prepared, with a half-maximal inhibitory concentration of 0.20 ng/mL and a limit of detection (LOD) of 0.03 ng/mL. The CG-ICA strip demonstrated a LOD of 0.48-0.58 mu g/L for three soft drink types, achieving recovery rates between 90.78% and 109.61% and a coefficient of variation (CV) between 2.39% and 5.24%. The accuracy of the method was further validated by liquid chromatography-tandem mass spectrometry (LC-MS). Without requiring complicated purification steps, the simple operation and rapid result-yielding ability of CG-ICA within 20 min demonstrate its suitability for field rapid screening of CMS in soft drinks. The method developed in this study represents a new exploration for CMS detection and provides a direction for the rapid screening of similar colorants.

Aflatoxins (AFTs) are highly carcinogenic and mainly contaminate cereals. In this study, we designed and screened a hapten by analyzing the same characteristic groups of AFTs (AFB1, AFB2, AFG1 and AFG2), prepared a monoclonal antibody (mAb) 4C11 with a high sensitivity and specificity that can simultaneously detect all the main AFTs, and established a colloidal gold immunochromatographic assay (CG-ICA) for the detection of AFTs in cereals. The limits of detection (LODs) were 0.77 mu g/kg, 1.40 mu g/kg and 0.71 mu g/kg for wheat, rice and maize, respectively, with linear ranges of 1.17-5.52 mu g/kg, 1.84-5.20 mu g/kg and 1.26-8.95 mu g/kg, respectively. The spiked recoveries of AFTs samples ranged from 95.6 % to 104.2 %, and the positive samples further validated the reliability of the method. The results demonstrated that the method can be used for rapid, sensitive and efficient on-site detection of AFTs in cereals.

Vitamin A (VA) deficiency can lead to abnormal immune system function and jeopardize health. Therefore, a simple and specific method for determining VA is needed. We analyzed the structure of hapten for the preparation of an anti-VA monoclonal antibody (mAb), assisted by computer simulation. The solution's organic solvent content was optimized during mAbs screening, taking into account its effect on antibody performance. Colloidal gold immunochromatographic assay (CGIA) strips were developed and applied to the detection of VA in infant formula, cheese, and VA dietary supplements, utilizing the prepared mAb that exhibits tolerance to 10

This study prepared a colloidal gold-based immunochromatographic strip (CG-ICS) for the detection of 5-fluorouracil (5-FU) in human plasma, for therapeutic drug monitoring. Three haptens were synthesized with different carboxyl introductory positions and with different carbon chain lengths for the spacer arm, and were used to screen the coating antigens and immunogens. A highly sensitive and specific monoclonal antibody (mAb) 3C12 with an IC50 value of 4.359 ng/mL detected by ic-ELISA was produced for the construction of the strip. The visual limit of detection (vLOD) for semi-quantitative analysis of the CG-ICS was 50 ng/mL and the cut-off value was 2000 ng/mL. Furthermore, the calculated LOD (cLOD) value and linear range for quantitative detection were 1.464 ng/mL and 5.432-367.627 ng/mL, respectively. This detection required at most 10 min. In addition, the recovery rate of the spiked 5-FU in human plasma detected by the CG-ICS was 91.77 % to 94.04 %, which matched very well the results from LC-MS/MS. For real positive samples, the test results of the CG-ICS were consistent with those of LC-MS/MS. These findings suggest that the CG-ICS detection method is suitable for the rapid detection of 5-FU.

Nonylphenols (NPs) are confirmed endocrine disruptors that are banned in many countries due to correlations with human cancers. NPs pollution in surfactant oilfield chemicals (OFCs) has become an important environmental safety issue. It is significant to establish a simple, accurate and low-cost method for detection of NPs in OFCs. In this research, computer-aided molecular design technology was utilized to design NPs haptens. High affinity monoclonal antibodies against NPs were obtained using a matrix effect-enhanced screening method, with an IC50 value of 183.01 ng/mL. A colloidal gold immunochromatography assay (ICA) for detection of NPs enabled rapid on-site detection of large volumes of OFCs. Under optimal conditions, the limit of detection was 0.72-1.82 mg/kg, with a detection range of 4.49-191.28 mg/kg. The recovery was 84 %-104 %, with coefficients of variation < 13 %. As confirmed by high-performance liquid chromatography of natural positive OFCs samples, the proposed colloidal gold ICA demonstrated accuracy and reliability, with potential for fast and economical on field test.

Glyphosate (GLY) is widely applied in agriculture and horticulture as a herbicide. The development of genetically modified plants has caused abuse of GLY, with excessive residues potentially causing harm to human health. Consequently, a novel method needs to be built to detect GLY in soybeans and corn. Computer simulation was used to design an excellent hapten which was used to produce an anti-GLY monoclonal antibody (mAb) with outstanding sensitivity and affinity, and its 50%-inhibitory concentration (IC50) was 128.59 ng mL-1. Afterwards, an immunochromatographic assay strip was developed based on the mAb. In soybeans and corn, the visual detection limits were 1 mg kg-1 and 0.2 mg kg-1, while the cut-off values were 50 mg kg-1 and 5 mg kg-1, respectively. The reliability of the strips was proved by the existing methods. Thus, a rapid method to detect GLY residues on-site in soybeans and corn was established. The determination of glyphosate in soybean (a) and corn (b) samples using a lateral strip assay.

With the global spread of antimicrobial resistance, it is imperative to satisfy the need to develop novel antibacterial agents. Here, we synthesized chiral Co3O4 nanoparticles (NPs) with obvious bactericidal effects. It was found that the circular dichroism (CD) spectra of L-Co3O4 NPs and D-Co3O4 NPs exhibited perfect mirror image inversion. Specifically, the survival rate of primary uterine fibroblast (PCS)cells reached above 90

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.

Contamination of oilfield chemicals (OFCs) by benzo[a]pyrene (B[a]P) is increasingly becoming a severe environmental security issue. There is an urgent need to develop a rapid and accurate method for B[a]P detection in OFCs. In this study, B[a]P hapten was designed using computer aided molecular design. A high -affinity, specific, and matrix -insensitive monoclonal antibody (mAb) with IC 50 values of 6.77 ng/mL was obtained. Based on this mAb, we developed a rapid gold nanoparticle-based immunochromatographic strip assay (GICA) with double Tline mode for on -site detection of B[a]P in OFCs samples. The GICA exhibited excellent detection performance in OFCs samples with strong acidity, strong alkalinity, and deep color. Under optimal conditions, the proposed method detected B[a]P in OFCs at 0.42 -300 mg/kg, and limit of detection was 0.23 -1.07 mg/kg. The recovery rate was 88 -106% with a coefficient of variation of 1.46 -6.35%. Confirmed by natural positive OFCs samples and high-performance liquid chromatography, this GICA is accurate and reliable, with great potential for rapid and cost-effective on -site detection.

Amitraz (AMT) is a broad-spectrum formamidine insecticide and acaricide. In this study, we produced an antiAMT monoclonal antibody (mAb) with high performance. The half-maximal inhibitory concentration of the antiAMT mAb was 4.418 ng/mL, the cross reactivity with other insecticides was negligible, and an affinity constant was 2.06 x 109 mmol/L. Additionally, we developed an immunochromatographic assay for the rapid detection of AMT residues in oranges, tomatoes, and eggplants. The cut-off values were 2000 mu g/kg in oranges and tomato samples and 1000 mu g/kg in eggplant samples and the calculated limits of detection were 14.521 mu g/kg, 6.281 mu g/ kg, and 3.518 mu g/kg in oranges, tomatoes, and eggplants, respectively, meeting the detection requirements for AMT in fruits and vegetables. The recovery rates ranged between 95.8 % and 105.2 %, consistent with the recovery rates obtained via LC-MS/MS. Our developed immunochromatographic assay can effectively, accurately, and rapidly determine AMT residues in oranges, tomatoes, and eggplants.

Butralin is a dinitrobenzene pesticide, has been widely used as a herbicide in many crops. Its high levels of residues threaten the ecological balance and human health. Therefore, establishment of a sensitive monoclonal antibody (mAb) for rapid detection of butralin residues is critical. In this study, special haptens were designed with good preservation of the characteristic structure of target compound. After mice immunization, a highly sensitive monoclonal antibody was produced. The half -maximum inhibitory concentration (IC 50 ) was 1.936 ng/ mL. And we applied it to develop a method of lateral flow immunoassay (LFIA), with vLOD value of the LFIA strip to be 10 ng/mL. In watermelon and pear samples, the cLOD values of the LFIA strip were 0.432 ng/mL and 0.426 ng/mL, respectively. The recoveries of the developed method ranged from 94.4% +/- 2.1%-112.1% +/- 3.4% and 89% +/- 5.4%-103% +/- 4.1% in watermelons and pears samples, with a CV of 2.9%-3.4% and 2.2%-5.2%, respectively. The results demonstrated that the developed method showed great prospect in the detection and monitoring of butralin in real food samples.