Competitive Format Research Articles

Development of a bioluminescent immunoassay based on Fc-specific conjugated antibody–nanoluciferase immunoreagents for determining aflatoxin B1

Aflatoxin B1 (AFB1) is a potent carcinogen, and is among the most hazardous mycotoxins in agricultural products. Therefore, the development of sensitive and convenient detection methods for AFB1 is significant for food safety against mycotoxins. Herein, a bioluminescent enzyme immunoassay (BLEIA) was developed for ultrasensitive detection of AFB1, based on the novel Fc-specific antibody–nanoluciferase (Ab–Nluc) conjugates which were fabricated using an IgG-binding protein-assisted photo-conjugation strategy. In indirect competitive immunoassay format, the proposed BLEIA exhibited the detection limit of 0.0232 ng mL−1, which was 37.4-fold lower than that obtained using the classical enzyme-linked immunosorbent assay (ELISA) based on Ab–horseradish peroxidase (Ab–HRP) chemical conjugates (0.868 ng mL−1). Meanwhile, the BLEIA exhibited high accuracy and precision. Thus, the proposed Fc-specific Ab–Nluc conjugates-based BLEIA provides an ultrasensitive and reliable method for detecting toxins and has potential for use in food safety monitoring.

Janus-structured colorimetric and fluorescent nanocomposites with highly luminescent retention to enhance point-of-care diagnosis

Lateral flow immunoassay (LFIA) with dual-readout signals offers significant advantages in point-of-care testing due to its adaptability to various analysis scenarios. However, colorimetric and fluorescent nanocomposites (cf-NCs) composed of plasmonic and luminescent components often suffer from low luminescent efficiency because of severe optical interference between the two functional components. Herein, we propose a simple self-assembly strategy for fabricating novel cf-NCs with a Janus structure (J-cf-NCs) using oleylamine ligand-coated gold nanoparticles (OA-AuNPs) and aggregation-induced emission luminogens (AIEgens) as building blocks. For comparison, two other cf-NCs with core–shell (CS-cf-NCs) and co-embedding (CE-cf-NCs) structures were synthesized to explore the effects of spatial intersection of OA-AuNPs and AIEgens on their optical properties. Our results demonstrate that J-cf-NCs exhibit the highest fluorescence retention (75 %), as the face-to-face spatial distribution of OA-AuNPs and AIEgens effectively prevents fluorescence resonance energy transfer and minimizes inner-filter effect-induced fluorescence quenching. When integrated with the LFIA platform, the developed J-cf-NC-LFIA demonstrated excellent detection performance for both qualitative and quantitative determination of various target analytes in sandwich and competitive formats. Specifically, the visual limit of detection (vLOD) for C-reactive protein using J-cf-NC-LFIA showed approximately an eight-fold improvement compared to the classical colloidal gold test strip, while the quantitative sensitivity was two orders of magnitude greater than that of colorimetric readout. Furthermore, the vLOD for aflatoxin M1 in milk samples was 0.5 ng⋅mL–1, with a quantitative sensitivity 38-fold higher than that of the colorimetric pattern. Overall, the proposed J-cf-NCs exhibit significant potential for enhancing the detection performance of LFIA platforms.

Development in competitive immunoassay of a point-of-care testing for cotinine (COT) detection in urine.

We present a sensitive and selective lateral flow immunoassay (LFIA) for cotinine (COT), the primary metabolite of nicotine. COT is widely recognized as a superior biomarker to evaluate tobacco smoke exposure. The LFIA uses a competitive assay format where the COT-BSA capture competes with the target COT in urine samples for binding to the monoclonal antibody against COT (mAb-COT) conjugated with gold nanoparticles (mAb-COT-AuNPs). To improve the sensitivity and selectivity of the LFIA-COT, we focused on optimizing the diameter of AuNPs, the conjugation of mAb-COT, and the concentration of the COT-BSA capture. Our findings reveal that the utilization of 40 nm AuNPs in conjugation with a concentration of 4 mg mL-1 of mAb-COT demonstrated significantly greater efficacy compared to LFAs utilizing 20 nm AuNPs. Under the optimal conditions, the LFIA-COT demonstrated sensitive detection of COT at a level of 150 ng mL-1 within 15 min, as observed by the naked eye. It possesses a linear range of 25 to 200 ng mL-1 of COT, with the limit of detection (LOD) of 11.94 ng mL-1 in human urine samples when the color intensity is analyzed using ImageJ software. Our LFIA described here is simple and requires less time for COT detection. It can be used for the rapid and quantitative detection of COT in urine samples in clinical settings.

Competitive formats and the competitiveness of women’s elite futsal teams: should we follow men’s standards?

Competitive formats and the competitiveness of women’s elite futsal teams: should we follow men’s standards?

Production and characterization of biologicals for disease diagnosis and pathological evaluation of elephant endotheliotropic herpesvirus (EEHV)

Elephant endotheliotropic herpesviruses (EEHV) belong to the family Herpesviridae and cause a highly fatal hemorrhagic infection in elephants. EEHV poses a global threat to the already endangered elephant population. Since EEHV is a non-cultivable virus, there is a scarcity of specific diagnostics, therapeutics, and vaccines. In this study, our objective was to develop biologicals for diagnosis and pathological studies against the most prevalent EEHV1A/1B. We expressed two truncated fragments of the DNA polymerase, glycoprotein B (gB), and glycoprotein (gL) of EEHV in the prokaryotic system. Hyperimmune serum against the purified antigens was raised in rabbits and guinea pigs. We validated the reactivity of this hyperimmune serum using western blotting, ELISA, and immune-histochemistry on known positive infected tissues. Samples collected from 270 animals across various states in India were evaluated with these biologicals. The raised antibodies successfully demonstrated virus in immune-cytochemistry. Additionally, all known positive samples consistently exhibited significant inhibition in the OD values when used in the competitive format of ELISA across all four antigens when compared to the serum collected from known negative animals. An apparent sero-prevalence of 10 % was observed in the randomly collected samples. In summary, our study successfully developed and validated biologicals that will be invaluable for EEHV diagnosis and control.

Optimized detection of Salmonella typhimurium using aptamer lateral flow assay.

Salmonella typhimurium, a pathogenic bacterium with significant implications in medicine and the food industry, poses a substantial threat by causing foodborne illnesses such as typhoid fever. Accurate diagnosis of S. typhimurium is challenging due to its overlap symptoms with various diseases. This underscores the need for a precise and efficient diagnostic approach. In this study, we developed a biosensor using the Taguchi optimization method based on aptamer lateral flow assay (LFA) for the detection of S. typhimurium. Therefore, signal probe and nanobioprobe were designed using anti-Salmonella aptamer, conjugated with gold nanoparticles (GNPs), and used in LFA. The strategy of this test is based on a competitive format between the bacteria immobilized on the membrane and the bacteria present in the tested sample. Moreovere, the optimization of various factors affecting the aptamer LFA, including the concentration of bacteria (immobilized and into the sample) and the concentration of nanobioprop, were performed using the Taguchi test designing method. The data showed that the optimal conditions for the LFA reaction was 108CFU/mL of immobilized bacteria and 1.5μg/μL of nanobioprop concentration. Then, the visual detection limit of S. typhimurium was estimated as 105CFU/mL. The reaction results were obtained within 20min, and there were no significant cross-reactions with other food pathogens. In conclusion, the aptamer-LFA diagnostic method, optimized using the Taguchi approach, emerges as a reliable, straightforward, and accurate tool for the detection of S. typhimurium. Overall, this method can be a portable diagnostic kit for the detection and identification of bacteria.

A review of antibody, aptamer, and nanomaterials synergistic systems for an amplified electrochemical signal.

The synergy between biomolecules with inorganic nanomaterials and nanoparticles has been investigated over the past years, primarily to improve biomarker reception, generate signals, and amplify the signals generated. In this paper, several articles on aptamer-based and antibody-based electrochemical biosensors that target antigens were examined. Among the key characteristics identified were the electrochemical platform development, which includes the usage of nanomaterials as electroactive or electrocatalytic labels, crosslinking of the biological agent with inorganic compounds, and electrode coating to provide an electronic source and support efficient electron transfer. A single approach using labeled or unlabeled biological receptors has become advantageous due to its simple architecture and more straightforward application method. However, the dual system approach allows the incorporation of more nanomaterials to boost the signal and add more features to the electrochemical system. The dual system approach uses a capture and reporter probe in a competitive or sandwich detection format. The reporter probe is often labeled by an electroactive or electrocatalytic compound or immobilized in a nanocarrier, resulting in an increase in measured peak current in proportion to the target's concentration. The reported limit of detection and linear range for each platform is presented to assess its efficiency. Generally, the dual system aptasensor showed higher sensitivity, stability, and reproducibility than the immunosensor in comparable settings. The aptasensor showed promising results for the development of point-of-care type applications.

Fluorescence Polarization Assays for Organic Compounds in Food Safety.

Elevated concentrations of toxic organic compounds observed in food products pose serious dangers to human health. Both natural and artificial pollutants can cause food contamination. The stages of food production, packaging, transportation, and storage can also largely cause the appearance of undesirable substances in food products. The health consequences of ingesting food containing toxic contaminants range from mild gastroenteritis to deaths resulting from dysfunctional internal organs and neurological syndromes. The World Health Organization (WHO) sets recommendations for the content of such chemicals in food, including a minimum allowable concentration considered safe for human consumption. However, the control of food products from chemical pollutants is necessary. Moreover, fast, sensitive, and inexpensive methods are needed to detect them at the point of need. Currently, immune analysis methods are most widely used to determine pollutants in food. The development of fluorescence polarization immunoassay (FPIA) methods in a competitive format is a powerful and modern tool for detecting organic molecules in various matrices, thereby making FPIA methods useful for food safety applications. Due to the availability of portable devices for measuring the fluorescence polarization signal, FPIA methods can be used at the point of need. The variety of fluorescent labels and recognizing elements (receptors, monoclonal and polyclonal antibodies, and nanobodies) permits fluorescence polarization (FP) assays to detect significantly lower limits of organic substances. The FP assay is a homogeneous, fast, and quantitative method. The development of various formats of FP assays makes them promising in determining food pollutants. This review summarizes publications on FP analyses for detecting organic contaminants (pesticides, hormones, toxins, antibiotics, and other pharmaceuticals) in food products during 2018-2023. Further, it demonstrates the prospects for using this method to determine pollutants at the point of need and for detecting high molecular weight substances, fungi, and bacterial infections during food safety inspections.

A prototype of ultrasensitive time-resolved fluoroimmunoassay for the quantitation of lead in plasma using a fluorescence-enhanced europium chelate label for the detection system.

This study describes the prototype of a novel ultra-sensitive time-resolved fluoroimmunoassay (TRFIA) for the quantification of lead (Pb) in plasma. The assay procedures were conducted in 96-microwell plates and involved the competitive binding format. The assay used a mouse monoclonal antibody, designated as 2C33, that specifically recognized the diethylenetriamine pentaacetic acid chelate of Pb (Pb-DTPA) but did not recognize Pb-free DTPA chelator. The antigen used for coating onto the inner surfaces of assay plate microwells was Pb-DTPA conjugated with bovine serum albumin protein (Pb-DTPA-BSA). The competitive binding reaction occurred between Pb-DTPA chelates, formed in the sample solutions by treating the samples with an excess DTPA, and the coated Pb-DTPA-BSA for a limited quantity of 2C33 antibody binding sites. The antigen-antibody complex formed in the plate wells was quantified by a europium-DTPA-labeled secondary antibody and a fluorescence enhancement solution. The conditions of the assay were refined, and its optimum procedures were established. The TRFIA was validated following the immunoassay validation guidelines, and all of the validation criteria were acceptable. The working range of the assay was 20-300 pg mL-1 and its limit of quantitation was 20 pg mL-1. Metals that are commonly encountered in blood plasma did not interfere with Pb in the analysis by the proposed TRFIA. The assay was applied to the quantitation of Pb in plasma samples with satisfactory accuracy and precision. The results were compared favorably with those obtained by atomic emission spectroscopy. In conclusion, the present study represents the first TRFIA for the quantitation of Pb in plasma. The assay is superior to the existing atomic spectrometric methods and other immunoassays for Pb in terms of sensitivity, convenience, and analysis throughputs. The proposed TRFIA is anticipated to effectively contribute to assessing Pb concentrations and controlling the exposure of humans to its potential toxicity.

Methods and applications of noncompetitive hapten immunoassays.

Hapten immunoassays have found extensive application across various domains such as disease diagnostics, environmental monitoring, as well as the evaluation of food and pharmaceutical safety. These techniques traditionally rely on competitive assay formats and often face challenges with sensitivity and specificity. This review focuses on the emergent noncompetitive immunoassay technologies that promise to transcend these limitations through innovative approaches. Noncompetitive immunoassays, leveraging novel elements such as anti-idiotype antibodies, anti-immunocomplex (IC) antibodies, and the strategic use of nanomaterial-enhanced signal detection, are setting new benchmarks for analytical performance. These advancements not only enhance the detection capabilities but also significantly improve specificity inherent in traditional methods. Moreover, the integration of novel materials and binding reagents in these assays offers substantial improvements in assay dynamics, providing faster, more accurate, and reliable results. This review consolidates the latest methodologies and their applications, underlining the transformative impact of noncompetitive technologies in the sensitive detection of haptens across various fields.

Sensitive immunoenzyme assay for the detection of antibiotic flumequine in honey.

Fluoroquinolone antibiotics are used to cure and protect bees and apiaries from infections. Consequently, they may contaminate honey and other products of beekeeping. In this study, a highly sensitive immunoenzyme assay (EIA) was for the first time developed for the determination of a fluoroquinolone flumequine (FLU) in honey. The EIA was carried out in an indirect competitive format with colorimetric detection. The analysis was characterized by a low limit of detection of 30 pg mL-1. The polyclonal antibodies used showed no cross-reactivity with 24 other (fluoro)quinolones; the assay was highly specific only toward FLU. Different coating FLU-protein conjugates were tested to achieve the most sensitive competitive immunodetection. A highly simplified and rapid (3-5 min) sample preparation was proposed based on the 100-300 times dilution of honey by a buffer. The developed EIA has been tested to detect FLU in honey of different origins, namely acacia, flower, buckwheat, chestnut, and linden honey. It has been demonstrated that 76.2-115.9% of FLU could be determined by the assay. The versatility, simplicity, and rapidity of the EIA enable us to propose this method as an effective tool to control the contamination of honey.

An Aptamer-Based Lateral Flow Biosensor for Low-Cost, Rapid and Instrument-Free Detection of Ochratoxin A in Food Samples.

In this work, a simple and cost-efficient aptasensor strip is developed for the rapid detection of OTA in food samples. The biosensor is based on the lateral flow assay concept using an OTA-specific aptamer for biorecognition of the target analyte. The strip consists of a sample pad, a conjugate pad, a nitrocellulose membrane (NC) and an absorbent pad. The conjugate pad is loaded with the OTA-specific aptamer conjugated with gold nanoparticles (AuNPs). The test line of the NC membrane is loaded with a specific OTA-aptamer probe and the control line is loaded with a control probe. The assay is based on a competitive format, where the OTA present in the sample combines with the OTA aptamer-AuNP conjugate and prevents the interaction between the specific probe immobilized on the test line and the OTA aptamer-AuNP conjugates; therefore, the color intensity of the test line decreases as the concentration of OTA in the sample increases. Qualitative detection of OTA is performed visually, while quantification is performed by reflectance colorimetry using a commercial scanner and image analysis. All the parameters of the assay are investigated in detail and the analytical features are established. The visual limit of detection (LOD) of the strip is 0.05 ng mL-1, while the LOD for semi-quantitative detection using reflectance colorimetry is 0.02 ng mL-1. The lateral flow strip aptasensor is applied to the detection of OTA in wine, beer, apple juice and milk samples with recoveries in the range from 91 to 114%. The assay exhibits a satisfactory selectivity for OTA with respect to other mycotoxins and lasts 20 min. Therefore, the lateral flow strip aptasensor could be useful for the rapid, low-cost and fit-for-purpose on-site detection of OTA in food samples.

“Fields of Ideas” for Science Diplomacy in the context of Russian “Pivot to East”

The crisis in Russian relations with the West has become a key trigger for a real “Pivot to East” in Russian foreign policy. The new edition of the Foreign Policy Concept of the Russian Federation, approved by the Decree of the President of Russia dated March 31, 2023, proclaims and describes this turn in sufficient detail, expanding the space for scientific diplomacy within the framework of international humanitarian cooperation. This space is filled with “fields of ideas” that are formed within the framework of the relationship of the expert community with decision makers within the country and with foreign colleagues and partners. These “fields of ideas” are currently rather poorly organized “exhibitions of ideas” than “markets of ideas”, where their active production and exchange takes place. The study of the reasons for this using the tools of institutional constructivism, discursive institutionalism and “institutional logic” allowed us to identify the problems of their functioning and possible prospects for development. The latter require the active development of Russian and international “fields of ideas” within the framework of scientific diplomacy in a competitive format, while being ready to compete with both Western and “non-Western” actors. On the way of such transformation, there may be several institutional traps and dead ends, on the successful overcoming of which the success of such a transformation will depend.

A highly sensitive hyperbranched Au plasmonic blackbody immunochromatographic assay for detection of leucomalachite green in fish and shrimp

A novel immunochromatographic assay (ICA) based on hyperbranched Au plasmonic blackbodies (AuPBs) with a smartphone readout was fabricated for the detection of leucomalachite green (LMG) in fish and shrimp products. The ICA was carried out in a competitive immunoassay format with AuPBs as labels. The developed AuPBs-ICA allowed for the LMG detection with a low detection limit (0.15 μg L−1) within 5 min by the smartphone reader. With the label-AuPBs ICA, the color intensity response was linearly related to the concentrations of the LMG (0.2 −1.7 μg L−1). The test line signal could be clearly distinguished at a 1.7 μg L−1 LMG as a cut-off level by the naked eye, which is lower than the conventional colloidal gold nanoparticle (2 μg L−1) and star-shaped nanoparticles (1.9 μg L−1) labeling. LMG contamination in samples was determined with the proposed AuPBs-ICA and the enzyme-linked immunosorbent (ELISA). The AuPBs-ICA results showed good agreement with those from the ELISA. The proposed AuPBs-ICA has the potential to be used as a rapid, sensitive, and simple device for the analysis of LMG residues in fish and shrimp samples.

Affinity-Switchable Interaction of Biotin and Streptavidin for the Signal-ON Detection of Small Molecules.

Lateral flow assay (LFA) based on gold nanoparticles (AuNPs) is a widely used analytical device for the rapid analysis of environmental hazards and biomarkers. Typically, a sandwich-type format is used for macromolecule detection, in which the appearance of a red test line indicates a positive result (Signal-ON). In contrast, small molecule detection usually relies on a competitive assay, where the absence of a test line indicates positive testing (Signal-OFF). However, such a "Signal-OFF" reading is usually detected within a narrower dynamic range and tends to generate false-negative signals at a low concentration. Moreover, inconsistent readings between macromolecule and small molecule testing might lead to misinterpretation when used by nonskilled individuals. Herein, we report a "Signal-ON" small molecule competitive assay based on the sterically modulated affinity-switchable interaction of biotin and streptavidin. In the absence of a small molecule target, a large steric hindrance can be imposed on the biotin to prevent interaction with streptavidin. However, in the presence of the small molecule target, this steric effect is removed, allowing the biotin to bind to streptavidin and generate the desired test line. In this article, we demonstrate the selective detection of two small molecule drugs, sulfonamides and trimethoprim, using this simple and modular affinity-switchable lateral flow assay (ASLFA). We believe that this affinity-switchable approach can also be adapted in drug discovery and clinical diagnosis, where the competitive assay format is always used for the rapid analysis of small molecules.

Borrowing Stigma and Lender of Last Resort Policies

Abstract How should the lender of last resort provide liquidity to banks during periods of financial distress? During the 2008–2010 crisis, banks avoided borrowing from the Fed’s long-standing discount window but actively participated in its special monetary program, the Term Auction Facility, although both programs had the same borrowing requirements. Using an adverse selection model with endogenous borrowing decisions, we explain why the two programs suffer from different stigma costs and how the introduction of TAF incentivized banks’ borrowing. We discuss the empirical relevance of the model’s predictions. [Banks] deliberately did not ask for the liquidity they needed for fear of damaging their reputation—the ‘stigma’ problem… I do not think we were conscious of this before the crisis started and I do not think central banks have a convincing answer to it… This is, I think, still a challenge in how to manage the process of central bank provision of liquidity support. This is one of the big intellectual issues that has not been fully resolved. (Governor Mervyn King, Bank of England (2016)) For various reasons, including the competitive format of the auctions, [Term Auction Facility] has not suffered the stigma of conventional discount window lending and has proved effective for injecting liquidity into the financial system… Another possible reason that [Term Auction Facility] has not suffered from stigma is that auctions are not settled for several days, which signals to the market that auction participants do not face an immediate shortage of funds. (Ben Bernanke, testimony to U.S. House of Representatives (2010))

A smartphone-integrated multi-model thermal immunochromatographic assay for sensitive detection of histamine in real samples

A smartphone-integrated multi-model thermal immunochromatographic assay has been constructed for the detection of histamine by using anti-histamine antibody coupled Cu2−xSe nanoparticles (Cu2−xSe@antibody) as photothermal nanoprobes. Base on a competitive format, the coated histamine antigen on T-line and histamine simultaneously competed for binding the lateral flow photothermal signal probes. With the increase of histamine concentration, the temperature of Cu2−xSe@antibody on T-line was decreased under the 808 nm laser irradiation, which can be monitored via the smartphone-thermal imager combination device. In addition, the color on T-line from nanoprobes gradually disappeared, and the inhibition rate calculated from the obtained temperature on T-line was increased. The smartphone-integrated multi-model thermal immunochromatographic assay enables detection of histamine in the range of 0.1–10.0 μg/L with limit of detection as low as 0.09 μg/L. The histamine concentrations in crab, tuna, saury, mackerel, shrimp were 5.67 mg/kg, 83.73 mg/kg, 14.03 mg/kg, 21.30 mg/kg, 3.22 mg/kg detected by the developed thermal immunochromatographic assay, respectively. The developed multi-model strategy provided good sensitivity, simple operation, effectiveness and practicability for histamine in real samples compared to ultra-performance liquid chromatography-tandem mass spectrometry UPLC-MS/MS and ELISA.

Immunoaffinity Chromatography for Protein Purification and Analysis.

Immunoaffinity chromatography (IAC) is a type of liquid chromatography that uses immobilized antibodies or related binding agents as selective stationary phases for sample separation or analysis. The strong binding and high selectivity of antibodies have made IAC a popular tool for the purification and analysis of many chemicals and biochemicals, including proteins. The basic principles of IAC are described as related to the use of this method for protein purification and analysis. The main factors to consider in this technique are also presented under a discussion of the general strategy to follow during the development of a new IAC method. Protocols, as illustrated using human serum albumin (HSA) as a model protein, are provided for the use of IAC in several formats. This includes both the use of IAC with traditional low-performance supports such as agarose for off-line immunoextraction and supports used in high-performance IAC for on-line immunoextraction. The use of IAC for protein analysis as a flow-based or chromatographic immunoassay is also discussed and described using HSA and a competitive binding assay format as an example. © 2023 Wiley Periodicals LLC. Basic Protocol 1: Off-line immunoextraction by traditional immunoaffinity chromatography Basic Protocol 2: On-line immunoextraction by high-performance immunoaffinity chromatography Basic Protocol 3: Competitive binding chromatographic immunoassay.

Application of Highly Sensitive Immunosensor Based on Optical Waveguide Light-Mode Spectroscopy (OWLS) Technique for the Detection of the Herbicide Active Ingredient Glyphosate.

The herbicide active ingredient glyphosate is the most widely applied herbicidal substance worldwide. Currently it is the market-leading pesticide, and its use is projected to further grow 4.5-fold between 2022 and 2029. Today, glyphosate use exceeds one megaton per year worldwide, which represents a serious environmental burden. A factor in the overall boost in the global use of glyphosate has been the spread of glyphosate-tolerant genetically modified (GM) crops that allow post-emergence applications of the herbicide on these transgenic crops. In turn, cultivation of glyphosate-tolerant GM crops represented 56% of the glyphosate use in 2019. Due to its extremely high application rate, xenobiotic behaviour and a water solubility (11.6 mg/mL at 25 °C) unusually high among pesticide active ingredients, glyphosate has become a ubiquitous water pollutant and a primary drinking water contaminant worldwide, presenting a threat to water quality. The goal of our research was to develop a rapid and sensitive method for detecting this herbicide active ingredient. For this purpose, we applied the novel analytical biosensor technique optical waveguide light-mode spectroscopy (OWLS) to the label-free detection of glyphosate in a competitive immunoassay format using glyphosate-specific polyclonal antibodies. After immobilising the antigen conjugate in the form of a glyphosate conjugated to human serum albumin for indirect measurement, the sensor chip was used in a flow-injection analyser system. For the measurements, an antibody stock solution was diluted to 2.5 µg/mL. During the measurement, standard solutions were mixed with the appropriate concentration of antibodies and incubated for 1 min before injection. The linear detection range and the EC50 value of the competitive detection method were between 0.01 and 100 ng/mL and 0.60 ng/mL, respectively. After investigating the indirect method, we tested the cross-reactivity of the antibody with glyphosate and structurally related compounds.

Introduction. Political arithmetic: old and new

ABSTRACT The articles in this Special Issue arose from a workshop in June 2021 (https://peoplelikeyou.ac.uk/activities/people-like-you-a-new-political-arithmetic/) which considered whether we might understand the enormous variety of calculations we encounter today as a political arithmetic. Our proposal was that the term provides a powerful way to understand the political nature of calculations of economic and social value. In this introduction we showcase how contributors address the proposal in studies of personalisation, competitive test formats, algorithmic profiling, YouTube personalities and the significance of information as an increasingly important medium of ‘the social. We suggest that, together, these developments are transforming relations between the individual and society today in ways that both intensify inequalities and provide the basis for new forms of individual and collective identity.