Wavelength-interrogated optical biosensor for multi-analyte screening of sulfonamide, fluoroquinolone, β-lactam and tetracycline antibiotics in milk

Bibliometrics Analysis of Research Progress of Electrochemical Detection of Tetracycline Antibiotics

Tetracycline is a broad-spectrum class of antibiotics. The use of excessive doses of tetracycline antibiotics can result in their residues in food, posing varying degrees of risk to human health. Therefore, the establishment of a rapid and sensitive field detection method for tetracycline residues is of great practical importance to improve the safety of food-derived animal foods. Electrochemical analysis techniques are widely used in the field of pollutant detection because of the simple detection principle, easy operation of the instrument, and low cost of analysis. In this review, we summarize the electrochemical detection of tetracycline antibiotics by bibliometrics. Unlike the previously published reviews, this article reviews and analyzes the development of this topic. The contributions of different countries and different institutions were analyzed. Keyword analysis was used to explain the development of different research directions. The results of the analysis revealed that developments and innovations in materials science can enhance the performance of electrochemical detection of tetracycline antibiotics. Among them, gold nanoparticles and carbon nanotubes are the most used nanomaterials. Aptamer sensing strategies are the most favored methodologies in electrochemical detection of tetracycline antibiotics.

A highly reproducible SERS sensor based on an Au nanoparticles/graphene oxide hybrid nanocomposite for label-free quantitative detection of antibiotics

Ampicillin and nitrofurantoin, as broad-spectrum antibiotics, are widely used in the prevention of animal diseases and to ensure livestock growth. Large amounts of antibiotic residues exist in animal-derived foods, affecting food quality and safety, causing adverse side effects, such as allergic and toxic reactions, and increasing bacterial resistance. A sensitive surface enhanced Raman scattering (SERS) sensor is provided to detect low-concentration antibiotics (ampicillin and nitrofurantoin). The sensor is based on an Au nanoparticles/graphene oxide hybrid nanocomposite prepared by an in situ reduction method. The detection limits of ampicillin and nitrofurantoin are as low as 0.01 ng mL^-1 and 5 ng mL^-1, respectively. The relative spectral intensity of the nitrofurantoin characteristic peak has a good linear relationship with the concentration of nitrofurantoin in the range of 500 ng mL^-1 and 5 ng mL^-1 (R² = 0.99235). The structure also allows multi-sample measurement for a variety of antibiotics at the same time. The SERS sensor is easy to prepare, with high uniformity and reproducibility, and the sample does not require complex pretreatment and preparation. Sensitive and quantitative detection of antibiotics by the SERS sensor is of great interest in the fields of health care, food preparation, and environmental sampling.

Biosensing approaches to detect potential milk contaminants: a comprehensive review

Accidentally present contaminants or intentionally added adulterants in milk lead potentially to delivering not only unhealthy but seriously hazardous products. Thorough, fast and sensitive analytical tools are essential for monitoring of milk quality, and for screening of any objectionable contaminants. Biosensors represent an innovative, time-efficient and on-site solution to assess milk quality in addition to their specificity towards target analytes alongside high accuracy within such complex matrices. Most biosensors use antibodies, aptamers or enzymes as the bio-receptor and rely on optical, electrochemical or thermometric transduction to generate a signal. The simplest biosensors appear to be those based on a colorimetric assay, being simple and having a signal that can be detected visually. Electrochemical sensors are more specific and sensitive, though with more complicated designs, whereas thermometric sensors have not been thoroughly explored concerning biosensing contaminants in milk. This review discusses recent advances in the field of biosensors and analyzes the various methods of bio-recognition and transduction with regard to their advantages, limitations, and application to milk products. Additionally, challenges facing further development of these strategies to fulfil the increasing demand for fast and on-line milk quality control are also presented.

Immunoassays on thiol-ene synthetic paper generate a superior fluorescence signal

The fluorescence-based detection of biological complexes on solid substrates is widely used in microarrays and lateral flow tests. Here, we investigate thiol-ene micropillar scaffold sheets ("synthetic paper") as the solid substrate in such assays. Compared to state-of-the-art glass and nitrocellulose substrates, assays on synthetic paper provide a stronger fluorescence signal, similar or better reproducibility, lower limit of detection (LOD), and the possibility of working with lower immunoreagent concentrations. Using synthetic paper, we detected the antibiotic enrofloxacin in whole milk with a LOD of 1.64 nM, which is on par or better than the values obtained with other common tests, and much lower than the maximum level allowed by European Union regulations. The significance of these results lays in that they indicate that synthetically-derived microstructured substrate materials have the potential to improve the performance of diagnostic assays.

A fiber optic nanoplasmonic biosensor for the sensitive detection of ampicillin and its analogs

A novel optical immunosensor for the screening of ampicillin (Amp) residues has been developed. The biosensor is based on fiber optic particle plasmon resonance detection and uses an enhancement method called as fiber optic nanogold-linked immunosorbent assay (FONLISA) for the sensitive detection of antibiotics. A commercial antibody which had a higher affinity for ampicillin than for other β-lactam antibiotics was chosen. A surface competitive binding assay was used in which a fixed concentration of antibiotic-conjugated gold nanoparticles (AuNPs) competes with free unlabeled antibiotic molecules to measure the amount of binding with antibody molecules immobilized on an optical fiber. The synthesis of the 11-mercaptoundecanoic acid (MUA)-ampicillin conjugate facilitates the attachment of the Amp molecules to AuNPs via MUA which acts as a linker between them. This AuNP-Amp conjugate was then used for the detection of β-lactam antibiotics. The practical limit of detection obtained for Amp was 0.74 ppb (7.4 × 10^-10 g/mL) which is lower than the recommended maximum residue limit (MRL) for β-lactams. The method also shows a wide linear range of 4 orders. Its applicability to the determination of ampicillin in spiked milk samples has been demonstrated with good recovery and reproducibility. Graphical abstract.

Boronic Acid Modified Polymer Nanoparticles for Enhanced Bacterial Deactivation

A new method has been developed to enhance the antibacterial efficiency of traditional antibiotics. Chloramphenicol-imprinted polymer particles were decorated with boronic acid to improve their binding to both Gram-negative and -positive bacteria. The polymer particles have a high antibiotic loading and provide a slow release of the antibiotic payload to deactivate the target bacteria. The boronic acid modified polymer particles not only contribute to enhanced antibacterial efficiency, but also have the potential to act as scavengers to remove unused antibiotic from the environment.

A kanamycin sensor based on an electrosynthesized molecularly imprinted poly-o-phenylenediamine film on a single-walled carbon nanohorn modified glassy carbon electrode

A single-walled carbon nanohorn (SWCNH) has been used to construct a molecularly imprinted electrochemical sensor for the first time. Kanamycin, a widely used aminoglycoside antibiotic, is used as a representative analyte to test the detection strategy. The kanamycin sensor was constructed by the electropolymerization of a molecularly imprinted poly-o-phenylenediamine film on a SWCNH modified glassy carbon electrode. The sensor was investigated in the presence or absence of kanamycin by cyclic voltammetry to verify the changes in the redox peak currents of K₃Fe(CN)₆. The sensor exhibits a linear range of 0.1-50 μM with a detection limit of 0.1 μM. It also shows high recognition ability, indicating that the SWCNH-based molecularly imprinted sensor is promising.

New methodologies in screening of antibiotic residues in animal-derived foods: Biosensors

Antibiotics are leading medicine asset for fighting against microbial infection, but also one of the important causes of death worldwide. Many antibiotics used as therapeutics and growth promotion agents in animals can lead to antibiotic residues in animal-derived food which harm the health of people. Hence, it is vital to screen antibiotic residues in animal derived foods. Typical methods for screening antibiotic residues are based on microbiological growth inhibition and immunological analyses. However these two methods have some disadvantages, such as poor sensitive, lack of specificity and etc. Therefore, it is necessary to develop simple, more efficient and high sensitive screening methods of antibiotic residues. These assays have been introduced for the screening of numerous food samples. Biosensors are emerging methods, applied in screening antibiotic residues in animal-derived foods. Two types of biosensors, whole-cell based biosensors and surface plasmon resonance-based sensors have been extensively used. Their advantages include portability, small sample requirement, high sensitivity and good specificity over the traditional screening methods.

Magnetic Nanoparticles for Antibiotics Detection

Widespread use of antibiotics has led to pollution of waterways, potentially creating resistance among freshwater bacterial communities. Microorganisms resistant to commonly prescribed antibiotics (superbug) have dramatically increased over the last decades. The presence of antibiotics in waters, in food and beverages in both their un-metabolized and metabolized forms are of interest for humans. This is due to daily exposure in small quantities, that, when accumulated, could lead to development of drug resistance to antibiotics, or multiply the risk of allergic reaction. Conventional analytical methods used to quantify antibiotics are relatively expensive and generally require long analysis time associated with the difficulties to perform field analyses. In this context, electrochemical and optical based sensing devices are of interest, offering great potentials for a broad range of analytical applications. This review will focus on the application of magnetic nanoparticles in the design of different analytical methods, mainly sensors, used for the detection of antibiotics in different matrices (human fluids, the environmental, food and beverages samples).

Comparison between a Direct-Flow SPR Immunosensor for Ampicillin and a Competitive Conventional Amperometric Device: Analytical Features and Possible Applications to Real Samples

In this research, we developed a direct-flow surface plasmon resonance (SPR) immunosensor for ampicillin to perform direct, simple, and fast measurements of this important antibiotic. In order to better evaluate the performance, it was compared with a conventional amperometric immunosensor, working with a competitive format with the aim of finding out experimental real advantages and disadvantages of two respective methods. Results showed that certain analytical features of the new SPR immunodevice, such as the lower limit of detection (LOD) value and the width of the linear range, are poorer than those of a conventional amperometric immunosensor, which adversely affects the application to samples such as natural waters. On the other hand, the SPR immunosensor was more selective to ampicillin, and measurements were more easily and quickly attained compared to those performed with the conventional competitive immunosensor.

A Flow SPR Immunosensor Based on a Sandwich Direct Method

In this study, we report the development of an SPR (Surface Plasmon Resonance) immunosensor for the detection of ampicillin, operating under flow conditions. SPR sensors based on both direct (with the immobilization of the antibody) and competitive (with the immobilization of the antigen) methods did not allow the detection of ampicillin. Therefore, a sandwich-based sensor was developed which showed a good linear response towards ampicillin between 10⁻³ and 10⁻¹ M, a measurement time of ≤20 min and a high selectivity both towards β-lactam antibiotics and antibiotics of different classes.

Biosensors, antibiotics and food

Antibiotics are medicine's leading asset for fighting microbial infection, which is one of the leading causes of death worldwide. However, the misuse of antibiotics has led to the rapid spread of antibiotic resistance among bacteria and the development of multiple resistant pathogens. Therefore, antibiotics are rapidly losing their antimicrobial value. The use of antibiotics in food production animals is strictly controlled by the European Union (EU). Veterinary use is regulated to prevent the spread of resistance. EU legislation establishes maximum residue limits for veterinary medicinal products in foodstuffs of animal origin and enforces the establishment and execution of national monitoring plans. Among samples selected for monitoring, suspected noncompliant samples are screened and then subjected to confirmatory analysis to establish the identity and concentration of the contaminant. Screening methods for antibiotic residues are typically based on microbiological growth inhibition, whereas physico-chemical methods are used for confirmatory analysis. This chapter discusses biosensors, especially whole-cell based biosensors, as emerging screening methods for antibiotic residues. Whole-cell biosensors can offer highly sensitive and specific detection of residues. Applications demonstrating quantitative analysis and specific analyte identification further improve their potential as screening methods.

Recent advances in sample preparation techniques and methods of sulfonamides detection - A review

Sulfonamides (SAs) have been the most widely used antimicrobial drugs for more than 70 years, and their residues in foodstuffs and environmental samples pose serious health hazards. For this reason, sensitive and specific methods for the quantification of these compounds in numerous matrices have been developed. This review intends to provide an updated overview of the recent trends over the past five years in sample preparation techniques and methods for detecting SAs. Examples of the sample preparation techniques, including liquid-liquid and solid-phase extraction, dispersive liquid-liquid microextraction and QuEChERS, are given. Different methods of detecting the SAs present in food and feed and in environmental, pharmaceutical and biological samples are discussed.

Simple and suitable immunosensor for β-lactam antibiotics analysis in real matrixes: milk, serum, urine

The anti-penicillin G was conjugated to avidin-peroxidase and biotin to obtain immunogen and competitor which were then used to develop a competitive immunosensor assay for the detection of penicillin G and other β-lactam antibiotics, with Kaff values of the order of 10(8) M(-1). The new immunosensor appears to afford a number of advantages in terms of sensitivity, possibility of "in situ" analysis, but especially of simplicity and lower costs, compared with other existing devices, or different chemical instrumental methods reported in the literature and used for the analysis of β-lactam compounds. Satisfactory results were found in the analysis of real matrixes and good recoveries were obtained by applying the standard addition method to spiked milk, urine, serum and drug samples. The new device uses an amperometric electrode for hydrogen peroxide as transducer, the BSA-penicillin G immobilized on polymeric membrane overlapping the amperometric transducer and the peroxidase enzyme as marker. It proved to be highly sensitive, inexpensive and easily reproducible; LOD was of the order of 10(-11)M. Lastly, the new immunosensor displayed low selectivity versus the entire class of β-lactam antibiotics and higher selectivity toward other classes of non-β-lactam antibiotics.

Rapid screening of multiple antibiotic residues in milk using disposable amperometric magnetosensors

Disposable amperometric magnetosensors, involving a mixture of modified-magnetic beads (MBs), for the multiplex screening of cephalosporins (CPHs), sulfonamides (SAs) and tetracyclines (TCs) antibiotic residues in milk are reported for the first time in this work. The multiplexed detection relies on the use of a mixture of target specific modified magnetic beads (MBs) and application of direct competitive assays using horseradish peroxidase (HRP)-labeled tracers. The amperometric responses measured at -0.20 V vs. the Ag pseudo-reference electrode of screen-printed carbon electrodes (SPCE) upon the addition of H2O2 in the presence of hydroquinone (HQ) as redox mediator, were used to monitor the extent of the different affinity reactions. The developed methodology, involving a simple and short pretreatment, allowed discrimination between no contaminated UHT and raw milk samples and samples containing antibiotic residues at the maximum residue limits (MRLs). The usefulness of the multiplexed magnetosensor was demonstrated by analyzing spiked milk samples in only 5 min. The results demonstrated that a clear discrimination of milk samples contaminated with antibiotics at their MRL level or their mixtures, allowing the identification of milk not complying with current legislation. These features make the developed methodology a promising alternative in the development of user-friendly devices for on-site analysis to ensure quality control for dairy products.

Chemical surface modifications for the development of silicon-based label-free integrated optical (IO) biosensors: a review

Increasing interest has been paid to label-free biosensors in recent years. Among them, refractive index (RI) optical biosensors enable high density and the chip-scale integration of optical components. This makes them more appealing to help develop lab-on-a-chip devices. Today, many RI integrated optical (IO) devices are made using silicon-based materials. A key issue in their development is the biofunctionalization of sensing surfaces because they provide a specific, sensitive response to the analyte of interest. This review critically discusses the biofunctionalization procedures, assay formats and characterization techniques employed in setting up IO biosensors. In addition, it provides the most relevant results obtained from using these devices for real sample biosensing. Finally, an overview of the most promising future developments in the fields of chemical surface modification and capture agent attachment for IO biosensors follows.

A Colorimetric Aptamer Biosensor Based on Gold Nanoparticles for the Ultrasensitive and Specific Detection of Tetracycline in Milk

This paper proposes a sensing strategy which employs an aptamer, unmodified gold nanoparticles (AuNP), and hexadecyltrimethylammonium bromide (CTAB) to detect tetracycline (TET) in raw milk. The method is based on the colorimetric assay of aggregating AuNP. In the absence of TET, the CTAB and aptamer form a complex which allows the aggregation of AuNP. In the presence of TET, the TET aptamer is exhausted first due to the formation of aptamer-TET complexes, which prevents assembly of the CTAB–aptamer supramolecule, causing a colour change and no aggregation of AuNP. This mechanism for the detection of TET proved to be sensitive and convenient. The colorimetric assay has a detection limit of 122 nM TET. This sensor has great potential for the sensitive, colorimetric detection of a wide range of molecular analytes.

Recent advances in multiplex immunoassays

The present review reports on the lastest developments in multiplex immunoassays. The selected examples are classified through their detection strategy (fluorescence, chemiluminescence, colorimetry or labeless) and their assay format (standard microtiter plate, polymeric membranes and glass slides). Finally, the degree of integration in a complete system, incorporating fluid handling and detection was also taken into account.

Disposable and integrated amperometric immunosensor for direct determination of sulfonamide antibiotics in milk

The preparation and performance of a disposable amperometric immunosensor, based on the use of a selective capture antibody and screen-printed carbon electrodes (SPCEs), for the specific detection and quantification of sulfonamide residues in milk is reported. The antibody was covalently immobilized onto a 4-aminobenzoic acid (4-ABA) film grafted on the disposable electrode, and a direct competitive immunoassay using a tracer with horseradish peroxidase (HRP) for the enzymatic labeling was performed. The amperometric response measured at -0.2 V vs the silver pseudo-reference electrode of the SPCE upon the addition of H(2)O(2) in the presence of hydroquinone (HQ) as mediator was used as transduction signal. The developed methodology showed very low limits of detection (in the low ppb level) for 6 sulfonamide antibiotics tested in untreated milk samples, and a good selectivity against other families of antibiotics residues frequently detected in milk and dairy products. These features, together with the short analysis time (30 min), the simplicity, and easy automation and miniaturization of the required instrumentation make the developed methodology a promising alternative in the development of devices for on-site analysis.

Biosensors for the analysis of microbiological and chemical contaminants in food

Increases in food production and the ever-present threat of food contamination from microbiological and chemical sources have led the food industry and regulators to pursue rapid, inexpensive methods of analysis to safeguard the health and safety of the consumer. Although sophisticated techniques such as chromatography and spectrometry provide more accurate and conclusive results, screening tests allow a much higher throughput of samples at a lower cost and with less operator training, so larger numbers of samples can be analysed. Biosensors combine a biological recognition element (enzyme, antibody, receptor) with a transducer to produce a measurable signal proportional to the extent of interaction between the recognition element and the analyte. The different uses of the biosensing instrumentation available today are extremely varied, with food analysis as an emerging and growing application. The advantages offered by biosensors over other screening methods such as radioimmunoassay, enzyme-linked immunosorbent assay, fluorescence immunoassay and luminescence immunoassay, with respect to food analysis, include automation, improved reproducibility, speed of analysis and real-time analysis. This article will provide a brief footing in history before reviewing the latest developments in biosensor applications for analysis of food contaminants (January 2007 to December 2010), focusing on the detection of pathogens, toxins, pesticides and veterinary drug residues by biosensors, with emphasis on articles showing data in food matrices. The main areas of development common to these groups of contaminants include multiplexing, the ability to simultaneously analyse a sample for more than one contaminant and portability. Biosensors currently have an important role in food safety; further advances in the technology, reagents and sample handling will surely reinforce this position.

Portable surface plasmon resonance immunosensor for the detection of fluoroquinolone antibiotic residues in milk

An inexpensive and portable surface plasmon resonance (SPR) sensor, SPReeta Evaluation Kit SPR3, has been used to develop a biosensor for the determination of fluoroquinolone antibiotics (FQs) and to demonstrate its performance analyzing FQ residues in milk samples. The SPReeta three-channel gold chips were activated with a mixed self-assembled monolayer (m-SAM) and functionalized with a FQ haptenized protein. Binding of the antibody produced a concentration-dependent increase of the SPR signal as a result of the change in the refraction index. Similarly, the presence of the FQ produced a dose-dependent decrease of the response, which allowed a good limit of detection (LOD) to be obtained (1.0 ± 0.4 μg L(-1) for enrofloxacin in buffer). The response was reproducible in all three channels, on different injections and days, and also between chips. Milk samples could be analyzed after a simple sample treatment involving fat removal by centrifugation and dilution with water. Under these conditions calibration curves were obtained showing that FQ residues can be analyzed in milk samples with an IC(50) value of 26.4 ± 7.2 μg L(-1) and a LOD of 2.0 ± 0.2 μg L(-1) (for enrofloxacin), far below the European Union regulations for this antibiotic family in this matrix. Finally, the paper also demonstrates that the biosensor is able to selectively detect the presence of FQs in milk samples, even in the presence of other antibiotics. Enrofloxacin, ciprofloxacin, and norfloxacin residues were detected in blind samples supplied by Nestlé Co.

Photonics-on-a-chip: recent advances in integrated waveguides as enabling detection elements for real-world, lab-on-a-chip biosensing applications

By leveraging advances in semiconductor microfabrication technologies, chip-integrated optical biosensors are poised to make an impact as scalable and multiplexable bioanalytical measurement tools for lab-on-a-chip applications. In particular, waveguide-based optical sensing technology appears to be exceptionally amenable to chip integration and miniaturization, and, as a result, the recent literature is replete with examples of chip-integrated waveguide sensing platforms developed to address a wide range of contemporary analytical challenges. As an overview of the most recent advances within this dynamic field, this review highlights work from the last 2-3 years in the areas of grating-coupled, interferometric, photonic crystal, and microresonator waveguide sensors. With a focus towards device integration, particular emphasis is placed on demonstrations of biosensing using these technologies within microfluidically controlled environments. In addition, examples of multiplexed detection and sensing within complex matrices--important features for real-world applicability--are given special attention.

A label-free and portable multichannel surface plasmon resonance immunosensor for on site analysis of antibiotics in milk samples

Techniques for immunosensing like surface plasmon resonance (SPR) may respond to the need for rapid screening methods to improve food safety. This paper describes the development of a novel portable six channel SPR biosensor based on the plasmon of gold diffraction grating surface for simultaneous multianalyte antibiotic detection in milk samples. Representative congeners from three important antibiotic families (FQs: fluoroquinolones, SAs: sulfonamides and CAP: phenicols) were chosen for this study. The chips are covalently biofunctionalized with haptenized proteins by means of a previously formed mixed self assembled monolayer (m-SAM) prepared using two types of mercapto alkyl reagents containing polyethyleneglycol (PEG) units. The samples or standards are mixed with specific polyclonal antibodies and injected into the sensor device. The detectability accomplished is very good (i.e. in buffer, enrofloxacin, 0.30 μg L(-1); sulfapyridine, 0.29 μg L(-1); and chloramphenicol, 0.26 μg L(-1)) and whole milk samples can be analyzed directly without clean-up steps, by just diluting the sample five times with water to remove non-specific interferences caused by the matrix. Although the detectability of CAP regarding the MRPL (minimum required performance limit) is slightly compromised by the dilution, the detectability accomplished by FQs and SAs was far below the maximum residue levels (MRLs) established by the European Union.

Surface plasmon resonance analysis of antibiotics using imprinted boronic acid-functionalized Au nanoparticle composites

Au nanoparticles (NPs) are functionalized with thioaniline electropolymerizable groups and (mercaptophenyl)boronic acid. The antibiotic substrates neomycin (NE), kanamycin (KA), and streptomycin (ST) include vicinal diol functionalities and, thus, bind to the boronic acid ligands. The electropolymerization of the functionalized Au NPs in the presence of NE, KA, or ST onto Au surfaces yields bisaniline-cross-linked Au NP composites that, after removal of the ligated antibiotics, provide molecularly imprinted matrixes which reveal high sensitivities toward the sensing of the imprinted antibiotic analytes (detection limits for analyzing NE, KA, and ST correspond to 2.00 +/- 0.21 pM, 1.00 +/- 0.10 pM, and 200 +/- 30 fM, respectively). The antibiotics are sensed by surface plasmon resonance (SPR) spectroscopy, where the coupling between the localized plasmon of the NPs and the surface plasmon wave associated with the Au surface is implemented to amplify the SPR responses. The imprinted Au NP composites are, then, used to analyze the antibiotics in milk samples.

Label-free immunochemistry approach to detect and identity antibiotics in milk

The rise of antibiotic-resistant bacteria is a major concern for the continued health and well-being of the general population. The widespread use of antibiotics within the farming industry is one of the factors that have been linked to the appearance of these resistant strains. Regulation exists to prevent antibiotic foodstuffs such as milk being distributed to consumers; however, for this to be effective, methods must exist for testing the milk to enforce these regulations. Current techniques are often time consuming and expensive, especially when applied to large number of samples. This has led to an interest in milk analyses, which can be carried out outside the laboratory. The development of immunosensors that exploit the exquisite specificity of antibody binding has been studied, both using labeled antibodies such as ELISA assays and, more recently, label-free approaches that directly detect the presence of the antibiotic on binding to a specific antibody. Within this review, we detail recent advances in the detection of antibiotics, especially in milk, using a variety of methods. Various techniques such as electrochemical and surface plasmon resonance methods are described.