Food safety and quality control pose serious issues to food industry and public health domains, in general, with direct effects on consumers. Any physical, chemical, or biological unexpected or ...unidentified food constituent may exhibit harmful effects on people and animals from mild to severe reactions. According to the World Health Organization (WHO), unsafe foodstuffs are especially dangerous for infants, young children, elderly, and chronic patients. It is imperative to continuously develop new technologies to detect foodborne pathogens and contaminants in order to aid the strengthening of healthcare and economic systems. In recent years, peptide-based sensors gained much attention in the field of food research as an alternative to immuno-, apta-, or DNA-based sensors. This review presents an overview of the electrochemical biosensors using peptides as molecular bio-recognition elements published mainly in the last decade, highlighting their possible application for rapid, non-destructive, and in situ analysis of food samples. Comparison with peptide-based optical and piezoelectrical sensors in terms of analytical performance is presented. Methods of foodstuffs pretreatment are also discussed.
Vancomycin (VAN) is a glycopeptide antibiotic, active against Gram-positive bacteria resistant to other antibiotics. VAN therefore needs to be monitored for maximum efficacy and minimum toxicity. ...Electrochemical sensors can be used for this purpose, using the direct electrochemical signal of VAN. Due to its molecular complexity and the need for analysis from complex matrices, the electrochemical detection of VAN requires the development of a complex electrochemical fingerprint (CEF), which covers a large variety of possible combinations of samples and interferents at concentrations of interest.
The objective of this study was to develop a CEF for VAN, involving a battery of tests and the elucidation of the mechanism of anodic oxidation of VAN, using high-performance liquid chromatography coupled with mass-spectrometric analysis of the products obtained after small-scale electrolysis.
A CEF for VAN was obtained, describing the electrochemical behavior of VAN at different commercially available screen-printed electrodes, with several electrolytes, considering successive analyses, after simple pretreatments, and examining both anodic and cathodic peaks. The concept was successfully applied to analysis of VAN in real samples and in the presence of some common interferents. Furthermore, a two-step combined electrochemical–chemical mechanism was proposed for the electrooxidation of VAN.
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•Therapeutic drug monitoring of vancomycin is needed for maximum efficacy.•A battery of tests with different commercially available SPEs was performed.•Both anodic and cathodic electrochemical analyses were performed.•A complex 3D electrochemical fingerprint for vancomycin was produced.•A mechanism for anodic oxidation of vancomycin was proposed.
In this study, a new electrochemical sensor was developed for the detection of cefalexin (CFX), based on the use of a molecularly imprinted polymer (MIP) obtained by electro‒polymerization in an ...aqueous medium of indole-3-acetic acid (I3AA) on a glassy carbon electrode (GCE) and on boron-doped diamond electrode (BDDE). The two different electrodes were used in order to assess how their structural differences and the difference in the potential applied during electrogeneration of the MIP translate to the performances of the MIP sensor. The quantification of CFX was performed by using the electrochemical signal of a redox probe before and after the rebinding of the template. The modified electrode was characterized using atomic force microscopy (AFM), scanning electron microscopy (SEM), cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The influence of different parameters on the fabrication of the sensor was tested, and the optimized method presented high selectivity and sensitivity. The MIP-based electrode presented a linear response for CFX concentration range of 10 to 1000 nM, and a limit of detection of 3.2 nM and 4.9 nM was obtained for the BDDE and the GCE, respectively. The activity of the sensor was successfully tested in the presence of some other cephalosporins and of other pharmaceutical compounds. The developed method was successfully applied to the detection of cefalexin from real environmental and pharmaceutical samples.
Healthcare-associated infections can occur in different care units and can affect both patients and healthcare professionals. Bacteria represent the most common cause of nosocomial infections and, ...due to the excessive and irrational use of antibiotics, resistant organisms have appeared. The most important healthcare-associated infections are central line-associated bloodstream infections, catheter-associated urinary tract infections, surgical site, soft tissue infections, ventilator-associated pneumonia, hospital acquired pneumonia, and
colitis. In Europe, some hospitalized patients develop nosocomial infections that lead to increased costs and prolonged hospitalizations. Healthcare-associated infection prevalence in developed countries is lower than in low-income and middle-income countries such as Romania, an Eastern European country, where several factors contribute to the occurrence of many nosocomial infections, but official data show a low reporting rate. For the rapid identification of bacteria that can cause these infections, fast, sensitive, and specific methods are needed, and they should be cost-effective. Therefore, this review focuses on the current situation regarding healthcare-associated infections in Europe and Romania, with discussions regarding the causes and possible solutions. As a possible weapon in the fight against the healthcare-associated infections, the diagnosis methods and tests used to determine the bacteria involved in healthcare-associated infections are evaluated.
The rapid diagnosis of Pseudomonas aeruginosa infection is very important because this bacterium is one of the main sources of healthcare-associated infections. Pseudomonas quinolone signal (PQS) is ...a specific molecule for quorum sensing (QS) in P. aeruginosa, a form of cell-to-cell bacterial communication and its levels can allow the determination of the bacterial population. In this study, the development of the first electrochemical detection of PQS using screen-printed electrodes modified with carbon nanotubes (CNT-SPE) is reported. The electrochemical fingerprint of PQS was determined using different electrode materials and screen-printed electrodes modified with different nanomaterials. The optimization of the method in terms of electrolyte, pH, and electrochemical technique was achieved. The quantification of PQS was performed using one of the anodic peaks in the electrochemical fingerprint of the PQS on the CNT-SPE. The sensor exhibited a linear range from 0.1 to 15 µM, with a limit of detection of 50 nM. The sensor allowed the selective detection of PQS, with low interference from other QS molecules. The sensor was successfully applied to analysis of real samples (spiked urine and human serum samples, spiked microbiological growth media, and microbiological cultures).
Illicit drugs use and abuse remains an increasing challenge for worldwide authorities and, therefore, it is important to have accurate methods to detect them in seized samples, biological fluids and ...wastewaters. They are recently classified as the latest group of emerging pollutants as their consumption increased tremendously in recent years. Nanomaterials have gained much attention over the last decade in the development of sensors for a myriad of applications. The applicability of these nanomaterials, functionalized or not, significantly increases and it is therefore highly suitable for use in the detection of illicit drugs. We have assessed the suitability of various nanoplatforms, such as graphene (GPH), multi-walled carbon nanotubes (MWCNTs), gold nanoparticles (AuNPs) and platinum nanoparticles (PtNPs) for the electrochemical detection of illicit drugs. GPH and MWCNTs were chosen as the most suitable platforms and cocaine, 3,4-methylendioxymethamfetamine (MDMA), 3-methylmethcathinone (MMC) and α-pyrrolidinovalerophenone (PVP) were tested. Due to the hydrophobicity of the nanomaterials-based platforms which led to low signals, two strategies were followed namely, pretreatment of the electrodes in sulfuric acid by cyclic voltammetry and addition of Tween 20 to the detection buffer. Both strategies led to an increase in the oxidation signal of illicit drugs. Binary mixtures of illicit drugs with common adulterants found in street samples were also investigated. The proposed strategies allowed the sensitive detection of illicit drugs in the presence of most adulterants. The suitability of the proposed sensors for the detection of illicit drugs in spiked wastewaters was finally assessed.
Pseudomonas aeruginosa, an opportunistic Gram-negative bacterium, is one of the main sources of infections in healthcare environments, making its detection very important. N-3-oxo-dodecanoyl ...L-homoserine lactone (3-O-C12-HSL) is a characteristic molecule of quorum sensing—a form of cell-to-cell communication between bacteria—in P. aeruginosa. Its detection can allow the determination of the bacterial population. In this study, the development of the first electrochemical aptasensor for the detection of 3-O-C12-HSL is reported. A carbon-based screen-printed electrode modified with gold nanoparticles proved to be the best platform for the aptasensor. Each step in the fabrication of the aptasensor (i.e., gold nanoparticles’ deposition, aptamer immobilization, incubation with the analyte) was optimized and characterized using cyclic voltammetry, differential pulse voltammetry, and electrochemical impedance spectroscopy. Different redox probes in solution were evaluated, the best results being obtained in the presence of Fe(CN)64−/Fe(CN)63−. The binding affinity of 106.7 nM for the immobilized thiol-terminated aptamer was determined using surface plasmon resonance. The quantification of 3-O-C12-HSL was performed by using the electrochemical signal of the redox probe before and after incubation with the analyte. The aptasensor exhibited a logarithmic range from 0.5 to 30 µM, with a limit of detection of 145 ng mL−1 (0.5 µM). The aptasensor was successfully applied for the analysis of real samples (e.g., spiked urine samples, spiked microbiological growth media, and microbiological cultures).
The recent increase in outbreaks of pathogenic bacteria and antimicrobial resistance represent major public health problems. Being the leading cause of death in humans, the bacterial infections need ...to be accurately and quickly diagnosed. Hence, the development of fast, cost-effective, sensitive and specific strategies for the detection of the targeted bacterium is of utmost importance.
This review presents a systematic, critical evaluation of the recent analytical methods for the characterization and diagnosis of infections caused by Pseudomonas aeruginosa. The clinical manifestations, incidence and treatment of the P. aeruginosa infection and the associated quorum sensing, biofilm formation and virulence factors are also discussed. An overview of a variety of analytical methods for the detection of P. aeruginosa is provided, including whole-cell detection (microbiological methods, biosensors), antigens, DNA, and relevant markers (quorum sensing molecules, virulence factors) detection. The latest trends in analytical methods, especially sensors, are the orientation towards portability and on-site detection. The efforts made so far to achieve these goals in the detection of P. aeruginosa and its markers are also presented and discussed in this review. The strengths and weaknesses of the current detection methods are evaluated, while exploring potential routes for further development.
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•Comprehensive description of analytical methods for Pseudomonas aeruginosa detection as whole bacterium.•The methods via some well-known metabolites and virulence factors were also described.•The main purpose was for diagnosis and to find the most effective treatment schemes.•The development of biofilms was also investigated with analytical methods.
The electrochemical oxidation of seven cephalosporins (ceftriaxone, cefotaxime, ceftazidime, cefadroxil, cefuroxime, cefaclor, cefalexin) was evaluated at high potential, using a bare boron-doped ...diamond electrode and the influence on the analytical response of the side chains was investigated. Based on the anodic oxidation of the cephalosporin nucleus, a simple and sensitive method was developed for the electrochemical detection of cefalexin by differential pulse voltammetry. After the optimization of the experimental conditions, a linear correlation was obtained between the peak height and the molar concentration of cefalexin in the range of 0.5 μM–700 μM, with a limit of detection of 34.74 ng mL−1. The anodic peak for cefalexin was evaluated in the presence of other cephalosporin molecules and of other common interferents. The developed method was applied to detection of cefalexin from real environmental, biomedical and pharmaceutical samples, with good results. The electrochemical oxidation of cephalosporins was successfully adapted for flow injection analyses, with sensitive and reproducible successive analyses of cefalexin, in different concentrations. The flow analyses allowed also the determination of the total amount of cephalosporins found in the sample.
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•The electrochemical oxidation at BDDE of seven cephalosporins was evaluated at high potential.•The influence on the analytical response of the cephalosporin side chains was investigated.•A simple and sensitive method was developed for the electrochemical detection of cefalexin by DPV.•Successful cefalexin detection from real environmental, biomedical and pharmaceutical samples.•The anodic oxidation of cephalosporins was successfully adapted for flow injection analyses.
•Selective & sensitive electrochemical detection of cyclic diguanosine-monophosphate.•Portable, easy-to-use screen-printed electrode modified with carbon nanotubes.•The sensor detected the biofilm ...formed by E. coli, P. aeruginosa or P. vulgaris.
The identification and monitoring of biofilm is of utmost importance because it ensures the survival of bacteria in a variety of environments, such as nature, medical indwelling devices, hospital surfaces, or the food industry. Here, we describe the novel application of a screen-printed electrode modified with nanomaterials for the in situ detection of bacterial biofilm. This approach enables simple, rapid, and highly sensitive and selective electrochemical detection of cyclic diguanosine-monophosphate (cdGMP). The best electrochemical signal of cdGMP was obtained after testing several electrode materials and screen-printed electrodes modified with different nanomaterials, different electrolyte solutions, pH, and electrochemical technique parameters. Using the anodic peak of the cdGMP on screen-printed electrodes modified with carbon nanotubes (CNT-SPE), the sensor showed excellent sensitivity, with a 25 nM–1 µM linear range, and a limit of detection of 15 nM. The sensor allowed the selective detection of cdGMP, with low interference from other molecules and was successfully applied to real sample analyses (laboratory biofilm produced by various bacterial species over distinct time intervals).
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