We present a compact surface plasmon resonance (SPR) biosensor for the detection of bisphenol A (BpA), an endocrine-disrupting chemical. The biosensor is based on an SPR sensor platform (SPRCD) and the binding inhibition detection format. The detection of BpA in PBS and wastewater was performed at concentrations ranging from 0.05 to 1,000 ng/ml. The limit of detection for BpA in PBS and wastewater was estimated to be 0.08 and 0.14 ng/ml, respectively. It was also demonstrated that the biosensor can be regenerated for repeated use. Results achieved with the SPR biosensor are compared with those obtained using ELISA and HPLC methods.
A surface plasmon resonance (SPR) biosensor for simultaneous detection of multiple organic pollutants exhibiting endocrine-disrupting activity, namely atrazine, benzo[a]pyrene, 2,4-dichlorophenoxyacetic acid (2,4-D) and 4-nonylphenol, is reported. The biosensor utilizes a multichannel SPR sensor based on wavelength modulation of SPR and wavelength division multiplexing (WDM) of sensing channels, antibodies as biorecognition element and a competitive immunoassay detection format. An analysis time of 45 min (including 30-min incubation of the sample with antibodies) and limits of detection as low as 0.05, 0.07, 0.16 and 0.26 ng mL(-1) are demonstrated for benzo[a]pyrene, atrazine, 2,4-D and 4-nonylphenol, respectively. The biosensor is also shown to be regenerable and suitable for repeated use.
- MeSH
- Atrazine analysis MeSH
- Benzo(a)pyrene analysis MeSH
- Biosensing Techniques methods instrumentation MeSH
- Time Factors MeSH
- Endocrine Disruptors analysis MeSH
- Phenols analysis MeSH
- Financing, Organized MeSH
- Immunoassay methods MeSH
- 2,4-Dichlorophenoxyacetic Acid analysis MeSH
- Surface Plasmon Resonance methods instrumentation MeSH
- Sensitivity and Specificity MeSH
Bisphenol A (BpA) is a chemical that is extensively used in common plastic products, such as food and drink containers. It can leach from the plastics and penetrate into the human body, where it acts as an endocrine disruptor with significant risks to human health. In order to minimize the exposure of human populations to BpA, methods for the detection of BpA are needed. In this work, we present a novel surface plasmon resonance (SPR) biosensor for ultrasensitive detection of BpA. Our approach combines a binding inhibition assay with functionalized gold nanoparticles for the enhancement of sensor response. We demonstrate that the developed biosensor enables the detection of BpA in a wide range of concentrations (0.01 to 100,000 ng/mL) with an extremely low limit of detection-5.2 pg/mL.
Procalcitonin is a blood protein and precursor of the hormone calcitonin. The procalcitonin level increases due to bacterial infections, sepsis, and other related pathologies. Here, we present a simple biosensor for procalcitonin assay suitable for point-of-care tests as an alternative to the current laboratory methods. The biosensor was based on a QCM piezoelectric sensor and a conjugate of gold nanoparticles-antibodies conjugate. It was suitable for the procalcitonin assay in biological samples and fully correlated to the standard ELISA method, and it did not suffer false positive or negative results or interferences. The detection limit was equal to 37.8 ng/l and the quantification limit to 104 ng/l for a sample of 25 μl. The dynamic range of the assay was 37.8 ng/l to 30.0 μg/l. The practical relevance of the biosensor is expected considering the findings, and the possible application of the assay principle for the development of biosensors for other markers is inferred.
The enzyme acetylcholinesterase (AChE) is an important part of cholinergic nervous system, where it stops neurotransmission by hydrolysis of the neurotransmitter acetylcholine. It is sensitive to inhibition by organophosphate and carbamate insecticides, some Alzheimer disease drugs, secondary metabolites such as aflatoxins and nerve agents used in chemical warfare. When immobilized on a sensor (physico-chemical transducer), it can be used for assay of these inhibitors. In the experiments described herein, an AChE- based electrochemical biosensor using screen printed electrode systems was prepared. The biosensor was used for assay of nerve agents such as sarin, soman, tabun and VX. The limits of detection achieved in a measuring protocol lasting ten minutes were 7.41 × 10(-12) mol/L for sarin, 6.31 × 10(-12) mol /L for soman, 6.17 × 10(-11) mol/L for tabun, and 2.19 × 10(-11) mol/L for VX, respectively. The assay was reliable, with minor interferences caused by the organic solvents ethanol, methanol, isopropanol and acetonitrile. Isopropanol was chosen as suitable medium for processing lipophilic samples.
- MeSH
- Acetylcholinesterase chemistry MeSH
- Equipment Failure Analysis MeSH
- Biosensing Techniques instrumentation MeSH
- Chemical Warfare Agents analysis chemistry MeSH
- Cholinesterase Inhibitors analysis chemistry MeSH
- Equipment Design MeSH
- Conductometry instrumentation MeSH
- Neurotoxins analysis chemistry MeSH
- Reproducibility of Results MeSH
- Sensitivity and Specificity MeSH
- Publication type
- Journal Article MeSH
- Research Support, Non-U.S. Gov't MeSH
In this analysis, we present results from measurements performed to determine the stability of a hand tracking system and the accuracy of the detected palm and finger's position. Measurements were performed for the evaluation of the sensor for an application in an industrial robot-assisted assembly scenario. Human-robot interaction is a relevant topic in collaborative robotics. Intuitive and straightforward control tools for robot navigation and program flow control are essential for effective utilisation in production scenarios without unnecessary slowdowns caused by the operator. For the hand tracking and gesture-based control, it is necessary to know the sensor's accuracy. For gesture recognition with a moving target, the sensor must provide stable tracking results. This paper evaluates the sensor's real-world performance by measuring the localisation deviations of the hand being tracked as it moves in the workspace.
This paper describes the direct label-free detection of antibodies against the Epstein-Barr virus (anti-EBNA) using a surface plasmon resonance (SPR) biosensor. The antibody detection was performed using the immunoreaction between anti-EBNA and a respective synthetic peptide (EBNA-1), which was conjugated with bovine serum albumin (BSA-EBNA) and immobilized on the sensor surface. Three immobilization chemistries for the attachment of BSA-EBNA were investigated to optimize ligand density and minimize loss of EBNA-1 immunoreactivity. The developed SPR biosensor functionalized with the optimal immobilization method was calibrated and characterized in terms of detection limit, reproducibility, regenerability and storability. It was demonstrated that the sensor is capable of detecting concentrations of anti-EBNA as low as 0.2 ng/ml (approximately 1 pM) both in buffer and 1% human serum and can be stored and regenerated for repeated use.
- MeSH
- Equipment Failure Analysis MeSH
- Biosensing Techniques methods instrumentation MeSH
- Equipment Design MeSH
- Financing, Organized MeSH
- Immunoassay methods instrumentation MeSH
- Antibodies analysis immunology MeSH
- Epstein-Barr Virus Nuclear Antigens analysis immunology MeSH
- Herpesvirus 4, Human immunology MeSH
Label-free affinity biosensors offer a promising platform for the development of a new generation of medical diagnostic technologies. Nevertheless, when such sensors are used in complex biological media, adsorption of non-targeted medium components prevents the specific detection of the analyte. In this work, we introduce for the first time a biosensor assay based on surface plasmon resonance (SPR) capable of diagnosing different stages of Epstein-Barr virus (EBV) infections in clinical serum samples. This was achieved by simultaneous detection of the antibodies against three different antigens present in the virus. To prevent the interference of the fouling from serum during the measurement, the SPR chips were coated by an antifouling layer of a polymer brush of poly[oligo(ethylene glycol) methacrylate] grown by surface-initiated atom transfer radical polymerization. The bioreceptors were then attached via hybridization of complementary oligonucleotides. This allowed the sensor surface to be regenerated after measurement by disrupting the complementary pairs above the oligonucleotides' melting temperature and attaching new bioreceptors. In this way, the same sensing surface could be used repeatedly. The procedure used in this work will serve as a prototype strategy for the development of label-free affinity biosensors for diagnostics in blood serum or plasma samples. This is the first example of detection of marker of a disease in clinical serum samples by an optical affinity biosensor.
- MeSH
- Equipment Failure Analysis MeSH
- Biosensing Techniques instrumentation MeSH
- Equipment Design MeSH
- Immunoassay instrumentation MeSH
- Epstein-Barr Virus Infections blood diagnosis immunology MeSH
- Humans MeSH
- Surface Plasmon Resonance instrumentation MeSH
- Antibodies, Viral immunology MeSH
- Reproducibility of Results MeSH
- Sensitivity and Specificity MeSH
- Check Tag
- Humans MeSH
- Publication type
- Journal Article MeSH
- Research Support, Non-U.S. Gov't MeSH
The treatment of some inborn metabolism errors requires cholesterol substitution therapy. Cholesterol plays a vital role in the human body. Therefore, the majority of cholesterol determination techniques are targeted to blood and blood serum. Nevertheless, cholesterol determination in food is important as well. In this paper, cholesterol determination using differential pulse voltammetry (DPV) in dairy products (e.g., milk, clotted cream, yogurt, butter, etc.) is reported with a novel nonenzymatic sensor based on diphosphonic acid of 1,4-diacetylglycoluril (DPADGU) as an electrode surface modifier. Stable anodic response was obtained from cholesterol on the modified carbon-based electrode. The sensor has high stability, sensitivity (20 μA mol L-1 cm-2), and a wide linear range from 1 up to 200 μM. The LOD and LOQ values are 1.5 and 5.1 μM, respectively. The developed methods were successfully applied to the above mentioned dairy products. Graphical abstract ᅟ.
- MeSH
- Food Analysis instrumentation MeSH
- Biosensing Techniques MeSH
- Cholesterol analysis standards MeSH
- Electrochemical Techniques instrumentation MeSH
- Calibration MeSH
- Catalysis MeSH
- Hydrogen-Ion Concentration MeSH
- Reference Standards MeSH
- Spectroscopy, Fourier Transform Infrared MeSH
- Publication type
- Journal Article MeSH
We propose a label-free biosensor concept based on the charge state manipulation of nitrogen-vacancy (NV) quantum color centers in diamond, combined with an electrochemical microfluidic flow cell sensor, constructed on boron-doped diamond. This device can be set at a defined electrochemical potential, locking onto the particular chemical reaction, whilst the NV center provides the sensing function. The NV charge state occupation is initially prepared by applying a bias voltage on a gate electrode and then subsequently altered by exposure to detected charged molecules. We demonstrate the functionality of the device by performing label-free optical detection of DNA molecules. In this experiment, a monolayer of strongly cationic charged polymer polyethylenimine is used to shift the charge state of near surface NV centers from negatively charged NV- to neutral NV0 or dark positively charged NV+. Immobilization of negatively charged DNA molecules on the surface of the sensor restores the NV centers charge state back to the negatively charged NV-, which is detected using confocal photoluminescence microscopy. Biochemical reactions in the microfluidic channel are characterized by electrochemical impedance spectroscopy. The use of the developed electrochemical device can also be extended to nuclear magnetic resonance spin sensing.
