Solid-Contact Potentiometric Sensors Based on Stimulus-Responsive Imprinted Polymers for Reversible Detection of Neutral Dopamine

Herein, we present for the first time a novel potentiometric sensor based on the stimulus-responsive molecularly imprinted polymer (MIP) as a selective receptor for neutral dopamine determination. This smart receptor can change its capabilities to recognize according to external environmental stimuli. Therefore, MIP-binding sites can be regenerated in the polymeric membrane by stimulating with stimulus after each measurement. Based on this effect, reversible detection of the analyte via potentiometric transduction can be achieved. MIPs based on 4-vinylphenylboronic acid as the functional monomer were prepared as the selective receptor. This monomer can successfully bind to dopamine via covalent binding and forming a five- or six-membered cyclic ester in a weakly alkaline aqueous solution. In acidic medium, the produced ester dissociates and regenerates new binding sites in the polymeric membrane. The proposed smart sensor exhibited fast response and good sensitivity towards dopamine with a limit of detection 0.15 µM over the linear range 0.2–10 µM. The selectivity pattern of the proposed ISEs was also evaluated and revealed an enhanced selectivity towards dopamine over several phenolic compounds. Constant-current chronopotentiometry is used for evaluating the short-term potential stability of the proposed ISEs. The obtained results confirm that the stimulus-responsive MIPs provide an attractive way towards reversible MIP-based electrochemical sensors designation.

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Ion-selective Electrodes Based on PVC Membranes for Potentiometric Sensor Applications: A Review

International Journal of Membrane Science and Technology ◽

10.15379/2410-1869.2021.08.02.06 ◽

2021 ◽

Vol 8 (2) ◽

pp. 76-84

Author(s):

Mohan Chandra ◽

Kumar Vinod

Keyword(s):

Electrochemical Sensors ◽

Research Work ◽

Analytical Techniques ◽

Potentiometric Sensors ◽

Polymeric Membrane ◽

Ion Selective Electrodes ◽

Fast Method ◽

Toxic Substances ◽

Electroactive Material ◽

Sensor Applications

Ion-selective electrodes (ISEs) are potentiometric sensors used to measure some of the most critical analytes in environmental laboratory. Recently ion sensors are taking place of various analytical techniques, as they provide a convenient and fast method of electroanalysis. Ion-selective electrodes are simple, relatively inexpensive, robust, durable, and ideal to be used for the detection of heavy metal ions. Important characterisctics of ISEs are selectivity, response time, detection limit, working range, effect of pH etc. Lot of research work is being done for the formation of ISEs by using polymeric membrane incorporated with ionophores or electroactive material. Various types of Schiff bases, macromolecules and metal complexes may be used as ionophores along with plasticizer, ion-excluder for the membrane preparation. Ion-selective electrodes will be optimized for pH range, selectivity, sensitivity, working concentration range and lifetime before their use as sensor electrode for determining the concentration of ions in solution. Various researchers are working in the field to develop Ion-selective electrodes which shows better selectivity and sensitivity than the previously reported electrodes and can be used as electrocatalysts. These ISEs can be used as electrochemical sensors for the analysis of food products, drinking water, beverages, fertilizers, and for the analysis of sample containing toxic substances.

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Potentiometric Signal Transduction for Selective Determination of 1-(3-Chlorophenyl)piperazine “Legal Ecstasy” Through Biomimetic Interaction Mechanism

Chemosensors ◽

10.3390/chemosensors7030046 ◽

2019 ◽

Vol 7 (3) ◽

pp. 46

Author(s):

Eman El-Naby

Keyword(s):

Dynamic Range ◽

Limit Of Detection ◽

Interaction Mechanism ◽

High Sensitivity ◽

Fast Response ◽

Polymeric Membrane ◽

Selective Determination ◽

Sensitivity And Selectivity ◽

Pharmacologically Active

1-(3-chlorophenyl)piperazine (mCPP) is a wide spread new psychoactive substance produces stimulant and hallucinogenic effects similar to those sought from ecstasy. Hence, in the recent years, mCPP has been introduced by the organized crime through the darknet as a part of the illicit ecstasy market with a variable complex profile of pharmacologically active substances that pose problematic risk patterns among people who take these seized products. Accordingly, the design of selective sensors for the determination of mCPP is a very important demand. In this respect, a supramolecular architecture; [Na(15-crown-5)][BPh4] from the assembly of 15-crown-5 and sodium tetraphenylboron has been utilized as an ionophore, for the first time in the selective recognition of mCPP in conjunction with potassium tetrakis(p-chlorophenyl)borate and dioctylphthalate through polymeric membrane ion sensors. The ionophore exhibited a strong binding affinity that resulted in a high sensitivity with a slope closed to the ideal Nernstian value; 58.9 ± 0.43 mV/decade, a larger dynamic range from 10−6 to 10−2 M, a lower limit of detection down to 5.0 × 10−7 M and a fast response time of 5 s. Very important also is it was afforded excellent selectivity towards mCPP over psychoactive substances of major concern, providing a potentially useful system for the determination of mCPP in the illicit market. On comparison with the natural β-cyclodextrin as an ionophore, it exhibited more sensitivity and selectivity estimated to be the superior.

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Surface Plasmon Resonance Assay for Label-Free and Selective Detection of HIV-1 p24 Protein

Biosensors ◽

10.3390/bios11060180 ◽

2021 ◽

Vol 11 (6) ◽

pp. 180

Author(s):

Lucia Sarcina ◽

Giuseppe Felice Mangiatordi ◽

Fabrizio Torricelli ◽

Paolo Bollella ◽

Zahra Gounani ◽

...

Keyword(s):

Limit Of Detection ◽

Covalent Binding ◽

Hiv Infections ◽

Selectivity Ratio ◽

Selective Detection ◽

Label Free ◽

Self Assembled Monolayer ◽

Label Free Detection ◽

P24 Protein ◽

Hiv 1

The early detection of the human immunodeficiency virus (HIV) is of paramount importance to achieve efficient therapeutic treatment and limit the disease spreading. In this perspective, the assessment of biosensing assay for the HIV-1 p24 capsid protein plays a pivotal role in the timely and selective detection of HIV infections. In this study, multi-parameter-SPR has been used to develop a reliable and label-free detection method for HIV-1 p24 protein. Remarkably, both physical and chemical immobilization of mouse monoclonal antibodies against HIV-1 p24 on the SPR gold detecting surface have been characterized for the first time. The two immobilization techniques returned a capturing antibody surface coverage as high as (7.5 ± 0.3) × 1011 molecule/cm2 and (2.4 ± 0.6) × 1011 molecule/cm2, respectively. However, the covalent binding of the capturing antibodies through a mixed self-assembled monolayer (SAM) of alkanethiols led to a doubling of the p24 binding signal. Moreover, from the modeling of the dose-response curve, an equilibrium dissociation constant KD of 5.30 × 10−9 M was computed for the assay performed on the SAM modified surface compared to a much larger KD of 7.46 × 10−5 M extracted for the physisorbed antibodies. The chemically modified system was also characterized in terms of sensitivity and selectivity, reaching a limit of detection of (4.1 ± 0.5) nM and an unprecedented selectivity ratio of 0.02.

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Molecularly imprinted polymer-based potentiometric sensor based on covalent recognition for determination of dopamine

Analytical Methods ◽

10.1039/d0ay02100h ◽

2021 ◽

Author(s):

Chan Wang ◽

Longbin Qi ◽

Rongning Liang

Keyword(s):

Organic Compounds ◽

Molecularly Imprinted Polymer ◽

Potentiometric Sensor ◽

Potentiometric Sensors ◽

Polymeric Membrane ◽

Imprinted Polymer ◽

Molecularly Imprinted

Polymeric membrane potentiometric sensors based on molecularly imprinted polymer (MIP) have been successfully designed for detection of organic compounds both in ionic and neutral forms. However, most of these sensors...

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Assay of Phospholipase D Activity by an Amperometric Choline Oxidase Biosensor

Sensors ◽

10.3390/s20051304 ◽

2020 ◽

Vol 20 (5) ◽

pp. 1304 ◽

Cited By ~ 1

Author(s):

Rosanna Ciriello ◽

Antonio Guerrieri

Keyword(s):

Phospholipase D ◽

Limit Of Detection ◽

High Sensitivity ◽

Fast Response ◽

Borate Buffer ◽

Choline Oxidase ◽

Linear Calibration ◽

Real Sample Analysis ◽

Polypyrrole Film ◽

Overoxidized Polypyrrole

A novel electrochemical method to assay phospholipase D (PLD) activity is proposed based on the employment of a choline biosensor realized by immobilizing choline oxidase through co-crosslinking on an overoxidized polypyrrole film previously deposited on a platinum electrode. To perform the assay, an aliquot of a PLD standard solution is typically added to borate buffer containing phosphatidylcholine at a certain concentration and the oxidation current of hydrogen peroxide is then measured at the rotating modified electrode by applying a detection potential of +0.7 V vs. SCE. Various experimental parameters influencing the assay were studied and optimized. The employment of 0.75% (v/v) Triton X-100, 0.2 mM calcium chloride, 5 mM phosphatidylcholine, and borate buffer at pH 8.0, ionic strength (I) 0.05 M allowed to achieve considerable current responses. In order to assure a controlled mass transport and, at the same time, high sensitivity, an electrode rotation rate of 200 rpm was selected. The proposed method showed a sensitivity of 24 (nA/s)⋅(IU/mL)−1, a wide linear range up to 0.33 IU/mL, fast response time and appreciable long-term stability. The limit of detection, evaluated from the linear calibration curve, was 0.005 IU/mL (S/N = 3). Finally, due to the presence of overoxidized polypyrrole film characterized by notable rejection properties towards electroactive compounds, a practical application to real sample analysis can be envisaged.

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Application of biosynthesized metal nanoparticles in electrochemical sensors

Journal of the Serbian Chemical Society ◽

10.2298/jsc200521077d ◽

2021 ◽

pp. 77-77

Author(s):

Totka Dodevska ◽

Dobrin Hadzhiev ◽

Ivan Shterev ◽

Yanna Lazarova

Keyword(s):

Green Synthesis ◽

Metal Nanoparticles ◽

Electrochemical Sensors ◽

Dynamic Range ◽

Limit Of Detection ◽

Cost Effective ◽

Electrochemical Sensing ◽

Synthesis Methods ◽

Range Limit ◽

Wide Range

Recently, the development of eco-friendly, cost-effective and reliable methods for synthesis of metal nanoparticles has drawn a considerable attention. The so-called green synthesis, using mild reaction conditions and natural resources as plant extracts and microorganisms, has established as a convenient, sustainable, cheap and environmentally safe approach for synthesis of a wide range of nanomaterials. Over the past decade, biosynthesis is regarded as an important tool for reducing the harmful effects of traditional nanoparticle synthesis methods commonly used in laboratories and industry. This review emphasizes the significance of biosynthesized metal nanoparticles in the field of electrochemical sensing. There is increasing evidence that green synthesis of nanoparticles provides a new direction in designing of cost-effective, highly sensitive and selective electrode-catalysts applicable in food, clinical and environmental analysis. The article is based on 157 references and provided a detailed overview on the main approaches for green synthesis of metal nanoparticles and their applications in designing of electrochemical sensor devices. Important operational characteristics including sensitivity, dynamic range, limit of detection, as well as data on stability and reproducibility of sensors have also been covered. Keywords: biosynthesis; green synthesis; nanomaterials; nanotechnology; modified electrodes

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Surface Epitope Coverage Affects Binding Characteristics of Bisphenol-A Functionalized Nanoparticles in a Competitive Inhibition Assay

Journal of Nanomaterials ◽

10.1155/2015/756056 ◽

2015 ◽

Vol 2015 ◽

pp. 1-9 ◽

Cited By ~ 3

Author(s):

Yang Lu ◽

Joshua Richard Peterson ◽

Erwann Luais ◽

John Justin Gooding ◽

Nanju Alice Lee

Keyword(s):

Bisphenol A ◽

Binding Sites ◽

Competitive Inhibition ◽

Limit Of Detection ◽

Molar Concentration ◽

Inhibition Assay ◽

Binding Characteristics ◽

Sensor Performance ◽

Reliable Detection ◽

Minimum Number

The biomolecule interface is a key element in immunosensor fabrication, which can greatly influence the sensor performance. This paper explores the effects of surface epitope coverage of small molecule functionalized nanoparticle on the apparent affinity (avidity) of antibody in a competitive inhibition assay using bisphenol-A (BPA) as a model target. An unconventional two-antibody competitive inhibition ELISA (ci-ELISA) using thiolated BPA modified gold nanoparticles (cysBPAv-AuNP) as a competing reagent was devised for this study. It was shown that the antibody complexation with cysBPAv-AuNPs required a minimum number of surface epitopes on the nanoparticle to form a sufficiently strong interaction and reliable detection. The binding of cysBPAv-AuNP to anti-BPA antibodies, for limited antibody binding sites, was enhanced by a greater number of epitope-modified nanoparticles (cysBPAv-AuNP) as well as with higher epitope coverage. Increasing the molar concentration of epitope present in an assay enhanced the binding between anti-BPA antibodies and cysBPAv-AuNP. This implies that, to increase the limit of detection of a competitive inhibition assay, a reduced molar concentration of epitope should be applied. This could be achieved by either lowering the epitope coverage on each cysBPAv-AuNP or the assay molar concentration of cysBPAv-AuNP or both of these factors.

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Potentiometric polymeric membrane electrodes for mercury detection using calixarene ionophores

Water Science & Technology ◽

10.2166/wst.2010.860 ◽

2010 ◽

Vol 61 (3) ◽

pp. 693-704 ◽

Cited By ~ 10

Author(s):

Sonika Tyagi ◽

Himanshu Agarwal ◽

Saiqa Ikram

Keyword(s):

Heavy Metal Ions ◽

Aqueous Media ◽

Active Material ◽

Potential Method ◽

Fast Response ◽

Analytical Tool ◽

Polymeric Membrane ◽

Membrane Electrodes ◽

Industrial Waste Water ◽

Mercury Detection

It is here established that potentiometric polymeric membrane electrodes based on electrically neutral ionophores are a useful analytical tool for the detection of heavy metal ions from environmental and industrial waste water. PVC based membrane containing p-tert-butyl-calix[4]arenethioether derivative as active material along with sodiumtetraphenylborate (NaTPB) as solvent mediator and dibutylphthalate as a plasticizer in the ratio 45:9:460:310 (w/w%) (I:NaTPB:DBP:PVC) exhibits good properties with a Nernstian response of 29.50±1.0 mV per decade of activity and a working concentration range of 7.2 × 10−8–1.0 × 10−1 M. The electrode gave more stable potential readings when used around pH 2.5–6.8 and exhibits fast response time of 14 s. The sensors were found to work satisfactorily in partially non-aqueous media up to 40% (v/v) content of acetone, methanol or ethanol and could be used over a period of 7–9 months. Excellent selectivity for Hg2+ ions is indicated by match potential method and fixed interference method. The sensors could be used successfully in the estimation of mercury in different sample.

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