Highly sensitive amperometric biosensor based on electrochemically-reduced graphene oxide-chitosan/hemoglobin nanocomposite for nitromethane determination.

PubMed

Wen, Yunping; Wen, Wei; Zhang, Xiuhua; Wang, Shengfu

2016-05-15

Nitromethane (CH3NO2) is an important organic chemical raw material with a wide variety of applications as well as one of the most common pollutants. Therefore it is pretty important to establish a simple and sensitive detection method for CH3NO2. In our study, a novel amperometric biosensor for nitromethane (CH3NO2) based on immobilization of electrochemically-reduced graphene oxide (rGO), chitosan (CS) and hemoglobin (Hb) on a glassy carbon electrode (GCE) was constructed. Scanning electron microscopy, infrared spectroscopy and electrochemical methods were used to characterize the Hb-CS/rGO-CS composite film. The effects of scan rate and pH of phosphate buffer on the biosensor have been studied in detail and optimized. Due to the graphene and chitosan nanocomposite, the developed biosensor demonstrating direct electrochemistry with faster electron-transfer rate (6.48s(-1)) and excellent catalytic activity towards CH3NO2. Under optimal conditions, the proposed biosensor exhibited fast amperometric response (<5s) to CH3NO2 with a wide linear range of 5 μM~1.46 mM (R=0.999) and a low detection limit of 1.5 μM (S/N=3). In addition, the biosensor had high selectivity, reproducibility and stability, providing the possibility for monitoring CH3NO2 in complex real samples. Copyright © 2016 Elsevier B.V. All rights reserved.

Development of an Amperometric Biosensor Platform for the Combined Determination of L-Malic, Fumaric, and L-Aspartic Acid.

PubMed

Röhlen, Désirée L; Pilas, Johanna; Schöning, Michael J; Selmer, Thorsten

2017-10-01

Three amperometric biosensors have been developed for the detection of L-malic acid, fumaric acid, and L -aspartic acid, all based on the combination of a malate-specific dehydrogenase (MDH, EC 1.1.1.37) and diaphorase (DIA, EC 1.8.1.4). The stepwise expansion of the malate platform with the enzymes fumarate hydratase (FH, EC 4.2.1.2) and aspartate ammonia-lyase (ASPA, EC 4.3.1.1) resulted in multi-enzyme reaction cascades and, thus, augmentation of the substrate spectrum of the sensors. Electrochemical measurements were carried out in presence of the cofactor β-nicotinamide adenine dinucleotide (NAD + ) and the redox mediator hexacyanoferrate (III) (HCFIII). The amperometric detection is mediated by oxidation of hexacyanoferrate (II) (HCFII) at an applied potential of + 0.3 V vs. Ag/AgCl. For each biosensor, optimum working conditions were defined by adjustment of cofactor concentrations, buffer pH, and immobilization procedure. Under these improved conditions, amperometric responses were linear up to 3.0 mM for L-malate and fumarate, respectively, with a corresponding sensitivity of 0.7 μA mM -1 (L-malate biosensor) and 0.4 μA mM -1 (fumarate biosensor). The L-aspartate detection system displayed a linear range of 1.0-10.0 mM with a sensitivity of 0.09 μA mM -1 . The sensor characteristics suggest that the developed platform provides a promising method for the detection and differentiation of the three substrates.

Development of Amperometric Biosensors Based on Nanostructured Tyrosinase-Conducting Polymer Composite Electrodes

PubMed Central

Lupu, Stelian; Lete, Cecilia; Balaure, Paul Cătălin; Caval, Dan Ion; Mihailciuc, Constantin; Lakard, Boris; Hihn, Jean-Yves; del Campo, Francisco Javier

2013-01-01

Bio-composite coatings consisting of poly(3,4-ethylenedioxythiophene) (PEDOT) and tyrosinase (Ty) were successfully electrodeposited on conventional size gold (Au) disk electrodes and microelectrode arrays using sinusoidal voltages. Electrochemical polymerization of the corresponding monomer was carried out in the presence of various Ty amounts in aqueous buffered solutions. The bio-composite coatings prepared using sinusoidal voltages and potentiostatic electrodeposition methods were compared in terms of morphology, electrochemical properties, and biocatalytic activity towards various analytes. The amperometric biosensors were tested in dopamine (DA) and catechol (CT) electroanalysis in aqueous buffered solutions. The analytical performance of the developed biosensors was investigated in terms of linear response range, detection limit, sensitivity, and repeatability. A semi-quantitative multi-analyte procedure for simultaneous determination of DA and CT was developed. The amperometric biosensor prepared using sinusoidal voltages showed much better analytical performance. The Au disk biosensor obtained by 50 mV alternating voltage amplitude displayed a linear response for DA concentrations ranging from 10 to 300 μM, with a detection limit of 4.18 μM. PMID:23698270

Composite electrochemical biosensors: a comparison of three different electrode matrices for the construction of amperometric tyrosinase biosensors.

PubMed

Serra, B; Jiménez, S; Mena, M L; Reviejo, A J; Pingarrón, J M

2002-03-01

A comparison of the behaviour of three different rigid composite matrices for the construction of amperometric tyrosinase biosensors, which are widely used for the detection of phenolic compounds, is reported. The composite electrode matrices were, graphite-Teflon; reticulated vitreous carbon (RVC)-epoxy resin; and graphite-ethylene/propylene/diene (EPD) terpolymer. After optimization of the experimental conditions, different aspects regarding the stability of the three composite tyrosinase electrode designs were considered and compared. A better reproducibility of the amperometric responses was found with the graphite-EPD electrodes, whereas a longer useful lifetime was observed for the graphite-Teflon electrodes. The kinetic parameters of the tyrosinase reaction were calculated for eight different phenolic compounds, as well as their corresponding calibration plots. The general trend in sensitivity was graphite-EPD>graphite-Teflon>RVC-epoxy resin. A correlation between sensitivity and the catalytic efficiency of the enzyme reaction for each phenolic substrate was found. Furthermore, differences in the sensitivity order for the phenolic compounds were observed among the three biocomposite electrodes, which suggests that the nature of the electrode matrix influences the interactions in the tyrosinase catalytic cycle.

Electrochemical Glucose Biosensor of Platinum Nanospheres Connected by Carbon Nanotubes

PubMed Central

Claussen, Jonathan C.; Kim, Sungwon S.; Haque, Aeraj ul; Artiles, Mayra S.; Porterfield, D. Marshall; Fisher, Timothy S.

2010-01-01

Background Glucose biosensors comprised of nanomaterials such as carbon nanotubes (CNTs) and metallic nanoparticles offer enhanced electrochemical performance that produces highly sensitive glucose sensing. This article presents a facile biosensor fabrication and biofunctionalization procedure that utilizes CNTs electrochemically decorated with platinum (Pt) nanospheres to sense glucose amperometrically with high sensitivity. Method Carbon nanotubes are grown in situ by microwave plasma chemical vapor deposition (MPCVD) and electro-chemically decorated with Pt nanospheres to form a CNT/Pt nanosphere composite biosensor. Carbon nanotube electrodes are immobilized with fluorescently labeled bovine serum albumin (BSA) and analyzed with fluorescence microscopy to demonstrate their biocompatibility. The enzyme glucose oxidase (GOX) is immobilized onto the CNT/Pt nanosphere biosensor by a simple drop-coat method for amperometric glucose sensing. Results Fluorescence microscopy demonstrates the biofunctionalization capability of the sensor by portraying adsorption of fluorescently labeled BSA unto MPCVD-grown CNT electrodes. The subsequent GOX–CNT/Pt nanosphere biosensor demonstrates a high sensitivity toward H2O2 (7.4 μA/mM/cm2) and glucose (70 μA/mM/cm2), with a glucose detection limit and response time of 380 nM (signal-to-noise ratio = 3) and 8 s (t90%), respectively. The apparent Michaelis–Menten constant (0.64 mM) of the biosensor also reflects the improved sensitivity of the immobilized GOX/nanomaterial complexes. Conclusions The GOX–CNT/Pt nanosphere biosensor outperforms similar CNT, metallic nanoparticle, and more conventional carbon-based biosensors in terms of glucose sensitivity and detection limit. The biosensor fabrication and biofunctionalization scheme can easily be scaled and adapted for microsensors for physiological research applications that require highly sensitive glucose sensing. PMID:20307391

Electrochemical glucose biosensor of platinum nanospheres connected by carbon nanotubes.

PubMed

Claussen, Jonathan C; Kim, Sungwon S; Haque, Aeraj Ul; Artiles, Mayra S; Porterfield, D Marshall; Fisher, Timothy S

2010-03-01

Glucose biosensors comprised of nanomaterials such as carbon nanotubes (CNTs) and metallic nanoparticles offer enhanced electrochemical performance that produces highly sensitive glucose sensing. This article presents a facile biosensor fabrication and biofunctionalization procedure that utilizes CNTs electrochemically decorated with platinum (Pt) nanospheres to sense glucose amperometrically with high sensitivity. Carbon nanotubes are grown in situ by microwave plasma chemical vapor deposition (MPCVD) and electro-chemically decorated with Pt nanospheres to form a CNT/Pt nanosphere composite biosensor. Carbon nanotube electrodes are immobilized with fluorescently labeled bovine serum albumin (BSA) and analyzed with fluorescence microscopy to demonstrate their biocompatibility. The enzyme glucose oxidase (GO(X)) is immobilized onto the CNT/Pt nanosphere biosensor by a simple drop-coat method for amperometric glucose sensing. Fluorescence microscopy demonstrates the biofunctionalization capability of the sensor by portraying adsorption of fluorescently labeled BSA unto MPCVD-grown CNT electrodes. The subsequent GO(X)-CNT/Pt nanosphere biosensor demonstrates a high sensitivity toward H(2)O(2) (7.4 microA/mM/cm(2)) and glucose (70 microA/mM/cm(2)), with a glucose detection limit and response time of 380 nM (signal-to-noise ratio = 3) and 8 s (t(90%)), respectively. The apparent Michaelis-Menten constant (0.64 mM) of the biosensor also reflects the improved sensitivity of the immobilized GO(X)/nanomaterial complexes. The GO(X)-CNT/Pt nanosphere biosensor outperforms similar CNT, metallic nanoparticle, and more conventional carbon-based biosensors in terms of glucose sensitivity and detection limit. The biosensor fabrication and biofunctionalization scheme can easily be scaled and adapted for microsensors for physiological research applications that require highly sensitive glucose sensing. (c) 2010 Diabetes Technology Society.

Layer-by-Layer Self-Assembling Gold Nanorods and Glucose Oxidase onto Carbon Nanotubes Functionalized Sol-Gel Matrix for an Amperometric Glucose Biosensor

PubMed Central

Wu, Baoyan; Hou, Shihua; Miao, Zhiying; Zhang, Cong; Ji, Yanhong

2015-01-01

A novel amperometric glucose biosensor was fabricated by layer-by-layer self-assembly of gold nanorods (AuNRs) and glucose oxidase (GOD) onto single-walled carbon nanotubes (SWCNTs)-functionalized three-dimensional sol-gel matrix. A thiolated aqueous silica sol containing SWCNTs was first assembled on the surface of a cleaned Au electrode, and then the alternate self-assembly of AuNRs and GOD were repeated to assemble multilayer films of AuNRs-GOD onto SWCNTs-functionalized silica gel for optimizing the biosensor. Among the resulting glucose biosensors, the four layers of AuNRs-GOD-modified electrode showed the best performance. The sol-SWCNTs-(AuNRs-GOD)4/Au biosensor exhibited a good linear range of 0.01–8 mM glucose, high sensitivity of 1.08 μA/mM, and fast amperometric response within 4 s. The good performance of the proposed glucose biosensor could be mainly attributed to the advantages of the three-dimensional sol-gel matrix and stereo self-assembly films, and the natural features of one-dimensional nanostructure SWCNTs and AuNRs. This study may provide a new facile way to fabricate the enzyme-based biosensor with high performance. PMID:28347080

[Amperometric biosensor for ethanol analysis in wines and grape must during wine fermentation].

PubMed

Shkotova, L V; Slast'ia, E A; Zhyliakova, T A; Soldatkin, O P; Schuhmann, W; Dziadevych, S V

2005-01-01

The amperometric biosensor for ethanol determination based on alcohol oxidase immobilised by the method of electrochemical polymerization has been developed. The industrial screen-printed platinum electrodes were used as transducers for creation of amperometric alcohol biosensor. Optimal conditions for electrochemical deposition of an active membrane with alcohol oxidase has been determined. Biosensors are characterised by good reproducibility and operational stability with minimal detection limit of ethanol 8 x 10(-5) M. The good correlation of results for ethanol detection in wine and during wine fermentation by using the developed amperometric biosensor with the data obtained by the standard methods was shown (r = 0.995).

Multienzymatic amperometric biosensor based on gold and nanocomposite planar electrodes for glycerol determination in wine.

PubMed

Monošík, Rastislav; Ukropcová, Dana; Streďanský, Miroslav; Šturdík, Ernest

2012-02-01

Amperometric biosensors based on gold planar or nanocomposite electrode containing multiwalled carbon nanotubes for determination of glycerol were developed. The biosensors were constructed by immobilization of a novel multienzyme cascade consisting of glycerol kinase/creatine kinase/creatinase/sarcosine oxidase/peroxidase between a chitosan "sandwich." A measuring buffer contained adenosine 5'-triphosphate (ATP), creatine phosphate, and an artificial electrochemical mediator ferrocyanide. The currents proportional to glycerol concentration were measured at working potential of -50 mV against Ag/AgCl reference electrode. The biosensors showed linearity over the ranges of 5-640 μM and 5-566 μM with detection limits of 1.96 and 2.24 μM and sensitivities of 0.80 and 0.81 nA μM(-1), respectively. Both types of biosensors had a response time of 70s. The biosensors demonstrated satisfactory operational stability (no loss of sensitivity after 90 consecutive measurements) and excellent storage stability (90% of the initial sensitivity after 15 months of storage at room temperature). The results obtained from measurements of wines correlated well with those obtained with an enzymatic-spectrophotometric assay. The presented multienzyme cascade can be used also for determination of triglycerides or various kinase substrates when glycerol kinase is replaced by other kinases. Copyright © 2011 Elsevier Inc. All rights reserved.

Bi-enzyme L-arginine-selective amperometric biosensor based on ammonium-sensing polyaniline-modified electrode.

PubMed

Stasyuk, Nataliya; Smutok, Oleh; Gayda, Galina; Vus, Bohdan; Koval'chuk, Yevgen; Gonchar, Mykhailo

2012-01-01

A novel L-arginine-selective amperometric bi-enzyme biosensor based on recombinant human arginase I isolated from the gene-engineered strain of methylotrophic yeast Hansenula polymorpha and commercial urease is described. The biosensing layer was placed onto a polyaniline-Nafion composite platinum electrode and covered with a calcium alginate gel. The developed sensor revealed a good selectivity to L-arginine. The sensitivity of the biosensor was 110 ± 1.3 nA/(mM mm(2)) with the apparent Michaelis-Menten constant (K(M)(app)) derived from an L-arginine (L-Arg) calibration curve of 1.27 ± 0.29 mM. A linear concentration range was observed from 0.07 to 0.6mM, a limit of detection being 0.038 mM and a response time - 10s. The developed biosensor demonstrated good storage stability. A laboratory prototype of the proposed amperometric biosensor was applied to the samples of three commercial pharmaceuticals ("Tivortin", "Cytrarginine", "Aminoplazmal 10% E") for L-Arg testing. The obtained L-Arg-content values correlated well with those declared by producers. Copyright © 2012 Elsevier B.V. All rights reserved.

Electrochemical Study and Characterization of an Amperometric Biosensor Based on the Immobilization of Laccase in a Nanostructure of TiO₂ Synthesized by the Sol-Gel Method.

PubMed

Romero-Arcos, Mariana; Garnica-Romo, Ma Guadalupe; Martínez-Flores, Héctor Eduardo

2016-07-07

Laccase amperometric biosensors were developed to detect the catechol compound. The laccase enzyme (LAC) immobilization was performed on nanostructures of (a) titania (TiO₂); (b) titania/Nafion (TiO₂/NAF) (both immobilized by the sol-gel method) and a third nanostructure, which consisted of a single biosensor composite of Nafion and laccase enzyme denoted as NAF/LAC. The Nafion was deposited on a graphite electrode and used to avoid "cracking" on the matrix. The TiO₂ particle size was an average of 66 nm. FTIR spectroscopy vibration modes of different composites were determined. The electrochemical behavior of the biosensor was studied using electrochemical spectroscopy (EIS) and cyclic voltammetry (CV). The biosensor based on TiO₂/NAF/LAC presented the best electro-chemical properties with regard to sensitivity, stability and detection limit after a period of 22 days.

Analytical Parameters of an Amperometric Glucose Biosensor for Fast Analysis in Food Samples.

PubMed

Artigues, Margalida; Abellà, Jordi; Colominas, Sergi

2017-11-14

Amperometric biosensors based on the use of glucose oxidase (GOx) are able to combine the robustness of electrochemical techniques with the specificity of biological recognition processes. However, very little information can be found in literature about the fundamental analytical parameters of these sensors. In this work, the analytical behavior of an amperometric biosensor based on the immobilization of GOx using a hydrogel (Chitosan) onto highly ordered titanium dioxide nanotube arrays (TiO₂NTAs) has been evaluated. The GOx-Chitosan/TiO₂NTAs biosensor showed a sensitivity of 5.46 μA·mM -1 with a linear range from 0.3 to 1.5 mM; its fundamental analytical parameters were studied using a commercial soft drink. The obtained results proved sufficient repeatability (RSD = 1.9%), reproducibility (RSD = 2.5%), accuracy (95-105% recovery), and robustness (RSD = 3.3%). Furthermore, no significant interferences from fructose, ascorbic acid and citric acid were obtained. In addition, the storage stability was further examined, after 30 days, the GOx-Chitosan/TiO₂NTAs biosensor retained 85% of its initial current response. Finally, the glucose content of different food samples was measured using the biosensor and compared with the respective HPLC value. In the worst scenario, a deviation smaller than 10% was obtained among the 20 samples evaluated.

Amperometric Choline Biosensor Fabricated through Electrostatic Assembly of Bienzyme/Polyelectrolyte Hybrid Layers on Carbon Nanotubes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang, Jun; Liu, Guodong; Lin, Yuehe

2006-03-01

We report a flow injection amperometric choline biosensors based on the electrostatic assembly of an enzyme of choline oxidase (ChO) and a bi-enzyme of ChO and horseradish peroxidase (HRP) onto multi-wall carbon nanotubes (MWCNT) modified glassy carbon (GC) electrodes. These choline biosensors were fabricated by immobilization of enzymes on the negatively charged MWCNT surface through alternatively assembling a cationic polydiallydiimethylammonium chloride (PDDA) layer and an enzyme layer. Using this layer-by-layer assembling approach, bioactive nanocomposite film of a PDDA/ChO/PDDA/HRP/PDDA/CNT (ChO/HRP/CNT) and a PDDA/ChO/PDDA/ CNT (ChO/ CNT) were fabricated on GC surface, respectively. Owning to the electrocatalytic effect of carbon nanotubes, themore » measurement of faradic responses resulting from enzymatic reactions has been realized at low potential with acceptable sensitivity. It is found the ChO/HRP/CNT biosensor is more sensitive than the ChO/CNT one. Experimental parameters affecting the sensitivity of biosensors, e.g. applied potential, flow rate, etc. were optimized and potential interference was examined. The response time for this choline biosensor is fast (less than a few seconds). The linear range of detection for the choline biosensor is from 5 x 10-5 to 5 x 10-3 M and the detection limit is determined to be about 1.0 x 10-5 M.« less

Amperometric biosensor based on prussian blue and nafion modified screen-printed electrode for screening of potential xanthine oxidase inhibitors from medicinal plants.

PubMed

El Harrad, Loubna; Amine, Aziz

2016-04-01

A simple and sensitive amperometric biosensor was developed for the screening of potential xanthine oxidase inhibitors from medicinal plants. This biosensor was prepared by immobilization of xanthine oxidase on the surface of prussian blue modified screen-printed electrodes using nafion and glutaraldehyde. The developed biosensor showed a linear amperometric response at an applied potential of +0.05 V toward the detection of hypoxanthine from 5 μM to 45 μM with a detection limit of 0.4 μM (S/N=3) and its sensitivity was found to be 600 mA M(-1) cm(-2). In addition, the biosensor exhibited a good storage stability. The inhibition of xanthine oxidase by allopurinol was studied under the optimized conditions. The linear range of allopurinol concentration is obtained up to 2.5 μM with an estimated 50% of inhibitionI50=1.8 μM. The developed biosensor was successfully applied to the screening of xanthine oxidase inhibitors from 13 medicinal plants belonging to different families. Indeed, Moroccan people traditionally use these plants as infusion for the treatment of gout and its related symptoms. For this purpose, water extracts obtained from the infusion of these plants were used for the experiments. In this work, 13 extracts were assayed and several of them demonstrated xanthine oxidase inhibitory effect, with an inhibition greater than 50% compared to spectrophotometry measurements that only few extracts showed an inhibition greater than 50%. Copyright © 2016 Elsevier Inc. All rights reserved.

Rapid amperometric detection of trace metals by inhibition of an ultrathin polypyrrole-based glucose biosensor.

PubMed

Ayenimo, Joseph G; Adeloju, Samuel B

2016-02-01

A sensitive and reliable inhibitive amperometric glucose biosensor is described for rapid trace metal determination. The biosensor utilises a conductive ultrathin (55 nm thick) polypyrrole (PPy) film for entrapment of glucose oxidase (GOx) to permit rapid inhibition of GOx activity in the ultrathin film upon exposure to trace metals, resulting in reduced glucose amperometric response. The biosensor demonstrates a relatively fast response time of 20s and does not require incubation. Furthermore, a complete recovery of GOx activity in the ultrathin PPy-GOx biosensor is quickly achieved by washing in 2mM EDTA for only 10s. The minimum detectable concentrations achieved with the biosensor for Hg(2+), Cu(2+), Pb(2+) and Cd(2+) by inhibitive amperometric detection are 0.48, 1.5, 1.6 and 4.0 µM, respectively. Also, suitable linear concentration ranges were achieved from 0.48-3.3 µM for Hg(2+), 1.5-10 µM for Cu(2+), 1.6-7.7 µM for Pb(2+) and 4-26 µM for Cd(2+). The use of Dixon and Cornish-Bowden plots revealed that the suppressive effects observed with Hg(2+) and Cu(2+) were via non-competitive inhibition, while those of Pb(2+) and Cd(2+) were due to mixed and competitive inhibition. The stronger inhibition exhibited by the trace metals on GOx activity in the ultrathin PPy-GOx film was also confirmed by the low inhibition constant obtained from this analysis. The biosensor was successfully applied to the determination of trace metals in tap water samples. Copyright © 2015 Elsevier B.V. All rights reserved.

Analytical Parameters of an Amperometric Glucose Biosensor for Fast Analysis in Food Samples

PubMed Central

2017-01-01

Amperometric biosensors based on the use of glucose oxidase (GOx) are able to combine the robustness of electrochemical techniques with the specificity of biological recognition processes. However, very little information can be found in literature about the fundamental analytical parameters of these sensors. In this work, the analytical behavior of an amperometric biosensor based on the immobilization of GOx using a hydrogel (Chitosan) onto highly ordered titanium dioxide nanotube arrays (TiO2NTAs) has been evaluated. The GOx–Chitosan/TiO2NTAs biosensor showed a sensitivity of 5.46 μA·mM−1 with a linear range from 0.3 to 1.5 mM; its fundamental analytical parameters were studied using a commercial soft drink. The obtained results proved sufficient repeatability (RSD = 1.9%), reproducibility (RSD = 2.5%), accuracy (95–105% recovery), and robustness (RSD = 3.3%). Furthermore, no significant interferences from fructose, ascorbic acid and citric acid were obtained. In addition, the storage stability was further examined, after 30 days, the GOx–Chitosan/TiO2NTAs biosensor retained 85% of its initial current response. Finally, the glucose content of different food samples was measured using the biosensor and compared with the respective HPLC value. In the worst scenario, a deviation smaller than 10% was obtained among the 20 samples evaluated. PMID:29135931

An integrated bienzyme glucose oxidase-fructose dehydrogenase-tetrathiafulvalene-3-mercaptopropionic acid-gold electrode for the simultaneous determination of glucose and fructose.

PubMed

Campuzano, Susana; Loaiza, Oscar A; Pedrero, María; de Villena, F Javier Manuel; Pingarrón, José M

2004-06-01

A bienzyme biosensor for the simultaneous determination of glucose and fructose was developed by coimmobilising glucose oxidase (GOD), fructose dehydrogenase (FDH), and the mediator, tetrathiafulvalene (TTF), by cross-linking with glutaraldehyde atop a 3-mercaptopropionic acid (MPA) self-assembled monolayer (SAM) on a gold disk electrode (AuE). The performance of this bienzyme electrode under batch and flow injection (FI) conditions, as well as an amperometric detection in high-performance liquid chromatography (HPLC), are reported. The order of enzyme immobilisation atop the MPA-SAM affected the biosensor amperometric response in terms of sensitivity, with the immobilisation order GOD, FDH, TTF being selected. Similar analytical characteristics to those obtained with single GOD or FDH SAM-based biosensors for glucose and fructose were achieved with the bienzyme electrode, indicating that no noticeable changes in the biosensor responses to the analytes occurred as a consequence of the coimmobilisation of both enzymes on the same MPA-AuE. The suitability of the bienzyme biosensor for the analysis of real samples under flow injection conditions was tested by determining glucose in two certified serum samples. The simultaneous determination of glucose and fructose in the same sample cannot be performed without a separation step because at the detection potential used (+0.10 V), both sugars show amperometric response. Consequently, HPLC with amperometric detection at the TTF-FDH-GOD-MPA-AuE was accomplished. Glucose and fructose were simultaneously determined in honey, cola softdrink, and commercial apple juice, and the results were compared with those obtained by using other reference methods.

Amperometric biosensor system for simultaneous determination of adenosine-5'-triphosphate and glucose.

PubMed

Kucherenko, Ivan S; Didukh, Daria Yu; Soldatkin, Oleksandr O; Soldatkin, Alexei P

2014-06-03

The majority of biosensors for adenosine-5'-triphosphate (ATP) determination are based on cascades of enzymatic reactions; therefore, they are sensitive to glucose or glycerol (depending on the enzymatic system) as well as to ATP. The presence of unknown concentrations of these substances in the sample greatly complicates the determination of ATP. To overcome this disadvantage of known biosensors, we developed a biosensor system consisting of two biosensors: the first one is based on glucose oxidase and is intended for measuring glucose concentration, and the second one is based on glucose oxidase and hexokinase and is sensitive toward both glucose and ATP. Using glucose concentration measured by the first biosensor, we can analyze the total response to glucose and ATP obtained by the second biosensor. Platinum disc electrodes were used as amperometric transducers. The polyphenilenediamine membrane was deposited onto the surface of platinum electrodes to avoid the response to electroactive substances. The effect of glucose concentration on biosensor determination of ATP was studied. The reproducibility of biosensor responses to glucose and ATP during a day was tested (relative standard deviation, RSD, of responses to glucose was 3-6% and to ATP was 8-12%) as well as storage stability of the biosensors (no decrease of glucose responses and 43% drop of ATP responses during 50 days). The measurements of ATP and glucose in pharmaceutical vials (including mixtures of ATP and glucose) were carried out. It was shown that the developed biosensor system can be used for simultaneous analysis of glucose and ATP concentrations in water solutions.

Electrochemical H2O2 biosensor composed of myoglobin on MoS2 nanoparticle-graphene oxide hybrid structure.

PubMed

Yoon, Jinho; Lee, Taek; Bapurao G, Bharate; Jo, Jinhee; Oh, Byung-Keun; Choi, Jeong-Woo

2017-07-15

In this research, the electrochemical biosensor composed of myoglobin (Mb) on molybdenum disulfide nanoparticles (MoS 2 NP) encapsulated with graphene oxide (GO) was fabricated for the detection of hydrogen peroxide (H 2 O 2 ). Hybrid structure composed of MoS 2 NP and GO (GO@MoS 2 ) was fabricated for the first time to enhance the electrochemical signal of the biosensor. As a sensing material, Mb was introduced to fabricate the biosensor for H 2 O 2 detection. Formation and immobilization of GO@MoS 2 was confirmed by transmission electron microscopy, ultraviolet-visible spectroscopy, scanning electron microscopy, and scanning tunneling microscopy. Immobilization of Mb, and electrochemical property of biosensor were investigated by cyclic voltammetry and amperometric i-t measurements. Fabricated biosensor showed the electrochemical signal enhanced redox current as -1.86μA at an oxidation potential and 1.95μA at a reduction potential that were enhanced relative to those of electrode prepared without GO@MoS 2 . Also, this biosensor showed the reproducibility of electrochemical signal, and retained the property until 9 days from fabrication. Upon addition of H 2 O 2 , the biosensor showed enhanced amperometric response current with selectivity relative to that of the biosensor prepared without GO@MoS 2 . This novel hybrid material-based biosensor can suggest a milestone in the development of a highly sensitive detecting platform for biosensor fabrication with highly sensitive detection of target molecules other than H 2 O 2 . Copyright © 2016 Elsevier B.V. All rights reserved.

Amperometric L-lysine biosensor based on carboxylated multiwalled carbon nanotubes-SnO2 nanoparticles-graphene composite

NASA Astrophysics Data System (ADS)

Kaçar, Ceren; Erden, Pınar Esra; Kılıç, Esma

2017-10-01

A novel matrix, carboxylated multiwalled carbon nanotubes-tin oxide nanoparticles-graphene-chitosan (c-MWCNTs-SnO2-GR-CS) composite, was prepared for biosensor construction. Lysine oxidase (LOx) enzyme was immobilized covalently on the surface of c-MWCNTs-GR-SnO2-CS composite modified glassy carbon electrode (GCE) using N-ethyl-N‧-(3-dimethyaminopropyl) carbodiimide (EDC) and N-hydroxyl succinimide (NHS). Effects of electrode composition and buffer pH on biosensor response were investigated to optimize the working conditions. The biosensor exhibited wide linear range (9.9 × 10-7 M-1.6 × 10-4 M), low detection limit (1.5 × 10-7 M), high sensitivity (55.20 μA mM-1 cm-2) and fast amperometric response (<25 s) at +0.70 V vs. Ag/AgCl. With good repeatability and long-term stability, the c-MWCNTs-SnO2-GR-CS based biosensor offered an alternative for L-lysine biosensing. The practical applicability of the biosensor in two dietary supplements has also been addressed.

Amperometric Biosensor Based on Diamine Oxidase/Platinum Nanoparticles/Graphene/Chitosan Modified Screen-Printed Carbon Electrode for Histamine Detection.

PubMed

Apetrei, Irina Mirela; Apetrei, Constantin

2016-03-24

This work describes the development and optimization studies of a novel biosensor employed in the detection and quantification of histamine in freshwater fish samples. The proposed biosensor is based on a modified carbon screen-printed electrode with diamineoxidase, graphene and platinum nanoparticles, which detects the hydrogen peroxide formed by the chemical process biocatalysed by the enzyme diamine oxidase and immobilized onto the nanostructurated surface of the receptor element. The amperometric measurements with the biosensor have been implemented in buffer solution of pH 7.4, applying an optimal low potential of +0.4 V. The novel biosensor shows high sensitivity (0.0631 μA·μM), low detection limit (2.54 × 10(-8) M) and a broad linear domain from 0.1 to 300 μM. The applicability in natural complex samples and the analytical parameters of this enzyme sensor have been performed in the quantification of histamine in freshwater fish. An excellent correlation among results achieved with the developed biosensor and results found with the standard method for all freshwater fish samples has been achieved.

Amperometric Biosensor Based on Diamine Oxidase/Platinum Nanoparticles/Graphene/Chitosan Modified Screen-Printed Carbon Electrode for Histamine Detection

PubMed Central

Apetrei, Irina Mirela; Apetrei, Constantin

2016-01-01

This work describes the development and optimization studies of a novel biosensor employed in the detection and quantification of histamine in freshwater fish samples. The proposed biosensor is based on a modified carbon screen-printed electrode with diamineoxidase, graphene and platinum nanoparticles, which detects the hydrogen peroxide formed by the chemical process biocatalysed by the enzyme diamine oxidase and immobilized onto the nanostructurated surface of the receptor element. The amperometric measurements with the biosensor have been implemented in buffer solution of pH 7.4, applying an optimal low potential of +0.4 V. The novel biosensor shows high sensitivity (0.0631 μA·μM), low detection limit (2.54 × 10−8 M) and a broad linear domain from 0.1 to 300 μM. The applicability in natural complex samples and the analytical parameters of this enzyme sensor have been performed in the quantification of histamine in freshwater fish. An excellent correlation among results achieved with the developed biosensor and results found with the standard method for all freshwater fish samples has been achieved. PMID:27023541

Amperometric hydrogen peroxide and glucose biosensor based on NiFe2/ordered mesoporous carbon nanocomposites.

PubMed

Xiang, Dong; Yin, Longwei; Ma, Jingyun; Guo, Enyan; Li, Qun; Li, Zhaoqiang; Liu, Kegao

2015-01-21

Nanocomposites of NiFex embedded in ordered mesoporous carbon (OMC) (x = 0, 1, 2) were prepared by a wet impregnation and hydrogen reduction process and were used to construct electrochemical biosensors for the amperometric detection of hydrogen peroxide (H2O2) or glucose. The NiFe2/OMC nanocomposites were demonstrated to have a large surface area, suitable mesoporous channels, many edge-plane-like defective sites, and a good distribution of alloyed nanoparticles. The NiFe2/OMC and Nafion modified glass carbon electrode (GCE) exhibited excellent electrocatalytic activities toward the reduction of H2O2 as well. By utilizing it as a bioplatform, GOx (glucose oxidase) cross-linked with Nafion was immobilized on the surface of the electrode for the construction of an amperometric glucose biosensor. Our results indicated that the amperometric hydrogen peroxide biosensor (NiFe2/OMC + Nafion + GCE) showed good analytical performances in term of a high sensitivity of 4.29 μA mM(-1) cm(-2), wide linearity from 6.2 to 42,710 μM and a low detection limit of 0.24 μM at a signal-to-noise ratio of 3 (S/N = 3). This biosensor exhibited excellent selectivity, high stability and negligible interference for the detection of H2O2. In addition, the immobilized enzyme on NiFe2/OMC + Nafion + GCE, retaining its bioactivity, exhibited a reversible two-proton and two-electron transfer reaction, a fast heterogeneous electron transfer rate and an effective Michaelis-Menten constant (K) (3.18 mM). The GOx + NiFe2/OMC + Nafion + GCE could be used to detect glucose based on the oxidation of glucose catalyzed by GOx and exhibited a wide detection range of 48.6-12,500 μM with a high sensitivity of 6.9 μA mM(-1) cm(-2) and a low detection limit of 2.7 μM (S/N = 3). The enzymic biosensor maintained a high selectivity and stability features, and shows great promise for application in the detection of glucose.

Alginate copper oxide nano-biocomposite as a novel material for amperometric glucose biosensing.

PubMed

Buk, Vuslat; Emregul, Emel; Emregul, Kaan Cebesoy

2017-05-01

A novel amperometric glucose biosensor based on alginate-CuO nano-biocomposite and glucose oxidase (GOD) film was developed and characterized. The properties of the alginate-CuO-GOD film were characterized using scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). Amperometric measurements were employed to characterize the analytical performance of the biosensor. Several parameters including amount of alginate, concentration of GOD and cross-linkers, amount of CuO nanoparticles, and effect of pH were studied and optimized. Under optimal conditions, the developed alginate-CuO-GOD biosensor was shown to have two linear ranges; from 0.04mM to 3mM (with a correlation coefficient of 0.9996 and the sensitivity of 30.443μAmM -1 cm -2 ) and from 4mM to 35mM (with a correlation coefficient of 0.9994 and the sensitivity of 7.205μAmM -1 cm -2 ). The overall detection limit was estimated to be 1.6μM (signal-to-noise ratio of 3) and the K m value of 2.82mM. The biosensor exhibited rather good performance with long-term stability (remainder of activity is 78% after 15days) and significant specificity for glucose when compared to possible interfering molecules such as ascorbic acid, uric acid and acetaminophen. Copyright © 2016 Elsevier B.V. All rights reserved.

Amperometric detection of glucose in fruit juices with polypyrrole-based biosensor with an integrated permselective layer for exclusion of interferences.

PubMed

Ayenimo, Joseph G; Adeloju, Samuel B

2017-08-15

A novel polypyrrole (PPy)-based bilayer amperometric glucose biosensor integrated with a permselective layer has been developed for detection of glucose in the presence of interferences. It comprises of a PPy-GOx film grown, in the absence of electrolyte, as an inner layer, and a permselective PPy-Cl film as an outer layer. The PPy-GOx/PPy-Cl bilayer biosensor was effective in rejecting 98% of ascorbic acid and 100% of glycine, glutamic acid and uric acid. With an outer layer thickness of 6.6nm, the bilayer biosensor gave nearly identical glucose response to that of a single layer PPy-GOx biosensor. The biosensor also exhibited good reproducibility (1.9% rsd, n=10), high stability (more than 2months), wide linear range (0.5-24mM), low K m (8.4mM), high I max (77.2μAcm -2 ), low detection limit (26.9μM) and good sensitivity (3.5μAcm -2 mM -1 ). The bilayer biosensor was successfully employed for glucose determination in various fruit juices. Copyright © 2017 Elsevier Ltd. All rights reserved.

Sensitive amperometric biosensor for the determination of biogenic and synthetic amines using pea seedlings amine oxidase: a novel approach for enzyme immobilisation.

PubMed

Wimmerová, M; Macholán, L

1999-12-01

We prepared a new inorganic sorbent based on modified triazine (2-[4,6-bis (aminoethylamine)-1,3,5-triazine]-Silasorb; BAT-Silasorb) which binds pea seedlings amine oxidase (PSAO) very tightly without loss of its catalytic activity. This unique feature as well as the wide substrate specificity of PSAO was successfully utilised in the construction of an amperometric biosensor based on a carbon paste electrode for the fast and sensitive detection of various amines at a formal potential 0 mV versus Ag/AgCl reference electrode. The reaction layer of the biosensor is created by the direct immobilisation of PSAO at the electrode surface via affinity carrier BAT-Silasorb. Used arrangement facilitates a simple restoration of the inactive biosensor. An amperometric signal results from horseradish peroxidase catalysed reduction of H2O2, a secondary product of the oxidative deamination of amines, catalysed by PSAO. The sensor was used for the basic characterisation of 55 biogenic and synthetic amines, from numerous mono-, di- and polyamines to various hydroxy-, thio-, benzyl- and aromatic derivatives in order to establish its suitability as a postcolumn detector. Its high sensitivity to putrescine 20.0 +/- 0.64 mA l-1 per mol (636.9 +/- 2.03 mA l-1 per mol per cm2), a limit of detection of 10 nmol l-1 (determined with respect to a signal-to-noise ratio 3:1), a linear range of current response to 0.01-100 mumol l-1 concentration of substrate and good reproducibility all indicate that the sensor could be applied to future industrial and clinical analyses.

Influence of aspect ratio and surface defect density on hydrothermally grown ZnO nanorods towards amperometric glucose biosensing applications

NASA Astrophysics Data System (ADS)

Shukla, Mayoorika; Pramila; Dixit, Tejendra; Prakash, Rajiv; Palani, I. A.; Singh, Vipul

2017-11-01

In this work, hydrothermally grown ZnO Nanorods Array (ZNA) has been synthesized over Platinum (Pt) coated glass substrate, for biosensing applications. In-situ addition of strong oxidizing agent viz KMnO4 during hydrothermal growth was found to have profound effect on the physical properties of ZNA. Glucose oxidase (GOx) was later immobilized over ZNA by means of physical adsorption process. Further influence of varying aspect ratio, enzyme loading and surface defects on amperometric glucose biosensor has been analyzed. Significant variation in biosensor performance was observed by varying the amount of KMnO4 addition during the growth. Moreover, investigations revealed that the suppression of surface defects and aspect ratio variation of the ZNA played key role towards the observed improvement in the biosensor performance, thereby significantly affecting the sensitivity and response time of the fabricated biosensor. Among different biosensors fabricated having varied aspect ratio and surface defect density of ZNA, the best electrode resulted into sensitivity and response time to be 18.7 mA cm-2 M-1 and <5 s respectively. The observed results revealed that apart from high aspect ratio nanostructures and the extent of enzyme loading, surface defect density also hold a key towards ZnO nanostructures based bio-sensing applications.

A novel amperometric biosensor based on gold nanoparticles anchored on reduced graphene oxide for sensitive detection of l-lactate tumor biomarker.

PubMed

Azzouzi, Sawsen; Rotariu, Lucian; Benito, Ana M; Maser, Wolfgang K; Ben Ali, Mounir; Bala, Camelia

2015-07-15

In this work, a novel amperometric biosensor based on gold nanoparticles anchored on reduced graphene oxide (RGO-AuNPs) and l-lactate dehydrogenase (LDH) was developed for the sensing of l-lactate. Firstly, the RGO-AuNPs modified screen printed electrodes were tested for NADH detection showing a wide dynamic range and a low detection limit. Next, the biosensor was constructed by incorporating both enzyme and RGO-AuNPs in a sol gel matrix derived from tetrametoxysilane and methyltrimetoxysilane. The enzyme loading, working pH, and coenzyme concentration were optimized. The biosensor linearly responded to l-lactate in the range of 10µM-5mM and showed a good specific sensitivity of 154µA/mMcm(2) with a detection limit of 0.13µM. This was accompanied by good reproducibility and operational stability. Tests on artificial serum proved that l-lactate can be determined practically without interferences from commonly interfering compounds such as urate, paracetamol and l-ascorbate. Our LDH/RGO-AuNPs/SPCE based biosensor thus performs as electrochemical device for the detection of l-lactate as a viable early cancer bio-marker. Copyright © 2015 Elsevier B.V. All rights reserved.

Homemade Bienzymatic-Amperometric Biosensor for Beverages Analysis

ERIC Educational Resources Information Center

Blanco-Lopez, M. C.; Lobo-Castanon, M. J.; Miranda-Ordieres, A. J.

2007-01-01

The construction of an amperometric biosensor for glucose analysis is described demonstrating that the analysis is easy to perform and the biosensor gives good analytical performance. This experiment helped the students to acquire problem-solving and teamwork skills, allowing them to reach a high level of independent and critical thought.

Construction of an improved amperometric acrylamide biosensor based on hemoglobin immobilized onto carboxylated multi-walled carbon nanotubes/iron oxide nanoparticles/chitosan composite film.

PubMed

Batra, Bhawna; Lata, Suman; Pundir, C S

2013-11-01

A method is described for construction of an improved amperometric acrylamide biosensor based on covalent immobilization of hemoglobin (Hb) onto nanocomposite of carboxylated multi-walled carbon nanotubes (cMWCNT) and iron oxide nanoparticles (Fe3O4NPs) electrodeposited onto Au electrode through chitosan (CHIT) film. The Hb/cMWCNT-Fe3O4NP/CHIT/Au electrode was characterized by scanning electron microscopy, Fourier transform infra-red spectroscopy, electrochemical impedance spectroscopy, and differential pulse voltammetry at different stages of its construction. The biosensor was based on interaction between acrylamide and Hb, which led to decrease in the electroactivity of Hb, i.e., current generated during its reversible conversion [Fe(II)/Fe(III)]. The biosensor showed optimum response within 8 s at pH 5.0 and 30 °C. The linear working range for acrylamide was 3-90 nM, with a detection limit of 0.02 nM and sensitivity of 36.9 μA/nM/cm(2). The biosensor was evaluated and employed for determination of acrylamide in potato crisps.

A novel Laccase Biosensor based on Laccase immobilized Graphene-Cellulose Microfiber Composite modified Screen-Printed Carbon Electrode for Sensitive Determination of Catechol

PubMed Central

Palanisamy, Selvakumar; Ramaraj, Sayee Kannan; Chen, Shen-Ming; Yang, Thomas C. K.; Yi-Fan, Pan; Chen, Tse-Wei; Velusamy, Vijayalakshmi; Selvam, Sonadevi

2017-01-01

In the present work, we demonstrate the fabrication of laccase biosensor to detect the catechol (CC) using laccase immobilized on graphene-cellulose microfibers (GR-CMF) composite modified screen printed carbon electrode (SPCE). The direct electrochemical behavior of laccase was investigated using laccase immobilized different modified SPCEs, such as GR/SPCE, CMF/SPCE and GR-CMF/SPCE. Compared with laccase immobilized GR and CMF modified SPCEs, a well-defined redox couple of CuI/CuII for laccase was observed at laccase immobilized GR-CMF composite modified SPCE. Cyclic voltammetry results show that the as-prepared biosensor has 7 folds higher catalytic activity with lower oxidation potential towards CC than SPCE modified with GR-CMF composite. Under optimized conditions, amperometric i-t method was used for the quantification of CC, and the amperometric response of the biosensor was linear over the concertation of CC ranging from 0.2 to 209.7 μM. The sensitivity, response time and the detection limit of the biosensor for CC is 0.932 μMμA−1 cm−2, 2 s and 0.085 μM, respectively. The biosensor has high selectivity towards CC in the presence of potentially active biomolecules and phenolic compounds. The biosensor also accessed for the detection of CC in different water samples and shows good practicality with an appropriate repea. PMID:28117357

An amperometric hydrogen peroxide biosensor based on Co3O4 nanoparticles and multiwalled carbon nanotube modified glassy carbon electrode

NASA Astrophysics Data System (ADS)

Kaçar, Ceren; Dalkiran, Berna; Erden, Pınar Esra; Kiliç, Esma

2014-08-01

In this work a new type of hydrogen peroxide biosensor was fabricated based on the immobilization of horseradish peroxidase (HRP) by cross-linking on a glassy carbon electrode (GCE) modified with Co3O4 nanoparticles, multiwall carbon nanotubes (MWCNTs) and gelatin. The introduction of MWCNTs and Co3O4 nanoparticles not only enhanced the surface area of the modified electrode for enzyme immobilization but also facilitated the electron transfer rate, resulting in a high sensitivity of the biosensor. The fabrication process of the sensing surface was characterized by scanning electron microscopy (SEM), cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). Amperometric detection of hydrogen peroxide was investigated by holding the modified electrode at -0.30 V (vs. Ag/AgCl). The biosensor showed optimum response within 5 s at pH 7.0. The optimized biosensor showed linear response range of 7.4 × 10-7-1.9 × 10-5 M with a detection limit of 7.4 × 10-7. The applicability of the purposed biosensor was tested by detecting hydrogen peroxide in disinfector samples. The average recovery was calculated as 100.78 ± 0.89.

Non-invasive determination of glucose directly in raw fruits using a continuous flow system based on microdialysis sampling and amperometric detection at an integrated enzymatic biosensor.

PubMed

Vargas, E; Ruiz, M A; Campuzano, S; Reviejo, A J; Pingarrón, J M

2016-03-31

A non-destructive, rapid and simple to use sensing method for direct determination of glucose in non-processed fruits is described. The strategy involved on-line microdialysis sampling coupled with a continuous flow system with amperometric detection at an enzymatic biosensor. Apart from direct determination of glucose in fruit juices and blended fruits, this work describes for the first time the successful application of an enzymatic biosensor-based electrochemical approach to the non-invasive determination of glucose in raw fruits. The methodology correlates, through previous calibration set-up, the amperometric signal generated from glucose in non-processed fruits with its content in % (w/w). The comparison of the obtained results using the proposed approach in different fruits with those provided by other method involving the same commercial biosensor as amperometric detector in stirred solutions pointed out that there were no significant differences. Moreover, in comparison with other available methodologies, this microdialysis-coupled continuous flow system amperometric biosensor-based procedure features straightforward sample preparation, low cost, reduced assay time (sampling rate of 7 h(-1)) and ease of automation. Copyright © 2016 Elsevier B.V. All rights reserved.

Peptide nanotube-modified electrodes for enzyme-biosensor applications.

PubMed

Yemini, Miri; Reches, Meital; Gazit, Ehud; Rishpon, Judith

2005-08-15

The fabrication and notably improved performance of composite electrodes based on modified self-assembled diphenylalanine peptide nanotubes is described. Peptide nanotubes were attached to gold electrodes, and we studied the resulting electrochemical behavior using cyclic voltammetry and chronoamperometry. The peptide nanotube-based electrodes demonstrated a direct and unmediated response to hydrogen peroxide and NADH at a potential of +0.4 V (vs SCE). This biosensor enables a sensitive determination of glucose by monitoring the hydrogen peroxide produced by an enzymatic reaction between the glucose oxidase attached to the peptide nanotubes and glucose. In addition, the marked electrocatalytic activity toward NADH enabled a sensitive detection of ethanol using ethanol dehydrogenase and NAD+. The peptide nanotube-based amperometric biosensor provides a potential new tool for sensitive biosensors and biomolecular diagnostics.

Whole cell immobilized amperometric biosensor based on Saccharomyces cerevisiae for selective determination of vitamin B1 (thiamine).

PubMed

Akyilmaz, Erol; Yaşa, Ihsan; Dinçkaya, Erhan

2006-07-01

A new amperometric whole cell biosensor based on Saccharomyces cerevisiae immobilized in gelatin was developed for selective determination of vitamin B1 (thiamine). The biosensor was constructed by using gelatin and crosslinking agent glutaraldehyde to immobilize S. cerevisiae cells on the Teflon membrane of dissolved oxygen (DO) probe used as the basic electrode system combined with a digital oxygen meter. The cells were induced by vitamin B1 in the culture medium, and the cells used it as a carbon source in the absence of glucose. So, when the vitamin B1 solution is injected into the whole cell biosensor system, an increase in respiration activity of the cells results from the metabolic activity and causes a decrease in the DO concentration of interval surface of DO probe related to vitamin B1 concentration. The response time of the biosensor is 3 min, and the optimal working conditions of the biosensor were carried out as pH 7.0, 50mM Tris-HCl, and 30 degrees C. A linear relationship was obtained between the DO concentration decrease and vitamin B1 concentration between 5.0 x 10(-3) and 10(-1) microM. In the application studies of the biosensor, sensitive determination of vitamin B1 in the vitamin tablets was investigated.

Determination of Organophosphate Pesticides at a Carbon Nanotube/Organophosphorus Hydrolase Electrochemical Biosensor

DOE Office of Scientific and Technical Information (OSTI.GOV)

Deo, R P.; Wang, Joseph; Block, I

2005-02-08

An amperometric biosensor for organophosphorus (OP) pesticides based on a carbon-nanotube (CNT) modified transducer and an organophosphorus hydrolase (OPH) biocatalyst is described. A bilayer approach with the OPH layer atop of the CNT film was used for preparing the CNT/OPH biosensor. The CNT layer leads to a greatly improved anodic detection of the enzymatically-generated p-nitrophenol product, including higher sensitivity and stability. The sensor performance was optimized with respect to the surface modification and operating conditions. Under the optimal conditions the biosensor was used to measure as low as 0.15 {micro}M paraoxon and 0.8 {micro}M methyl parathion with sensitivities of 25more » and 6 nA/{micro}M, respectively.« less

Amperometric glucose biosensor based on layer-by-layer films of microperoxidase-11 and liposome-encapsulated glucose oxidase.

PubMed

Graça, J S; de Oliveira, R F; de Moraes, M L; Ferreira, M

2014-04-01

An important step in several bioanalytical applications is the immobilization of biomolecules. Accordingly, this procedure must be carefully chosen to preserve their biological structure and fully explore their properties. For this purpose, we combined the versatility of the layer-by-layer (LbL) method for the immobilization of biomolecules with the protective behavior of liposome-encapsulated systems to fabricate a novel amperometric glucose biosensor. To obtain the biosensing unit, an LbL film of the H2O2 catalyst polypeptide microperoxidase-11 (MP-11) was assembled onto an indium-tin oxide (ITO) electrode followed by the deposition of a liposome-encapsulated glucose oxidase (GOx) layer. The biosensor response toward glucose detection showed a sensitivity of 0.91±0.09 (μA/cm2)/mM and a limit of detection (LOD) of 8.6±1.1 μM, demonstrating an improved performance compared to similar biosensors with a single phospholipid-liposome or even containing a non-encapsulated GOx layer. Finally, glucose detection was also performed in a zero-lactose milk sample to demonstrate the potential of the biosensor for food analysis. Copyright © 2014 Elsevier B.V. All rights reserved.

Amperometric catechol biosensor based on laccase immobilized on nitrogen-doped ordered mesoporous carbon (N-OMC)/PVA matrix

NASA Astrophysics Data System (ADS)

Guo, Meiqing; Wang, Hefeng; Huang, Di; Han, Zhijun; Li, Qiang; Wang, Xiaojun; Chen, Jing

2014-06-01

A functionalized nitrogen-containing ordered mesoporous carbon (N-OMC), which shows good electrical properties, was synthesized by the carbonization of polyaniline inside a SBA-15 mesoporous silica template. Based on this, through entrapping laccase onto the N-OMC/polyvinyl alcohol (PVA) film a facilely fabricated amperometric biosensor was developed. Laccase from Trametes versicolor was assembled on a composite film of a N-OMC/PVA modified Au electrode and the electrochemical behavior was investigated. The results indicated that the N-OMC modified electrode exhibits electrical properties towards catechol. The optimum experimental conditions of a biosensor for the detection of catechol were studied in detail. Under the optimal conditions, the sensitivity of the biosensor was 0.29 A*M-1 with a detection limit of 0.31 μM and a linear detection range from 0.39 μM to 8.98 μM for catechol. The calibration curve followed the Michaelis-Menten kinetics and the apparent Michaelis-Menten \\left( K_{M}^{app} \\right) was 6.28 μM. This work demonstrated that the N-OMC/PVA composite provides a suitable support for laccase immobilization and the construction of a biosensor.

Biosensor for the enantioselective analysis of the thyroid hormones (+)-3,3',5-triiodo-L-thyronine (T3) and (+)-3,3',5,5'-tetraiodo-L-thyronine (T4).

PubMed

Aboul-Enein, Hassan V; Stefan, Raluca-Ioana; Litescu, Simona; Radu, Gabriel Lucian

2002-01-01

An amperometric biosensor based on L-aminoacid oxidase is proposed for enantioselective assay of (+)-3,3',5-triiodo-L-thyronine (L-T3) and (+)-3,3',5,5'-tetraiodo-L-thyronine (L-T4), due to the fact that only the L enantiomer has the hormonal activity. The construction of the amperometric biosensor is simple and reproducible. The analytical information obtained from enantioselective analysis are reliable. The RSD <1% assured by using the amperometric biosensors for L enantiomers assay as raw materials, and from tablets, demonstrated their suitability for the analysis of T3 and T4 at ppb concentration levels.

Development of Amperometric Glucose Biosensor Based on Prussian Blue Functionlized TiO2 Nanotube Arrays

PubMed Central

Gao, Zhi-Da; Qu, Yongfang; Li, Tongtong; Shrestha, Nabeen K.; Song, Yan-Yan

2014-01-01

Amperometric biosensors consisting of oxidase and peroxidase have attracted great attention because of their wide application. The current work demonstrates a novel approach to construct an enzymatic biosensor based on TiO2 nanotube arrays (TiNTs) as a supporting electrode on which Prussian Blue (PB)-an “artificial enzyme peroxidase” and enzyme glucose oxidase (GOx) have been immobilized. For this, PB nanocrystals are deposited onto the nanotube wall photocatalytically using the intrinsic photocatalytical property of TiO2, and the GOx/AuNPs nanobiocomposites are subsequently immobilized into the nanotubes via the electrodeposition of polymer. The resulting electrode exhibits a fast response, wide linear range, and good stability for glucose sensing. The sensitivity of the sensor is as high as 248 mA M−1 cm−2, and the detection limit is about 3.2 μM. These findings demonstrate a promising strategy to integrate enzymes and TiNTs, which could provide an analytical access to a large group of enzymes for bioelectrochemical applications including biosensors and biofuel cells. PMID:25367086

Amperometric biosensor based on a single antibody of dual function for rapid detection of Streptococcus agalactiae.

PubMed

Vásquez, Gersson; Rey, Alba; Rivera, Camilo; Iregui, Carlos; Orozco, Jahir

2017-01-15

Pathogenic bacteria are responsible for several diseases in humans and in a variety of hosts. Detection of pathogenic bacteria is imperative to avoid and/or fight their potential harmful effects. This work reports on the first amperometric biosensor for the rapid detection of Streptococcus agalactiae (S. agalactiae). The biosensor relies on a single biotinylated antibody that immobilizes the bacteria on a screen-printed carbon electrode while is further linked to a streptavidin-conjugated HRP reporter. The biotinylated antibody provides selectivity to the biosensor whereas serves as an anchoring point to the reporter for further amplification of the electrochemical signal. The resultant immunosensor is simple, responds rapidly, and allows for the selective and highly sensitive quantification of S. agalactiae cells in a concentration range of 10 1 -10 7 CFUml -1 , with a detection limit of 10CFUml -1 . The approach not only enables a rapid detection and quantification of S. agalactiae in environmental samples but also opens up new opportunities for the simple fabrication of electrochemical immunosensors for different target pathogens. Copyright © 2016 Elsevier B.V. All rights reserved.

Simultaneous and accurate real-time monitoring of glucose and ethanol in alcoholic drinks, must, and biomass by a dual-amperometric biosensor.

PubMed

Mentana, Annalisa; Palermo, Carmen; Nardiello, Donatella; Quinto, Maurizio; Centonze, Diego

2013-01-09

In this work the optimization and application of a dual-amperometric biosensor for simultaneous monitoring of glucose and ethanol content, as quality markers in drinks and alcoholic fermentation media, are described. The biosensor is based on glucose oxidase (GOD) and alcohol oxidase (AOD) immobilized by co-cross-linking with bovine serum albumin (BSA) and glutaraldehyde (GLU) both onto a dual gold electrode, modified with a permselective overoxidized polypyrrole film (PPYox). Response, rejection of interferents, and stability of the dual biosensor were optimized in terms of PPYox thickness, BSA, and enzyme loading. The biosensor was integrated in a flow injection system coupled with an at-line microdialysis fiber as a sampling tool. Flow rates inside and outside the fiber were optimized in terms of linear responses (0.01-1 and 0.01-1.5 M) and sensitivities (27.6 ± 0.4 and 31.0 ± 0.6 μA·M(-1)·cm(-2)) for glucose and ethanol. Excellent anti-interference characteristics, the total absence of "cross-talk", and good response stability under operational conditions allowed application of the dual biosensor in accurate real-time monitoring (at least 15 samples/h) of alcoholic drinks, white grape must, and woody biomass.

Electrochemical glucose biosensor based on nickel oxide nanoparticle-modified carbon paste electrode.

PubMed

Erdem, Ceren; Zeybek, Derya Koyuncu; Aydoğdu, Gözde; Zeybek, Bülent; Pekyardımcı, Sule; Kılıç, Esma

2014-08-01

In the present work, we designed an amperometric glucose biosensor based on nickel oxide nanoparticles (NiONPs)-modified carbon paste electrode. The biosensor was prepared by incorporation of glucose oxidase and NiONPs into a carbon paste matrix. It showed good analytical performances such as high sensitivity (367 μA mmolL(-1)) and a wide linear response from 1.9×10(-3) mmolL(-1) to 15.0 mmolL(-1) with a limit of detection (0.11 μmolL(-1)). The biosensor was used for the determination of glucose in human serum samples. The results illustrate that NiONPs have enormous potential in the construction of biosensor for determination of glucose.

An Amperometric Acetylcholinesterase Sensor Based on the Bio-templated Synthesis of Hierarchical Mesoporous Bioactive Glass Microspheres

NASA Astrophysics Data System (ADS)

Lv, Zhuo; Luo, Ruiping; Xi, Lijuan; Chen, Yang; Wang, Hongsu

2017-11-01

This work describes the synthesis of three-dimensional hollow hierarchical mesoporous bioactive glass (HMBG) microspheres based on Herba leonuri pollen grains via a hydrothermal method. The HMBG microspheres perfectly copied the hierarchical porous structure and inner hollow structure constituting the double-layer surface of the natural Herba leonuri pollen grains. This structural mimicry of the pollen grains resulted in a higher degree of adsorption of acetylcholinesterase (AChE) on HMBG microspheres in comparison with mesoporous bioactive glass. Subsequently, an amperometric biosensor for the detection of Malathion was fabricated by immobilizing AChE onto an HMBG microspheres-modified carbon paste electrode. The biosensor response exhibited two good linear ranges during an incubation time of 10 min in the malathion concentration ranges of 0.02-50 ppb and 50-600 ppb, with a detection limit of 0.0135 ppb ( S/ N = 3). Overall, the prepared enzymatic biosensor showed high sensitivity in the rapid detection of Malathion and could be applied to detect pesticide residues in vegetable matter.

[Amperometric biosensor for lactate analysis in wines and grape must during fermentation].

PubMed

Shkotova, L V; Horiushkina, T B; Slast'ia, E A; Soldatkin, O P; Tranh-Minh, S; Chovelon, J M; Dziadevych, S V

2005-01-01

The amperometric biosensor based on lactate oxidase for determination of lactate has been developed, and two methods of immobilization of lactate oxidase on the surface of industrial screen-printed platinum electrodes SensLab were compared. A sensor with immobilized in the Resydrol polymer lactate oxidase by the method of physical adsorption is characterized of narrow dynamic range and greater response value in comparison with a biosensor based on immobilised in poly(3,4-ethylenedioxythiophene) lactate oxidase by the method of electrochemical polymerization. Operational stability of the biosensor developed was studied and it was shown, that the immobilization method does not influence their stability. The analysis of the lactate in wine and during wine fermentation has been conducted. High correlation of the data obtained by means of amperometric lactate biosensor and a standard method of an ionic chromatography has been shown. The developed biosensor could be applied in the food industry for the control and optimization of the wine fermentation process, and quality control of wine.

An amperometric glutamate biosensor based on immobilization of glutamate oxidase onto carboxylated multiwalled carbon nanotubes/gold nanoparticles/chitosan composite film modified Au electrode.

PubMed

Batra, Bhawna; Pundir, C S

2013-09-15

A method is described for the construction of a novel amperometric glutamate biosensor based on covalent immobilization of glutamate oxidase (GluOx) onto, carboxylated multi walled carbon nanotubes (cMWCNT), gold nanoparticles (AuNPs) and chitosan (CHIT) composite film electrodeposited on the surface of a Au electrode. The GluOx/cMWCNT/AuNP/CHIT modified Au electrode was characterized by scanning electron microscopy (SEM), fourier transform infra-red (FTIR) spectroscopy, electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV). The biosensor measured current due to electrons generated at 0.135V against Ag/AgCl from H2O2, which is produced from glutamate by immobilized GluOx. The biosensor showed optimum response within 2s at pH 7.5 and 35°C. A linear relationship was obtained between a wide glutamate concentration range (5-500μM) and current (μA) under optimum conditions. The biosensor showed high sensitivity (155nA/μM/cm(2)), low detection limit (1.6μM) and good storage stability. The biosensor was unaffected by a number of serum substances at their physiological concentrations. The biosensor was evaluated and employed for determination of glutamate in sera from apparently healthy subjects and persons suffering from epilepsy. Copyright © 2013 Elsevier B.V. All rights reserved.

Biosensor Based on Self-Assembling Acetylcholinesterase on Carbon Nanotubes for Flow injection/Amperometric Detection of Organophosphate Pesticides and Nerve Agents

DOE Office of Scientific and Technical Information (OSTI.GOV)

Liu, Guodong; Lin, Yuehe

A highly sensitive flow-injection amperometric biosensor for organophosphate pesticides and nerve agents based on self-assembly of acetylcholinesterase (AChE) on carbon nanotube (CNT)-modified glassy carbon (GC) electrode is described. AChE is immobilized on the negatively-charged CNT surface by alternatively assembling a cationic polydiallyldimethylammonium chloride (PDDA) layer and an AChE layer. Transmission electron microscopy images confirm the formation of layer-by-layer nanostructures on carboxyl functionalized CNTs. The unique sandwich-like structure (PDDA/AChE/PDDA) on the CNT surface formed by self-assembly provides a favorable microenvironment to keep the bioactivity of AChE and to prevent enzyme molecule leakage. The electrocatalytic activity of CNT leads to a greatlymore » improved electrochemical detection of the enzymatically generated thiocholine product, including a low oxidation overvoltage (+150 mV), higher sensitivity, and stability. The developed PDDA/AChE/PDDA/CNT/GC biosensor integrated into a flow injection system was used to monitor organophosphate pesticides and nerve agents, such as paraoxon. The sensor performance, including inhibition time and regeneration conditions, was optimized with respect to operating conditions. Under the optimal conditions, the biosensor was used to measure as low as 0.4 pM paraoxon with a 6-min inhibition time. The biosensor had excellent operational lifetime stability with no decrease in the activity of enzymes for more than 20 repeated measurements over a 1-week period. The developed biosensor system is an ideal tool for online monitoring of organophosphate pesticides and nerve agents.« less

An Amperometric Biosensor Utilizing a Ferrocene-Mediated Horseradish Peroxidase Reaction for the Determination of Capsaicin (Chili Hotness)

PubMed Central

Mohammad, Rosmawani; Ahmad, Musa; Heng, Lee Yook

2013-01-01

Chili hotness is very much dependent on the concentration of capsaicin present in the chili fruit. A new biosensor based on a horseradish peroxidase enzyme-capsaicin reaction mediated by ferrocene has been successfully developed for the amperometric determination of chili hotness. The amperometric biosensor is fabricated based on a single-step immobilization of both ferrocene and horseradish peroxidase in a photocurable hydrogel membrane, poly(2-hydroxyethyl methacrylate). With mediation by ferrocene, the biosensor could measure capsaicin concentrations at a potential 0.22 V (vs. Ag/AgCl), which prevented potential interference from other electroactive species in the sample. Thus a good selectivity towards capsaicin was demonstrated. The linear response range of the biosensor towards capsaicin was from 2.5–99.0 μM with detection limit of 1.94 μM. A good relative standard deviation (RSD) for reproducibility of 6.4%–9.9% was obtained. The capsaicin biosensor demonstrated long-term stability for up to seven months. The performance of the biosensor has been validated using a standard method for the analysis of capsaicin based on HPLC. PMID:23921830

Prototype amperometric biosensor for sialic acid determination.

PubMed

Marzouk, Sayed A M; Ashraf, S S; Tayyari, Khawla A Al

2007-02-15

This paper describes the first report on the development, characterization, and applications of a prototype amperometric biosensor for free sialic acid (SA). The sensor was constructed by the coimmobilization of two enzymes, i.e., N-acetylneuraminic acid aldolase and pyruvate oxidase, on a polyester microporous membrane, which was then mounted on top of a platinum disk electrode. The SA biosensor operation was based on the sequential action of the two enzymes to ultimately produce hydrogen peroxide, which was then detected by anodic amperometry at the platinum electrode. The surface of the platinum electrode was coated with an electropolymeric layer to enhance the biosensor selectivity in the presence of interfering oxidizable species. Optimization of the enzyme layer composition resulted in a fast and steady current response in phosphate buffer pH 7.2 at 37 degrees C. The limit of detection was 10 microM, and the response was linear to 3.5 mM (r = 0.9987). The prepared SA biosensors retained approximately 85% of their initial sensitivity after 8 days and showed excellent response reproducibility (CV = 2.3%). Utilization of a third enzyme, sialidase, expanded the scope of the present SA biosensor to determine bound sialic acid as well. The merits of the described biosensor allowed its successful application in determining SA in biological and pharmaceutical samples. The obtained results indicated that the presented SA biosensor should be a useful bioanalytical tool in several biological and clinical applications such as screening of SA as a nonspecific tumor marker as well as monitoring of tumor therapy.

Thin-film amperometric multibiosensor for simultaneous determination of lactate and glucose in wine.

PubMed

Shkotova, Lyudmyla V; Piechniakova, Nataliia Y; Kukla, Oleksandr L; Dzyadevych, Sergei V

2016-04-15

An amperometric multi-biosensor based on lactate and glucose oxidases has been developed for determination of lactate and glucose in wine. Gold thin-film amperometric electrodes were used as multi-transducers. Analytical characteristics of the multi-biosensor developed were studied. The minimum detectable concentration was 5×10(-6) mol/l for both glucose and lactate. High reproducibility and storage stability of the multi-biosensor are demonstrated in this paper. Lactate and glucose were determined in wine, and a good correlation was obtained with concentrations determined using high-performance liquid chromatography (correlation coefficient for glucose R(2)=0.998, for lactate R(2)=0.718). Copyright © 2015 Elsevier Ltd. All rights reserved.

A sensitive acetylcholinesterase biosensor based on gold nanorods modified electrode for detection of organophosphate pesticide.

PubMed

Lang, Qiaolin; Han, Lei; Hou, Chuantao; Wang, Fei; Liu, Aihua

2016-08-15

A sensitive amperometric acetylcholinesterase (AChE) biosensor, based on gold nanorods (AuNRs), was developed for the detection of organophosphate pesticide. Compared with Au@Ag heterogeneous NRs, AuNRs exhibited excellent electrocatalytic properties, which can electrocatalytically oxidize thiocholine, the hydrolysate of acetylthiocholine chloride (ATCl) by AChE at +0.55V (vs. SCE). The AChE/AuNRs/GCE biosensor was fabricated on basis of the inhibition of AChE activity by organophosphate pesticide. The biosensor could detect paraoxon in the linear range from 1nM to 5μM and dimethoate in the linear range from 5nM to 1μM, respectively. The detection limits of paraoxon and dimethoate were 0.7nM and 3.9nM, which were lower than the reported AChE biosensor. The proposed biosensor could restore to over 95% of its original current, which demonstrated the good reactivation. Moreover, the biosensor can be applicable to real water sample measurement. Thus, the biosensor exhibited low applied potential, high sensitivity and good stability, providing a promising tool for analysis of pesticides. Copyright © 2016 Elsevier B.V. All rights reserved.

Highly ordered mesoporous carbons as electrode material for the construction of electrochemical dehydrogenase- and oxidase-based biosensors.

PubMed

Zhou, Ming; Shang, Li; Li, Bingling; Huang, Lijian; Dong, Shaojun

2008-11-15

In this work, the excellent catalytic activity of highly ordered mesoporous carbons (OMCs) to the electrooxidation of nicotinamide adenine dinucleotide (NADH) and hydrogen peroxide (H(2)O(2)) was described for the construction of electrochemical alcohol dehydrogenase (ADH) and glucose oxidase (GOD)-based biosensors. The high density of edge-plane-like defective sites and high specific surface area of OMCs could be responsible for the electrocatalytic behavior at OMCs modified glassy carbon electrode (OMCs/GE), which induced a substantial decrease in the overpotential of NADH and H(2)O(2) oxidation reaction compared to carbon nanotubes modified glassy carbon electrode (CNTs/GE). Such ability of OMCs permits effective low-potential amperometric biosensing of ethanol and glucose, respectively, at Nafion/ADH-OMCs/GE and Nafion/GOD-OMCs/GE. Especially, as an amperometric glucose biosensor, Nafion/GOD-OMCs/GE showed large determination range (500-15,000 micromoll(-1)), high sensitivity (0.053 nA micromol(-1)), fast (9+/-1s) and stable response (amperometric response retained 90% of the initial activity after 10h stirring of 2 mmoll(-1) glucose solution) to glucose as well as the effective discrimination to the possible interferences, which may make it to readily satisfy the need for the routine clinical diagnosis of diabetes. By comparing the electrochemical performance of OMCs with that of CNTs as electrode material for the construction of ADH- and GOD-biosensors in this work, we reveal that OMCs could be a favorable and promising carbon electrode material for constructing other electrochemical dehydrogenase- and oxidase-based biosensors, which may have wide potential applications in biocatalysis, bioelectronics and biofuel cells.

In vivo continuous and simultaneous monitoring of brain energy substrates with a multiplex amperometric enzyme-based biosensor device.

PubMed

Cordeiro, C A; de Vries, M G; Ngabi, W; Oomen, P E; Cremers, T I F H; Westerink, B H C

2015-05-15

Enzyme-based amperometric biosensors are widely used for monitoring key biomarkers. In experimental neuroscience there is a growing interest in in vivo continuous and simultaneous monitoring of metabolism-related biomarkers, like glucose, lactate and pyruvate. The use of multiplex biosensors will provide better understanding of brain energy metabolism and its role in neuropathologies such as diabetes, ischemia, and epilepsy. We have developed and characterized an implantable multiplex microbiosensor device (MBD) for simultaneous and continuous in vivo monitoring of glucose, lactate, and pyruvate. First, we developed and characterized amperometric microbiosensors for monitoring lactate and pyruvate. In vitro evaluation allowed us to choose the most suitable biosensors for incorporation into the MBD, along with glucose and background biosensors. Fully assembled MBDs were characterized in vitro. The calculated performance parameters (LOD, LR, LRS, IMAX and appKM) showed that the multiplex MBD was highly selective and sensitive (LRS≥100 nA/mM) for each analyte and within an adequate range for in vivo application. Finally, MBDs were implanted in the mPFC of anesthetized adult male Wistar rats for in vivo evaluation. Following an equilibration period, baseline brain levels of glucose (1.3±0.2 mM), lactate (1.5±0.4 mM) and pyruvate (0.3±0.1 mM) were established. Subsequently, the MBDs recorded the responses of the animals when submitted to hyperglycemic (40% glucose i.v.) and hypoglycemic (5 U/kg insulin i.v.) challenges. Afterwards, MBDs were recalibrated to convert electrochemical readings into accurate substrate concentrations and to assess biofouling. The presented MBD can monitor simultaneously multiple biomarkers in vivo. Copyright © 2014 Elsevier B.V. All rights reserved.

Integrated electrochemical gluconic acid biosensor based on self-assembled monolayer-modified gold electrodes. Application to the analysis of gluconic acid in musts and wines.

PubMed

Campuzano, S; Gamella, M; Serra, B; Reviejo, A J; Pingarrón, J M

2007-03-21

An integrated amperometric gluconic acid biosensor constructed using a gold electrode (AuE) modified with a self-assembled monolayer (SAM) of 3-mercaptopropionic acid (MPA) on which gluconate dehydrogenase (GADH, 0.84 U) and the mediator tetrathiafulvalene (TTF, 1.5 micromol) were coimmobilized by covering the electrode surface with a dialysis membrane is reported. The working conditions selected were Eapp=+0.15 V and 25+/-1 degrees C. The useful lifetime of one single TTF-GADH-MPA-AuE was surprisingly long. After 53 days of continuous use, the biosensor exhibited 86% of the original sensitivity. A linear calibration plot was obtained for gluconic acid over the 6.0x10(-7) to 2.0x10(-5) M concentration range, with a limit of detection of 1.9x10(-7) M. The effect of potential interferents (glucose, fructose, galactose, arabinose, and tartaric, citric, malic, ascorbic, gallic, and caffeic acids) on the biosensor response was evaluated. The behavior of the biosensor in a flow-injection system in connection with amperometric detection was tested. The analytical usefulness of the biosensor was evaluated by determining gluconic acid in wine and must samples, and the results obtained were validated by comparison with those provided by using a commercial enzyme test kit.

Parallel synthesis of libraries of anodic and cathodic functionalized electrodeposition paints as immobilization matrix for amperometric biosensors.

PubMed

Ngounou, Bertrand; Aliyev, Elchin H; Guschin, Dmitrii A; Sultanov, Yusif M; Efendiev, Ayaz A; Schuhmann, Wolfgang

2007-09-01

The integration of flexible anchoring groups bearing imidazolyl or pyridyl substituents into the structure of electrodeposition paints (EDP) is the basis for the parallel synthesis of a library containing 107 members of different cathodic and anodic EDPs with a high variation in polymer properties. The obtained EDPs were used as immobilization matrix for biosensor fabrication using glucose oxidase as a model enzyme. Amperometric glucose sensors based on the different EDPs showed a wide variation in their sensor characteristics with respect to the apparent Michaelis-Menten constant (KM(app)) representing the linear measuring range and the maximum current (Imax(app)). Based on these results first assumptions concerning the impact of different side chains in the EDP on the expected biosensor properties could be obtained allowing for an improved rational optimization of EDPs used as immobilization matrix in amperometric biosensors.

Functionalization of carbon nanotubes with water-insoluble porphyrin in ionic liquid: direct electrochemistry and highly sensitive amperometric biosensing for trichloroacetic acid.

PubMed

Tu, Wenwen; Lei, Jianping; Ju, Huangxian

2009-01-01

A functional composite of single-walled carbon nanotubes (SWNTs) with hematin, a water-insoluble porphyrin, was first prepared in 1-butyl-3-methylimidazolium hexafluorophosphate ([BMIM][PF(6)]) ionic liquid. The novel composite in ionic liquid was characterized by scanning electron microscopy, ultraviolet absorption spectroscopy, and electrochemical impedance spectroscopy, and showed a pair of direct redox peaks of the Fe(III)/Fe(II) couple. The composite-[BMIM][PF(6)]-modified glassy carbon electrode showed excellent electrocatalytic activity toward the reduction of trichloroacetic acid (TCA) in neutral media due to the synergic effect among SWNTs, [BMIM][PF(6)], and porphyrin, which led to a highly sensitive and stable amperometric biosensor for TCA with a linear range from 9.0x10(-7) to 1.4x10(-4) M. The detection limit was 3.8x10(-7) M at a signal-to-noise ratio of 3. The TCA biosensor had good analytical performance, such as rapid response, good reproducibility, and acceptable accuracy, and could be successfully used for the detection of residual TCA in polluted water. The functional composite in ionic liquid provides a facile way to not only obtain the direct electrochemistry of water-insoluble porphyrin, but also construct novel biosensors for monitoring analytes in real environmental samples.

Capability of parasulfonato calix[6]arene, as an anion dopant, and organic solvents in enhancing the sensitivity and loading of glucose oxidase (GOx) on polypyrrole film in a biosensor: a comparative study.

PubMed

Safarnavadeh, Vahideh; Zare, Karim; Fakhari, Ali Reza

2013-11-15

In this study, the effects of two solvents (acetonitrile and water) and an anion dopant (para sulfonato calix[6]arene ((C[6]S)(-6))), on the manufacturing and properties of a polypyrrole (Ppy)-based, glucose oxidase amperometric biosensor were studied. Pyrrole was polymerized using galvanostatic mode in two different solvents, and the effect of (C[6]S)(-6) was studied in aqueous solution. The morphology of the obtained polypyrrole films was studied by scanning electron microscopy (SEM). Glucose oxidase (GOx) was adsorbed on the Ppy films via cross-linking method. Then the amperometric responses of the Pt/Ppy/GOx electrodes were measured using the amperometric method at the potential of 0.7 V in steps of adding a glucose solution to a potassium phosphate buffer. We found that acetonitrile and (C[6]S)(-6) increase the sensitivity of the enzyme electrode up to 79.30 µA M(-1)cm(-2) in comparison with 31.60 μA M(-1)cm(-2) for the electrode synthesized in calixarene free aqueous solvent. Also (C[6]S)(-6) has the main role in preventing leaching the enzyme from the electrode. This fact increases loading of the enzyme and stability of the biosensor. So that the steady state current density of the aforementioned electrode increases linearly with increasing glucose concentration up to 190 mM. Whereas the linearity was observed up to 61 mM and 80 mM for the electrodes made using calixarene free acetonitrile and aqueous solutions, respectively. Copyright © 2013 Elsevier B.V. All rights reserved.

Design and development of amperometric biosensor for the detection of lead and mercury ions in water matrix-a permeability approach.

PubMed

Gumpu, Manju Bhargavi; Krishnan, Uma Maheswari; Rayappan, John Bosco Balaguru

2017-07-01

Intake of water contaminated with lead (Pb 2+ ) and mercury (Hg 2+ ) ions leads to various toxic effects and health issues. In this context, an amperometric urease inhibition-based biosensor was developed to detect Pb 2+ and Hg 2+ ions in water matrix. The modified Pt/CeO 2 /urease electrode was fabricated by immobilizing CeO 2 nanoparticles and urease using a semi-permeable adsorption layer of nafion. With urea as a substrate, urease catalytic activity was examined through cyclic voltammetry. Further, maximum amperometric inhibitive response of the modified Pt/CeO 2 /urease electrode was observed in the presence of Pb 2+ and Hg 2+ ions due to the urease inhibition at specific potentials of -0.03 and 0 V, respectively. The developed sensor exhibited a detection limit of 0.019 ± 0.001 μM with a sensitivity of 89.2 × 10 -3  μA μM -1 for Pb 2+ ions. A detection limit of 0.018 ± 0.003 with a sensitivity of 94.1 × 10 -3  μA μM -1 was achieved in detecting Hg 2+ ions. The developed biosensor showed a fast response time (<1 s) with a linear range of 0.5-2.2 and 0.02-0.8 μM for Pb 2+ and Hg 2+ ions, respectively. The modified electrode offered a good stability for 20 days with a good repeatability and reproducibility. The developed sensor was used to detect Pb 2+ and Hg 2+ ions contaminating Cauvery river water and the observed results were in good co-ordination with atomic absorption spectroscopic data.

Effect of immobilization technique on performance ZnO nanorods based enzymatic electrochemical glucose biosensor

NASA Astrophysics Data System (ADS)

Shukla, Mayoorika; Pramila; Palani, I. A.; Singh, Vipul

2017-11-01

In this paper, ZnO Nanorods (ZNR) have been synthesized over Platinum (Pt) coated glass substrate with in-situ addition KMnO4 during hydrothermal growth process. Significant variation in ZnO nanostructures was observed by KMnO4 addition during the growth. Glucose oxidase was later immobilized over ZNRs. The as-prepared ZNRs were further utilized for glucose detection by employing amperometric electrochemical transduction method. In order to optimize the performance of the prepared biosensor two different immobilization techniques i.e. physical adsorption and cross linking have been employed and compared. Further investigations suggest that immobilization via cross linking method resulted in the improvement of the biosensor performance, thereby significantly affecting the sensitivity and linear range of the fabricated biosensor. Among the two types of biosensors fabricated using ZNR, the best performance was shown by cross linked electrodes. The sensitivity for the same was found to be 17.7 mA-cm-2-M-1, along with a wide linear range of 0.5-8.5 mM.

Amperometric cholesterol biosensor based on in situ reconstituted cholesterol oxidase on an immobilized monolayer of flavin adenine dinucleotide cofactor.

PubMed

Vidal, Juan-C; Espuelas, Javier; Castillo, Juan-R

2004-10-01

A new amperometric biosensor for determining cholesterol based on deflavination of the enzyme cholesterol oxidase (ChOx) and subsequent reconstitution of the apo-protein with a complexed flavin adenine dinucleotide (FAD) monolayer is described. The charge transfer mediator pyrroquinoline quinone (PQQ) was covalently bound to a cystamine self-assembled monolayer (SAM) on an Au electrode. Boronic acid (BA) was then bound to PQQ using the carbodiimide procedure, and the BA ligand was complexed to the FAD molecules on which the apo-ChOx was subsequently reconstituted. The effective release of the FAD from the enzyme and the successful reconstitution were verified using molecular fluorescence and cyclic voltammetry. The optimal orientation of FAD toward the PQQ mediator and the distances between FAD and PQQ and between PQQ and electrode enhance the charge transfer, very high sensitivity (about 2,500 nAmM(-1)cm(-2)) being obtained for cholesterol determination. The biosensor is selective toward electroactive interferents (ascorbic acid and uric acid) and was tested in reference serum samples, demonstrating excellent accuracy (relative errors below 3% in all cases). The biosensor activity can be successfully regenerated in a simple process by successive reconstitution with batches of recently prepared apo-ChOx on the same immobilized Au/SAM-PQQ-BA-FAD monolayer (it was tested five times); the lifetime of the biosensor is about 45-60 days.

Electrolyte-free Amperometric Immunosensor using a Dendritic Nanotip†

PubMed Central

Kim, Jong-Hoon; Hiraiwa, Morgan; Lee, Hyun-Boo; Lee, Kyong-Hoon; Cangelosi, Gerard A.; Chung, Jae-Hyun

2013-01-01

Electric detection using a nanocomponent may lead to platforms for rapid and simple biosensing. Sensors composed of nanotips or nanodots have been described for highly sensitive amperometry enabled by confined geometry. However, both fabrication and use of nanostructured sensors remain challenging. This paper describes a dendritic nanotip used as an amperometric biosensor for highly sensitive detection of target bacteria. A dendritic nanotip is structured by Si nanowires coated with single-walled carbon nanotubes (SWCNTs) for generation of a high electric field. For reliable measurement using the dendritic structure, Si nanowires were uniformly fabricated by ultraviolet (UV) lithography and etching. The dendritic structure effectively increased the electric current density near the terminal end of the nanotip according to numerical computation. The electrical characteristics of a dendritic nanotip with additional protein layers was studied by cyclic voltammetry and I–V measurement in deionized (DI) water. When the target bacteria dielectrophoretically captured onto a nanotip were bound with fluorescence antibodies, the electric current through DI water decreased. Measurement results were consistent with fluorescence- and electron microscopy. The sensitivity of the amperometry was 10 cfu/sample volume (103 cfu/mL), which was equivalent to the more laborious fluorescence measurement method. The simple configuration of a dendritic nanotip can potentially offer an electrolyte-free detection platform for sensitive and rapid biosensors. PMID:23585927

Electrolyte-free Amperometric Immunosensor using a Dendritic Nanotip.

PubMed

Kim, Jong-Hoon; Hiraiwa, Morgan; Lee, Hyun-Boo; Lee, Kyong-Hoon; Cangelosi, Gerard A; Chung, Jae-Hyun

2013-01-01

Electric detection using a nanocomponent may lead to platforms for rapid and simple biosensing. Sensors composed of nanotips or nanodots have been described for highly sensitive amperometry enabled by confined geometry. However, both fabrication and use of nanostructured sensors remain challenging. This paper describes a dendritic nanotip used as an amperometric biosensor for highly sensitive detection of target bacteria. A dendritic nanotip is structured by Si nanowires coated with single-walled carbon nanotubes (SWCNTs) for generation of a high electric field. For reliable measurement using the dendritic structure, Si nanowires were uniformly fabricated by ultraviolet (UV) lithography and etching. The dendritic structure effectively increased the electric current density near the terminal end of the nanotip according to numerical computation. The electrical characteristics of a dendritic nanotip with additional protein layers was studied by cyclic voltammetry and I-V measurement in deionized (DI) water. When the target bacteria dielectrophoretically captured onto a nanotip were bound with fluorescence antibodies, the electric current through DI water decreased. Measurement results were consistent with fluorescence- and electron microscopy. The sensitivity of the amperometry was 10 cfu/sample volume (10 3 cfu/mL), which was equivalent to the more laborious fluorescence measurement method. The simple configuration of a dendritic nanotip can potentially offer an electrolyte-free detection platform for sensitive and rapid biosensors.

Electrodepositable alginate membranes for enzymatic sensors: An amperometric glucose biosensor for whole blood analysis.

PubMed

Márquez, A; Jiménez-Jorquera, C; Domínguez, C; Muñoz-Berbel, X

2017-11-15

Simple and disposable point of care systems are usually the best solution for chronic patients to get a rapid diagnosis in home care context. However, their main drawback relies on the poor reliability derived from the low stability of the bio-recognition elements and low quality of the transducers. In the current work, we study the use of electrodeposited calcium alginate hydrogels as a biocompatible matrix in the development of enzymatic amperometric biosensors for whole blood analysis, to enhance the enzymes stability and to protect the transducer from biofouling. The alginate electrodeposition involves the controlled Ca 2+ release, so the gel thickness can be modulated. In the biosensor, horseradish peroxidase (HRP) and glucose oxidase (GOD) were electrodeposited within the hydrogel and the activity of the bi-enzymatic system was analyzed chronoamperometrically using 3,3',5,5'-Tetramethylbenzidine (TMB) as the mediator. Besides enzyme entrapment, the obtained gels protected the transducer from biofouling, enabling the reuse of the transducer after hydrogel removal and re-electrodeposition. The biosensors showed good analytical characteristics to glucose determination in whole blood samples, discriminating among healthy and hyperglycemic samples, with good sensitivity (- 0.27µAcm -2 mM -1 ), low limit of detection (126µM) and long lineal range (2-12mM). Copyright © 2017. Published by Elsevier B.V.

Flow-injection amperometric determination of glucose using a biosensor based on immobilization of glucose oxidase onto Au seeds decorated on core Fe₃O₄ nanoparticles.

PubMed

Samphao, Anchalee; Butmee, Preeyanut; Jitcharoen, Juthamas; Švorc, Ľubomír; Raber, Georg; Kalcher, Kurt

2015-09-01

An amperometric biosensor based on chemisorption of glucose oxidase (GOx) on Au seeds decorated on magnetic core Fe3O4 nanoparticles (Fe3O4@Au) and their immobilization on screen-printed carbon electrode bulk-modified with manganese oxide (SPCE{MnO2}) was designed for the determination of glucose. The Fe3O4@Au/GOx modified SPCE{MnO2} was used in a flow-injection analysis (FIA) arrangement. The experimental conditions were investigated in amperometric mode with the following optimized parameters: flow rate 1.7 mL min(-1), applied potential +0.38 V, phosphate buffer solution (PBS; 0.1 mol L(-1), pH 7.0) as carrier and 3.89 unit mm(-2) enzyme glucose oxidase loading on the active surface of the SPCE. The designed biosensor in FIA arrangement yielded a linear dynamic range for glucose from 0.2 to 9.0 mmol L(-1) with a sensitivity of 2.52 µA mM(-1) cm(-2), a detection limit of 0.1 mmol L(-1) and a quantification limit of 0.3 mmol L(-1). Moreover, a good repeatability of 2.8% (number of measurements n=10) and a sufficient reproducibility of 4.0% (number of sensors n=3) were achieved. It was found that the studied system Fe3O4@Au facilitated not only a simpler enzyme immobilization but also provided wider linear range. The practical application of the proposed biosensor for FIA quantification of glucose was tested in glucose sirup samples, honeys and energy drinks with the results in good accordance with those obtained by an optical glucose meter and with the contents declared by the producers. Copyright © 2015. Published by Elsevier B.V.

Amperometric inhibitive biosensor based on horseradish peroxidase-nanoporous gold for sulfide determination

PubMed Central

Sun, Huihui; Liu, Zhuang; Wu, Chao; Xu, Ping; Wang, Xia

2016-01-01

As a well-known toxic pollutant, sulfide is harmful to human health. In this study, a simple and sensitive amperometric inhibitive biosensor was developed for the determination of sulfide in the environment. By immobilizing nanoporous gold (NPG) on glassy carbon electrode (GCE), and encapsulating horseradish peroxidase (HRP) onto NPG, a HRP/NPG/GCE bioelectrode for sulfide detection was successfully constructed based on the inhibition of sulfide on HRP activity with o-Phenylenediamine (OPD) as a substrate. The resulted HRP/NPG/GCE bioelectrode achieved a wide linear range of 0.1–40 μM in sulfide detection with a high sensitivity of 1720 μA mM−1 cm−2 and a low detection limit of 0.027 μM. Additionally, the inhibition of sulfide on HRP is competitive inhibition with OPD as a substrate by Michaelis-Menten analysis. Notably, the recovery of HRP activity was quickly achieved by washing the HRP/NPG/GCE bioelectrode using differential pulse voltammetry (DPV) technique in deaerated PBS (50 mM, pH 7.0) for only 60 s. Furthermore, the real sample analysis of sulfide by the HRP/NPG/GCE bioelectrode was achieved. Based on above results, the HRP/NPG/GCE bioelectrode could be a better choice for the real determination of sulfide compared to inhibitive biosensors previously reported. PMID:27515253

Amperometric inhibitive biosensor based on horseradish peroxidase-nanoporous gold for sulfide determination

NASA Astrophysics Data System (ADS)

Sun, Huihui; Liu, Zhuang; Wu, Chao; Xu, Ping; Wang, Xia

2016-08-01

As a well-known toxic pollutant, sulfide is harmful to human health. In this study, a simple and sensitive amperometric inhibitive biosensor was developed for the determination of sulfide in the environment. By immobilizing nanoporous gold (NPG) on glassy carbon electrode (GCE), and encapsulating horseradish peroxidase (HRP) onto NPG, a HRP/NPG/GCE bioelectrode for sulfide detection was successfully constructed based on the inhibition of sulfide on HRP activity with o-Phenylenediamine (OPD) as a substrate. The resulted HRP/NPG/GCE bioelectrode achieved a wide linear range of 0.1-40 μM in sulfide detection with a high sensitivity of 1720 μA mM-1 cm-2 and a low detection limit of 0.027 μM. Additionally, the inhibition of sulfide on HRP is competitive inhibition with OPD as a substrate by Michaelis-Menten analysis. Notably, the recovery of HRP activity was quickly achieved by washing the HRP/NPG/GCE bioelectrode using differential pulse voltammetry (DPV) technique in deaerated PBS (50 mM, pH 7.0) for only 60 s. Furthermore, the real sample analysis of sulfide by the HRP/NPG/GCE bioelectrode was achieved. Based on above results, the HRP/NPG/GCE bioelectrode could be a better choice for the real determination of sulfide compared to inhibitive biosensors previously reported.

Biosensors and Bio-Bar Code Assays Based on Biofunctionalized Magnetic Microbeads

PubMed Central

Jaffrezic-Renault, Nicole; Martelet, Claude; Chevolot, Yann; Cloarec, Jean-Pierre

2007-01-01

This review paper reports the applications of magnetic microbeads in biosensors and bio-bar code assays. Affinity biosensors are presented through different types of transducing systems: electrochemical, piezo electric or magnetic ones, applied to immunodetection and genodetection. Enzymatic biosensors are based on biofunctionalization through magnetic microbeads of a transducer, more often amperometric, potentiometric or conductimetric. The bio-bar code assays relie on a sandwich structure based on specific biological interaction of a magnetic microbead and a nanoparticle with a defined biological molecule. The magnetic particle allows the separation of the reacted target molecules from unreacted ones. The nanoparticles aim at the amplification and the detection of the target molecule. The bio-bar code assays allow the detection at very low concentration of biological molecules, similar to PCR sensitivity.

Direct laser immobilization of photosynthetic material on screen printed electrodes for amperometric biosensor

DOE Office of Scientific and Technical Information (OSTI.GOV)

Boutopoulos, Christos; Zergioti, Ioanna; Touloupakis, Eleftherios

This letter demonstrates the direct laser printing of photosynthetic material onto low cost nonfunctionalized screen printed electrodes for the fabrication of photosynthesis-based amperometric biosensors. The high kinetic energy of the transferred material induces direct immobilization of the thylakoids onto the electrodes without the use of linkers. This type of immobilization is able to establish efficient electrochemical contact between proteins and electrode, stabilizing the photosynthetic biomolecule and transporting electrons to the solid state device with high efficiency. The functionality of the laser printed biosensors was evaluated by the detection of a common herbicide such as Linuron.

Selenium containing conducting polymer based pyranose oxidase biosensor for glucose detection.

PubMed

Gokoglan, Tugba Ceren; Soylemez, Saniye; Kesik, Melis; Toksabay, Sinem; Toppare, Levent

2015-04-01

A novel amperometric pyranose oxidase (PyOx) biosensor based on a selenium containing conducting polymer has been developed for the glucose detection. For this purpose, a conducting polymer; poly(4,7-bis(thieno[3,2-b]thiophen-2-yl)benzo[c][1,2,5] selenadiazole) (poly(BSeTT)) was synthesized via electropolymerisation on gold electrode to examine its matrix property for glucose detection. For this purpose, PyOx was used as the model enzyme and immobilised via physical adsorption technique. Amperometric detection of consumed oxygen was monitored at -0.7 V vs Ag reference electrode in a phosphate buffer (50 mM, pH 7.0). K(M)(app), Imax, LOD and sensitivity were calculated as 0.229 mM, 42.37 nA, 3.3 × 10(-4)nM and 6.4 nA/mM cm(2), respectively. Scanning electron microscopy (SEM), Electrochemical Impedance Spectroscopy (EIS) and cyclic voltammetry (CV) techniques were used to monitor changes in surface morphologies and to run electrochemical characterisations. Finally, the constructed biosensor was applied for the determination of glucose in beverages successfully. Copyright © 2014 Elsevier Ltd. All rights reserved.

Design of nanostructured-based glucose biosensors

NASA Astrophysics Data System (ADS)

Komirisetty, Archana; Williams, Frances; Pradhan, Aswini; Konda, Rajini B.; Dondapati, Hareesh; Samantaray, Diptirani

2012-04-01

This paper presents the design of glucose sensors that will be integrated with advanced nano-materials, bio-coatings and electronics to create novel devices that are highly sensitive, inexpensive, accurate, and reliable. In the work presented, a glucose biosensor and its fabrication process flow have been designed. The device is based on electrochemical sensing using a working electrode with bio-functionalized zinc oxide (ZnO) nano-rods. Among all metal oxide nanostructures, ZnO nano-materials play a significant role as a sensing element in biosensors due to their properties such as high isoelectric point (IEP), fast electron transfer, non-toxicity, biocompatibility, and chemical stability which are very crucial parameters to achieve high sensitivity. Amperometric enzyme electrodes based on glucose oxidase (GOx) are used due to their stability and high selectivity to glucose. The device also consists of silicon dioxide and titanium layers as well as platinum working and counter electrodes and a silver/silver chloride reference electrode. Currently, the biosensors are being fabricated using the process flow developed. Once completed, the sensors will be bio-functionalized and tested to characterize their performance, including their sensitivity and stability.

A novel organophosphorus hydrolase-based biosensor using mesoporous carbons and carbon black for the detection of organophosphate nerve agents.

PubMed

Lee, Joon Hwan; Park, Jae Yeon; Min, Kyoungseon; Cha, Hyung Joon; Choi, Suk Soon; Yoo, Young Je

2010-03-15

To detect organophosphate chemicals, which are used both as pesticides and as nerve agents, a novel biosensor based on organophosphorus hydrolase was developed. By using mesoporous carbon (MC) and carbon black (CB) as an anodic layer, the sensitivity of the sensor to p-nitrophenol (PNP), which is the product of the organophosphorus hydrolase reaction, was greatly improved. The MC/CB/glass carbon (GC) layer exhibited an enhanced amperometric response relative to a carbon nanotube (CNT)-modified electrode because it promoted electron transfer of enzymatically generated phenolic compounds (p-nitrophenol). The well-ordered nanopores, many edge-plane-like defective sites (EDSs), and high surface area of the MC resulted in increased sensitivity, and allowed for nanomolar-range detection of the analyte paraoxon. Thus, MCs are suitable for use in real-time biosensors. Under the optimized experimental conditions, the biosensor had a detection limit of 0.12 microM (36 ppb) and a sensitivity of 198 nA/microM for paraoxon. (c) 2009 Elsevier B.V. All rights reserved.

Construction and amperometric biosensing performance of a novel platform containing carbon nanotubes-zinc phthalocyanine and a conducting polymer.

PubMed

Buber, Ece; Yuzer, Abdulcelil; Soylemez, Saniye; Kesik, Melis; Ince, Mine; Toppare, Levent

2017-03-01

A novel glucose oxidase (GOx) based amperometric biosensor utilizing a conducting polymer (CP), multi walled carbon nanotubes (MWCNTs) and a novel water soluble zinc phthalocyanine (ZnPc) was constructed. For this purpose, a novel ZnPc was synthesized to examine the role of being a part of support material for enzyme deposition. High water solubility was achieved with the introduction of tetra quaternized imidazolyl moieties at the peripheral positions of phthalocyanine. In order to fabricate the proposed biosensor, a graphite electrode was firstly modified with poly[9,9-di-(2-ethylhexyl)- fluorenyl-2,7-diyl] end capped with N,N-Bis(4- methylphenyl)-4-aniline (PFLA) and MWCNTs. Then, GOx was co-immobilized with ZnPc onto the modified surface. To the best our knowledge, a sensor design which combines conjugated polymer/MWCNTs/ZnPc was attempted for the first time and this approach resulted in improved biosensor characteristics. The constructed biosensor showed a linear response for glucose between 0.025-1.0mM with a detection limit of 0.018mM. K M app and sensitivity values were calculated as 0.53mM and 82.18μAmm -1 cm -2 , respectively. Moreover, scanning electron microscopy (SEM) and cyclic voltammetry (CV) techniques were used to investigate the surface modifications. Finally, fabricated biosensor was tested on beverages for glucose detection successfully. Copyright © 2016 Elsevier B.V. All rights reserved.

Construction of ferrocene modified conducting polymer based amperometric urea biosensor.

PubMed

Dervisevic, Muamer; Dervisevic, Esma; Senel, Mehmet; Cevik, Emre; Yildiz, Huseyin Bekir; Camurlu, Pınar

2017-07-01

Herein, an electrochemical urea sensing bio-electrode is reported that has been constructed by firstly electropolymerizing 4-(2,5-Di(thiophen-2-yl)-1H-pyrrol-1-yl)aniline monomer (SNS-Aniline) on Pencil Graphite Electrode (PGE), then modifying the polymer coated electrode surface with di-amino-Ferrocene (DAFc) as the mediator, and lastly Urease enzyme through glutaraldehyde crosslinking. The effect of pH, temperature, polymer thickness, and applied potential on the electrode current response was investigated besides performing storage and operational stability experiments with the interference studies. The resulting urea biosensor's amperometric response was linear in the range of 0.1-8.5mM with the sensitivity of 0.54μA/mM, detection limit of 12μM, and short response time of 2s. The designed bio-electrode was tested with real human blood and urine samples where it showed excellent analytical performance with insignificant interference. Copyright © 2017 Elsevier Inc. All rights reserved.

Amperometric urea biosensors based on sulfonated graphene/polyaniline nanocomposite

PubMed Central

Das, Gautam; Yoon, Hyon Hee

2015-01-01

An electrochemical biosensor based on sulfonated graphene/polyaniline nanocomposite was developed for urea analysis. Oxidative polymerization of aniline in the presence of sulfonated graphene oxide was carried out by electrochemical methods in an aqueous environment. The structural properties of the nanocomposite were characterized by Fourier-transform infrared, Raman spectroscopy, X-ray photoelectron spectroscopy, and scanning electron microscopy techniques. The urease enzyme-immobilized sulfonated graphene/polyaniline nanocomposite film showed impressive performance in the electroanalytical detection of urea with a detection limit of 0.050 mM and a sensitivity of 0.85 (μA · cm−2·mM−1. The biosensor achieved a broad linear range of detection (0.12–12.3 mM) with a notable response time of approximately 5 seconds. Moreover, the fabricated biosensor retained 81% of its initial activity (based on sensitivity) after 15 days of storage at 4°C. The ease of fabrication coupled with the low cost and good electrochemical performance of this system holds potential for the development of solid-state biosensors for urea detection. PMID:26346240

Design of a macroalgae amperometric biosensor; application to the rapid monitoring of organophosphate insecticides in an agroecosystem.

PubMed

Nunes, G S; Lins, J A P; Silva, F G S; Araujo, L C; Silva, F E P S; Mendonça, C D; Badea, M; Hayat, A; Marty, J-L

2014-09-01

The immobilization of enzymes onto transducer support is a mature technology and has been successfully implemented to improve biocatalytic processes for diverse applications. However, there exists still need to design more sophisticated and specialized strategies to enhance the functional properties of the biosensors. In this work, a biosensor platform based on innovative fabrication strategy was designed, and employed for the detection of organophosphate (OP) in natural waters. The biosensor was prepared by incorporating acetylcholinesterase enzyme (AChE) to the graphite paste modified with tetracyanoquinodimethane (TCNQ) mediator, along with the use of a macroalgae (Cladaphropsis membranous) as a functional immobilization support. The novel immobilization design resulted in a synergic effect, and led to enhanced stability and sensitivity of the biosensor. The designed biosensor was used to analyze methyl parathion OP insecticide in water samples collected from a demonstrably contaminated lake of São Luis Island, Maranhão, Northeast of Brazil. Water analysis revealed that the aquatic ecosystem was polluted by sub-ppm concentrations of the OP insecticide, and a good correlation was found between values obtained through biosensor and GC-MS techniques. Our results demonstrated that macroalgae-biosensor could be used as a low-cost and sensitive screening method to detect target analyte. Copyright © 2014 Elsevier Ltd. All rights reserved.

Enzyme Biosensors for Biomedical Applications: Strategies for Safeguarding Analytical Performances in Biological Fluids

PubMed Central

Rocchitta, Gaia; Spanu, Angela; Babudieri, Sergio; Latte, Gavinella; Madeddu, Giordano; Galleri, Grazia; Nuvoli, Susanna; Bagella, Paola; Demartis, Maria Ilaria; Fiore, Vito; Manetti, Roberto; Serra, Pier Andrea

2016-01-01

Enzyme-based chemical biosensors are based on biological recognition. In order to operate, the enzymes must be available to catalyze a specific biochemical reaction and be stable under the normal operating conditions of the biosensor. Design of biosensors is based on knowledge about the target analyte, as well as the complexity of the matrix in which the analyte has to be quantified. This article reviews the problems resulting from the interaction of enzyme-based amperometric biosensors with complex biological matrices containing the target analyte(s). One of the most challenging disadvantages of amperometric enzyme-based biosensor detection is signal reduction from fouling agents and interference from chemicals present in the sample matrix. This article, therefore, investigates the principles of functioning of enzymatic biosensors, their analytical performance over time and the strategies used to optimize their performance. Moreover, the composition of biological fluids as a function of their interaction with biosensing will be presented. PMID:27249001

Graphitized carbon nanofiber-Pt nanoparticle hybrids as sensitive tool for preparation of screen printing biosensors. Detection of lactate in wines and ciders.

PubMed

Loaiza, Oscar A; Lamas-Ardisana, Pedro J; Añorga, Larraitz; Jubete, Elena; Ruiz, Virginia; Borghei, Maryam; Cabañero, Germán; Grande, Hans J

2015-02-01

This work describes the fabrication of a new lactate biosensor. The strategy is based on the use of a novel hybrid nanomaterial for amperometric biosensors i.e. platinum nanoparticles (PtNps) supported on graphitized carbon nanofibers (PtNps/GCNF) prepared by chemical reduction of the Pt precursor at GCNF surfaces. The biosensors were constructed by covalent immobilization of lactate oxidase (LOx) onto screen printed carbon electrodes (SPCEs) modified with PtNps (PtNps/GCNF-SPCEs) using polyethyleneimine (PEI) and glutaraldehyde (GA). Experimental variables concerning both the biosensor design and the detection process were investigated for an optimal analytical performance. Lactate biosensors show good reproducibility (RSD 4.9%, n=10) and sensitivity (41,302±546) μA/Mcm(2), with a good limit of detection (6.9μM). Covalent immobilization of the enzyme allows the reuse of the biosensor for several measurements, converting them in a cheap alternative to the solid electrodes. The long-term stability of the biosensors was also evaluated. 90% of the signal was kept after 3months of storage at room temperature (RT), while 95% was retained after 18months at -20°C. These results demonstrate that the method provides sensitive electrochemical lactate biosensors where the stability of the enzymatic activity can be preserved for a long period of time in adequate storage conditions. Copyright © 2014 Elsevier B.V. All rights reserved.

Glucose Oxidase Biosensor Modeling and Predictors Optimization by Machine Learning Methods.

PubMed

Gonzalez-Navarro, Felix F; Stilianova-Stoytcheva, Margarita; Renteria-Gutierrez, Livier; Belanche-Muñoz, Lluís A; Flores-Rios, Brenda L; Ibarra-Esquer, Jorge E

2016-10-26

Biosensors are small analytical devices incorporating a biological recognition element and a physico-chemical transducer to convert a biological signal into an electrical reading. Nowadays, their technological appeal resides in their fast performance, high sensitivity and continuous measuring capabilities; however, a full understanding is still under research. This paper aims to contribute to this growing field of biotechnology, with a focus on Glucose-Oxidase Biosensor (GOB) modeling through statistical learning methods from a regression perspective. We model the amperometric response of a GOB with dependent variables under different conditions, such as temperature, benzoquinone, pH and glucose concentrations, by means of several machine learning algorithms. Since the sensitivity of a GOB response is strongly related to these dependent variables, their interactions should be optimized to maximize the output signal, for which a genetic algorithm and simulated annealing are used. We report a model that shows a good generalization error and is consistent with the optimization.

An Oxidase-Based Electrochemical Fluidic Sensor with High-Sensitivity and Low-Interference by On-Chip Oxygen Manipulation

PubMed Central

Radhakrishnan, Nitin; Park, Jongwon; Kim, Chang-Soo

2012-01-01

Utilizing a simple fluidic structure, we demonstrate the improved performance of oxidase-based enzymatic biosensors. Electrolysis of water is utilized to generate bubbles to manipulate the oxygen microenvironment close to the biosensor in a fluidic channel. For the proper enzyme reactions to occur, a simple mechanical procedure of manipulating bubbles was developed to maximize the oxygen level while minimizing the pH change after electrolysis. The sensors show improved sensitivities based on the oxygen dependency of enzyme reaction. In addition, this oxygen-rich operation minimizes the ratio of electrochemical interference signal by ascorbic acid during sensor operation (i.e., amperometric detection of hydrogen peroxide). Although creatinine sensors have been used as the model system in this study, this method is applicable to many other biosensors that can use oxidase enzymes (e.g., glucose, alcohol, phenol, etc.) to implement a viable component for in-line fluidic sensor systems. PMID:23012527

Amperometric glucose biosensor based on glucose oxidase dispersed in multiwalled carbon nanotubes/graphene oxide hybrid biocomposite.

PubMed

Palanisamy, Selvakumar; Cheemalapati, Srikanth; Chen, Shen-Ming

2014-01-01

An amperometric glucose biosensor based on enhanced and fast direct electron transfer (DET) of glucose oxidase (GOx) at enzyme dispersed multiwalled carbon nanotubes/graphene oxide (MWCNT/GO) hybrid biocomposite was developed. The fabricated hybrid biocomposite was characterized by transmission electron microscopy (TEM), Raman and infrared spectroscopy (IR). The TEM image of hybrid biocomposite reveals that a thin layer of GOx was covered on the surface of MWCNT/GO hybrid composite. IR results validate that the hybrid biocomposite was formed through the electrostatic interactions between GOx and MWCNT/GO hybrid composite. Further, MWCNT/GO hybrid composite has also been characterized by TEM and UV-visible spectroscopy. A pair of well-defined redox peak was observed for GOx immobilized at the hybrid biocomposite electrode than that immobilized at the MWCNT modified electrode. The electron transfer rate constant (Ks) of GOx at the hybrid biocomposite was calculated to be 11.22s(-1). The higher Ks value revealed that fast DET of GOx occurred at the electrode surface. Moreover, fabricated biosensor showed a good sensitivity towards glucose oxidation over a linear range 0.05-23.2mM. The limit of detection (LOD) was estimated to be 28μM. The good features of the proposed biosensor could be used for the accurate detection of glucose in the biological samples. © 2013.

Highly sensitive and selective cholesterol biosensor based on direct electron transfer of hemoglobin.

PubMed

Zhao, Changzhi; Wan, Li; Jiang, Li; Wang, Qin; Jiao, Kui

2008-12-01

A cholesterol biosensor based on direct electron transfer of a hemoglobin-encapsulated chitosan-modified glassy carbon electrode has been developed for highly sensitive and selective analysis of serum samples. Modified by films containing hemoglobin and cholesterol oxidase, the electrode was prepared by encapsulation of enzyme in chitosan matrix. The hydrogen peroxide produced by the catalytic oxidation of cholesterol by cholesterol oxidase was reduced electrocatalytically by immobilized hemoglobin and used to obtain a sensitive amperometric response to cholesterol. The linear response of cholesterol concentrations ranged from 1.00 x 10(-5) to 6.00 x 10(-4) mol/L, with a correlation coefficient of 0.9969 and estimated detection limit of cholesterol of 9.5 micromol/L at a signal/noise ratio of 3. The cholesterol biosensor can efficiently exclude interference by the commonly coexisting ascorbic acid, uric acid, dopamine, and epinephrine. The sensitivity to the change in the concentration of cholesterol as the slope of the calibration curve was 0.596 A/M. The relative standard deviation was under 4.0% (n=5) for the determination of real samples. The biosensor is satisfactory in the determination of human serum samples.

Assembling Amperometric Biosensors for Clinical Diagnostics

PubMed Central

Belluzo, María Soledad; Ribone, María Élida; Lagier, Claudia Marina

2008-01-01

Clinical diagnosis and disease prevention routinely require the assessment of species determined by chemical analysis. Biosensor technology offers several benefits over conventional diagnostic analysis. They include simplicity of use, specificity for the target analyte, speed to arise to a result, capability for continuous monitoring and multiplexing, together with the potentiality of coupling to low-cost, portable instrumentation. This work focuses on the basic lines of decisions when designing electron-transfer-based biosensors for clinical analysis, with emphasis on the strategies currently used to improve the device performance, the present status of amperometric electrodes for biomedicine, and the trends and challenges envisaged for the near future. PMID:27879771

Bienzyme biosensors for glucose, ethanol and putrescine built on oxidase and sweet potato peroxidase.

PubMed

Castillo, Jaime; Gáspár, Szilveszter; Sakharov, Ivan; Csöregi, Elisabeth

2003-05-01

Amperometric biosensors for glucose, ethanol, and biogenic amines (putrescine) were constructed using oxidase/peroxidase bienzyme systems. The H(2)O(2) produced by the oxidase in reaction with its substrate is converted into a measurable signal via a novel peroxidase purified from sweet potato peels. All developed biosensors are based on redox hydrogels formed of oxidases (glucose oxidase, alcohol oxidase, or amine oxidase) and the newly purified sweet potato peroxidase (SPP) cross-linked to a redox polymer. The developed electrodes were characterized (sensitivity, stability, and performances in organic medium) and compared with similarly built ones using the 'classical' horseradish peroxidase (HRP). The SPP-based electrodes displayed higher sensitivity and better detection limit for putrescine than those using HRP and were also shown to retain their activity in organic phase much better than the HPR based ones. The importance of attractive or repulsive electrostatic interactions between the peroxidases and oxidases (determined by their isoelectric points) were found to play an important role in the sensitivity of the obtained sensors.

Development of a biosensor telemetry system for monitoring fermentation in craft breweries.

PubMed

Farina, Donatella; Zinellu, Manuel; Fanari, Mauro; Porcu, Maria Cristina; Scognamillo, Sergio; Puggioni, Giulia Maria Grazia; Rocchitta, Gaia; Serra, Pier Andrea; Pretti, Luca

2017-03-01

The development and applications of biosensors in the food industry has had a rapid grown due to their sensitivity, specificity and simplicity of use with respect to classical analytical methods. In this study, glucose and ethanol amperometric biosensors integrated with a wireless telemetry system were developed and used for the monitoring of top and bottom fermentations in beer wort samples. The collected data were in good agreement with those obtained by reference methods. The simplicity of construction, the low cost and the short time of analysis, combined with easy interpretation of the results, suggest that these devices could be a valuable alternative to conventional methods for monitoring fermentation processes in the food industry. Copyright © 2016 Elsevier Ltd. All rights reserved.

Simultaneous topographic and amperometric membrane mapping using an AFM probe integrated biosensor.

PubMed

Stanca, Sarmiza Elena; Csaki, Andrea; Urban, Matthias; Nietzsche, Sandor; Biskup, Christoph; Fritzsche, Wolfgang

2011-02-15

The investigation of the plasma membrane with intercorrelated multiparameter techniques is a prerequisite for understanding its function. Presented here, is a simultaneous electrochemical and topographic study of the cell membrane using a miniaturized amperometric enzymatic biosensor. The fabrication of this biosensor is also reported. The biosensor combines a scanning force microscopy (AFM) gold-coated cantilever and an enzymatic transducer layer of peroxidases (PODs). When these enzymes are brought in contact with the substrate, the specific redox reaction produces an electric current. The intensity of this current is detected simultaneously with the surface imaging. For sensor characterization, hydroquinone-2-carboxylic acid (HQ) is selected as an intrinsic source of H(2)O(2). HQ has been electrochemically regenerated by the reduction of antraquinone-2-carboxylic acid (AQ). The biosensor reaches the steady state value of the current intensity in 1 ± 0.2s. Copyright © 2010 Elsevier B.V. All rights reserved.

Amperometric Biosensors Based on 3-Dimensional Hydrogel-Forming Epoxy Networks

DTIC Science & Technology

1993-05-24

are epoxy- embedded and contained in a 0.3mm diameter biocompatible polyimide tubing. The ensemble of epoxy-embedded fiber tips is coated with the...electrode is then overcoated with a biocompatible film. The electrode’s sensitivity is 2.5xI0 2 A cm’ 2 M 1. It can be stored at 40 C for 4 months with no

A screen-printed microband glucose biosensor system for real-time monitoring of toxicity in cell culture.

PubMed

Pemberton, R M; Xu, J; Pittson, R; Drago, G A; Griffiths, J; Jackson, S K; Hart, J P

2011-01-15

Microband biosensors, screen-printed from a water-based carbon ink containing cobalt phthalocyanine redox mediator and glucose oxidase (GOD) enzyme, were used to monitor glucose levels continuously in buffer and culture medium. Five biosensors were operated amperometrically (E(app) of +0.4V), in a 12-well tissue culture plate system at 37°C, using a multipotentiostat. After 24 h, a linear calibration plot was obtained from steady-state current responses for glucose concentrations up to 10 mM (dynamic range 30 mM). Within the linear region, a correlation coefficient (R(2)) of 0.981 was obtained between biosensor and spectrophotometric assays. Over 24 h, an estimated 0.15% (89 nmol) of the starting glucose concentration (24 mM) was consumed by the microbiosensor. The sensitivity of the biosensor response in full culture medium was stable between pHs 7.3 and 8.4. Amperometric responses for HepG2 monolayer cultures decreased with time in inverse proportionality to cell number (for 0 to 10(6) cell/ml), as glucose was being metabolised. HepG2 3D cultures (spheroids) were also shown to metabolise glucose, at a rate which was independent of spheroid age (between 6 and 15 days). Spheroids were used to assay the effect of a typical hepatotoxin, paracetamol. At 1 mM paracetamol, glucose uptake was inhibited by 95% after 6 h in culture; at 500 μM, around 15% inhibition was observed after 16 h. This microband biosensor culture system could form the basis for an in vitro toxicity testing system. Copyright © 2010 Elsevier B.V. All rights reserved.

Fabrication of mediator-free hybrid nano-interfaced electrochemical biosensor for monitoring cancer cell proliferation.

PubMed

Madhurantakam, Sasya; Jayanth Babu, K; Balaguru Rayappan, John Bosco; Krishnan, Uma Maheswari

2017-01-15

Glucose, a chief energy source in cellular metabolism, has a significant role in cell proliferation. Cancer cells utilize more glucose than normal cells to meet the energy demand arising due to their uncontrolled proliferation. The present work reports the development of a nano-interfaced amperometric biosensor for rapid and accurate monitoring of glucose utilization by cancer cells. A hybrid nano-interface comprising a blend of carbon nanotubes (CNTs) and graphene (GR) was employed to enhance the surface area of the working electrode and favour direct electron transfer. Glucose oxidase (GOx) immobilized on the interface serves as the sensing element due to its high selectivity and sensitivity towards glucose. Utilization of glucose was monitored at pre-determined time intervals in MiaPaCa-2 cancer cells. The results obtained from the amperometric technique were compared with the values obtained from a commercial glucometer. Alamar blue assay was performed to check the proliferation rate of the cells. A good correlation was obtained between the proliferation rate and glucose utilization. The designed biosensor was found to be unaffected by the presence of potential interferents and hence may serve as a novel in vitro tool to rapidly quantify the proliferation rates of cancer cells in response to different treatment strategies. Copyright © 2016 Elsevier B.V. All rights reserved.

A probe for NADH and H2O2 amperometric detection at low applied potential for oxidase and dehydrogenase based biosensor applications.

PubMed

Ricci, Francesco; Amine, Aziz; Moscone, Danila; Palleschi, Giuseppe

2007-01-15

Modified screen-printed electrodes for amperometric detection of H(2)O(2) and nicotinamide adenine dinucleotide (NADH) at low applied potential are presented in this paper. The sensors are obtained by modifying the working electrode surface with Prussian Blue, a well known electrochemical mediator for H(2)O(2) reduction. The coupling of this sensor with phenazine methosulfate (PMS) in the working solution gives the possibility of measuring both NAD(P)H and H(2)O(2). PMS reacts with NADH producing PMSH, which in the presence of oxygen, gives an equimolar amount of H(2)O(2). This allows the measurement of both analytes with similar sensitivity (357 mA mol(-1)L cm(-2) for H(2)O(2) and 336 mA mol(-1)L cm(-2) for NADH) and LOD (5x10(-7)mol L(-1) for H(2)O(2) and NADH) and opens the possibility of a whole series of biosensor applications. In this paper, results obtained with a variety of dehydrogenase enzymes (alcohol, malic, lactate, glucose, glycerol and glutamate) for the detection of enzymatic substrates or enzymatic activity are presented demonstrating the suitability of the proposed method for future biosensor applications.

Integrated amperometric affinity biosensors using Co2+-tetradentate nitrilotriacetic acid modified disposable carbon electrodes: application to the determination of β-lactam antibiotics.

PubMed

Conzuelo, Felipe; Gamella, María; Campuzano, Susana; Martínez-Ruiz, Paloma; Esteban-Torres, María; de las Rivas, Blanca; Reviejo, A Julio; Muñoz, Rosario; Pingarrón, José M

2013-03-19

A novel strategy for the construction of disposable amperometric affinity biosensors is described in this work. The approach uses a recombinant bacterial penicillin binding protein (PBP) tagged by an N-terminal hexahistidine tail which was immobilized onto Co(2+)-tetradentate nitrilotriacetic acid (NTA)-modified screen-printed carbon electrodes (SPCEs). The biosensor was employed for the specific detection and quantification of β-lactam antibiotics residues in milk, which was accomplished by means of a direct competitive assay using a tracer with horseradish peroxidase (HRP) for the enzymatic labeling. The amperometric response measured at -0.20 V versus the Ag pseudoreference electrode of the SPCE upon the addition of H2O2 in the presence of hydroquinone (HQ) as redox mediator was used as the transduction signal. The developed affinity sensor allowed limits of detection to be obtained in the low part-per-billion level for the antibiotics tested in untreated milk samples. Moreover, the biosensor exhibited a good selectivity against other antibiotics residues frequently detected in milk and dairy products. The analysis time was of approximately 30 min.

Amperometric Glucose Biosensor Based on Effective Self-Assembly Technology for Preparation of Poly(allylamine hydrochloride)/Au Nanoparticles Multilayers.

PubMed

Ye, Yuhang; Xie, Hangqing; Shao, Xiaobao; Wei, Yuan; Liu, Yuhong; Zhao, Wenbo; Xia, Xinyi

2016-03-01

Novel nanomaterials and nanotechnology for use in bioassay applications represent a rapidly advancing field. This study developed a novel method to fabricate the glucose biosensor with good gold nanoparticles (AuNPs) fixed efficiency based on effective self-assembly technology for preparation of multilayers composed of poly(allylamine hydrochloride) (PAH) and AuNPs. The electrochemical properties of the biosensor based on (AuNPs/PAH)n/AuNPs/glucose oxide (GOD) with different multilayers were systematically investigated. Among the resulting glucose biosensors, electrochemical properties of the biosensor with three times self-assembly processes ((AuNPs/PAH)3/AuNPs/GOD) is best. The GOD biosensor exhibited a fast amperometric response (5 s) to glucose, a good linear current-time relation over a wide range of glucose concentrations from 0.05 to 162 mM, and a low detection limit of 0.029 mM. The GOD biosensor modified with (AuNPs/PAH)n layers will have essential significance and practical application in future owing to the simple method of fabrication and good performance.

Facile hydrothermal synthesis of mn doped ZnO nanopencils for development of amperometric glucose biosensors

NASA Astrophysics Data System (ADS)

Shukla, Mayoorika; Pramila; Agrawal, Jitesh; Dixit, Tejendra; Palani, I. A.; Singh, Vipul

2018-05-01

Mn doped ZnO nanopencils were synthesized via low temperature hydrothermal process for fabrication of enzymatic electrochemical glucose biosensor. The KMnO4 was found to play a dual role in modifying morphology and inducing Mn doping. Interestingly, two different types of morphologies viz nanorods and nanopencils along with Mn doping in the later were obtained. Incorporation of Mn has shown a tremendous effect on the morphological variations, repression of defects and electrochemical charge transfer at electrode electrolyte interface. The possible reason behind obtained morphological changes has been proposed which in turn were responsible for the improvement in the different figure of merits of as fabricated enzymatic electrochemical biosensor. There has been a 17 fold enhancement in the sensitivity of the as fabricated glucose biosensor from ZnO nanorods to Mn doped ZnO nanopencils which can be attributed to morphological variation and Mn doping.

A new PANI biosensor based on catalase for cyanide determination.

PubMed

Özcan, Hakkı Mevlüt; Aydin, Tuba

2016-01-01

Cyanide is one of the most widespread of compounds measured in environmental analysis due to their toxic effects on environment and health. We report a highly sensitive, reliable, selective amperometric sensor for determination of cyanide, using a polyaniline conductive polymer. The enzyme catalase was immobilized by electropolymerization. The steps during the immobilization were controlled by electrochemical impedance spectroscopy. Optimum pH, temperature, aniline concentration, enzyme concentration, and the number of scans obtained during electropolymerization, were investigated. In addition, the cyanide present in artificial waste water samples was determined. In the characterization studies of the biosensor, some parameters such as reproducibility and storage stability, were analyzed.

A Comprehensive Review of Glucose Biosensors Based on Nanostructured Metal-Oxides

PubMed Central

Rahman, Md. Mahbubur; Saleh Ahammad, A. J.; Jin, Joon-Hyung; Ahn, Sang Jung; Lee, Jae-Joon

2010-01-01

Nanotechnology has opened new and exhilarating opportunities for exploring glucose biosensing applications of the newly prepared nanostructured materials. Nanostructured metal-oxides have been extensively explored to develop biosensors with high sensitivity, fast response times, and stability for the determination of glucose by electrochemical oxidation. This article concentrates mainly on the development of different nanostructured metal-oxide [such as ZnO, Cu(I)/(II) oxides, MnO2, TiO2, CeO2, SiO2, ZrO2, and other metal-oxides] based glucose biosensors. Additionally, we devote our attention to the operating principles (i.e., potentiometric, amperometric, impedimetric and conductometric) of these nanostructured metal-oxide based glucose sensors. Finally, this review concludes with a personal prospective and some challenges of these nanoscaled sensors. PMID:22399911

Magnetic Beads-Based Sensor with Tailored Sensitivity for Rapid and Single-Step Amperometric Determination of miRNAs.

PubMed

Vargas, Eva; Torrente-Rodríguez, Rebeca M; Ruiz-Valdepeñas Montiel, Víctor; Povedano, Eloy; Pedrero, María; Montoya, Juan J; Campuzano, Susana; Pingarrón, José M

2017-11-09

This work describes a sensitive amperometric magneto-biosensor for single-step and rapid determination of microRNAs (miRNAs). The developed strategy involves the use of direct hybridization of the target miRNA (miRNA-21) with a specific biotinylated DNA probe immobilized on streptavidin-modified magnetic beads (MBs), and labeling of the resulting heteroduplexes with a specific DNA-RNA antibody and the bacterial protein A (ProtA) conjugated with an horseradish peroxidase (HRP) homopolymer (Poly-HRP40) as an enzymatic label for signal amplification. Amperometric detection is performed upon magnetic capture of the modified MBs onto the working electrode surface of disposable screen-printed carbon electrodes (SPCEs) using the H₂O₂/hydroquinone (HQ) system. The magnitude of the cathodic signal obtained at -0.20 V (vs. the Ag pseudo-reference electrode) demonstrated linear dependence with the concentration of the synthetic target miRNA over the 1.0 to 100 pM range. The method provided a detection limit (LOD) of 10 attomoles (in a 25 μL sample) without any target miRNA amplification in just 30 min (once the DNA capture probe-MBs were prepared). This approach shows improved sensitivity compared with that of biosensors constructed with the same anti-DNA-RNA Ab as capture instead of a detector antibody and further labeling with a Strep-HRP conjugate instead of the Poly-HRP40 homopolymer. The developed strategy involves a single step working protocol, as well as the possibility to tailor the sensitivity by enlarging the length of the DNA/miRNA heteroduplexes using additional probes and/or performing the labelling with ProtA conjugated with homopolymers prepared with different numbers of HRP molecules. The practical usefulness was demonstrated by determination of the endogenous levels of the mature target miRNA in 250 ng raw total RNA (RNA t ) extracted from human mammary epithelial normal (MCF-10A) and cancer (MCF-7) cells and tumor tissues.

Influence of different nanoparticles on electrochemical behavior of glucose biosensor

NASA Astrophysics Data System (ADS)

Nenkova, R. D.; Ivanov, Y. L.; Godjevargova, T. I.

2017-02-01

The influence of nanosized particles on the glucose oxidase loading and the performance of amperometric glucose bionsensors were studied. Four enzyme electrodes (Pt/PAN/GOD, Pt/PAN/NZ/GOD, Pt/PAN/NZ/MNP/GOD, Pt/PAN/NZ/MWNT/GOD) were prepared by cross-linking of glucose oxidase (GOD) on nanocomposite material. Nanocomposites were prepared by entrapping nanozeolite (NZ), multiwalled carbon nanotubes (MWNT) and magnetic nanoparticles (MNP) in polyacrylonitrile (PAN) film. Cyclic voltammetric kinetic studies have been carried out with the four biosensors and the surface concentration of the adsorbed electroactive species on the electrodes was estimated. The highest enzyme concentration on the electrode surface corresponded to the electrodes prepared by nanozeolite separate (Pt/PAN/NZ/GOD) and combined with multi-walled carbon nanotubes (Pt/PAN/NZ/MWNT/GOD). The sensitivity of these two biosensors was the highest and that is in accordance with the greater amount of the adsorbed electroactive species on the electrodes (0.373 mol.cm-2). This was indication that a good synergistic effect happened when MWNTs and NZ were combined and these greatly improve the electron transfer ability of the sensor interface. Amperometric measurement of the two glucose oxidase electrodes (Pt/PAN/NZ/GOD and Pt/PAN/NZ/MWNT/GOD) with best results was carried out. The linear concentration interval of the Pt/PAN/NZ/MWNT/GOD biosensor was up to 3 mM, the detection limit - 0.02 mM glucose and the storage stability - 81% of its initial current response after 30 days.

Amperometric L-lactate biosensor based on screen-printed carbon electrode containing cobalt phthalocyanine, coated with lactate oxidase-mesoporous silica conjugate layer.

PubMed

Shimomura, Takeshi; Sumiya, Touru; Ono, Masatoshi; Ito, Tetsuji; Hanaoka, Taka-aki

2012-02-10

A novel amperometric biosensor for the measurement of L-lactate has been developed. The device comprises a screen-printed carbon electrode containing cobalt phthalocyanine (CoPC-SPCE), coated with lactate oxidase (LOD) that is immobilized in mesoporous silica (FSM8.0) using a polymer matrix of denatured polyvinyl alcohol; a Nafion layer on the electrode surface acts as a barrier to interferents. The sampling unit attached to the SPCE requires only a small sample volume of 100 μL for each measurement. The measurement of l-lactate is based on the signal produced by hydrogen peroxide, the product of the enzymatic reaction. The behavior of the biosensor, LOD-FSM8.0/Naf/CoPC-SPCE, was examined in terms of pH, applied potential, sensitivity and operational range, selectivity, and storage stability. The sensor showed an optimum response at a pH of 7.4 and an applied potential of +450 mV. The determination range and the response time for L-lactate were 18.3 μM to 1.5 mM and approximately 90s, respectively. In addition, the sensor exhibited high selectivity for L-lactate and was quite stable in storage, showing no noticeable change in its initial response after being stored for over 9 months. These results indicate that our method provides a simple, cost-effective, high-performance biosensor for l-lactate. Copyright © 2011 Elsevier B.V. All rights reserved.

Electrodeposition of gold-platinum alloy nanoparticles on ionic liquid-chitosan composite film and its application in fabricating an amperometric cholesterol biosensor.

PubMed

Safavi, Afsaneh; Farjami, Fatemeh

2011-01-15

An electrodeposition method was applied to form gold-platinum (AuPt) alloy nanoparticles on the glassy carbon electrode (GCE) modified with a mixture of an ionic liquid (IL) and chitosan (Ch) (AuPt-Ch-IL/GCE). AuPt nanoparticles were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and electrochemical methods. AuPt-Ch-IL/GCE electrocatalyzed the reduction of H(2)O(2) and thus was suitable for the preparation of biosensors. Cholesterol oxidase (ChOx) was then, immobilized on the surface of the electrode by cross-linking ChOx and chitosan through addition of glutaraldehyde (ChOx/AuPt-Ch-IL/GCE). The fabricated biosensor exhibited two wide linear ranges of responses to cholesterol in the concentration ranges of 0.05-6.2 mM and 6.2-11.2 mM. The sensitivity of the biosensor was 90.7 μA mM(-1) cm(-2) and the limit of detection was 10 μM of cholesterol. The response time was less than 7 s. The Michaelis-Menten constant (K(m)) was found as 0.24 mM. The effect of the addition of 1 mM ascorbic acid and glucose was tested on the amperometric response of 0.5 mM cholesterol and no change in response current of cholesterol was observed. Copyright © 2010 Elsevier B.V. All rights reserved.

A lactate electrochemical biosensor with a titanate nanotube as direct electron transfer promoter

NASA Astrophysics Data System (ADS)

Yang, Mingli; Wang, Jin; Li, Huaqing; Zheng, Jian-Guo; Wu, Nianqiang Nick

2008-02-01

Hydrogen titanate (H2Ti3O7) nanotubes (TNTs) have been synthesized by a one-step hydrothermal processing. Lactate oxidase (LOx) enzyme has been immobilized on the three-dimensional porous TNT network to make an electrochemical biosensor for lactate detection. Cyclic voltammetry and amperometry tests reveal that the LOx enzyme, which is supported on TNTs, maintains their substrate-specific catalytic activity. The nanotubes offer the pathway for direct electron transfer between the electrode surface and the active redox centers of LOx, which enables the biosensor to operate at a low working potential and to avoid the influence of the presence of O2 on the amperometric current response. The biosensor exhibits a sensitivity of 0.24 µA cm-2 mM-1, a 90% response time of 5 s, and a linear response in the range from 0.5 to 14 mM and the redox center of enzyme obviates the need of redox mediators for electrochemical enzymatic sensors, which is attractive for the development of reagentless biosensors.

Electrochemical Enzyme Biosensors Revisited: Old Solutions for New Problems.

PubMed

Monteiro, Tiago; Almeida, Maria Gabriela

2018-05-14

Worldwide legislation is driving the development of novel and highly efficient analytical tools for assessing the composition of every material that interacts with Consumers or Nature. The biosensor technology is one of the most active R&D domains of Analytical Sciences focused on the challenge of taking analytical chemistry to the field. Electrochemical biosensors based on redox enzymes, in particular, are highly appealing due to their usual quick response, high selectivity and sensitivity, low cost and portable dimensions. This review paper aims to provide an overview of the most important advances made in the field since the proposal of the first biosensor, the well-known hand-held glucose meter. The first section addresses the current needs and challenges for novel analytical tools, followed by a brief description of the different components and configurations of biosensing devices, and the fundamentals of enzyme kinetics and amperometry. The following sections emphasize on enzyme-based amperometric biosensors and the different stages of their development.

Integrated multienzyme electrochemical biosensors for the determination of glycerol in wines.

PubMed

Gamella, M; Campuzano, S; Reviejo, A J; Pingarrón, J M

2008-02-25

The construction and performance of integrated amperometric biosensors for the determination of glycerol are reported. Two different biosensor configurations have been evaluated: one based on the glycerol dehydrogenase/diaphorase (GDH/DP) bienzyme system, and another using glycerol kinase/glycerol-3-phosphate oxidase/peroxidase (GK/GPOx/HRP). Both enzyme systems were immobilized together with the mediator tetrathiafulvalene (TTF) on a 3-mercaptopropionic acid (MPA) self-assembled monolayer (SAM)-modified gold electrode by using a dialysis membrane. The electrochemical oxidation of TTF at +150mV (vs. Ag/AgCl), and the reduction of TTF(+) at 0mV were used for the monitoring of the enzyme reactions for the bienzyme and trienzyme configurations, respectively. Experimental variables concerning both the biosensors composition and the working conditions were optimized for each configuration. A good repeatability of the measurements with no need of cleaning or pretreatment of the biosensors was obtained in both cases. After 51 days of use, the GDH/DP biosensor still exhibited 87% of the original sensitivity, while the GK/GPOx/HRP biosensor yielded a 46% of the original response after 8 days. Calibration graphs for glycerol with linear ranges of 1.0x10(-6) to 2.0x10(-5) or 1.0x10(-6) to 1.0x10(-5)M glycerol and sensitivities of 1214+/-21 or 1460+/-34microAM(-1) were obtained with GDH/DP and GK/GPOx/HRP biosensors, respectively. The calculated detection limits were 4.0x10(-7) and 3.1x10(-7)M, respectively. The biosensors exhibited a great sensitivity with no significant interferences in the analysis of wines. The biosensors were applied to the determination of glycerol in 12 different wines and the results advantageously compared with those provided by a commercial enzyme kit.

Glucose Oxidase Biosensor Modeling and Predictors Optimization by Machine Learning Methods †

PubMed Central

Gonzalez-Navarro, Felix F.; Stilianova-Stoytcheva, Margarita; Renteria-Gutierrez, Livier; Belanche-Muñoz, Lluís A.; Flores-Rios, Brenda L.; Ibarra-Esquer, Jorge E.

2016-01-01

Biosensors are small analytical devices incorporating a biological recognition element and a physico-chemical transducer to convert a biological signal into an electrical reading. Nowadays, their technological appeal resides in their fast performance, high sensitivity and continuous measuring capabilities; however, a full understanding is still under research. This paper aims to contribute to this growing field of biotechnology, with a focus on Glucose-Oxidase Biosensor (GOB) modeling through statistical learning methods from a regression perspective. We model the amperometric response of a GOB with dependent variables under different conditions, such as temperature, benzoquinone, pH and glucose concentrations, by means of several machine learning algorithms. Since the sensitivity of a GOB response is strongly related to these dependent variables, their interactions should be optimized to maximize the output signal, for which a genetic algorithm and simulated annealing are used. We report a model that shows a good generalization error and is consistent with the optimization. PMID:27792165

Selective detection of hypertoxic organophosphates pesticides via PDMS composite based acetylcholinesterase-inhibition biosensor.

PubMed

Zhao, Wei; Ge, Pei-Yu; Xu, Jing-Juan; Chen, Hong-Yuan

2009-09-01

We report on a pair of highly sensitive amperometric biosensors for organophosphate pesticides (OPs) based on assembling acetylcholinesterase (AChE) on poly(dimethylsiloxane) (PDMS)-poly(diallydimethylemmonium) (PDDA)/gold nanoparticles (AuNPs) composite film. Two AChE immobilization strategies are proposed based on the composite film with hydrophobic and hydrophilic surface tailored by oxygen plasma. The twin biosensors show interesting different electrochemical performances. The hydrophobic surface based PDMS-PDDAN AuNPs/choline oxidase (ChO)/AChE biosensor (biosensor-1) shows excellent stability and unique selectivity to hypertoxic organophosphate. At optimal conditions, this biosensor-1 could measure 5.0 x 10(-10) g/L paraoxon and 1.0 x 10(-9) g/L parathion. As for the hydrophilic surface based biosensor (biosensor-2), it shows no selectivity but can be commonly used for the detection of most OPs. Based on the structure of AChE, it is assumed that via the hydrophobic interaction between enzyme molecules and hydrophobic surface, the enzyme active sites surrounded by hydrophobic amino acids face toward the surface and get better protection from OPs. This assumption may explain the different performances of the twin biosensors and especially the unique selectivity of biosensor-1 to hypertoxic OPs. Real sample detection was performed and the omethoate residue on Cottomrose Hibiscus leaves was detected with biosensor-1.

A novel amperometric alcohol biosensor developed in a 3rd generation bioelectrode platform using peroxidase coupled ferrocene activated alcohol oxidase as biorecognition system.

PubMed

Chinnadayyala, Somasekhar R; Kakoti, Ankana; Santhosh, Mallesh; Goswami, Pranab

2014-05-15

Alcohol oxidase (AOx) with a two-fold increase in efficiency (Kcat/Km) was achieved by physical entrapment of the activator ferrocene in the protein matrix through a simple microwave based partial unfolding technique and was used to develop a 3rd generation biosensor for improved detection of alcohol in liquid samples. The ferrocene molecules were stably entrapped in the AOx protein matrix in a molar ratio of ~3:1 through electrostatic interaction with the Trp residues involved in the functional activity of the enzyme as demonstrated by advanced analytical techniques. The sensor was fabricated by immobilizing ferrocene entrapped alcohol oxidase (FcAOx) and sol-gel chitosan film coated horseradish peroxidase (HRP) on a multi-walled carbon nanotube (MWCNT) modified glassy carbon electrode through layer-by-layer technique. The bioelectrode reactions involved the formation of H2O2 by FcAOx biocatalysis of substrate alcohol followed by HRP-catalyzed reduction of the liberated H2O2 through MWCNT supported direct electron transfer mechanism. The amperometric biosensor exhibited a linear response to alcohol in the range of 5.0 × 10(-6) to 30 × 10(-4)mol L(-1) with a detection limit of 2.3 × 10(-6) mol L(-1), and a sensitivity of 150 µA mM(-1) cm(-2). The biosensor response was steady for 28 successive measurements completed in a period of 5h and retained ~90% of the original response even after four weeks when stored at 4 °C. The biosensor was successfully applied for the determination of alcohol in commercial samples and its performance was validated by comparing with the data obtained by GC analyses of the samples. © 2013 Published by Elsevier B.V.

Determination of ammonium ion using a reagentless amperometric biosensor based on immobilized alanine dehydrogenase.

PubMed

Tan, Ling Ling; Musa, Ahmad; Lee, Yook Heng

2011-01-01

The use of the enzyme alanine dehydrogenase (AlaDH) for the determination of ammonium ion (NH(4)(+)) usually requires the addition of pyruvate substrate and reduced nicotinamide adenine dinucleotide (NADH) simultaneously to effect the reaction. This addition of reagents is inconvenient when an enzyme biosensor based on AlaDH is used. To resolve the problem, a novel reagentless amperometric biosensor using a stacked methacrylic membrane system coated onto a screen-printed carbon paste electrode (SPE) for NH(4)(+) ion determination is described. A mixture of pyruvate and NADH was immobilized in low molecular weight poly(2-hydroxyethyl methacrylate) (pHEMA) membrane, which was then deposited over a photocured pHEMA membrane (photoHEMA) containing alanine dehydrogenase (AlaDH) enzyme. Due to the enzymatic reaction of AlaDH and the pyruvate substrate, NH(4)(+) was consumed in the process and thus the signal from the electrocatalytic oxidation of NADH at an applied potential of +0.55 V was proportional to the NH(4)(+) ion concentration under optimal conditions. The stacked methacrylate membranes responded rapidly and linearly to changes in NH(4)(+) ion concentrations between 10-100 mM, with a detection limit of 0.18 mM NH(4)(+) ion. The reproducibility of the amperometrical NH(4)(+) biosensor yielded low relative standard deviations between 1.4-4.9%. The stacked membrane biosensor has been successfully applied to the determination of NH(4)(+) ion in spiked river water samples without pretreatment. A good correlation was found between the analytical results for NH(4)(+) obtained from the biosensor and the Nessler spectrophotometric method.

Enhancing biosensor properties of conducting polymers via copolymerization: Synthesis of EDOT-substituted bis(2-pyridylimino)isoindolato-palladium complex and electrochemical sensing of glucose by its copolymerized film.

PubMed

Tekbaşoğlu, Tuğçe Yazıcı; Soganci, Tugba; Ak, Metin; Koca, Atıf; Şener, M Kasım

2017-01-15

1,3-Bis(2-pyridylimino)isoindoline derivative bearing 3,4-ethylenedioxythiophene (EDOT-BPI) and its palladium complex (EDOT-PdBPI) were synthesized and characterized by FT-IR, 1 H NMR, 13 C NMR, UV-Vis spectroscopies and via mass spectrometric analysis. Polymerization of EDOT-PdBPI and copolymerization with 4-amino-N-(2,5-di(thiophene-2-yl)-1H-pyrrol-1-yl)benzamide (HKCN) were carried out by an electrochemical method. In addition, P(EDOT-PdBPI-co-HKCN) modified graphite rod electrode was improved for amperometric glucose sensor based on glucose oxidase (GOx). In this novel biosensor matrix, amino groups in HKCN were used for the enzyme immobilization. On the other hand, EDOT-PdBPI used to mediate the bioelectrocatalytic reaction. Amperometric detection was carried out following oxygen consumption at -0.7V vs. the Ag reference electrode in phosphate buffer (50mM, pH 6.0). The novel biosensor showed a linear amperometric response for glucose within a concentration range of 0.25mM to 2.5mM (LOD: 0.176mM). Amperometric signals at 1mM of glucose were 17.9μA under anaerobic conditions. Amperometric response of the P(EDOT-PdBPI-co-HKCN)/GOx electrode decreased only by 13% within eight weeks. The P(EDOT-PdBPI-co-HKCN)/GOx electrode showed good selectivity in the presence of ethanol and phenol. This result shows that, modification of the proposed biosensor by copolymerization of amine functionalized monomer, which is indispensable to the enzyme immobilization, with palladium complex bearing monomer, which is mediate the bioelectrocatalytic reaction, have provided to give perfect response to different glucose concentrations. Copyright © 2016 Elsevier B.V. All rights reserved.

Ferritin-mediated biomimetic synthesis of bimetallic Au-Ag nanoparticles on graphene nanosheets for electrochemical detection of hydrogen peroxide

NASA Astrophysics Data System (ADS)

Wang, Li; Wang, Jiku; Ni, Pengjuan; Li, Zhuang

2015-03-01

We demonstrated a biomimetic green synthesis of bimetallic Au-Ag nanoparticles (NPs) on graphene nanosheets (GNs). The spherical protein, ferritin (Fr), was bound onto GNs and served as the template for the synthesis of GN/Au-Ag nanohybrids. The created GN/Au-Ag nanohybrids were further utilized to fabricate a non-enzymatic amperometric biosensor for the sensitive detection of hydrogen peroxide (H2O2), and this biosensor displayed high performances to determine H2O2 with a detection limit of 20.0 × 10-6 M and a linear detection range from 2.0 μM to 7.0 mM.

Monitoring of malolactic fermentation in wine using an electrochemical bienzymatic biosensor for L-lactate with long term stability.

PubMed

Giménez-Gómez, Pablo; Gutiérrez-Capitán, Manuel; Capdevila, Fina; Puig-Pujol, Anna; Fernández-Sánchez, César; Jiménez-Jorquera, Cecilia

2016-01-28

L-lactic acid is monitored during malolactic fermentation process of wine and its evolution is strongly related with the quality of the final product. The analysis of L-lactic acid is carried out off-line in a laboratory. Therefore, there is a clear demand for analytical tools that enabled real-time monitoring of this process in field and biosensors have positioned as a feasible alternative in this regard. The development of an amperometric biosensor for L-lactate determination showing long-term stability is reported in this work. The biosensor architecture includes a thin-film gold electrochemical transducer selectively modified with an enzymatic membrane, based on a three-dimensional matrix of polypyrrole (PPy) entrapping lactate oxidase (LOX) and horseradish peroxidase (HRP) enzymes. The experimental conditions of the biosensor fabrication regarding the pyrrole polymerization and the enzymes entrapment are optimized. The biosensor response to L-lactate is linear in a concentration range of 1 × 10(-6)-1 × 10(-4) M, with a detection limit of 5.2 × 10(-7) M and a sensitivity of - (13500 ± 600) μA M(-1) cm(-2). The biosensor shows an excellent working stability, retaining more than 90% of its original sensitivity after 40 days. This is the determining factor that allowed for the application of this biosensor to monitor the malolactic fermentation of three red wines, showing a good agreement with the standard colorimetric method. Copyright © 2015 Elsevier B.V. All rights reserved.

An amperometric biosensor for glucose detection from glucose oxidase immobilized in polyaniline-polyvinylsulfonate-potassium ferricyanide film.

PubMed

Arslan, Fatma; Beskan, Umut

2014-08-01

In this study, a novel amperometric glucose biosensor with immobilization of glucose oxidase on electrochemically polymerized polyaniline-polyvinylsulphonate-potassium ferricyanide (Pani-Pvs-Fc) films has been accomplished via the entrapment technique. Potassium ferricyanide was used as the mediator. Determination of glucose was carried out by the oxidation of potassium ferrocyanide at 0.3 V vs. Ag/AgCl. The effects of pH and temperature were investigated, and the optimum pH value was found to be 7.5. The storage stability and the operational stability of the enzyme electrode were also studied.

Development of an amperometric biosensor based on acetylcholine esterase covalently bound to a new support material.

PubMed

Khayyami, M; Pérez Pita, M T; Peña Garcia, N; Johansson, G; Danielsson, B; Larsson, P O

1998-01-01

A new type of amperometric biosensor based on immobilised acetylcholine esterase was designed and constructed. The enzyme was immobilised on a flow-through working electrode, which was prepared from reticulated vitreous carbon (RVC) or from a composite material consisting of RVC and superporous agarose. The sensor was operated in FIA mode using acetylthiocholine as a substrate. The sensor responded to inhibitors such as paraoxon-10(-9) mol was detected by the sensor in a non-optimised configuration. The practical lifetime of the sensor was at least 1 month.

Amperometric detection of catechol using tyrosinase modified electrodes enhanced by the layer-by-layer assembly of gold nanocubes and polyelectrolytes.

PubMed

Karim, Md Nurul; Lee, Ji Eun; Lee, Hye Jin

2014-11-15

A novel amperometric biosensor for catechol was developed using the layer-by-layer (LbL) self-assembly of positively charged hexadecyltrimethylammonium stabilized gold nanocubes (AuNCs), negatively charged poly(sodium 4-styrenesulfonate) and tyrosinase on a screen printed carbon electrode (SPCE). A carboxylic acid terminated alkanethiol assembled on electrochemically deposited Au nanoparticles on a SPCE was used as a platform for LbL assembly. Each SPCE sensor surface was terminated with tyrosinase and the electrocatalytic response due to the tyrosinase reaction with catechol was measured using cyclic voltammetry and square wave voltammetry (SWV). The effect of introducing AuNCs into the LbL assembly to further enhance the catechol detection performance was then investigated by comparing the SWV results to those from biosensors created using both the tyrosinase modified LbL assembly in the absence of NCs and the covalent attachment of tyrosinase. A wide dynamic range from 10nM to 80 µM of catechol with an excellent sensitivity of 13.72 A/M and a detection limit of 0.4 nM were both achieved alongside a good selectivity and reproducibility for the AuNC-modified electrodes. As a demonstration, the optimized biosensor design was applied to determine catechol concentrations in tea samples. Copyright © 2014 Elsevier B.V. All rights reserved.

An interference-free glucose biosensor based on an anionic redox polymer-mediated enzymatic oxidation of glucose.

PubMed

Deng, Huimin; Shen, Wei; Gao, Zhiqiang

2013-07-22

Herein a novel strategy for the construction of an amperometric biosensor for highly sensitive and selective determination of glucose is described. The biosensor is made of a biocomposite membrane of glucose oxidase (GOx) and an Os(bpy)2 (bpy=2,2'-bipyridine)-based anionic redox polymer (Os-RP) mediator. The biosensor is fabricated through the co-immobilization of GOx and the Os-RP on the surface of a glassy carbon electrode by a simple one-step chemical crosslinking process. The crosslinked Os-RP/GOx composite membrane shows excellent catalytic activity toward the oxidation of glucose. Under optimal experimental conditions, a linear correlation between the oxidation current of glucose in amperometry at 0.25 V (vs. Ag/AgCl) and glucose concentration up to 10 mM with a sensitivity of 16.5 μA mM(-1) cm(-2) and a response time <5 s. Due to the presence of anionic sulfonic acid groups in the backbone of the redox polymer, the biosensor exhibits excellent selectivity to glucose in the presence of ascorbic acid and uric acid. The low hydrophobicity of the composite membrane also effectively retards the transport of molecular oxygen within the membrane. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Fabrication of nanoindented electrodes for glucose detection.

PubMed

Slaughter, Gymama

2010-03-01

The objective of this article was to design, fabricate, and evaluate a novel type of glucose biosensors based on the use of atomic force microscopy to create nanoindented electrodes (NIDEs) for the selective detection of glucose. Atomic force microscopy nanoindentation techniques were extended to covalently immobilized glucose oxidase on NIDEs via composite hydrogel membranes composed of interpenetrating networks of inherently conductive poly(3,4-ethylenedioxythiophene) tetramethacrylate grown within ultraviolet cross-linked hydroxyethylmethacrylate-based hydrogels to produce an in vitro amperometric NIDE biosensor for the long-term monitoring of glucose. The calibration curve for glucose was linear from 0.25 to 20 mM. Results showed that the NIDE glucose biosensor has a much higher detection sensitivity of 0.32 microA/mM and rapid response times (<5 seconds). There was no interference from the competing interferent (fructose) present; the only interference was from species that react with H(2)O(2) (ascorbic acid). The linear equation was B(response) (microA) = 0.323 [glucose] (mM) + 0.634 (microA); n = 24, r(2) = 0.994. Results showed that the resultant NIDE glucose biosensor increases the dynamic range, device sensitivity, and response time and has excellent detecting performance for glucose. (c) 2010 Diabetes Technology Society.

Biosensors Fabricated through Electrostatic Assembly of Enzymes/Polyelectrolyte Hybrid Layers on Carbon Nanotubes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lin, Yuehe; Liu, Guodong; Wang, Jun

2006-06-01

Carbon nanotubes (CNTs) have emerged as new class of nanomaterials that is receiving considerable interest because of their unique structure, mechanical, and electronic properties. One promising application of CNTs is to fabricate highly sensitive chemo/biosensors.1-4 For construction of these CNT-based sensors, the CNTs first have to be modified with some molecules specific to the interests. Generally, covalent binding, affinity, and electrostatic interaction have been utilized for the modification of CNTs. Among them, the electrostatic method is attractive due to its simplicity and high efficiency. In present work, we have developed highly sensitively amperometric biosensors for glucose, choline, organophosphate pesticide (OPP)more » and nerve agents (NAs) based on electrostatically assembling enzymes on the surface of CNTs. All these biosensors were fabricated by immobilization of enzymes on the negatively charged CNTs surface through alternately assembling a cationic poly(diallydimethylammonium chloride) (PDDA) layer and an enzyme layer. Using this layer-by-layer (LBL) technique, a bioactive nanocomposite film was fabricated on the electrode surface. Owing to the electrocatalytic effect of CNTs, an amplified electrochemical signal was achieved, which leads to low detections limits for glucose, choline, and OPP and NAs.« less

REMOTE BIOSENSOR FOR IN SITU MONITORING OF ORGANOPHOSPHATE NERVE AGENTS. (R823663)

EPA Science Inventory

A remote electrochemical biosensor for field monitoring of organophosphate nerve agents is described. The new sensor relies on the coupling of the effective biocatalytic action of organophosphorus hydrolase (OPH) with a submersible amperometric probe design. This combination resu...

Gold nanoparticles-decorated silver-bipyridine nanobelts for the construction of mediatorless hydrogen peroxide biosensor.

PubMed

Boujakhrout, Abderrahmane; Díez, Paula; Sánchez, Alfredo; Martínez-Ruíz, Paloma; Pingarrón, José M; Villalonga, Reynaldo

2016-11-15

Au nanoparticles modified with 4-mercaptopyridine and 6-mercapto-1-hexanol were used as coordination agents to prepare a novel hybrid nanomaterial with Ag:4,4'-bipyridine nanobelts. This nanohybrid was employed to modify glassy carbon electrodes and to construct a horseradish peroxidase-based mediatorless amperometric biosensor for H2O2. The electrode, poised at -100mV, exhibited a rapid response within 4s and a linear calibration range from 90pM to 6.5nM H2O2. The biosensor showed a high sensitivity of 283A/Mcm(2) and a very low detection limit of 45pM at a signal-to-noise ratio of 3. The enzyme biosensor showed high stability when stored at 4°C under dry conditions, retaining over 96% and 78% of its initial activity after 15 and 30days of storage at 4°C, respectively. Copyright © 2016 Elsevier Inc. All rights reserved.

Monitoring of monosaccharides, oligosaccharides, ethanol and glycerol during wort fermentation by biosensors, HPLC and spectrophotometry.

PubMed

Monošík, Rastislav; Magdolen, Peter; Stredanský, Miroslav; Šturdík, Ernest

2013-05-01

The aim of the present study was to analyze sugar levels (namely maltose, maltotriose, glucose and fructose) and alcohols (ethanol and glycerol) during the fermentation process in wort samples by amperometric enzymatic biosensors developed by our research group for industrial application, HPLC and spectrophotometry, and to compare the suitability of the presented methods for determination of individual analytes. We can conclude that for the specific monitoring of maltose or maltotriose only the HPLC method was suitable. On the other hand, biosensors and spectrophotometry reflected a decrease in total sugar concentration better and were able to detect both glucose and fructose in the later stages of fermentation, while HPLC was not. This can be attributed to the low detection limits and good sensitivity of the proposed methods. For the ethanol and glycerol analysis all methods proved to be suitable. However, concerning the cost expenses and time analysis, biosensors represented the best option. Copyright © 2012 Elsevier Ltd. All rights reserved.

Development of an amperometric-based glucose biosensor to measure the glucose content of fruit.

PubMed

Ang, Lee Fung; Por, Lip Yee; Yam, Mun Fei

2015-01-01

An amperometric enzyme-electrode was introduced where glucose oxidase (GOD) was immobilized on chitosan membrane via crosslinking, and then fastened on a platinum working electrode. The immobilized enzyme showed relatively high retention activity. The activity of the immobilized enzyme was influenced by its loading, being suppressed when more than 0.6 mg enzyme was used in the immobilization. The biosensor showing the highest response to glucose utilized 0.21 ml/cm2 thick chitosan membrane. The optimum experimental conditions for the biosensors in analysing glucose dissolved in 0.1 M phosphate buffer (pH 6.0) were found to be 35°C and 0.6 V applied potential. The introduced biosensor reached a steady-state current at 60 s. The apparent Michaelis-Menten constant ([Formula: see text]) of the biosensor was 14.2350 mM, and its detection limit was 0.05 mM at s/n > 3, determined experimentally. The RSD of repeatability and reproducibility of the biosensor were 2.30% and 3.70%, respectively. The biosensor was showed good stability; it retained ~36% of initial activity after two months of investigation. The performance of the biosensors was evaluated by determining the glucose content in fruit homogenates. Their accuracy was compared to that of a commercial glucose assay kit. There was no significance different between two methods, indicating the introduced biosensor is reliable.

Development of an Amperometric-Based Glucose Biosensor to Measure the Glucose Content of Fruit

PubMed Central

Ang, Lee Fung; Por, Lip Yee; Yam, Mun Fei

2015-01-01

An amperometric enzyme-electrode was introduced where glucose oxidase (GOD) was immobilized on chitosan membrane via crosslinking, and then fastened on a platinum working electrode. The immobilized enzyme showed relatively high retention activity. The activity of the immobilized enzyme was influenced by its loading, being suppressed when more than 0.6 mg enzyme was used in the immobilization. The biosensor showing the highest response to glucose utilized 0.21 ml/cm2 thick chitosan membrane. The optimum experimental conditions for the biosensors in analysing glucose dissolved in 0.1 M phosphate buffer (pH 6.0) were found to be 35°C and 0.6 V applied potential. The introduced biosensor reached a steady-state current at 60 s. The apparent Michaelis-Menten constant (KMapp) of the biosensor was 14.2350 mM, and its detection limit was 0.05 mM at s/n > 3, determined experimentally. The RSD of repeatability and reproducibility of the biosensor were 2.30% and 3.70%, respectively. The biosensor was showed good stability; it retained ~36% of initial activity after two months of investigation. The performance of the biosensors was evaluated by determining the glucose content in fruit homogenates. Their accuracy was compared to that of a commercial glucose assay kit. There was no significance different between two methods, indicating the introduced biosensor is reliable. PMID:25789757

An improved amperometric triglyceride biosensor based on co-immobilization of nanoparticles of lipase, glycerol kinase and glycerol 3-phosphate oxidase onto pencil graphite electrode.

PubMed

Narwal, Vinay; Pundir, C S

2017-05-01

Nanoparticles (NPs) of commercial lipase from Candida rugosa, of glycerol kinase (GK) from Cellulomonas species, of glycerol-3- phosphate oxidase (GPO) from Aerococcus viridans were prepared, characterized and co-immobilized onto a pencil graphite (PG) electrode. The morphological and electrochemical characterization of PG electrode was performed by scanning electron microscopy (SEM), cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) before and after co-immobilization of enzyme nanoparticles (ENPs). An improved amperometric triglyceride (TG) biosensor was fabricated using Lipase NPs/GKNPs/GPONPs/PG electrode as the working electrode, Ag/AgCl as the standard electrode and Pt wire as auxiliary electrode. The biosensor showed optimum response within 2.5s at a pH 7.0 and temperature of 35°C. The biosensor measured current due to electrons generated at 0.1V against Ag/AgCl, from H 2 O 2 , which is produced from triolein by co-immobilized ENPs. A linear relationship was obtained over between a wide triolein concentration range (0.1mM-45mM) and current (mA) under optimal conditions. The Lipase NPs/GKNPs/GPONPs/PG electrode showed high sensitivity (1241±20mAcm -2 mM -1 ); a lower detection limit (0.1nM) and good correlation coeficient (R 2 =0.99) with a standard enzymic colorimetric method. Analytical recovery of added triolein in serum was 98.01%, within and between batch coefficients of variation (CV) were 0.05% and 0.06% respectively. The biosensor was evaluated and employed for determination of TG in the serum of apparently healthy subject and persons suffering from hypertriglyceridemia. The biosensor lost 20% of its initial activity after its continued uses over a period of 240days, while being stored at 4°C. Copyright © 2017 Elsevier Inc. All rights reserved.

Impedimetric and amperometric bifunctional glucose biosensor based on hybrid organic-inorganic thin films.

PubMed

Wang, Huihui; Ohnuki, Hitoshi; Endo, Hideaki; Izumi, Mitsuru

2015-02-01

A novel glucose biosensor with an immobilized mediator was studied using electrochemical impedance spectroscopy (EIS) and amperometry measurements. The biosensor has a characteristic ultrathin form and is composed of a self-assembled monolayer anchoring glucose oxidase (GOx) covered with Langmuir-Blodgett (LB) films of Prussian blue (PB). The immobilized PB in the LB films acts as a mediator and enables the biosensor to work under a low potential (0.0V vs. Ag/AgCl). In the EIS measurements, a dramatic decrease in charge transfer resistance (Rct) was observed with sequential addition of glucose, which can be attributed to enzymatic activity. The linearity of the biosensor response was observed by the variation of the sensor response (1/Rct) as a function of glucose concentration in the range 0 to 25mM. The sensor also showed linear amperometric response below 130mM glucose. The organic-inorganic system of GOx and PB nanoclusters demonstrated bifunctional sensing action, both amperometry and EIS modes, as well as long sensing stability for 4 days. Copyright © 2014 Elsevier B.V. All rights reserved.

Electrochemical estimation of the polyphenol index in wines using a laccase biosensor.

PubMed

Gamella, M; Campuzano, S; Reviejo, A J; Pingarrón, J M

2006-10-18

The use of a laccase biosensor, under both batch and flow injection (FI) conditions, for a rapid and reliable amperometric estimation of the total content of polyphenolic compounds in wines is reported. The enzyme was immobilized by cross-linking with glutaraldehyde onto a glassy carbon electrode. Caffeic acid and gallic acid were selected as standard compounds to carry out such estimation. Experimental variables such as the enzyme loading, the applied potential, and the pH value were optimized, and different aspects regarding the operational stability of the laccase biosensor were evaluated. Using batch amperometry at -200 mV, the detection limits obtained were 2.6 x 10(-3) and 7.2 x 10(-4) mg L(-1) gallic acid and caffeic acid, respectively, which compares advantageously with previous biosensor designs. An extremely simple sample treatment consisting only of an appropriate dilution of wine sample with the supporting electrolyte solution (0.1 mol L(-1) citrate buffer of pH 5.0) was needed for the amperometric analysis of red, rosé, and white wines. Good correlations were found when the polyphenol indices obtained with the biosensor (in both the batch and FI modes) for different wine samples were plotted versus the results achieved with the classic Folin-Ciocalteu method. Application of the calibration transfer chemometric model (multiplicative fitting) allowed that the confidence intervals (for a significance level of 0.05) for the slope and intercept values of the amperometric index versus Folin-Ciocalteu index plots (r = 0.997) included the unit and zero values, respectively. This indicates that the laccase biosensor can be successfully used for the estimation of the polyphenol index in wines when compared with the Folin-Ciocalteu reference method.

Amperometric determination of total phenolic content in wine by laccase immobilized onto silver nanoparticles/zinc oxide nanoparticles modified gold electrode.

PubMed

Chawla, Sheetal; Rawal, Rachna; Kumar, Dheeraj; Pundir, Chandra Shekhar

2012-11-01

A method is described for construction of a highly sensitive amperometric biosensor for measurement of total phenolic compounds in wine by immobilizing laccase covalently onto nanocomposite of silver nanoparticles (AgNPs)/zinc oxide nanoparticles (ZnONPs) electrochemically deposited onto gold (Au) electrode. Scanning electron microscopy, X-ray diffraction, and electrochemical impedance spectroscopy were applied for characterization of the surface morphology of the modified electrode, and cyclic voltammetry was used to investigate the electrochemical properties of the proposed electrode toward the oxidation of guaiacol. The linearity between the oxidation current and the guaiacol concentration was obtained in a range of 0.1 to 500μM with a detection limit of 0.05μM (signal-to-noise ratio (S/N)=3) and sensitivity of 0.71μAμM(-1)cm(-2). The electrode showed increased oxidation and reduced reduction current with the deposition of AgNPs/ZnONPs on it. R(CT) values of ZnONPs/Au, AgNPs/ZnONPs/Au, and laccase/AgNPs/ZnONPs/Au electrode were 220, 175, and 380Ω, respectively. The biosensor showed an optimal response within 8s at pH 6.0 (0.1M acetate buffer) and 35°C when operated at 0.22V against Ag/AgCl. Analytical recovery of added guaiacol was 98%. The method showed a good correlation (r=0.99) with the standard spectrophotometric method, with the regression equation being y=1.0053x-3.5541. The biosensor lost 25% of its initial activity after 200 uses over 5months. Copyright © 2012 Elsevier Inc. All rights reserved.

Single-walled carbon nanotubes covalently functionalized with polytyrosine: A new material for the development of NADH-based biosensors.

PubMed

Eguílaz, Marcos; Gutierrez, Fabiana; González-Domínguez, Jose Miguel; Martínez, María T; Rivas, Gustavo

2016-12-15

We report for the first time the use of single-walled carbon nanotubes (SWCNT) covalently functionalized with polytyrosine (Polytyr) (SWCNT-Polytyr) as a new electrode material for the development of nicotinamide adenine dinucleotide (NADH)-based biosensors. The oxidation of glassy carbon electrodes (GCE) modified with SWCNT-Polytyr at potentials high enough to oxidize the tyrosine residues have allowed the electrooxidation of NADH at low potentials due to the catalytic activity of the quinones generated from the primary oxidation of tyrosine without any additional redox mediator. The amperometric detection of NADH at 0.200V showed a sensitivity of (217±3)µAmM(-1)cm(-2) and a detection limit of 7.9nM. The excellent electrocatalytic activity of SWCNT-Polytyr towards NADH oxidation has also made possible the development of a sensitive ethanol biosensor through the immobilization of alcohol dehydrogenase (ADH) via Nafion entrapment, with excellent analytical characteristics (sensitivity of (5.8±0.1)µAmM(-1)cm(-2), detection limit of 0.67µM) and very successful application for the quantification of ethanol in different commercial beverages. Copyright © 2016 Elsevier B.V. All rights reserved.

Recent advances in rapid pathogen detection method based on biosensors.

PubMed

Chen, Ying; Wang, Zhenzhen; Liu, Yingxun; Wang, Xin; Li, Ying; Ma, Ping; Gu, Bing; Li, Hongchun

2018-06-01

As strain variation and drug resistance become more pervasive, the prevention and control of infection have been a serious problem in recent years. The detection of pathogen is one of the most important parts of the process of diagnosis. Having a series of advantages, such as rapid response, high sensitivity, ease of use, and low cost, biosensors have received much attention and been studied deeply. Moreover, relying on its characteristics of small size, real time, and multiple analyses, biosensors have developed rapidly and used widely and are expected to be applied for microbiological detection in order to meet higher accuracy required by clinical diagnosis. The main goal of this contribution is not to simply collect and list all papers related to pathogen detection based on biosensors published recently, but to discuss critically the development and application of many kinds of biosensors such as electrochemical (amperometric, impedimetric, potentiometric, and conductometric), optical (fluorescent, fibre optic and surface plasmon resonance), and piezoelectric (quartz crystal microbalances and atomic force microscopy) biosensors in pathogen detection as well as the comparisons with the existing clinical detection methods (traditional culture, enzyme-linked immunosorbent assay, polymerase chain reaction, and mass spectrometry).

Amperometric sensor for ethanol based on one-step electropolymerization of thionine-carbon nanofiber nanocomposite containing alcohol oxidase.

PubMed

Wu, Lina; McIntosh, Mike; Zhang, Xueji; Ju, Huangxian

2007-12-15

Thionine had strong interaction with carbon nanofiber (CNF) and was used in the non-covalent functionalization of carbon nanofiber for the preparation of stable thionine-CNF nanocomposite with good dispersion. With a simple one-step electrochemical polymerization of thionine-CNF nanocomposite and alcohol oxidase (AOD), a stable poly(thionine)-CNF/AOD biocomposite film was formed on electrode surface. Based on the excellent catalytic activity of the biocomposite film toward reduction of dissolved oxygen, a sensitive ethanol biosensor was proposed. The ethanol biosensor could monitor ethanol ranging from 2.0 to 252 microM with a detection limit of 1.7 microM. It displayed a rapid response, an expanded linear response range as well as excellent reproducibility and stability. The combination of catalytic activity of CNF and the promising feature of the biocomposite with one-step non-manual technique favored the sensitive determination of ethanol with improved analytical capabilities.

Mercaptobenzothiazole-on-gold organic phase biosensor systems: 1. Enhanced organosphosphate pesticide determination.

PubMed

Somerset, V; Baker, P; Iwuoha, E

2009-02-01

This paper reports the construction of the gold/mercaptobenzothiazole/polyaniline/acetylcholinesterase/polyvinylacetate (Au/ MBT/PANI/AChE/PVAc) thick-film biosensor for the determination of certain organophosphate pesticide solutions in selected aqueous organic solvent solutions. The Au/MBT/PANI/AChE/PVAc electrocatalytic biosensor device was constructed by encapsulating acetylcholinesterase (AChE) enzyme in the PANI polymer composite, followed by the coating of poly(vinyl acetate) (PVAc) on top to secure the biosensor film from disintegration in the organic solvents evaluated. The electroactive substrate called acetylthiocholine (ATCh) was employed to provide the movement of electrons in the amperometric biosensor. The voltammetric results have shown that the current shifts more anodically as the Au/MBT/PANI/AChE/PVAc biosensor responded to successive acetylthiocholine (ATCh) substrate addition under anaerobic conditions in 0.1 M phosphate buffer, KCl (pH 7.2) solution and aqueous organic solvent solutions. For the Au/MBT/PANI/AChE/PVAc biosensor, various performance and stability parameters were evaluated. These factors include the optimal enzyme loading, effect of pH, long-term stability of the biosensor, temperature stability of the biosensor, the effect of polar organic solvents, and the effect of non-polar organic solvents on the amperometric behavior of the biosensor. The biosensor was then applied to detect a series of 5 organophosphorous pesticides in aqueous organic solvents and the pesticides studied were parathion-methyl, malathion and chlorpyrifos. The results obtained have shown that the detection limit values for the individual pesticides were 1.332 nM (parathion-methyl), 0.189 nM (malathion), 0.018 nM (chlorpyrifos).

Fabrication of sensitive enzymatic biosensor based on multi-layered reduced graphene oxide added PtAu nanoparticles-modified hybrid electrode

PubMed Central

Hossain, Md Faruk; Park, Jae Y.

2017-01-01

A highly sensitive amperometric glucose sensor was developed by immobilization of glucose oxidase (GOx) onto multi-layer reduced graphene oxide (MRGO) sheets decorated with platinum and gold flower-like nanoparticles (PtAuNPs) modified Au substrate electrode. The fabricated MRGO/PtAuNPs modified hybrid electrode demonstrated high electrocatalytic activities toward oxidation of H2O2, to which it had a wide linear response that ranged from 0.5 to 8 mM (R2 = 0.997), and high sensitivity of 506.25 μA/mMcm2. Furthermore, glucose oxidase-chitosan composite and cationic polydiallyldimethylammonium chloride (PDDA) were assembled by a casting method on the surface of MRGO/PtAuNPs modified electrode. This as-fabricated hybrid biosensor electrode exhibited high electrocatalytic activity for the detection of glucose in PBS. It demonstrated good analytical properties in terms of a low detection limit of 1 μM (signal-to-noise ratio of 3), short response time (3 s), high sensitivity (17.85 μA/mMcm2), and a wide linear range (0.01–8 mM) for glucose sensing. These results reveal that the newly developed sensing electrode offers great promise for new type enzymatic biosensor applications. PMID:28333943

Amperometric immunosensor for rapid detection of Mycobacterium tuberculosis

NASA Astrophysics Data System (ADS)

Hiraiwa, Morgan; Kim, Jong-Hoon; Lee, Hyun-Boo; Inoue, Shinnosuke; Becker, Annie L.; Weigel, Kris M.; Cangelosi, Gerard A.; Lee, Kyong-Hoon; Chung, Jae-Hyun

2015-05-01

Tuberculosis (TB) has been a major public health problem, which can be better controlled by using accurate and rapid diagnosis in low-resource settings. A simple, portable, and sensitive detection method is required for point-of-care (POC) settings. This paper studies an amperometric biosensor using a microtip immunoassay for a rapid and low-cost detection of Mycobacterium tuberculosis (MTB) in sputum. MTB in sputum is specifically captured on the functionalized microtip surface and detected by electric current. According to the numerical study, the current signal on the microtip surface is linearly changed with increasing immersion depth. Using a reference microtip, the immersion depth is compensated for a sensing microtip. On the microtip surface, target bacteria are concentrated and organized by a coffee-ring effect, which amplifies the electric current. To enhance the signal-to-noise ratio, both the sample processing and rinsing steps are presented with the use of deionized water as a medium for the amperometric measurement. When applied to cultured MTB cells spiked into human sputum, the detection limit was 100 CFU mL-1, comparable to a more labor-intensive fluorescence detection method reported previously.

Use of Fe3O4 Nanoparticles for Enhancement of Biosensor Response to the Herbicide 2,4-Dichlorophenoxyacetic Acid

PubMed Central

Loh, Kee-Shyuan; Lee, Yook Heng; Musa, Ahmad; Salmah, Abdul Aziz; Zamri, Ishak

2008-01-01

Magnetic nanoparticles of Fe3O4 were synthesized and characterized using transmission electron microscopy and X-ray diffraction. The Fe3O4 nanoparticles were found to have an average diameter of 5.48 ±1.37 nm. An electrochemical biosensor based on immobilized alkaline phosphatase (ALP) and Fe3O4 nanoparticles was studied. The amperometric biosensor was based on the reaction of ALP with the substrate ascorbic acid 2-phosphate (AA2P). The incorporation of the Fe3O4 nanoparticles together with ALP into a sol gel/chitosan biosensor membrane has led to the enhancement of the biosensor response, with an improved linear response range to the substrate AA2P (5-120 μM) and increased sensitivity. Using the inhibition property of the ALP, the biosensor was applied to the determination of the herbicide 2,4-dichlorophenoxyacetic acid (2,4-D). The use of Fe3O4 nanoparticles gives a two-fold improvement in the sensitivity towards 2,4-D, with a linear response range of 0.5-30 μgL-1. Exposure of the biosensor to other toxicants such as heavy metals demonstrated only slight interference from metals such as Hg2+, Cu2+, Ag2+ and Pb2+. The biosensor was shown to be useful for the determination of the herbicide 2, 4-D because good recovery of 95-100 percent was obtained, even though the analysis was performed in water samples with a complex matrix. Furthermore, the results from the analysis of 2,4-D in water samples using the biosensor correlated well with a HPLC method. PMID:27873839

Disposable L-lactate biosensor based on a screen-printed carbon electrode enhanced by graphene

NASA Astrophysics Data System (ADS)

Tu, Dandan; He, Yu; Rong, Yuanzhen; Wang, You; Li, Guang

2016-04-01

In this work, an amperometric L-lactate biosensor based on a graphene-modified screen-printed carbon electrode (SPCE) was constructed. First, the electrocatalytic performance of the SPCE modified with graphene by a one-step electrodeposition process (OerGO/SPCE) was investigated. The cyclic voltammogram of OerGO/SPCE, which showed a well-defined redox peak, had a smaller peak potential separation than that of SPCE, revealing the improvement in electron transfer speed brought about by modifying with graphene. Next, lactate oxidase and potassium ferricyanide were dropped on the OerGO/SPCE to construct a graphene-modified L-lactate biosensor (LOD/K3[Fe(CN)6]/OerGO/SPCE). The proposed biosensor, with a detection limit of 60 μM, had a high sensitivity (42.42 μA mM-1 cm-2) when working at a low working potential (0.15 V). The linear range was 0.5 mM-15 mM, covering the detecting range of L-lactate in clinical applications. The L-lactate biosensor had a short response time (10 s) and required only 10 μl of the sample. This L-lactate sensor modified with electrodeposited graphene had a larger sensitivity than that based on the bare SPCE. Thus, our low-cost and disposable L-lactate biosensor enhanced by graphene can perform as an attractive electrochemical device that can be manufactured for point-of-care testing (POCT) devices and be employed in POCT applications.

Flow electrochemical biosensors based on enzymatic porous reactor and tubular detector of silver solid amalgam.

PubMed

Josypčuk, Bohdan; Barek, Jiří; Josypčuk, Oksana

2013-05-17

A flow amperometric enzymatic biosensor for the determination of glucose was constructed. The biosensor consists of a flow reactor based on porous silver solid amalgam (AgSA) and a flow tubular detector based on compact AgSA. The preparation of the sensor and the determination of glucose occurred in three steps. First, a self-assembled monolayer of 11-mercaptoundecanoic acid (MUA) was formed at the porous surface of the reactor. Second, enzyme glucose oxidase (GOx) was covalently immobilized at MUA-layer using N-ethyl-N'-(3-dimethylaminopropyl) carboimide and N-hydroxysuccinimide chemistry. Finally, a decrease of oxygen concentration (directly proportional to the concentration of glucose) during enzymatic reaction was amperometrically measured on the tubular detector under flow injection conditions. The following parameters of glucose determination were optimized with respect to amperometric response: composition of the mobile phase, its concentration, the potential of detection and the flow rate. The calibration curve of glucose was linear in the concentration range of 0.02-0.80 mmol L(-1) with detection limit of 0.01 mmol L(-1). The content of glucose in the sample of honey was determined as 35.5±1.0 mass % (number of the repeated measurements n=7; standard deviation SD=1.2%; relative standard deviation RSD=3.2%) which corresponds well with the declared values. The tested biosensor proved good long-term stability (77% of the current response of glucose was retained after 35 days). Copyright © 2013 Elsevier B.V. All rights reserved.

All Inkjet-Printed Amperometric Multiplexed Biosensors Based on Nanostructured Conductive Hydrogel Electrodes.

PubMed

Li, Lanlan; Pan, Lijia; Ma, Zhong; Yan, Ke; Cheng, Wen; Shi, Yi; Yu, Guihua

2018-06-13

Multiplexing, one of the main trends in biosensors, aims to detect several analytes simultaneously by integrating miniature sensors on a chip. However, precisely depositing electrode materials and selective enzymes on distinct microelectrode arrays remains an obstacle to massively produced multiplexed sensors. Here, we report on a "drop-on-demand" inkjet printing process to fabricate multiplexed biosensors based on nanostructured conductive hydrogels in which the electrode material and several kinds of enzymes were printed on the electrode arrays one by one by employing a multinozzle inkjet system. The whole inkjet printing process can be finished within three rounds of printing and only one round of alignment. For a page of sensor arrays containing 96 working electrodes, the printing process took merely ∼5 min. The multiplexed assays can detect glucose, lactate, and triglycerides in real time with good selectivity and high sensitivity, and the results in phosphate buffer solutions and calibration serum samples are comparable. The inkjet printing process exhibited advantages of high efficiency and accuracy, which opens substantial possibilities for massive fabrication of integrated multiplexed biosensors for human health monitoring.

Amperometric Biosensor Based on Zirconium Oxide/Polyethylene Glycol/Tyrosinase Composite Film for the Detection of Phenolic Compounds.

PubMed

Ahmad, Nor Monica; Abdullah, Jaafar; Yusof, Nor Azah; Ab Rashid, Ahmad Hazri; Abd Rahman, Samsulida; Hasan, Md Rakibul

2016-06-29

A phenolic biosensor based on a zirconium oxide/polyethylene glycol/tyrosinase composite film for the detection of phenolic compounds has been explored. The formation of the composite film was expected via electrostatic interaction between hexacetyltrimethylammonium bromide (CTAB), polyethylene glycol (PEG), and zirconium oxide nanoparticles casted on screen printed carbon electrode (SPCE). Herein, the electrode was treated by casting hexacetyltrimethylammonium bromide on SPCE to promote a positively charged surface. Later, zirconium oxide was mixed with polyethylene glycol and the mixture was dropped cast onto the positively charged SPCE/CTAB. Tyrosinase was further immobilized onto the modified SPCE. Characterization of the prepared nanocomposite film and the modified SPCE surface was investigated by scanning electron microscopy (SEM), Electrochemical Impedance Spectroscopy (EIS), and Cyclic voltamogram (CV). The developed biosensor exhibits rapid response for less than 10 s. Two linear calibration curves towards phenol in the concentrations ranges of 0.075-10 µM and 10-55 µM with the detection limit of 0.034 µM were obtained. The biosensor shows high sensitivity and good storage stability for at least 30 days.

ZnO-Based Amperometric Enzyme Biosensors

PubMed Central

Zhao, Zhiwei; Lei, Wei; Zhang, Xiaobing; Wang, Baoping; Jiang, Helong

2010-01-01

Nanostructured ZnO with its unique properties could provide a suitable microenvironment for immobilization of enzymes while retaining their biological activity, and thus lead to an expanded use of this nanomaterial for the construction of electrochemical biosensors with enhanced analytical performance. ZnO-based enzyme electrochemical biosensors are summarized in several tables for an easy overview according to the target biosensing analyte (glucose, hydrogen peroxide, phenol and cholesterol), respectively. Moreover, recent developments in enzyme electrochemical biosensors based on ZnO nanomaterials are reviewed with an emphasis on the fabrications and features of ZnO, approaches for biosensor construction (e.g., modified electrodes and enzyme immobilization) and biosensor performances. PMID:22205864

Wearable Sensor System Powered by a Biofuel Cell for Detection of Lactate Levels in Sweat (Postprint)

DTIC Science & Technology

2016-05-04

attractive for development of sensing technology for the monitoring of human performance. Amperometric biosensors are known to be inexpensive, repro...biofuel cells for self-powered biosensors was first discussed in 2001 and has gained momentum in recent years.32–34 Information technology has...lactate biosensor ,35,36 a glucose oxidase BFC power source, an energy har- vester and a micropotentiostat. The following sections describe the development

Development of urine glucose meter based on micro-planer amperometric biosensor and its clinical application for self-monitoring of urine glucose.

PubMed

Miyashita, Mariko; Ito, Narushi; Ikeda, Satoshi; Murayama, Tatsuro; Oguma, Koji; Kimura, Jun

2009-01-01

The highly sensitive urine glucose meter based on amperometric glucose sensor was developed and commercialized. It shows remarkable performances of wide measurement range in 0-2000 mgdl(-1), rapid response time as 6s and robustness against influence by interferents like ascorbic acid or acetaminophen. Correlation between the developed urine glucose meter and commercialized clinical-use urine glucose analyzer showed excellent linear relationship. The monitoring of postmeal blood glucose levels by assess of urine glucose of actual subjects was performed with the developed urine glucose meter. The experimental results suggest the urine glucose level 120 min following the meal should be the appropriate index for diabetes or impaired glucose tolerance to control blood glucose level. The new portable meter was developed, and is expected for flexible use at places other than home or office.

A glucose biosensor based on partially unzipped carbon nanotubes.

PubMed

Hu, Huifang; Feng, Miao; Zhan, Hongbing

2015-08-15

An amperometric glucose biosensor based on direct electron transfer of glucose oxidase (GOD) self-assembled on the surface of partially unzipped carbon nanotubes (PUCNTs) modified glassy carbon electrode (GCE) has been successfully fabricated. PUCNTs were synthesized via a facile chemical oxidative etching CNTs and used as a novel immobilization matrix for GOD. The cyclic voltammetric result of the PUCNT/GOD/GCE showed a pair of well-defined and quasi-reversible redox peaks with a formal potential of -0.470V and a peak to peak separation of 37mV, revealing that the fast direct electron transfer between GOD and the electrode has been achieved. It is notable that the glucose determination has been achieved in mediator-free condition. The developed biosensor displayed satisfactory analytical performance toward glucose including high sensitivity (19.50μA mM(-1)cm(-2)), low apparent Michaelis-Menten (5.09mM), a wide linear range of 0-17mM, and also preventing the interference from ascorbic acid, uric acid and dopamine usually coexisting with glucose in human blood. In addition, the biosensor acquired excellent storage stabilities. This facile, fast, environment-friendly and economical preparation strategy of PUCNT-GOD may provide a new platform for the fabrication of biocompatible glucose biosensors and other types of biosensors. Copyright © 2015 Elsevier B.V. All rights reserved.

Alcohol biosensing by polyamidoamine (PAMAM)/cysteamine/alcohol oxidase-modified gold electrode.

PubMed

Akin, Mehriban; Yuksel, Merve; Geyik, Caner; Odaci, Dilek; Bluma, Arne; Höpfner, Tim; Beutel, Sascha; Scheper, Thomas; Timur, Suna

2010-01-01

A highly stable and sensitive amperometric alcohol biosensor was developed by immobilizing alcohol oxidase (AOX) through Polyamidoamine (PAMAM) dendrimers on a cysteamine-modified gold electrode surface. Ethanol determination is based on the consumption of dissolved oxygen content due to the enzymatic reaction. The decrease in oxygen level was monitored at -0.7 V vs. Ag/AgCl and correlated with ethanol concentration. Optimization of variables affecting the system was performed. The optimized ethanol biosensor showed a wide linearity from 0.025 to 1.0 mM with 100 s response time and detection limit of (LOD) 0.016 mM. In the characterization studies, besides linearity some parameters such as operational and storage stability, reproducibility, repeatability, and substrate specificity were studied in detail. Stability studies showed a good preservation of the bioanalytical properties of the sensor, 67% of its initial sensitivity was kept after 1 month storage at 4 degrees C. The analytical characteristics of the system were also evaluated for alcohol determination in flow injection analysis (FIA) mode. Finally, proposed biosensor was applied for ethanol analysis in various alcoholic beverage as well as offline monitoring of alcohol production through the yeast cultivation. Copyright 2010 American Institute of Chemical Engineers

Disposable amperometric biosensor based on nanostructured bacteriophages for glucose detection

NASA Astrophysics Data System (ADS)

Kang, Yu Ri; Hwang, Kyung Hoon; Kim, Ju Hwan; Nam, Chang Hoon; Kim, Soo Won

2010-10-01

The selection of electrode material profoundly influences biosensor science and engineering, as it heavily influences biosensor sensitivity. Here we propose a novel electrochemical detection method using a working electrode consisting of bio-nanowires from genetically modified filamentous phages and nanoparticles. fd-tet p8MMM filamentous phages displaying a three-methionine (MMM) peptide on the major coat protein pVIII (designated p8MMM phages) were immobilized on the active area of an electrochemical sensor through physical adsorption and chemical bonding. Bio-nanowires composed of p8MMM phages and silver nanoparticles facilitated sensitive, rapid and selective detection of particular molecules. We explored whether the composite electrode with bio-nanowires was an effective platform to detect the glucose oxidase. The current response of the bio-nanowire sensor was high at various glucose concentrations (0.1 µm-0.1 mM). This method provides a considerable advantage to demonstrate analyte detection over low concentration ranges. Especially, phage-enabled bio-nanowires can serve as receptors with high affinity and specificity for the detection of particular biomolecules and provide a convenient platform for designing site-directed multifunctional scaffolds based on bacteriophages and may serve as a simple method for label-free detection.

Implementation of a new integrated d-lactic acid biosensor in a semiautomatic FIA system for the simultaneous determination of lactic acid enantiomers. Application to the analysis of beer samples.

PubMed

Vargas, E; Ruiz, M A; Campuzano, S; González de Rivera, G; López-Colino, F; Reviejo, A J; Pingarrón, J M

2016-05-15

An integrated amperometric d-lactic acid biosensor involving a gold film deposited by sputtering on a stainless steel disk electrode where the enzymes D-lactic acid dehydrogenase (DLDH) and diaphorase (DP) as well as the redox mediator tetrathiafulvalene (TTF) are coimmobilized by using a dialysis membrane, is reported in this work. Amperometry in stirred solutions at a detection potential of +0.15 V (vs Ag/AgCl reference electrode) provided a linear calibration plot for D-lactic acid over the 1.0×10(-4) to 3.8×10(-3) g L(-1) concentration range, with a limit of detection of 3.1×10(-5) g L(-1). The usefulness of the biosensor was demonstrated by determining D-lactic acid in beer samples with good results. Additionally, the biosensor was implemented together with a commercial L-lactic amperometric biosensor in a semiautomatic flow-injection analysis (FIA) system able to perform a rapid and simple stereo-specific determination of D- and D-lactic without a previous separation step. The operational characteristics of the biosensors under flow conditions were evaluated and its applicability was demonstrated through the simultaneous determination of both enantiomers in beer samples. Copyright © 2016 Elsevier B.V. All rights reserved.

Horseradish peroxidase and toluidine blue covalently immobilized leak-free sol-gel composite biosensor for hydrogen peroxide.

PubMed

Thenmozhi, K; Narayanan, S Sriman

2017-01-01

The enzyme horseradish peroxidase and the water-soluble mediator toluidine blue were covalently immobilized to 3-aminopropyl trimethoxy silane precursor through glutaraldehyde crosslinker. A rigid ceramic composite electrode was fabricated from this modified silane along with graphite powder, which resulted in an amperometric biosensor for H 2 O 2 . The electrochemical behaviour of the modified biosensor was monitored using cyclic voltammetry in the potential range of 0.2V to -0.4V vs SCE. The biosensor exhibited a stable voltammogram with cathodic peak at -0.234V and anodic peak at -0.172V, with a formal potential of -0.203V. Various factors influencing the performance of the biosensor such as buffer solution, pH, temperature and potential were examined for optimizing the working conditions. The modified biosensor exhibited a good catalytic behaviour for the reduction of H 2 O 2 at a lower potential of -0.25V without any barrier from possible interferents. The analytical working range was found to be 0.429μM to 0.455mM of H 2 O 2 with a detection limit of 0.171μM. The fabricated biosensor is robust for long-term usage in addition to the high sensitivity, rapid response and having an advantage of surface renewability by simple mechanical polishing. Copyright © 2016 Elsevier B.V. All rights reserved.

Functional design of electrolytic biosensor

NASA Astrophysics Data System (ADS)

Gamage Preethichandra, D. M.; Mala Ekanayake, E. M. I.; Onoda, M.

2017-11-01

A novel amperometric biosensbased on conjugated polypyrrole (PPy) deposited on a Pt modified ITO (indium tin oxide) conductive glass substrate and their performances are described. We have presented a method of developing a highly sensitive and low-cost nano-biosensor for blood glucose measurements. The fabrication method proposed decreases the cost of production significantly as the amount of noble metals used is minimized. A nano-corrugated PPy substrate was developed through pulsed electrochemical deposition. The sensitivity achieved was 325 mA/(Mcm2) and the linear range of the developed sensor was 50-60 mmol/l. Then the application of the electrophoresis helps the glucose oxidase (GOx) on the PPy substrate. The main reason behind this high enzyme loading is the high electric field applied across the sensor surface (working electrode) and the counter electrode where that pushes the nano-scale enzyme particles floating in the phosphate buffer solution towards the substrate. The novel technique used has provided an extremely high sensitivities and very high linear ranges for enzyme (GOx) and therefore can be concluded that this is a very good technique to load enzyme onto the conducting polymer substrates.

Determination of total creatine kinase activity in blood serum using an amperometric biosensor based on glucose oxidase and hexokinase.

PubMed

Kucherenko, I S; Soldatkin, O O; Lagarde, F; Jaffrezic-Renault, N; Dzyadevych, S V; Soldatkin, A P

2015-11-01

Creatine kinase (CK: adenosine-5-triphosphate-creatine phosphotransferase) is an important enzyme of muscle cells; the presence of a large amount of the enzyme in blood serum is a biomarker of muscular injuries, such as acute myocardial infarction. This work describes a bi-enzyme (glucose oxidase and hexokinase based) biosensor for rapid and convenient determination of CK activity by measuring the rate of ATP production by this enzyme. Simultaneously the biosensor determines glucose concentration in the sample. Platinum disk electrodes were used as amperometric transducers. Glucose oxidase and hexokinase were co-immobilized via cross-linking with BSA by glutaraldehyde and served as a biorecognition element of the biosensor. The biosensor work at different concentrations of CK substrates (ADP and creatine phosphate) was investigated; optimal concentration of ADP was 1mM, and creatine phosphate - 10 mM. The reproducibility of the biosensor responses to glucose, ATP and CK during a day was tested (relative standard deviation of 15 responses to glucose was 2%, to ATP - 6%, to CK - 7-18% depending on concentration of the CK). Total time of CK analysis was 10 min. The measurements of creatine kinase in blood serum samples were carried out (at 20-fold sample dilution). Twentyfold dilution of serum samples was chosen as optimal for CK determination. The biosensor could distinguish healthy and ill people and evaluate the level of CK increase. Thus, the biosensor can be used as a test-system for CK analysis in blood serum or serve as a component of multibiosensors for determination of important blood substances. Determination of activity of other kinases by the developed biosensor is also possible for research purposes. Copyright © 2015 Elsevier B.V. All rights reserved.

Amperometric determination of acetylcholine-A neurotransmitter, by chitosan/gold-coated ferric oxide nanoparticles modified gold electrode.

PubMed

Chauhan, Nidhi; Pundir, C S

2014-11-15

An amperometric acetylcholine biosensor was constructed by co-immobilizing covalently, a mixture of acetylcholinesterase (AChE) and choline oxidase (ChO) onto nanocomposite of chitosan (CHIT)/gold-coated ferric oxide nanoparticles (Fe@AuNPs) electrodeposited onto surface of a Au electrode and using it as a working electrode, Ag/AgCl as reference electrode and Pt wire as auxiliary electrode connected through potentiostat. The biosensor is based on electrochemical measurement of H2O2 generated from oxidation of choline by immobilized ChO, which in turn is produced from hydrolysis of acetylcholine by immobilized AChE. The biosensor exhibited optimum response within 3s at +0.2V, pH 7.0 and 30°C. The enzyme electrode had a linear working range of 0.005-400 µM, with a detection limit of 0.005 µM for acetylcholine. The biosensor measured plasma acetylcholine in apparently healthy and persons suffering from Alzheimer's disease. The enzyme electrode was unaffected by a number of serum substances but lost 50% of its initial activity after its 100 uses over a period of 3 months, when stored at 4°C. Copyright © 2014 Elsevier B.V. All rights reserved.

Laccase-based biosensor for the determination of polyphenol index in wine.

PubMed

Di Fusco, Massimo; Tortolini, Cristina; Deriu, Daniela; Mazzei, Franco

2010-04-15

In this work we have developed and characterized the use of Laccases from Trametes versicolor (TvL) and Trametes hirsuta (ThL) as biocatalytic components of electrochemical biosensors for the determination of polyphenol index in wines. Polyazetidine prepolimer (PAP) was used as immobilizing agent, multi-walled and single-walled carbon nanotubes screen-printed electrodes as sensors (MWCNTs-SPE and SWCNTs-SPE) and gallic acid as standard substrate. The amperometric measurements were carried out by using a flow system at a fixed potential of -100 mV vs. silver/silver chloride electrode in Britton-Robinson buffer 0.1 mol L(-1), pH 5. The results were compared with those obtained with the Folin-Ciocalteau reference method. The results obtained in the analysis of twelve Italian wines put in evidence the better suitability of ThL-MWCNTs-based biosensor in the determination of the polyphenol index in wines. This biosensor shows fast and reliable amperometric responses to gallic acid with a linear range 0.1-18.0 mg L(-1) (r(2)=0.999). The influence of the interferences on both spectrophotometric and electrochemical measurements have been carefully evaluated. (c) 2009 Elsevier B.V. All rights reserved.

Amperometric Enzyme Sensor to Check the Total Antioxidant Capacity of Several Mixed Berries. Comparison with Two Other Spectrophotometric and Fluorimetric Methods

PubMed Central

Tomassetti, Mauro; Serone, Maruschka; Angeloni, Riccardo; Campanella, Luigi; Mazzone, Elisa

2015-01-01

The aim of this research was to test the correctness of response of a superoxide dismutase amperometric biosensor used for the purpose of measuring and ranking the total antioxidant capacity of several systematically analysed mixed berries. Several methods are described in the literature for determining antioxidant capacity, each culminating in the construction of an antioxidant capacity scale and each using its own unit of measurement. It was therefore endeavoured to correlate and compare the results obtained using the present amperometric biosensor method with those resulting from two other different methods for determining the total antioxidant capacity selected from among those more frequently cited in the literature. The purpose was to establish a methodological approach consisting in the simultaneous application of different methods that it would be possible to use to obtain an accurate estimation of the total antioxidant capacity of different mixed berries and the food products containing them. Testing was therefore extended to also cover jams, yoghurts and juices containing mixed berries. PMID:25654720

DOE Office of Scientific and Technical Information (OSTI.GOV)

Liu, Hongying, E-mail: liuhongying@hdu.edu.cn; Gu, Chunchuan; Li, Dujuan

Graphical abstract: A non-enzymatic H{sub 2}O{sub 2} sensor with high selectivity and sensitivity based on rose-shaped FeMoO{sub 4} synthesized by the convenient microwave-assisted hydrothermal method, was fabricated. - Highlights: • Rose-shaped FeMoO{sub 4} is synthesized within 10 min via microwave-assisted hydrothermal approach. • Non-enzymatic hydrogen peroxide biosensor based on FeMoO{sub 4} nanomaterials is fabricated. • The biosensor exhibits good performance. - Abstract: In this work, we demonstrated a simple, rapid and reliable microwave-assisted hydrothermal approach to synthesize the uniform rose-shaped FeMoO{sub 4} within 10 min. The morphologies of the synthesized materials were characterized by X-ray powder diffraction and scanning electronmore » microscopy. Moreover, a non-enzymatic amperometric sensor for the detection of hydrogen peroxide (H{sub 2}O{sub 2}) was fabricated on the basis of the FeMoO{sub 4} as electrocatalysis. The resulting FeMoO{sub 4} exhibited high sensitivity and good stability for the detection of H{sub 2}O{sub 2}, which may be attributed to the rose-shaped structure of the material and the catalytic property of FeMoO{sub 4}. Amperometric response showed that the modified electrode had a good response for H{sub 2}O{sub 2} with a linear range from 1 μM to 1.6 mM, a detection limit of 0.5 μM (S/N = 3), high selectivity and short response time. Additionally, good recoveries of analytes in real milk samples confirm the reliability of the prepared sensor in practical applications.« less

In Vivo Analytical Performance of Nitric Oxide-Releasing Glucose Biosensors

PubMed Central

2015-01-01

The in vivo analytical performance of percutaneously implanted nitric oxide (NO)-releasing amperometric glucose biosensors was evaluated in swine for 10 d. Needle-type glucose biosensors were functionalized with NO-releasing polyurethane coatings designed to release similar total amounts of NO (3.1 μmol cm–2) for rapid (16.0 ± 4.4 h) or slower (>74.6 ± 16.6 h) durations and remain functional as outer glucose sensor membranes. Relative to controls, NO-releasing sensors were characterized with improved numerical accuracy on days 1 and 3. Furthermore, the clinical accuracy and sensitivity of rapid NO-releasing sensors were superior to control and slower NO-releasing sensors at both 1 and 3 d implantation. In contrast, the slower, extended, NO-releasing sensors were characterized by shorter sensor lag times (<4.2 min) in response to intravenous glucose tolerance tests versus burst NO-releasing and control sensors (>5.8 min) at 3, 7, and 10 d. Collectively, these results highlight the potential for NO release to enhance the analytical utility of in vivo glucose biosensors. Initial results also suggest that this analytical performance benefit is dependent on the NO-release duration. PMID:24984031

In vivo analytical performance of nitric oxide-releasing glucose biosensors.

PubMed

Soto, Robert J; Privett, Benjamin J; Schoenfisch, Mark H

2014-07-15

The in vivo analytical performance of percutaneously implanted nitric oxide (NO)-releasing amperometric glucose biosensors was evaluated in swine for 10 d. Needle-type glucose biosensors were functionalized with NO-releasing polyurethane coatings designed to release similar total amounts of NO (3.1 μmol cm(-2)) for rapid (16.0 ± 4.4 h) or slower (>74.6 ± 16.6 h) durations and remain functional as outer glucose sensor membranes. Relative to controls, NO-releasing sensors were characterized with improved numerical accuracy on days 1 and 3. Furthermore, the clinical accuracy and sensitivity of rapid NO-releasing sensors were superior to control and slower NO-releasing sensors at both 1 and 3 d implantation. In contrast, the slower, extended, NO-releasing sensors were characterized by shorter sensor lag times (<4.2 min) in response to intravenous glucose tolerance tests versus burst NO-releasing and control sensors (>5.8 min) at 3, 7, and 10 d. Collectively, these results highlight the potential for NO release to enhance the analytical utility of in vivo glucose biosensors. Initial results also suggest that this analytical performance benefit is dependent on the NO-release duration.

Amperometric Biosensor Based on Zirconium Oxide/Polyethylene Glycol/Tyrosinase Composite Film for the Detection of Phenolic Compounds

PubMed Central

Ahmad, Nor Monica; Abdullah, Jaafar; Yusof, Nor Azah; Ab Rashid, Ahmad Hazri; Abd Rahman, Samsulida; Hasan, Md. Rakibul

2016-01-01

A phenolic biosensor based on a zirconium oxide/polyethylene glycol/tyrosinase composite film for the detection of phenolic compounds has been explored. The formation of the composite film was expected via electrostatic interaction between hexacetyltrimethylammonium bromide (CTAB), polyethylene glycol (PEG), and zirconium oxide nanoparticles casted on screen printed carbon electrode (SPCE). Herein, the electrode was treated by casting hexacetyltrimethylammonium bromide on SPCE to promote a positively charged surface. Later, zirconium oxide was mixed with polyethylene glycol and the mixture was dropped cast onto the positively charged SPCE/CTAB. Tyrosinase was further immobilized onto the modified SPCE. Characterization of the prepared nanocomposite film and the modified SPCE surface was investigated by scanning electron microscopy (SEM), Electrochemical Impedance Spectroscopy (EIS), and Cyclic voltamogram (CV). The developed biosensor exhibits rapid response for less than 10 s. Two linear calibration curves towards phenol in the concentrations ranges of 0.075–10 µM and 10–55 µM with the detection limit of 0.034 µM were obtained. The biosensor shows high sensitivity and good storage stability for at least 30 days. PMID:27367738

Detection of triglyceride using an iridium nano-particle catalyst based amperometric biosensor.

PubMed

Liao, Wei-Yin; Liu, Chung-Chiun; Chou, Tse-Chuan

2008-12-01

The detection and quantification of triglyceride (TG) using an iridium nano-particle modified carbon based biosensor was successfully carried out in this study. The detection procedures were based on the electrochemical detection of enzymatically produced NADH. TG was hydrolyzed by lipase and the glycerol produced was catalytically oxidized by NAD-dependent glycerol dehydrogenase producing NADH in a solution containing NAD(+). Glyceryl tributyrate, a short chain triglyceride, was chosen as the substrate for the evaluation of this TG biosensor in bovine serum and human serum. A linear response to glyceryl tributyrate in the concentration range of 0 to 10 mM and a sensitivity of 7.5 nA mM(-1) in bovine serum and 7.0 nA mM(-1) in human serum were observed experimentally. The potential interference of species such as uric acid (UA) and ascorbic acid (AA) was assessed. The incorporation of a selected surfactant and an increase in the incubation temperature appeared to enhance the performance of this biosensor. The conditions for the determination of TG levels in bovine serum using this biosensor were optimized, with sunflower seed oil being used as an analyte to simulate the detection of TG in blood. The experimental results demonstrated that this iridium nano-particle modified working electrode based biosensor provided a relatively simple means for the accurate determination of TG in serum.

Electrochemical affinity biosensors for detection of mycotoxins: A review.

PubMed

Vidal, Juan C; Bonel, Laura; Ezquerra, Alba; Hernández, Susana; Bertolín, Juan R; Cubel, Carlota; Castillo, Juan R

2013-11-15

This review discusses the current state of electrochemical biosensors in the determination of mycotoxins in foods. Mycotoxins are highly toxic secondary metabolites produced by molds. The acute toxicity of these results in serious human and animal health problems, although it has been only since early 1960s when the first studied aflatoxins were found to be carcinogenic. Mycotoxins affect a broad range of agricultural products, most important cereals and cereal-based foods. A majority of countries, mentioning especially the European Union, have established preventive programs to control contamination and strict laws of the permitted levels in foods. Official methods of analysis of mycotoxins normally requires sophisticated instrumentation, e.g. liquid chromatography with fluorescence or mass detectors, combined with extraction procedures for sample preparation. For about sixteen years, the use of simpler and faster analytical procedures based on affinity biosensors has emerged in scientific literature as a very promising alternative, particularly electrochemical (i.e., amperometric, impedance, potentiometric or conductimetric) affinity biosensors due to their simplicity and sensitivity. Typically, electrochemical biosensors for mycotoxins use specific antibodies or aptamers as affinity ligands, although recombinant antibodies, artificial receptors and molecular imprinted polymers show potential utility. This article deals with recent advances in electrochemical affinity biosensors for mycotoxins and covers complete literature from the first reports about sixteen years ago. Copyright © 2013 Elsevier B.V. All rights reserved.

A novel nitromethane biosensor based on biocompatible conductive redox graphene-chitosan/hemoglobin/graphene/room temperature ionic liquid matrix.

PubMed

Wang, Lu; Zhang, Xiuhua; Xiong, Huayu; Wang, Shengfu

2010-11-15

A novel amperometric biosensor for nitromethane (CH(3)NO(2)) based on immobilization of graphene (GR), chitosan (CS), hemoglobin (Hb) and room temperature ionic liquid (IL) on a glassy carbon electrode (GCE) was developed for the first time. The surface morphologies of a set of representative membranes were characterized by means of scanning electron microscopy (SEM). The electrochemical performance of the biosensor was evaluated by cyclic voltammetry (CV) and chronoamperometry. A pair of stable and well-defined redox peaks of Hb with a formal potential of -0.240 V was observed at the GR-CS/Hb/GR/IL/GCE. The effects of phosphate buffer pH, scan rate, and temperature on the biosensor were investigated to provide optimum analytical performance. Moreover, several electrochemical parameters, e.g., the heterogeneous electron transfer rate constant (k(s)), were calculated in detail. The presence of both GR and IL not only dramatically facilitated the electron transfer of Hb, but also greatly enhanced electrocatalytic activity towards CH(3)NO(2). The apparent Michaelis-Menten constant was down to 0.16 μM, indicating that the biosensor possessed high affinity to CH(3)NO(2). Besides this, the proposed biosensor exhibited fast amperometric response (<5s), low detection limit (6.0 × 10(-10)M), and excellent long-time storage stability for the determination of CH(3)NO(2). Copyright © 2010 Elsevier B.V. All rights reserved.

Amperometric biosensor based on reductive H2O2 detection using pentacyanoferrate-bound polymer for creatinine determination.

PubMed

Nieh, Chi-Hua; Tsujimura, Seiya; Shirai, Osamu; Kano, Kenji

2013-03-12

Pentacyanoferrate-bound poly(1-vinylimidazole) (PVI[Fe(CN)5]) was selected as a mediator for amperometric creatinine determination based on the reductive H2O2 detection. Creatinine amidohydrolase (CNH), creatine amidohydrolase (CRH), sarcosine oxidase (SOD), peroxidase (POD), and PVI[Fe(CN)5] were crosslinked with poly(ethylene glycol) diglycidyl ether (PEGDGE) on a glassy carbon (GC) electrode for a creatinine biosensor fabrication. Reduction current was monitored at -0.1V in the presence of creatinine and O2. It is revealed that PVI[Fe(CN)5] is suitable as a mediator for a bioelectrocatalytic reaction of POD, since PVI[Fe(CN)5] neither reacts with reactants nor works as an electron acceptor of SOD. The amounts of PVI[Fe(CN)5], PEGDGE, and enzymes were optimized toward creatinine detection. Nafion as a protecting film successfully prevented the enzyme layer from interferences. The detection limit and linear range in creatinine determination were 12μM and 12-500μM (R(2)=0.993), respectively, and the sensitivity was 11mAcm(-2)M(-1), which is applicable for urine creatinine tests. The results of the creatinine determination for four urine samples measured with this proposed method were compared with Jaffe method, and a good correlation was obtained between the results. Copyright © 2013 Elsevier B.V. All rights reserved.

Electrochemical affinity biosensors for fast detection of gene-specific methylations with no need for bisulfite and amplification treatments.

PubMed

Povedano, Eloy; Vargas, Eva; Montiel, Víctor Ruiz-Valdepeñas; Torrente-Rodríguez, Rebeca M; Pedrero, María; Barderas, Rodrigo; Segundo-Acosta, Pablo San; Peláez-García, Alberto; Mendiola, Marta; Hardisson, David; Campuzano, Susana; Pingarrón, José M

2018-04-23

This paper describes two different electrochemical affinity biosensing approaches for the simple, fast and bisulfite and PCR-free quantification of 5-methylated cytosines (5-mC) in DNA using the anti-5-mC antibody as biorecognition element. One of the biosensing approaches used the anti-5-mC as capture bioreceptor and a sandwich type immunoassay, while the other one involved the use of a specific DNA probe and the anti-5-mC as a detector bioreceptor of the captured methylated DNA. Both strategies, named for simplicity in the text as immunosensor and DNA sensor, respectively, were implemented on the surface of magnetic microparticles and the transduction was accomplished by amperometry at screen-printed carbon electrodes by means of the hydrogen peroxide/hydroquinone system. The resulting amperometric biosensors demonstrated reproducibility throughout the entire protocol, sensitive determination with no need for using amplification strategies, and competitiveness with the conventional enzyme-linked immunosorbent assay methodology and the few electrochemical biosensors reported so far in terms of simplicity, sensitivity and assay time. The DNA sensor exhibited higher sensitivity and allowed the detection of the gene-specific methylations conversely to the immunosensor, which detected global DNA methylation. In addition, the DNA sensor demonstrated successful applicability for 1 h-analysis of specific methylation in two relevant tumor suppressor genes in spiked biological fluids and in genomic DNA extracted from human glioblastoma cells.

Nanomaterial-based Electrochemical Sensors for the Detection of Glucose and Cholesterol

NASA Astrophysics Data System (ADS)

Ahmadalinezhad, Asieh

Electrochemical detection methods are highly attractive for the monitoring of glucose, cholesterol, cancer, infectious diseases, and biological warfare agents due to their low cost, high sensitivity, functionality despite sample turbidity, easy miniaturization via microfabrication, low power requirements, and a relatively simple control infrastructure. The development of implantable biosensors is laden with great challenges, which include longevity and inherent biocompatibility, coupled with the continuous monitoring of analytes. Deficiencies in any of these areas will necessitate their surgical replacement. In addition, random signals arising from non-specific adsorption events can cause problems in diagnostic assays. Hence, a great deal of effort has been devoted to the specific control of surface structures. Nanotechnology involves the creation and design of structures with at least one dimension that is below 100 nm. The optical, magnetic, and electrical properties of nanostructures may be manipulated by altering their size, shape, and composition. These attributes may facilitate improvements in biocompatibility, sensitivity and the specific attachment of biomaterials. Thus, the central theme of this dissertation pertains to highlighting the critical roles that are played by the morphology and intrinsic properties of nanomaterials when they are applied in the development of electrochemical biosensors. For this PhD project, we initially designed and fabricated a novel amperometric glucose biosensor based on the immobilization of glucose oxidase (GOx) on a Prussian blue modified nanoporous gold surface, which exhibited a rapid response and a low detection limit of 2.5 microM glucose. The sensitivity of the biosensor was found to be very high (177 microA/mM) and the apparent Michaelis--Menten constant was calculated to be 2.1 mM. Our study has demonstrated that nanoporous gold provides an excellent matrix for enzyme immobilization. To adopt these advanced properties, we fabricated a highly sensitive and mediator-free electrochemical biosensor for the determination of total cholesterol. The developed biosensor possessed high selectivity and sensitivity (29.33 microA mM--1cm --2). The apparent Michaelis--Menten constant, KappM of this biosensor was very low (0.64 mM), which originated from both the effective immobilization process and the nanoporous structure of the substrate. The biosensor exhibited a wide linear range, up to 300 mg dL--1 , in a physiological environment (pH 7.4); making it a promising candidate for the clinical determination of cholesterol. The fabricated biosensor was tested further by utilizing actual food samples (e.g., margarine, butter and fish oil). The results indicated that it has the potential capacity to be employed as a facile cholesterol detection tool in the food industry and for supplement quality control. To enhance the stability of the biosensors in the continuous monitoring of glucose, we designed a novel platform that was based on buckypaper. The fabricated biosensor responded to glucose with a considerable functional lifetime of over 80 days and detected glucose with a dynamic linear range of over 9 mM with a detection limit of 0.01 mM. To investigate the effects of the physical dimensions of nanomaterials on electrochemical biosensing, we synthesized TiO2 nanowires with controllable dimensions via a facile thermal oxidation treatment of a Ti substrate. To improve the conductivity of the TiO2 nanowires and to facilitate the immobilization of enzymes, a thin layer of carbon was deposited onto the TiO2 nanowires via a chemical vapour deposition method. Upon the immobilization of glucose oxidase as a model protein, direct electron transfer was observed in a mediator-free biosensing environment. Our electrochemical studies have revealed that the electron transfer rate of the immobilized glucose oxidase is strongly dependent on the dimensions of the carbonized TiO 2 nanowires, and that the designed glucose biosensor exhibits a wide linear range, up to 18 mM glucose, as well as high sensitivity and selectivity. Glucose measurements of human serum using the developed biosensor showed excellent agreement with the data recorded by a commercial blood glucose monitoring assay. Finally, we fabricated an enzyme-free glucose sensor based on nanoporous palladium-cadmium (PdCd) networks. A hydrothermal method was applied in the synthesis of PdCd nanomaterials. The effect of the composition of the PdCd nanomaterials on the performance of the electrode was investigated by cyclic voltammetry (CV). Amperometric studies showed that the nanoporous PdCd electrode was responsive to the direct oxidation of glucose with high electrocatalytic activity. The sensitivity of the sensor for continuous glucose monitoring was 146.21 microAmM--1cm--2, with linearity up to 10 mM and a detection limit of 0.05 mM. In summary, the electrochemical biosensors proposed in my PhD study exhibited high sensitivity and selectivity for the continuous monitoring of analytes in the presence of common interference species. Our results have shown that the performance of the biosensors is significantly dependent on the dimensions and morphologies of nanostructured materials. The unique nanomaterials-based platforms proposed in this dissertation open the door to the design and fabrication of high-performance electrochemical biosensors for medical diagnostics.

Polypyrrole-based bilayer nitrate amperometric biosensor with an integrated permselective poly-ortho-phenylenediamine layer for exclusion of inorganic interferences.

PubMed

Adeloju, Samuel B; Sohail, Manzar

2011-07-15

A bilayer amperometric nitrate biosensor with an integrated permselective layer has been developed for exclusion of inorganic anion and cation interferences. The inner PPy(polypyrrole)-NaR-NADH layer of the biosensor is formed by galvanostatic polymerization of pyrrole (Py) in presence of nitrate reductase (NaR) and nicotinamide adenine dinucleotide (NADH), followed by formation of the outer permselective poly-ortho-phenylenediamine (P-o-PDA) layer by potentiodynamic polymerization of ortho-phenylenediamine (o-PDA). The exclusion efficiency (E(eff)) of the outer layer in rejecting inorganic cation and anion interferences is evaluated by a new proposed relationship. 73-87% and 47-84% of anion and cation interferences, respectively, were efficiently rejected with the permselective layer. Further improvement in the exclusion efficiency for cations was accomplished by combining the use of the outer layer with the addition of 1mM EDTA into the measurement solution. The addition of EDTA improved the E(eff) achieved for cation rejection by 10-40% to give net E(eff) of 89-94%. The inclusion of the outer layer also aided the retention of NaR and NADH in the inner PPy-NaR-NADH layer and, hence, enabled improved amperometric detection of nitrate, achieving a detection limit of 0.20 μM and a linear concentration range of 10-500 μM with a 3.4%rsd (n=10). Copyright © 2011 Elsevier B.V. All rights reserved.

Monoamine oxidase B layer-by-layer film fabrication and characterization toward dopamine detection.

PubMed

Miyazaki, Celina Massumi; Pereira, Tamyris Paschoal; Mascagni, Daniela Branco Tavares; de Moraes, Marli Leite; Ferreira, Marystela

2016-01-01

In this work nanostructured film composites of the monoamine oxidase B (MAO-B) enzyme, free or encapsulated in liposomes, were fabricated by the layer-by-layer (LbL) self-assembly technique, employing polyethylene imine (PEI) as polycation. Initially, the MAO-B enzyme was incorporated into liposomes in order to preserve its enzymatic structure ensuring their activity and catalytic stability. The LbL film growth was monitored by surface plasmon resonance (SPR) by gold resonance angle shift analysis after each bilayer deposition. Subsequently, the films were applied as amperometric biosensors for dopamine detection using Prussian Blue (PB) as the electron mediator. The biosensor fabricated by MAO-B incorporated into liposomes composed of DPPG:POPG in the ratio (1:4) (w/w) showed the best performance with a sensitivity of 0.86 (μA cm(-2))/(mmol L(-1)) and a detection limit of 0.33 mmol L(-1).

Bioelectrocatalytic application of titania nanotube array for molecule detection.

PubMed

Xie, Yibing; Zhou, Limin; Huang, Haitao

2007-06-15

A bioelectrocatalysis system based on titania nanotube electrode has been developed for the quantitative detection application. Highly ordered titania nanotube array with inner diameter of 60 nm and total length of 540 nm was formed by anodizing titanium foils. The functionalization modification was achieved by embedding glucose oxidases inside tubule channels and electropolymerizing pyrrole for interfacial immobilization. Morphology and microstructure characterization, electrochemical properties and bioelectrocatalytic reactivities of this composite were fully investigated. The direct detection of hydrogen peroxide by electrocatalytic reduction reaction was fulfilled on pure titania nanotube array with a detection limit up to 2.0 x 10(-4)mM. A biosensor based on the glucose oxidase-titania/titanium electrode was constructed for amperometric detection and quantitative determination of glucose in a phosphate buffer solution (pH 6.8) under a potentiostatic condition (-0.4V versus SCE). The resulting glucose biosensor showed an excellent performance with a response time below 5.6s and a detection limit of 2.0 x 10(-3)mM. The corresponding detection sensitivity was 45.5 microA mM(-1)cm(-2). A good operational reliability was also achieved with relative standard deviations below 3.0%. This novel biosensor exhibited quite high response sensitivity and low detection limit for potential applications.

Improvement in glucose biosensing response of electrochemically grown polypyrrole nanotubes by incorporating crosslinked glucose oxidase.

PubMed

Palod, Pragya Agar; Singh, Vipul

2015-10-01

In this paper a novel enzymatic glucose biosensor has been reported in which platinum coated alumina membranes (Anodisc™s) have been employed as templates for the growth of polypyrrole (PPy) nanotube arrays using electrochemical polymerization. The PPy nanotube arrays were grown on Anodisc™s of pore diameter 100 nm using potentiostatic electropolymerization. In order to optimize the polymerization time, immobilization of glucose oxidase (GOx) was first performed using physical adsorption followed by measuring its biosensing response which was examined amperometrically for increasing concentrations of glucose. In order to further improve the sensing performance of the biosensor fabricated for optimum polymerization duration, enzyme immobilization was carried out using cross-linking with glutaraldehyde and bovine serum albumin (BSA). Approximately six fold enhancement in the sensitivity was observed in the fabricated electrodes. The biosensors also showed a wide range of linear operation (0.2-13 mM), limit of detection of 50 μM glucose concentration, excellent selectivity for glucose, notable reliability for real sample detection and substantially improved shelf life. Copyright © 2015 Elsevier B.V. All rights reserved.

Laser Scribed Graphene Biosensor for Detection of Biogenic Amines in Food Samples Using Locally Sourced Materials.

PubMed

Vanegas, Diana C; Patiño, Laksmi; Mendez, Connie; Oliveira, Daniela Alves de; Torres, Alba M; Gomes, Carmen L; McLamore, Eric S

2018-04-24

In foods, high levels of biogenic amines (BA) are the result of microbial metabolism that could be affected by temperatures and storage conditions. Thus, the level of BA is commonly used as an indicator of food safety and quality. This manuscript outlines the development of laser scribed graphene electrodes, with locally sourced materials, for reagent-free food safety biosensing. To fabricate the biosensors, the graphene surface was functionalized with copper microparticles and diamine oxidase, purchased from a local supermarket; and then compared to biosensors fabricated with analytical grade materials. The amperometric biosensor exhibits good electrochemical performance, with an average histamine sensitivity of 23.3 µA/mM, a lower detection limit of 11.6 µM, and a response time of 7.3 s, showing similar performance to biosensors constructed from analytical grade materials. We demonstrated the application of the biosensor by testing total BA concentration in fish paste samples subjected to fermentation with lactic acid bacteria. Biogenic amines concentrations prior to lactic acid fermentation were below the detection limit of the biosensor, while concentration after fermentation was 19.24 ± 8.21 mg histamine/kg, confirming that the sensor was selective in a complex food matrix. The low-cost, rapid, and accurate device is a promising tool for biogenic amine estimation in food samples, particularly in situations where standard laboratory techniques are unavailable, or are cost prohibitive. This biosensor can be used for screening food samples, potentially limiting food waste, while reducing chances of foodborne outbreaks.

Biotechnology Conference: Diagnostics 󈨛 Held in Cambridge, England on 10 and 11 December 1987.

DTIC Science & Technology

1988-05-25

settings. 1 -hour culture confirmation test for herpes (ColorGene DNA hybridization test for HSV confirmation). This test NEW AMPEROMETRIC BIOSENSORS...I Thin Layer Technology: Monolayers to Multi Thin Films ................. 1 Single-Step Immunoassay Systems...if this thin-layer pr•ccss~is probe technolh,,y. and biosensors. The aim of the con- demonstrated in Figure 1 . which shows the disposition of ference

Amperometric inhibition biosensors based on horseradish peroxidase and gold sononanoparticles immobilized onto different electrodes for cyanide measurements.

PubMed

Attar, Aisha; Cubillana-Aguilera, Laura; Naranjo-Rodríguez, Ignacio; de Cisneros, José Luis Hidalgo-Hidalgo; Palacios-Santander, José María; Amine, Aziz

2015-02-01

New biosensors based on inhibition for the detection of cyanide and the comparison of the analytical performances of nine enzyme biosensor designs by using three different electrodes: Sonogel-Carbon, glassy carbon and gold electrodes were discussed. Three different horseradish peroxidase immobilization procedures with and without gold sononanoparticles were studied. The amperometric measurements were performed at an applied potential of -0.15V vs. Ag/AgCl in 50mM sodium acetate buffer solution pH=5.0. The apparent kinetic parameters (Kmapp, Vmaxapp) of immobilized HRP were calculated in the absence of inhibitor (cyanide) by using caffeic acid, hydroquinone, and catechol as substrates. The presence of gold sononanoparticles enhanced the electron transfer reaction and improved the analytical performance of the biosensors. The HRP kinetic interactions reveal non-competitive binding of cyanide with an apparent inhibition constant (Ki) of 2.7μM and I50 of 1.3μM. The determination of cyanide can be achieved in a dynamic range of 0.1-58.6μM with a detection limit of 0.03μM which is lower than those reported by previous studies. Hence this biosensing methodology can be used as a new promising approach for detecting cyanide. Copyright © 2014. Published by Elsevier B.V.

An electrochemical dopamine sensor based on the ZnO/CuO nanohybrid structures.

PubMed

Khun, K; Ibupoto, Z H; Liu, X; Mansor, N A; Turner, A P F; Beni, V; Willander, M

2014-09-01

The selective detection of dopamine (DA) is of great importance in the modern medicine because dopamine is one of the main regulators in human behaviour. In this study, ZnO/CuO nanohybrid structures, grown on the gold coated glass substrate, have been investigated as a novel electrode material for the electrochemical detection of dopamine. Scanning electron microscopy (SEM), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) techniques were used for the material characterization and the obtained results are in good agreement. The selective determination of dopamine was demonstrated by cyclic voltammetry (CV) and amperometric experiments. The amperometric response was linear for dopamine concentrations between 1.0 x 10(-3) and 8.0 mM with a sensitivity of 90.9 μA mM(-1) cm(-2). The proposed dopamine biosensor is very stable, selective over common interferents as glucose, uric acid and ascorbic acid, and also good reproducibility was observed for seven electrodes. Moreover, the dopamine sensor exhibited a fast response time of less than 10 s. The wide range and acceptable sensitivity of the presented dopamine sensor provide the possible application in analysing the dopamine from the real samples.

Highly sensitive and stable electrochemical sulfite biosensor incorporating a bacterial sulfite dehydrogenase.

PubMed

Kalimuthu, Palraj; Tkac, Jan; Kappler, Ulrike; Davis, Jason J; Bernhardt, Paul V

2010-09-01

This paper describes a highly sensitive electrochemical (voltammetric) determination of sulfite using a combination of Starkeya novella sulfite dehydrogenase (SDH), horse heart cytochrome c (cyt c), and a self-assembled monolayer of 11-mercaptoundecanol (MU) cast on a gold electrode. The biosensor was optimized in terms of pH and the ratio of cyt c/SDH. The electrocatalytic oxidation current of sulfite increased linearly from 1 to 6 microM at the enzyme-modified electrode with a correlation coefficient of 0.9995 and an apparent Michaelis constant (K(M,app)) of 43 microM. Using an amperometric method, the low detection limit for sulfite at the enzyme-modified electrode was 44 pM (signal-to-noise ratio = 3). The modified electrode retained a stable response for 3 days while losing only ca. 4% of its initial sensitivity during a 2 week storage period in 50 mM Tris buffer solution at 4 degrees C. The enzyme electrode was successfully used for the determination of sulfite in beer and white wine samples. The results of these electrochemical analyses agreed well with an independent spectrophotometric method using Ellman's reagent, but the detection limit was far superior using the electrochemical method.

An improved amperometric creatinine biosensor based on nanoparticles of creatininase, creatinase and sarcosine oxidase.

PubMed

Kumar, Parveen; Jaiwal, Ranjana; Pundir, C S

2017-11-15

An improved amperometric biosensor for detection of creatinine was developed based on immobilization of nanoparticles (NPs) of creatininase (CA), creatinase (CI), and sarcosine oxidase (SOx) onto glassy carbon (GC) electrode. Transmission electron microscopy (TEM) and fourier transform infrared spectroscopy (FTIR) were employed for characterization of enzyme nanoparticles (ENPs). The GC electrode was characterized by scanning electron microscopy (SEM), cyclic voltammetry (CV) and electrochemical impedance spectra (EIS) at different stages of its amendment. The biosensor showed optimum response within 2s at pH 6.0 in 0.1 M sodium phosphate buffer and 25 °C, when operated at 1.0 V against Ag/AgCl. Biosensor exhibited wider linear range from 0.01 μM to 12 μM with a limit of detection (LOD) of 0.01 μM. The analytical recoveries of added creatinine in sera were 97.97 ± 0.1% for 0.1 mM and 98.76 ± 0.2% for 0.15 mM, within and between batch coefficients of variation (CV) were 2.06% and 3.09% respectively. A good correlation (R 2  = 0.99) was observed between sera creatinine values obtained by standard enzymic colorimetric method and the present biosensor. This biosensor measured creatinine level in sera of apparently healthy subjects and persons suffering from renal and muscular dysfunction. The ENPs electrode lost 10% of its initial activity within 240 days of its regular uses, when stored at 4 °C. Copyright © 2017 Elsevier Inc. All rights reserved.

An improved amperometric L-lactate biosensor based on covalent immobilization of microbial lactate oxidase onto carboxylated multiwalled carbon nanotubes/copper nanoparticles/polyaniline modified pencil graphite electrode.

PubMed

Dagar, Kusum; Pundir, C S

2017-01-01

An improved amperometric l-lactate biosensor was constructed based on covalent immobilization of lactate oxidase (LOx) from Pediococcus species onto carboxylated multiwalled carbon nanotubes (cMWCNT)/copper nanoparticles (CuNPs)/polyaniline (PANI) hybrid film electrodeposited on the surface of a pencil graphite electrode (PGE). The enzyme electrode was characterized by cyclic voltammetry (CV), scanning electron microscopy (SEM), Fourier transform infrared (FTIR) spectroscopy and electrochemical impedance spectroscopy (EIS), while CuNPs synthesized by chemical reduction method, were characterized by transmission electron microscopy (TEM), UV spectrascopy and X-ray diffraction (XRD). The biosensor showed maximum response within 5s at pH 8.0 in 0.05M sodium phosphate buffer and 37°C, when operated at 20mVs -1 . The biosensor had a detection limit of 0.25μM with a wide working range between 1μM-2500μM. The biosensor was employed for measurement of l-lactic acid level in plasma of apparently healthy and diseased persons. Analytical recovery of added lactic acid in plasma was 95.5%. Within- and between-batch coefficients of variations were 6.24% and 4.19% respectively. There was a good correlation (R 2 =0.97) between plasma lactate values as measured by standard enzymatic spectrophotometric method and the present biosensor. The working enzyme electrode was used 180 times over a period of 140 days, when stored at 4°C. Copyright © 2016. Published by Elsevier Inc.

MoS{sub 2} nanosheet functionalized with Cu nanoparticles and its application for glucose detection

DOE Office of Scientific and Technical Information (OSTI.GOV)

Huang, Jingwei; Dong, Zhengping; Gansu Provincial Engineering Laboratory for Chemical Catalysis, College of Chemistry and Chemical Engineering, Lanzhou University, Lanzhou 730000

Graphical abstract: - Highlights: • First report on decorating MoS{sub 2} nanosheet with Cu nanoparticles by chemical reduction. • Cu nanoparticles were uniformly decorated on MoS{sub 2} nanosheet. • Glucose biosensor based on copper nanoparticles-MoS{sub 2} nanosheet hybrid is fabricated. • The biosensor exhibits high sensitivity. - Abstract: For the first time, Cu nanoparticles were evenly decorated on MoS{sub 2} nanosheet by chemical reduction. The as-prepared Cu-MoS{sub 2} hybrid was characterized by atomic force microscope (AFM), Raman spectroscopy, transmission electron microscopy (TEM), X-ray diffraction (XRD) and then used to fabricate a non-enzymatic glucose sensor. The performance of our sensor wasmore » investigated by cyclic voltammetry and amperometric measurement in alkaline media. Electrochemical tests showed that Cu-MoS{sub 2} hybrid exhibited synergistic electrocatalytic activity on the oxidation of glucose with a high sensitivity of 1055 μA mM{sup −1} cm{sup −2} and a linear range up to 4 mM.« less

Mucin and carbon nanotube-based biosensor for detection of glucose in human plasma.

PubMed

Comba, Fausto N; Romero, Marcelo R; Garay, Fernando S; Baruzzi, Ana M

2018-06-01

This work reports an amperometric enzyme-electrode prepared with glucose oxidase, which have been immobilized by a cross-linking step with glutaraldehyde in a mixture containing albumin and a novel carbon nanotubes-mucin composite (CNT-muc). The obtained hydrogel matrix was trapped between two polycarbonate membranes and then fixed at the surface of a Pt working electrode. The developed biosensor was optimized by evaluating different compositions and the analytical properties of an enzymatic matrix with CNT-muc. Then, the performance of the resulting enzymatic matrix was evaluated for direct glucose quantification in human blood plasma. The novel CNT-muc composite provided a sensitivity of 0.44 ± 0.01 mA M -1 and a response time of 28 ± 2 s. These values were respectively 20% higher and 40% shorter than those obtained with a sandwich-type biosensor prepared without CNT. Additionally, CNT-muc based biosensor exhibited more than 3 orders of magnitude of linear dynamic calibration range and a detection limit of 3 μM. The short-term and long-term stabilities of the biosensors were also examined and excellent results were obtained through successive experiments performed within the first 60 days from their preparation. Finally, the storage stability was remarkable during the first 300 days. Copyright © 2018 Elsevier Inc. All rights reserved.

Glucose biosensor based on glucose oxidase immobilized at gold nanoparticles decorated graphene-carbon nanotubes.

PubMed

Devasenathipathy, Rajkumar; Mani, Veerappan; Chen, Shen-Ming; Huang, Sheng-Tung; Huang, Tsung-Tao; Lin, Chun-Mao; Hwa, Kuo-Yuan; Chen, Ting-Yo; Chen, Bo-Jun

2015-10-01

Biopolymer pectin stabilized gold nanoparticles were prepared at graphene and multiwalled carbon nanotubes (GR-MWNTs/AuNPs) and employed for the determination of glucose. The formation of GR-MWNTs/AuNPs was confirmed by scanning electron microscopy, X-ray diffraction, UV-vis and FTIR spectroscopy methods. Glucose oxidase (GOx) was successfully immobilized on GR-MWNTs/AuNPs film and direct electron transfer of GOx was investigated. GOx exhibits highly enhanced redox peaks with formal potential of -0.40 V (vs. Ag/AgCl). The amount of electroactive GOx and electron transfer rate constant were found to be 10.5 × 10(-10) mol cm(-2) and 3.36 s(-1), respectively, which were significantly larger than the previous reports. The fabricated amperometric glucose biosensor sensitively detects glucose and showed two linear ranges: (1) 10 μM - 2 mM with LOD of 4.1 μM, (2) 2 mM - 5.2 mM with LOD of 0.95 mM. The comparison of the biosensor performance with reported sensors reveals the significant improvement in overall sensor performance. Moreover, the biosensor exhibited appreciable stability, repeatability, reproducibility and practicality. The other advantages of the fabricated biosensor are simple and green fabrication approach, roughed and stable electrode surface, fast in sensing and highly reproducible. Copyright © 2015 Elsevier Inc. All rights reserved.

Acetylcholinesterase inhibition-based biosensor for aluminum(III) chronoamperometric determination in aqueous media.

PubMed

Barquero-Quirós, Miriam; Domínguez-Renedo, Olga; Alonso-Lomillo, Maria Asunción; Arcos-Martínez, María Julia

2014-05-07

A novel amperometric biosensor for the determination of Al(III) based on the inhibition of the enzyme acetylcholinesterase has been developed. The immobilization of the enzyme was performed on screen-printed carbon electrodes modified with gold nanoparticles. The oxidation signal of acetylthiocholine iodide enzyme substrate was affected by the presence of Al(III) ions leading to a decrease in the amperometric current. The developed system has a detection limit of 2.1 ± 0.1 μM for Al(III). The reproducibility of the method is 8.1% (n = 4). Main interferences include Mo(VI), W(VI) and Hg(II) ions. The developed method was successfully applied to the determination of Al(III) in spiked tap water . The analysis of a certified standard reference material was also carried out. Both results agree with the certified values considering the respective associated uncertainties.

Acetylcholinesterase Inhibition-Based Biosensor for Aluminum(III) Chronoamperometric Determination in Aqueous Media

PubMed Central

Barquero-Quirós, Miriam; Domínguez-Renedo, Olga; Alonso-Lomillo, Maria Asunción; Arcos-Martínez, María Julia

2014-01-01

A novel amperometric biosensor for the determination of Al(III) based on the inhibition of the enzyme acetylcholinesterase has been developed. The immobilization of the enzyme was performed on screen-printed carbon electrodes modified with gold nanoparticles. The oxidation signal of acetylthiocholine iodide enzyme substrate was affected by the presence of Al(III) ions leading to a decrease in the amperometric current. The developed system has a detection limit of 2.1 ± 0.1 μM for Al(III). The reproducibility of the method is 8.1% (n = 4). Main interferences include Mo(VI), W(VI) and Hg(II) ions. The developed method was successfully applied to the determination of Al(III) in spiked tap water. The analysis of a certified standard reference material was also carried out. Both results agree with the certified values considering the respective associated uncertainties. PMID:24811076

A novel amperometric biosensor based on banana peel (Musa cavendish) tissue homogenate for determination of phenolic compounds.

PubMed

Ozcan, Hakki Mevlut; Sagiroglu, Ayten

2010-08-01

In this study the biosensor was constructed by immobilizing tissue homogenate of banana peel onto a glassy carbon electrode surface. Effects of immobilization materials amounts, effects of pH, buffer concentration and temperature on biosensor response were studied. In addition, the detection ranges of 13 phenolic compounds were obtained with the help of the calibration graphs. Storage stability, repeatability of the biosensor, inhibitory effect and sample applications were also investigated. A typical calibration curve for the sensor revealed a linear range of 10-80 microM catechol. In reproducibility studies, variation coefficient and standard deviation were calculated as 2.69%, 1.44 x 10(-3) microM, respectively.

Amine oxidase-based biosensors for spermine and spermidine determination.

PubMed

Boffi, Alberto; Favero, Gabriele; Federico, Rodolfo; Macone, Alberto; Antiochia, Riccarda; Tortolini, Cristina; Sanzó, Gabriella; Mazzei, Franco

2015-02-01

The present work describes the development and optimization of electrochemical biosensors for specific determination of the biogenic polyamine spermine (Spm) and spermidine (Spmd) whose assessment represents a novel important analytical tool in food analysis and human diagnostics. These biosensors have been prepared using novel engineered enzymes: polyamine oxidase (PAO) endowed with selectivity towards Spm and Spmd and spermine oxidase (SMO) characterized by strict specificity towards Spm. The current design entails biosensors in which the enzymes were entrapped in poly(vinyl alcohol) bearing styrylpyridinium groups (PVA-SbQ), a photocrosslinkable gel, onto an electrode surface. Screen-printed electrodes (SPEs) were used as electrochemical transducers for enzymatically produced hydrogen peroxide, operating at different potential vs Ag/AgCl according to the material of the working electrode (WE): +700 mV for graphite (GP) or -100 mV for Prussian blue (PB)-modified SPE, respectively. Biosensor performances were evaluated by means of flow injection amperometric (FIA) measurements. The modified electrodes showed good sensitivity, long-term stability and reproducibility. Under optimal conditions, the PAO biosensor showed a linear range 0.003-0.3 mM for Spm and 0.01-0.4 mM for Spmd, while with the SMO biosensor, a linear range of 0.004-0.5 mM for Spm has been obtained. The main kinetic parameters apparent Michaelis constant (K M), turnover number (K cat) and steady-state current (I max) were determined. The proposed device was then applied to the determination of biogenic amines in blood samples. The results obtained were in good agreement with those obtained with the GC-MS reference method.

Use of one- and two-mediator systems for developing a BOD biosensor based on the yeast Debaryomyces hansenii.

PubMed

Zaitseva, A S; Arlyapov, V A; Yudina, N Yu; Alferov, S V; Reshetilov, A N

2017-03-01

We investigated the use of one- and two-mediator systems in amperometric BOD biosensors (BOD, biochemical oxygen demand) based on the yeast Debaryomyces hansenii. Screening of nine mediators potentially capable of electron transfer - ferrocene, 1,1'-dimethylferrocene, ferrocenecarboxaldehyde, ferroceneacetonitrile, neutral red, 2,6-dichlorophenolindophenol, thionine, methylene blue and potassium ferricyanide - showed only ferrocene and neutral red to be efficient electron carriers for the eukaryotes studied. Two-mediator systems based on combinations of the investigated compounds were used to increase the efficiency of electron transfer. The developed two-mediator biosensors exceeded their one-mediator analogs by their characteristics. The most preferable two-mediator system for developing a BOD biosensor was a ferrocene-methylene blue combination that ensured a satisfactory long-time stability (43 days), selectivity, sensitivity (the lower limit of the determined BOD 5 concentrations, 2.5mg О 2 /dm 3 ) and speed (assay time for one sample, not greater than 10min) of BOD determination. Analysis of water samples showed that the use of a ferrocene-methylene blue two-mediator system and the yeast D. hansenii enabled registration of data that highly correlated with the results of the standard method (R=0.9913). Copyright © 2017 Elsevier Inc. All rights reserved.

A novel amperometric biosensor based on covalently attached multilayer assemblies of gold nanoparticles, diazo-resins and acetylcholinesterase for the detection of organophosphorus pesticides.

PubMed

Jiang, Bin; Dong, Pei; Zheng, Jianbin

2018-06-01

Using an ionic layer-by-layer self-assembly technique, colloidal gold nanoparticles (AuNPs) and diazo-resins (DAR) were immobilised on the surface of a p-aminobenzenesulfonic acid-modified glassy carbon electrode to form a matrix composite membrane for acetylcholinesterase (AChE) immobilisation. Photo-sensitive DAR was used as the assembly interlayer to convert the ionic bond into a covalent bond to improve the biosensor stability. These fabrication processes were followed by electrochemical impedance spectroscopy and cyclic voltammetry to verify the membrane formation. Because of the introduction of AuNPs/DAR/AChE biofilms, the modified electrode exhibited excellent electron transfer mediation and electrical conductivity. In addition, it exhibited high sensitivity in the range of linear concentration from 1.0 × 10 -8 to 1.0 × 10 -12 g L -1 with the detection limit of 5.12 × 10 -13 and 5.85 × 10 -13 g L -1 for malathion and methyl parathion, respectively. More importantly, the presented biosensor considerably improved stability because the electrostatic interaction was converted into covalent bonds by UV irradiation. It is a simple, cheap and stable method for quantitative detection of organophosphorus pesticides, and this method may pave a way for the sensitive, simple detection of different analytes without the need of expensive instrumentation. Copyright © 2018 Elsevier B.V. All rights reserved.

SCREEN-PRINTED TYROSINASE-CONTAINING ELECTRODES FOR THE BIOSENSING OF ENZYME INHIBITORS

EPA Science Inventory

Disposal amperometric inhibition biosensors have been microfabricated by screen printing a tyrosinase-containing carbon ink. The decrease in the substrate (catechol) steady-state current, caused by the addition of various pesticides and herbicides, offers convenient quantitation ...

Amperometric biosensors based on deposition of gold and platinum nanoparticles on polyvinylferrocene modified electrode for xanthine detection.

PubMed

Baş, Salih Zeki; Gülce, Handan; Yıldız, Salih; Gülce, Ahmet

2011-12-15

In this study, new xanthine biosensors, XO/Au/PVF/Pt and XO/Pt/PVF/Pt, based on electroless deposition of gold(Au) and platinum(Pt) nanoparticles on polyvinylferrocene(PVF) coated Pt electrode for detection of xanthine were presented. The amperometric responses of the enzyme electrodes were measured at the constant potential, which was due to the electrooxidation of enzymatically produced H(2)O(2). Compared with XO/PVF/Pt electrode, XO/Au/PVF/Pt and XO/Pt/PVF/Pt exhibited excellent electrocatalytic activity towards the oxidation of the analyte. Effect of Au and Pt nanoparticles was investigated by monitoring the response currents at the different deposition times and the different concentrations of KAuCl(4) and PtBr(2). Under the optimal conditions, the calibration curves of XO/Au/PVF/Pt and XO/Pt/PVF/Pt were obtained over the range of 2.5 × 10(-3) to 0.56 mM and 2.0 × 10(-3) to 0.66 mM, respectively. The detection limits were 7.5 × 10(-4)mM for XO/Au/PVF/Pt and 6.0 × 10(-4)mM for XO/Pt/PVF/Pt. The effects of interferents, the operational and the storage stabilities of the biosensors and the applicabilities of the proposed biosensors to the drug samples analysis were also evaluated. Copyright © 2011 Elsevier B.V. All rights reserved.

An amperometric biosensor based on horseradish peroxidase immobilized onto maize tassel-multi-walled carbon nanotubes modified glassy carbon electrode for determination of heavy metal ions in aqueous solution.

PubMed

Moyo, Mambo; Okonkwo, Jonathan O; Agyei, Nana M

2014-03-05

A biosensor for trace metal ions based on horseradish peroxidase (HRP) immobilized on maize tassel-multiwalled carbon nanotube (MT-MWCNT) through electrostatic interactions is described herein. The biosensor was characterized using Fourier transform infrared (FTIR), UV-vis spectrometry, voltammetric and amperometric methods. The FTIR and UV-vis results inferred that HRP was not denatured during its immobilization on MT-MWCNT composite. The biosensing principle was based on the determination of the cathodic responses of the immobilized HRP to H₂O₂, before and after incubation in trace metal standard solutions. Under optimum conditions, the inhibition rates of trace metals were proportional to their concentrations in the range of 0.092-0.55 mg L⁻¹, 0.068-2 mg L⁻¹ for Pb²⁺ and Cu²⁺ respectively. The limits of detection were 2.5 μg L⁻¹ for Pb²⁺ and 4.2 μg L⁻¹ for Cu²⁺. Representative Dixon and Cornish-Bowden plots were used to deduce the mode of inhibition induced by the trace metal ions. The inhibition was reversible and mixed for both metal ions. Furthermore, the biosensor showed good stability, selectivity, repeatability and reproducibility. Copyright © 2013 Elsevier Inc. All rights reserved.

Rapid sucrose monitoring in green coffee samples using multienzymatic biosensor.

PubMed

Stredansky, Miroslav; Redivo, Luca; Magdolen, Peter; Stredansky, Adam; Navarini, Luciano

2018-07-15

Amperometric biosensor utilizing FAD-dependent glucose dehydrogenase (FAD-GDH) for a specific sucrose monitoring in green coffee is described. FAD-GDH was co-immobilized with invertase and mutarotase on a thin-layer gold planar electrode using chitosan. The biosensor showed a wide linearity (from 10 to 1200 μM), low detection limit (8.4 μM), fast response time (50 s), and appeared to be O2 independent. In addition the biosensors exhibited a good operational (3 days) and storage (1 year) stability. Finally, the results achieved from the biosensor measurements of sucrose in 17 samples of green coffee (Coffea arabica, C. canephora and C. liberica) were compared with those obtained by the standard HPLC method. The good correlation among results of real samples, satisfactory analytical performance and simple use of the presented biosensor make it suitable for application in coffee industry. Copyright © 2018 Elsevier Ltd. All rights reserved.

Immobilization of Ni-Pd/core-shell nanoparticles through thermal polymerization of acrylamide on glassy carbon electrode for highly stable and sensitive glutamate detection.

PubMed

Yu, Huicheng; Ma, Zhenzhen; Wu, Zhaoyang

2015-10-08

The preparation of a persistently stable and sensitive biosensor is highly important for practical applications. To improve the stability and sensitivity of glutamate sensors, an electrode modified with glutamate dehydrogenase (GDH)/Ni-Pd/core-shell nanoparticles was developed using the thermal polymerization of acrylamide (AM) to immobilize the synthesized Ni-Pd/core-shell nanoparticles onto a glassy carbon electrode (GCE). The modified electrode was characterized by scanning electron microscopy (SEM), Fourier transform infrared (FTIR) spectroscopy, cyclic voltammetry (CV), and electrochemical impedance spectroscopy (EIS). Electrochemical data showed that the prepared biosensor had remarkably enhanced electrocatalytic activity toward glutamate. Moreover, superior reproducibility and excellent stability were observed (relative average deviation was 2.96% after continuous use of the same sensor for 60 times, and current responses remained at 94.85% of the initial value after 60 d). The sensor also demonstrated highly sensitive amperometric detection of glutamate with a low limit of detection (0.052 μM, S/N = 3), high sensitivity (4.768 μA μM(-1) cm(-2)), and a wide, useful linear range (0.1-500 μM). No interference from potential interfering species such as l-cysteine, ascorbic acid, and l-aspartate were noted. The determination of glutamate levels in actual samples achieved good recovery percentages. Copyright © 2015 Elsevier B.V. All rights reserved.

Carbon Nanotubes (CNTs) for the Development of Electrochemical Biosensors

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lin, Yuehe; Yantasee, Wassana; Wang, Joseph

2005-01-01

Carbon nanotube (CNT) is a very attractive material for the development of biosensors because of its capability to provide strong electrocatalytic activity and minimize surface fouling of the sensors. This article reviews our recent developments of oxidase- and dehydrogenase-amperometric biosensors based on the immobilization of CNTs, the co-immobilization of enzymes on the CNTs/Nafion or the CNT/Teflon composite materials, or the attachment of enzymes on the controlled-density aligned CNT-nanoelectrode arrays. The excellent electrocatalytic activities of the CNTs on the redox reactions of hydrogen peroxide, nicotinamide adenine dinucleotide (NADH), and homocysteine have been demonstrated. Successful applications of the CNT-based biosensors reviewed hereinmore » include the low-potential detections of glucose, organophosphorus compounds, and alcohol.« less

Bulk-modified modified screen-printing carbon electrodes with both lactate oxidase (LOD) and horseradish peroxide (HRP) for the determination of L-lactate in flow injection analysis mode.

PubMed

Ghamouss, Fouad; Ledru, Sophie; Ruillé, Nadine; Lantier, Françoise; Boujtita, Mohammed

2006-06-16

A screen-printed carbon electrode modified with both HRP and LOD (SPCE-HRP/LOD) has been developed for the determination of L-lactate concentration in real samples. The resulting SPCE-HRP/LOD was prepared in a one-step procedure, and was then optimised as an amperometric biosensor operating at [0, -100]mV versus Ag/AgCl for L-lactate determination in flow injection mode. A significant improvement in the reproducibility (coefficient variation of about 10%) of the preparation of the biosensors was obtained when graphite powder was modified with LOD in the presence of HRP previously oxidised by periodate ion (IO4-). Optimisation studies were performed by examining the effects of LOD loading, periodation step and rate of the binder on analytical performances of SPCE-HRP/LOD. The sensitivity of the optimised SPCE-HRP/LOD to L-lactate was 0.84 nAL micromol(-1) in a detection range between 10 and 180 microMol. The possibility of using the developed biosensor to determine L-lactate concentrations in various dairy products was also evaluated.

Indirect electrocatalytic determination of choline by monitoring hydrogen peroxide at the choline oxidase-prussian blue modified iron phosphate nanostructures.

PubMed

Zhang, Hui; Yin, Yajing; Wu, Ping; Cai, Chenxin

2012-01-15

Choline, as a marker of cholinergic activity in brain tissue, is very important in biological and clinical analysis, especially in the clinical detection of the neurodegenerative disorders disease. This work presents an electrochemical approach for the detection of choline based on prussian blue modified iron phosphate nanostructures (PB-FePO(4)). The obtained nanostructures showed a good catalysis toward the electroreduction of H(2)O(2), and an amperometric choline biosensor was developed by immobilizing choline oxidase on the PB-FePO(4) nanostructures. The biosensor exhibited a rapid response (ca. 2s), low detection limit (0.4±0.05 μM), wide linear range (2 μM to 3.2 mM), high sensitivity (~75.2 μAm M(-1) cm(-2)), as well as good stability and repeatability. In addition, the common interfering species, such as ascorbic acid, uric acid and 4-acetamidophenol did not cause obvious interference due to the low detection potential (-0.05 V versus saturated calomel electrode). This nanostructure could be used as a promise platform for the construction of other oxidase-based biosensors. Copyright © 2011 Elsevier B.V. All rights reserved.

Glucose biosensor based on the immobilization of glucose oxidase on electrochemically synthesized polypyrrole-poly(vinyl sulphonate) composite film by cross-linking with glutaraldehyde.

PubMed

Colak, Ozlem; Yaşar, Ahmet; Cete, Servet; Arslan, Fatma

2012-10-01

In this study, a novel amperometric glucose biosensor was developed by immobilizing glucose oxidase (GOX) by cross-linking via glutaraldehyde on electrochemically polymerized polypyrrole-poly(vinyl sulphonate) (PPy-PVS) films on the surface of a platinum (Pt) electrode. Electropolymerization of pyrrole and poly(vinyl sulphonate) on the Pt surface was carried out with an electrochemical cell containing pyrrole and poly(vinyl sulphonate) by cyclic voltammetry between -1.0 and + 2.0 V (vs.Ag/AgCl) at a scan rate of 50 mV/s upon the Pt electrode. The amperometric determination was based on the electrochemical detection of H(2)O(2) generated in enzymatic reaction of glucose. Determination of glucose was carried out by the oxidation of enzymatically produced H(2)O(2) at 0.4 V vs. Ag/AgCl. The effects of pH and temperature were investigated and optimum parameters were found to be 7.5 and 65°C, respectively. The effect of working potential was investigated and optimum potential was determined to be 0.4 V. The operational stability of the enzyme electrode was also studied. The response of the PPy/PVS-GOX glucose biosensor exhibited good reproducibility with a relative standard deviation (RSD) of 2.48%. The glucose biosensor retained 63% of initial activity after 93 days when stored in 0.1 M phosphate buffer solution of pH 7.5 at 4°C. With the low operating potential, the biosensor demonstrated little interference from the possible interferants.

Future of biosensors: a personal view.

PubMed

Scheller, Frieder W; Yarman, Aysu; Bachmann, Till; Hirsch, Thomas; Kubick, Stefan; Renneberg, Reinhard; Schumacher, Soeren; Wollenberger, Ulla; Teller, Carsten; Bier, Frank F

2014-01-01

Biosensors representing the technological counterpart of living senses have found routine application in amperometric enzyme electrodes for decentralized blood glucose measurement, interaction analysis by surface plasmon resonance in drug development, and to some extent DNA chips for expression analysis and enzyme polymorphisms. These technologies have already reached a highly advanced level and need minor improvement at most. The dream of the "100-dollar" personal genome may come true in the next few years provided that the technological hurdles of nanopore technology or of polymerase-based single molecule sequencing can be overcome. Tailor-made recognition elements for biosensors including membrane-bound enzymes and receptors will be prepared by cell-free protein synthesis. As alternatives for biological recognition elements, molecularly imprinted polymers (MIPs) have been created. They have the potential to substitute antibodies in biosensors and biochips for the measurement of low-molecular-weight substances, proteins, viruses, and living cells. They are more stable than proteins and can be produced in large amounts by chemical synthesis. Integration of nanomaterials, especially of graphene, could lead to new miniaturized biosensors with high sensitivity and ultrafast response. In the future individual therapy will include genetic profiling of isoenzymes and polymorphic forms of drug-metabolizing enzymes especially of the cytochrome P450 family. For defining the pharmacokinetics including the clearance of a given genotype enzyme electrodes will be a useful tool. For decentralized online patient control or the integration into everyday "consumables" such as drinking water, foods, hygienic articles, clothing, or for control of air conditioners in buildings and cars and swimming pools, a new generation of "autonomous" biosensors will emerge.

Nitrogen-doped carbon nanospheres derived from cocoon silk as metal-free electrocatalyst for glucose sensing.

PubMed

Li, Tongtong; Li, Yahang; Wang, Chunyu; Gao, Zhi-Da; Song, Yan-Yan

2015-11-01

Nitrogen-doped carbon materials have attracted tremendous attention because of their high activity in electrocatalysis. In the present work, cocoon silk -- a biomass material is used to prepare porous carbon fibers due to its abundant nitrogen content. The as-prepared carbon microfibers have been activated and disintegrated into carbon nanospheres (CNS) with a diameter of 20--60 nm by a simple nitric acid refluxing process. Considering their excellent electrocatalytic activity towards the reduction of oxygen, the CNS modified electrodes are further applied in the construction of glucose amperometric biosensor using glucose oxidase as a model. The proposed biosensor exhibits fast response, high sensitivity, good stability and selectivity for glucose detection with a wide linear range from 79.7 to 2038.9 μM, and a detection limit of 39.1 μM. The performance is comparable to leading literature results indicating a great potential for electrochemical sensing application. Copyright © 2015 Elsevier B.V. All rights reserved.

Non-covalent biofunctionalization of single-walled carbon nanotubes via biotin attachment by π-stacking interactions and pyrrole polymerization.

PubMed

Haddad, R; Cosnier, S; Maaref, A; Holzinger, M

2009-12-01

Single-walled carbon nanotubes were functionalized with biotin using either electropolymerization or formation of pi-stacking interactions for the construction of biosensors. Thanks to the high affinity of the avidin-biotin interactions, a biotinylated glucose oxidase (B-GOX) as a biomolecule model was immobilized on the biotinylated nanotubes. The influence of the biosensor configuration on their amperometric performances was investigated by changing the amount of nanotubes and the numbers of avidin/B-GOX layers. By increasing the amount of nanotube and avidin/B-GOX layers, both sensor setups show a perfect linear increase of immobilized enzymes reflecting a high reproducibility of our systems. The highest sensitivities (up to 5.2 mA M(-1) cm(-2)) and maximum current densities (up to 55 microA cm(-2)) were obtained using nanotube deposits modified by electrochemical coatings. In contrast, non-covalently functionalized biotin-nanotubes show a better permeability for the enzymatically generated hydrogen peroxide.

Integrated multienzyme electrochemical biosensors for monitoring malolactic fermentation in wines.

PubMed

Gamella, M; Campuzano, S; Conzuelo, F; Curiel, J A; Muñoz, R; Reviejo, A J; Pingarrón, José M

2010-05-15

Integrated amperometric biosensors for the determination of L-malic and L-lactic acids were developed by coimmobilization of the enzymes L-malate dehydrogenase (MDH) and diaphorase (DP), or L-lactate oxidase (LOX) and horseradish peroxidase (HRP), respectively, together with the redox mediator tetrathiafulvalene (TTF), on a 3-mercaptopropionic acid (MPA) self-assembled monolayer (SAM)-modified gold electrode by using a dialysis membrane. The electrochemical oxidation of TTF at +100mV (vs. Ag/AgCl), and the reduction of TTF(+) at -50mV were used for the monitoring of the enzyme reactions involved in L-malic and L-lactic acid determinations, respectively. Experimental variables concerning the biosensors composition and the detection conditions were optimized for each biosensor. Good relative standard deviation values were obtained in both cases for the measurements carried out with the same biosensor, with no need of cleaning or pretreatment of the bioelectrodes surface, and with different biosensors constructed in the same manner. After 7 days of continuous use, the MDH/DP biosensor still exhibited 90% of the original sensitivity, while the LOX/HRP biosensor yielded a 91% of the original response after 5 days. Calibration graphs for L-malic and L-lactic were obtained with linear ranges of 5.2x10(-7) to 2.0x10(-5) and 4.2x10(-7) to 2.0x10(-5)M, respectively. The calculated detection limits were 5.2x10(-7) and 4.2x10(-7)M, respectively. The biosensors exhibited a high selectivity with no significant interferences. They were applied to monitor malolactic fermentation (MLF) induced by inoculation of Lactobacillus plantarum CECT 748(T) into a synthetic wine. Samples collected during MLF were assayed for L-malic and L-lactic acids, and the results obtained with the biosensors exhibited a very good correlation when plotted against those obtained by using commercial enzymatic kits.

Development of electrochemical biosensors with various types of zeolites

NASA Astrophysics Data System (ADS)

Soldatkina, O. V.; Kucherenko, I. S.; Soldatkin, O. O.; Pyeshkova, V. M.; Dudchenko, O. Y.; Akata Kurç, B.; Dzyadevych, S. V.

2018-03-01

In the work, different types of zeolites were used for the development of enzyme-based electrochemical biosensors. Zeolites were added to the biorecognition elements of the biosensors and served as additional components of the biomembranes or adsorbents for enzymes. Three types of biosensors (conductometric, amperometric and potentiometric) were studied. The developed biosensors were compared with the similar biosensors without zeolites. The biosensors contained the following enzymes: urease, glucose oxidase, glutamate oxidase, and acetylcholinesterase and were intended for the detection of urea, glucose, glutamate, and acetylcholine, respectively. Construction of the biosensors using the adsorption of enzymes on zeolites has several advantages: simplicity, good reproducibility, quickness, absence of toxic compounds. These benefits are particularly important for the standardization and further mass production of the biosensors. Furthermore, a biosensor for the sucrose determination contained a three-enzyme system (invertase/mutatorase/glucose oxidase), immobilized by a combination of adsorption on silicalite and cross-linking via glutaraldehyde; such combined immobilization demonstrated better results as compared with adsorption or cross-linking separately. The analysis of urea and sucrose concentrations in the real samples was carried out. The results, obtained with biosensors, had high correlation with the results of traditional analytical methods, thus the developed biosensors are promising for practical applications.

Effect of Diffusion Limitations on Multianalyte Determination from Biased Biosensor Response

PubMed Central

Baronas, Romas; Kulys, Juozas; Lančinskas, Algirdas; Žilinskas, Antanas

2014-01-01

The optimization-based quantitative determination of multianalyte concentrations from biased biosensor responses is investigated under internal and external diffusion-limited conditions. A computational model of a biocatalytic amperometric biosensor utilizing a mono-enzyme-catalyzed (nonspecific) competitive conversion of two substrates was used to generate pseudo-experimental responses to mixtures of compounds. The influence of possible perturbations of the biosensor signal, due to a white noise- and temperature-induced trend, on the precision of the concentration determination has been investigated for different configurations of the biosensor operation. The optimization method was found to be suitable and accurate enough for the quantitative determination of the concentrations of the compounds from a given biosensor transient response. The computational experiments showed a complex dependence of the precision of the concentration estimation on the relative thickness of the outer diffusion layer, as well as on whether the biosensor operates under diffusion- or kinetics-limited conditions. When the biosensor response is affected by the induced exponential trend, the duration of the biosensor action can be optimized for increasing the accuracy of the quantitative analysis. PMID:24608006

Electrodeposition of flower-like platinum on electrophoretically grown nitrogen-doped graphene as a highly sensitive electrochemical non-enzymatic biosensor for hydrogen peroxide detection

NASA Astrophysics Data System (ADS)

Tajabadi, M. T.; Sookhakian, M.; Zalnezhad, E.; Yoon, G. H.; Hamouda, A. M. S.; Azarang, Majid; Basirun, W. J.; Alias, Y.

2016-11-01

An efficient non-enzymatic biosensor electrode consisting of nitrogen-doped graphene (N-graphene) and platinum nanoflower (Pt NF) with different N-graphene loadings were fabricated on indium tin oxide (ITO) glass using a simple layer-by-layer electrophoretic and electrochemical sequential deposition approach. N-graphene was synthesized by annealing graphene oxide with urea at 900 °C. The structure and morphology of the as-fabricated non-enzymatic biosensor electrodes were determined using X-ray diffraction, field emission electron microscopy, transmission electron microscopy, Raman and X-ray photoelectron spectra. The as-fabricated Pt NF-N-graphene-modified ITO electrodes with different N-graphene loadings were utilized as a non-enzymatic biosensor electrode for the detection of hydrogen peroxide (H2O2). The behaviors of the hybrid electrodes towards H2O2 reduction were assessed using chronoamperometry, cyclic voltammetry and electrochemical impedance spectroscopy analysis. The Pt NF-N-graphene-modified ITO electrode with a 0.05 mg ml-1 N-graphene loading exhibited the lowest detection limit, fastest amperometric sensing, a wide linear response range, excellent stability and reproducibility for the non-enzymatic H2O2 detection, due to the synergistic effect between the electrocatalytic activity of the Pt NF and the high conductivity and large surface area of N-graphene.

Glucose biosensor from covalent immobilization of chitosan-coupled carbon nanotubes on polyaniline-modified gold electrode.

PubMed

Wan, Dong; Yuan, Shaojun; Li, G L; Neoh, K G; Kang, E T

2010-11-01

An amperometric glucose biosensor was prepared using polyaniline (PANI) and chitosan-coupled carbon nanotubes (CS-CNTs) as the signal amplifiers and glucose oxidase (GOD) as the glucose detector on a gold electrode (the Au-g-PANI-c-(CS-CNTs)-GOD biosensor). The PANI layer was prepared via oxidative graft polymerization of aniline from the gold electrode surface premodified by self-assembled monolayer of 4-aminothiophenol. CS-CNTs were covalently coupled to the PANI-modified gold substrate using glutaradehyde as a bifunctional linker. GOD was then covalently bonded to the pendant hydroxyl groups of chitosan using 1,4-carbonyldiimidazole as the bifunctional linker. The surface functionalization processes were ascertained by X-ray photoelectron spectroscopy (XPS) analyses. The field emission scanning electron microscopy (FESEM) images of the Au-g-PANI-c-(CS-CNTs) electrode revealed the formation of a three-dimensional surface network structure. The electrode could thus provide a more spatially biocompatible microenvironment to enhance the amount and biocatalytic activity of the immobilized enzyme and to better mediate the electron transfer. The resulting Au-g-PANI-c-(CS-CNTs)-GOD biosensor exhibited a linear response to glucose in the concentration range of 1-20 mM, good sensitivity (21 μA/(mM·cm(2))), good reproducibility, and retention of >80% of the initial response current after 2 months of storage.

Elimination of the acetaminophen interference in an implantable glucose sensor.

PubMed

Zhang, Y; Hu, Y; Wilson, G S; Moatti-Sirat, D; Poitout, V; Reach, G

1994-04-01

Acetaminophen has been one of the most serious electrochemical interferences to oxidase-based amperometric biosensors that measure H2O2. A study was carried out to investigate various polymer materials for their selectivity as the sensor inner membrane. A composite membrane of cellulose acetate and Nafion was found to eliminate acetaminophen and other electrochemical interferences effectively while at the same time maintaining reasonable diffusivity for hydrogen peroxide. The excellent in vivo performance of the sensor was attributed not only to significantly reduced steady-state sensitivity to acetaminophen but also to very slow acetaminophen response. These features, combined with rapid acetaminophen clearance pharmacokinetics, led to the decreased response as demonstrated in the rat.

A comparative study of carbon-platinum hybrid nanostructure architecture for amperometric biosensing.

PubMed

Vanegas, Diana C; Taguchi, Masashige; Chaturvedi, Prachee; Burrs, Stephanie; Tan, Michael; Yamaguchi, Hitomi; McLamore, Eric S

2014-02-07

Carbon and noble metal nanomaterials exhibit unique properties that have been explored over the last few decades for developing electrochemical sensors and biosensors. Hybridization of nanometals to carbon nanomaterials such as graphene or carbon nanotubes produces a synergistic effect on the electrocatalytic activity when compared to either material alone. However, to date there are no comparative studies that directly investigate the effects of nanocarbon concentration and nanocomposite arrangement on electron transport. This comparative study investigated the efficacy of various platinum-carbon hybrid nanostructures for amperometric biosensing. Electroactive surface area, sensitivity towards hydrogen peroxide, response time, limit of detection, and surface roughness were measured for various hybrid nanomaterial arrangements. Both design factors (nanocarbon concentration and network arrangement) influenced the performance of the reduced graphene oxide-based platforms; whereas only nanomaterial arrangement affected the performance of the carbon nanotube-composites. The highest sensitivity towards hydrogen peroxide for reduced graphene oxide nanocomposites (45 ± 3.2 μA mM(-1)) was measured for a graphene concentration of 2 mg mL(-1) in a "sandwich" structure; nanoplatinum layers enveloping the reduced graphene oxide. Likewise, the best carbon nanotube performance toward H2O2 (49 ± 1.4 μA mM(-1)) was measured for a sandwich-type structure with nanoplatinum. The enhanced electrocatalytic activity of this "sandwich" structure was due to a combined effect of electrical junctions formed amongst nanocarbon, and nanocomposite soldering to the electrode surface. The top-down carbon-platinum hybrid nanocomposites in this paper represent a simple, low-cost, approach for formation of high fidelity amperometric sensors with remarkable performance characteristics that are similar to bottom-up fabrication approaches.

An electrospun nanofiber matrix based on organo-clay for biosensors: PVA/PAMAM-Montmorillonite

NASA Astrophysics Data System (ADS)

Unal, Betul; Yalcinkaya, Esra Evrim; Demirkol, Dilek Odaci; Timur, Suna

2018-06-01

Diagnostic techniques based on biomolecules have huge a potential to be applied in the application in various areas such as food/beverage industries, diseases diagnostics, monitoring of bio-processes and environmental pollutants. Immobilization of biomolecules on a transducer is the key parameter to being able to prepare a highly stable diagnostic tests. Electrospun nanofibers are a good alternative to immobilize biomolecules. Here, electrospun nanofibers based on an organoclay were used to design the first generation amperometric enzyme biosensor. PAMAM G2 dendrimers were used to intercalate montmorillonite clay (Mt) and then the modification of Mt by PAMAM was characterized using FTIR, XRD, TGA and zeta potential measurements. After that nanofibers were prepared by electrospinning Mt and PAMAM-Mt using poly(vinyl) alcohol (PVA) as an auxiliary polymer and the formed PVA/PAMAM-Mt electrospun nanofibers were proved by SEM, TEM and AFM techniques. Finally, pyranose oxidases (PyOx) were immobilized on a glassy carbon electrode surface, which was modified using the PVA/PAMAM-Mt electrospun nanofibers. Amperometric measurements were carried out using buffer solution at -0.7 V under stirring conditions. The linear response for glucose was from 0.005 mM to 0.25 mM using PVA/Mt/PyOx and PVA/PAMAM-Mt/PyOx biosensors. The limit of detection was 0.7 μM glucose with PVA/PAMAM-Mt/PyOx biosensor. To detect glucose in real sample, measurements were carried out using soft drink cola as a substrate instead of glucose.

Development of glucose biosensor based on reconstitution of glucose oxidase onto polymeric redox mediator coated pencil graphite electrodes.

PubMed

Dervisevic, Muamer; Cevik, Emre; Senel, Mehmet

2015-01-01

In this study, a novel glucose biosensor was fabricated by reconstitutional immobilization of glucose oxidase (GOx) onto a poly(glycidyl methacrylate-co-vinylferrocene) (poly(GMA-co-VFc)) film coated pencil graphite electrode (PGE). The amperometric current response of poly(GMA-co-VFc)-GOx to glucose is linear in the concentration range between 1 and 16mM (correlation coefficient of 0.9998) with a detection limit of 2.7μM (S/N=3). Experimental parameters were studied in detail and optimized, including the pH and temperature governing the analytical performance of the biosensor. The stability and reusability of the biosensor as well as its kinetic parameters have also been studied. Copyright © 2014 Elsevier Inc. All rights reserved.

Eyeglasses based wireless electrolyte and metabolite sensor platform.

PubMed

Sempionatto, Juliane R; Nakagawa, Tatsuo; Pavinatto, Adriana; Mensah, Samantha T; Imani, Somayeh; Mercier, Patrick; Wang, Joseph

2017-05-16

The demand for wearable sensors has grown rapidly in recent years, with increasing attention being given to epidermal chemical sensing. Here, we present the first example of a fully integrated eyeglasses wireless multiplexed chemical sensing platform capable of real-time monitoring of sweat electrolytes and metabolites. The new concept has been realized by integrating an amperometric lactate biosensor and a potentiometric potassium ion-selective electrode into the two nose-bridge pads of the glasses and interfacing them with a wireless electronic backbone placed on the glasses' arms. Simultaneous real-time monitoring of sweat lactate and potassium levels with no apparent cross-talk is demonstrated along with wireless signal transduction. The electrochemical sensors were screen-printed on polyethylene terephthalate (PET) stickers and placed on each side of the glasses' nose pads in order to monitor sweat metabolites and electrolytes. The electronic backbone on the arms of the glasses' frame offers control of the amperometric and potentiometric transducers and enables Bluetooth wireless data transmission to the host device. The new eyeglasses system offers an interchangeable-sensor feature in connection with a variety of different nose-bridge amperometric and potentiometric sensor stickers. For example, the lactate bridge-pad sensor was replaced with a glucose one to offer convenient monitoring of sweat glucose. Such a fully integrated wireless "Lab-on-a-Glass" multiplexed biosensor platform can be readily expanded for the simultaneous monitoring of additional sweat electrolytes and metabolites.

Pd nanoparticle assemblies--as the substitute of HRP, in their biosensing applications for H2O2 and glucose.

PubMed

Han, Min; Liu, Suli; Bao, Jianchun; Dai, Zhihui

2012-01-15

The spherical porous Pd nanoparticle assemblies (NPAs) have been successfully synthesized by starch-assisted chemical reduction of Pd(II) species at room temperature. Such Pd NPAs are not simply used to enlarge the surface area and to promote the electron transfer. They also catalyze the reduction of H(2)O(2) which are regarded as horseradish peroxidase (HRP) substitutes in electron transfer process. By using them as electrocatalysts, as low as 6.8×10(-7) M H(2)O(2) can be detected with a linear range from 1.0×10(-6) to 8.2×10(-4) M. Moreover, through co-immobilization of such Pd NPAs and glucose oxidase (GOx), a sensitive and selective glucose biosensor is developed. The detection principle lies on measuring the increase of cathodic current by co-reduction of dissolved oxygen and the in situ generated H(2)O(2) during the enzymatic reaction. Under optimal conditions, the detection limit is down to 6.1×10(-6) M with a very wide linear range from 4.0×10(-5) to 2.2×10(-2) M. The proposed biosensor shows a fast response, good stability, high selectivity and reproducibility of serum glucose level. It provides a promising strategy to construct fast, sensitive, stable and anti-interferential amperometric biosensors for early diagnosis and prevention of diabetes. Copyright © 2011 Elsevier B.V. All rights reserved.

FLOW INJECTION AMPEROMETRIC DETECTION OF OP NERVE AGENTS BASED ON AN ORGANOPHOSPHORUS-HYDROLASE BIOSENSOR DETECTOR. (R828160)

EPA Science Inventory

The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...

A highly sensitive electrochemical biosensor for catechol using conducting polymer reduced graphene oxide-metal oxide enzyme modified electrode.

PubMed

Sethuraman, V; Muthuraja, P; Anandha Raj, J; Manisankar, P

2016-10-15

The fabrication, characterization and analytical performances were investigated for a catechol biosensor, based on the PEDOT-rGO-Fe2O3-PPO composite modified glassy carbon (GC) electrode. The graphene oxide (GO) doped conducting polymer poly (3,4-ethylenedioxythiophene) (PEDOT) was prepared through electrochemical polymerization by potential cycling. Reduction of PEDOT-GO was carried out by amperometric method. Fe2O3 nanoparticles were synthesized in ethanol by hydrothermal method. The mixture of Fe2O3, PPO and glutaraldehyde was casted on the PEDOT-rGO electrode. The surface morphology of the modified electrodes was studied by FE-SEM and AFM. Cyclic voltammetric studies of catechol on the enzyme modified electrode revealed higher reduction peak current. Determination of catechol was carried out successfully by Differential Pulse Voltammetry (DPV) technique. The fabricated biosensor investigated shows a maximum current response at pH 6.5. The catechol biosensor exhibited wide sensing linear range from 4×10(-8) to 6.20×10(-5)M, lower detection limit of 7×10(-9)M, current maxima (Imax) of 92.55µA and Michaelis-Menten (Km) constant of 30.48µM. The activation energy (Ea) of enzyme electrode is 35.93KJmol(-1) at 50°C. There is no interference from d-glucose and l-glutamic acid, ascorbic acid and o-nitrophenol. The PEDOT-rGO-Fe2O3-PPO biosensor was stable for at least 75 days when stored in a buffer at about 4°C. Copyright © 2015 Elsevier B.V. All rights reserved.

Acetylcholinesterase biosensor based on single-walled carbon nanotubes--Co phtalocyanine for organophosphorus pesticides detection.

PubMed

Ivanov, A N; Younusov, R R; Evtugyn, G A; Arduini, F; Moscone, D; Palleschi, G

2011-07-15

A simple and reliable technique has been developed for the construction of an amperometric acetylcholinesterase biosensor based on screen-printed carbon electrodes. For the first time, one-step modification using single-walled carbon nanotubes and Co phtalocyanine has been proposed to decrease the working potential and to increase the signal of thiocholine oxidation. The biosensor developed made it possible to detect 5-50 ppb of paraoxon and 2-50 ppb of malaoxon with detection limits of 3 and 2 ppb, respectively (incubation 15 min). The biosensor showed high reproducibility when measurements of the substrate and inhibitor were performed (R.S.D. about 1% and 2.5%, respectively). The reliability of the inhibition measurements was confirmed by testing spiked samples of sparkling and tape waters. Copyright © 2011 Elsevier B.V. All rights reserved.

Amperometric immunosensor for α-fetoprotein antigen in human serum based on co-immobilizing dinuclear copper complex and gold nanoparticle doped chitosan film

NASA Astrophysics Data System (ADS)

Gan, Ning; Meng, Ling Hua; Wang, Feng

2009-09-01

A sensitive amperometric immunosensor for α-fetoprotein (AFP), a tumor marker for the diagnosis of hepatocellular carcinoma (HCC), was constructed, The immunosensor is prepared by co-immobilizing [Cu2(phen)2Cl2] (μ-Cl)2 (CuL), nano-Au/Chitosan(Chit) composite, horseradish peroxidase (HRP) and AFP antibody(anti-AFP) on a glassy carbon electrode (GCE). Firstly, CuL was irreversibly absorb on GCE electrode through π-π stacking interaction; then nano-Au/Chit composite was immobilized onto the electrode because of its excellent membrane-forming ability, finally HRP and anti-AFP was adsorbed onto the surface of the gold nanoparticles to construct GCE | CuL/nanoAu-chit/HRP/anti-AFP immunosensor. The preparation procedure of the electrode was characterized by electrochemical and spectroscopy method. The results showed that this immunosensor exhibited an excellent electrocatalytic response to the reduction of hydrogen peroxide (H2O2) without the aid of an electron mediator, offers a high-sensitivity (1710 nA · ng-1 · ml-1) for the detection of AFP and has good correlation for detection of AFP in the range of 0.2 to 120.0 ng/ml with a detection limit of 0.05 ng/ml. The biosensor showed high selectivity as well as good stability and reproductivity.

Iron oxide/carbon black (Fe2O3/CB) composite electrode for the detection of reduced nicotinamide cofactors using an amperometric method under a low overpotential.

PubMed

Kim, Yang Hee; Kim, Taeho; Ryu, Ji Heon; Yoo, Young Je

2010-01-15

An amperometric biosensor for the detection of the reduced nicotinamide cofactors NADH and NADPH was designed, based on the electrochemical oxidation of NAD(P)H with an iron oxide/carbon black composite (Fe(2)O(3)/CB) electrode. The electrode exhibited excellent performances in that it led to a substantial decrease in the overpotential of electrochemical NADH oxidation. Iron oxide plays a significant role as a catalyst for NADH oxidation and the reaction occurs at +0.00 V (vs. Ag/AgCl). The method of the sensor construction is very simple and the sensor performed well, giving high sensitivity, high stability, and a broad detection range. The sensitivity of this system is 2.54 microA mM(-1) and the limit of detection (S/N=3) is 10 microM. A linear range was observed between 10 microM and 1000 microM of NADH (R(2)=0.993), which is preferable to that of the previous studies. The Fe(2)O(3)/CB electrode also oxidizes NADPH under the same condition and can be applied as an NADPH sensor. Moreover, when the sensor system was integrated into a dehydrogenase-based sensor system, it also showed a good sensing performance. Copyright 2009 Elsevier B.V. All rights reserved.

Isolation and characterization of mutated alcohol oxidases from the yeast Hansenula polymorpha with decreased affinity toward substrates and their use as selective elements of an amperometric biosensor

PubMed Central

Dmytruk, Kostyantyn V; Smutok, Oleh V; Ryabova, Olena B; Gayda, Galyna Z; Sibirny, Volodymyr A; Schuhmann, Wolfgang; Gonchar, Mykhailo V; Sibirny, Andriy A

2007-01-01

Background Accurate, rapid, and economic on-line analysis of ethanol is very desirable. However, available biosensors achieve saturation at very low ethanol concentrations and thus demand the time and labour consuming procedure of sample dilution. Results Hansenula polymorpha (Pichia angusta) mutant strains resistant to allyl alcohol in methanol medium were selected. Such strains possessed decreased affinity of alcohol oxidase (AOX) towards methanol: the KM values for AOX of wild type and mutant strains CA2 and CA4 are shown to be 0.62, 2.48 and 1.10 mM, respectively, whereas Vmax values are increased or remain unaffected. The mutant AOX alleles from H. polymorpha mutants CA2 and CA4 were isolated and sequenced. Several point mutations in the AOX gene, mostly different between the two mutant alleles, have been identified. Mutant AOX forms were isolated and purified, and some of their biochemical properties were studied. An amperometric biosensor based on the mutated form of AOX from the strain CA2 was constructed and revealed an extended linear response to the target analytes, ethanol and formaldehyde, as compared to the sensor based on the native AOX. Conclusion The described selection methodology opens up the possibility of isolating modified forms of AOX with further decreased affinity toward substrates without reduction of the maximal velocity of reaction. It can help in creation of improved ethanol biosensors with a prolonged linear response towards ethanol in real samples of wines, beers or fermentation liquids. PMID:17567895

Preparation of carbon paste electrodes including poly(styrene) attached glycine-Pt(IV) for amperometric detection of glucose.

PubMed

Dönmez, Soner; Arslan, Fatma; Sarı, Nurşen; Kurnaz Yetim, Nurdan; Arslan, Halit

2014-04-15

In this study, a novel carbon paste electrode that is sensitive to glucose was prepared using the nanoparticles modified (4-Formyl-3-methoxyphenoxymethyl) with polystyren (FMPS) with L-Glycine-Pt(IV) complexes. Polymeric nanoparticles having Pt(IV) ion were prepared from (4-Formyl-3-methoxyphenoxymethyl) polystyren, glycine and PtCl4 by template method. Glucose oxidase enzyme was immobilized to a modified carbon paste electrode (MCPE) by cross-linking with glutaraldehyde. Determination of glucose was carried out by oxidation of enzymatically produced H2O2 at 0.5 V vs. Ag/AgCl. Effects of pH and temperature were investigated, and optimum parameters were found to be 8.0 and 55°C, respectively. Linear working range of the electrode was 5.0×10(-6)-1.0×10(-3) M, R(2)=0.997. Storage stability and operational stability of the enzyme electrode were also studied. Glucose biosensor gave perfect reproducible results after 10 measurements with 2.3% relative standard deviation. Also, it had good storage stability (gave 53.57% of the initial amperometric response at the end of 33th day). © 2013 Published by Elsevier B.V.

Improvement of amperometric transducer selectivity using nanosized phenylenediamine films

NASA Astrophysics Data System (ADS)

Soldatkina, O. V.; Kucherenko, I. S.; Pyeshkova, V. M.; Alekseev, S. A.; Soldatkin, O. O.; Dzyadevych, S. V.

2017-11-01

In this work, we studied the conditions of deposition of a semipermeable polyphenylenediamine (PPD)-based membrane on amperometric disk platinum electrodes. Restricting an access of interfering substances to the electrode surface, the membrane prevents their impact on the sensor operation. Two methods of membrane deposition by electropolymerization were compared—at varying potential (cyclic voltammetry) and at constant potential. The cyclic voltammetry was shown to be easier in performing and providing better properties of the membrane. The dependence of PPD membrane effectiveness on the number of cyclic voltammograms and phenylenediamine concentration was analyzed. It was shown that the impact of interfering substances (ascorbic acid, dopamine, cysteine, uric acid) on sensor operation could be completely avoided using three cyclic voltammograms in 30 mM phenylenediamine. On the other hand, when working with diluted samples, i.e., at lower concentrations of electroactive substances, it is reasonable to decrease the phenylenediamine concentration to 5 mM, which would result in a higher sensitivity of transducers to hydrogen peroxide due to a thinner PPD layer. The PPD membrane was tested during continuous operation and at 8-day storage and turned out to be efficient in sensor and biosensors.

AMPEROMETRIC MICROBIAL BIOSENSOR FOR DIRECT DETERMINATION OF ORGANOPHOSPHATE NERVE AGENTS USING RECOMBINANT MORAXELLA SP. WITH SURFACE EXPRESSED ORGANOPHOSPHORUS HYDROLASE. (R828160)

EPA Science Inventory

The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...

Bendable Electro-chemical Lactate Sensor Printed with Silver Nano-particles

NASA Astrophysics Data System (ADS)

Abrar, Md Abu; Dong, Yue; Lee, Paul Kyuheon; Kim, Woo Soo

2016-07-01

Here we report a flexible amperometric lactate biosensor using silver nanoparticle based conductive electrode. Mechanically bendable cross-serpentine-shaped silver electrode is generated on flexible substrate for the mechanical durability such as bending. The biosensor is designed and fabricated by modifying silver electrode with lactate oxidase immobilized by bovine serum albumin. The in-sensor pseudo Ag/AgCl reference electrode is fabricated by chloridization of silver electrode, which evinced its long-term potential stability against a standard commercial Ag/AgCl reference electrode. The amperometric response of the sensor shows linear dependence with lactate concentration of 1~25 mM/L. Anionic selectivity is achieved by using drop-casted Nafion coated on silver electrode against anionic interferences such as ascorbate. This non-invasive electrochemical lactate sensor also demonstrates excellent resiliency against mechanical deformation and temperature fluctuation which leads the possibility of using it on human epidermis for continuous measurement of lactate from sweat. Near field communication based wireless data transmission is demonstrated to reflect a practical approach of the sensor to measure lactate concentration portably using human perspiration.

Bendable Electro-chemical Lactate Sensor Printed with Silver Nano-particles

PubMed Central

Abrar, Md Abu; Dong, Yue; Lee, Paul Kyuheon; Kim, Woo Soo

2016-01-01

Here we report a flexible amperometric lactate biosensor using silver nanoparticle based conductive electrode. Mechanically bendable cross-serpentine-shaped silver electrode is generated on flexible substrate for the mechanical durability such as bending. The biosensor is designed and fabricated by modifying silver electrode with lactate oxidase immobilized by bovine serum albumin. The in-sensor pseudo Ag/AgCl reference electrode is fabricated by chloridization of silver electrode, which evinced its long-term potential stability against a standard commercial Ag/AgCl reference electrode. The amperometric response of the sensor shows linear dependence with lactate concentration of 1~25 mM/L. Anionic selectivity is achieved by using drop-casted Nafion coated on silver electrode against anionic interferences such as ascorbate. This non-invasive electrochemical lactate sensor also demonstrates excellent resiliency against mechanical deformation and temperature fluctuation which leads the possibility of using it on human epidermis for continuous measurement of lactate from sweat. Near field communication based wireless data transmission is demonstrated to reflect a practical approach of the sensor to measure lactate concentration portably using human perspiration. PMID:27465437

Direct electrochemistry of cytochrome c immobilized on titanium nitride/multi-walled carbon nanotube composite for amperometric nitrite biosensor.

PubMed

Haldorai, Yuvaraj; Hwang, Seung-Kyu; Gopalan, Anantha-Iyengar; Huh, Yun Suk; Han, Young-Kyu; Voit, Walter; Sai-Anand, Gopalan; Lee, Kwang-Pill

2016-05-15

In this report, titanium nitride (TiN) nanoparticles decorated multi-walled carbon nanotube (MWCNTs) nanocomposite is fabricated via a two-step process. These two steps involve the decoration of titanium dioxide nanoparticles onto the MWCNTs surface and a subsequent thermal nitridation. Transmission electron microscopy shows that TiN nanoparticles with a mean diameter of ≤ 20 nm are homogeneously dispersed onto the MWCNTs surface. Direct electrochemistry and electrocatalysis of cytochrome c immobilized on the MWCNTs-TiN composite modified on a glassy carbon electrode for nitrite sensing are investigated. Under optimum conditions, the current response is linear to its concentration from 1 µM to 2000 µM with a sensitivity of 121.5 µA µM(-1)cm(-2) and a low detection limit of 0.0014 µM. The proposed electrode shows good reproducibility and long-term stability. The applicability of the as-prepared biosensor is validated by the successful detection of nitrite in tap and sea water samples. Copyright © 2015 Elsevier B.V. All rights reserved.

CdS quantum dots modified CuO inverse opal electrodes for ultrasensitive electrochemical and photoelectrochemical biosensor

PubMed Central

Xia, Lei; Xu, Lin; Song, Jian; Xu, Ru; Liu, Dali; Dong, Biao; Song, Hongwei

2015-01-01

The CuO inverse opal photonic crystals (IOPCs) were synthesized by the sol-gel method and modified with CdS quantum dots by successive ionic layer adsorption and reaction (SILAR). CdS QDs modified CuO IOPCs FTO electrodes of different SILAR cycles were fabricated and their electrochemical properties were studied by cyclic voltammetry (CV) and chronoamperometry (I–t). Structure and morphology of the samples were characterized by transmission electron microscopy (TEM), scanning electron microscopy (SEM), high-resolution TEM (HRTEM), Energy-dispersive X-ray analysis (EDX) and X-ray diffraction pattern (XRD). The result indicated that the structure of IOPCs and loading of CdS QDs could greatly improve the electrochemical properties. Three SILAR cycles of CdS QDs sensitization was the optimum condition for preparing electrodes, it exhibited a sensitivity of 4345 μA mM-1 cm-2 to glucose with a 0.15 μM detection limit (S/N= 3) and a linear range from 0.15 μM to 0.5 mM under a working potential of +0.7 V. It also showed strong stability, good reproducibility, excellent selectivity and fast amperometric response. This work provides a promising approach for realizing excellent photoelectrochemical nonenzymatic glucose biosensor of similar composite structure. PMID:26042520

Single-Step Incubation Determination of miRNAs in Cancer Cells Using an Amperometric Biosensor Based on Competitive Hybridization onto Magnetic Beads.

PubMed

Vargas, Eva; Povedano, Eloy; Montiel, Víctor Ruiz-Valdepeñas; Torrente-Rodríguez, Rebeca M; Zouari, Mohamed; Montoya, Juan José; Raouafi, Noureddine; Campuzano, Susana; Pingarrón, José M

2018-03-15

This work reports an amperometric biosensor for the determination of miRNA-21, a relevant oncogene. The methodology involves a competitive DNA-target miRNA hybridization assay performed on the surface of magnetic microbeads (MBs) and amperometric transduction at screen-printed carbon electrodes (SPCEs). The target miRNA competes with a synthetic fluorescein isothiocyanate (FITC)-modified miRNA with an identical sequence for hybridization with a biotinylated and complementary DNA probe (b-Cp) immobilized on the surface of streptavidin-modified MBs (b-Cp-MBs). Upon labeling, the FITC-modified miRNA attached to the MBs with horseradish peroxidase (HRP)-conjugated anti-FITC Fab fragments and magnetic capturing of the MBs onto the working electrode surface of SPCEs. The cathodic current measured at -0.20 V (versus the Ag pseudo-reference electrode) was demonstrated to be inversely proportional to the concentration of the target miRNA. This convenient biosensing method provided a linear range between 0.7 and 10.0 nM and a limit of detection (LOD) of 0.2 nM (5 fmol in 25 μL of sample) for the synthetic target miRNA without any amplification step. An acceptable selectivity towards single-base mismatched oligonucleotides, a high storage stability of the b-Cp-MBs, and usefulness for the accurate determination of miRNA-21 in raw total RNA (RNA t ) extracted from breast cancer cells (MCF-7) were demonstrated.

Sensitive electrochemical detection of NADH and ethanol at low potential based on pyrocatechol violet electrodeposited on single walled carbon nanotubes-modified pencil graphite electrode.

PubMed

Zhu, Jun; Wu, Xiao-Yan; Shan, Dan; Yuan, Pei-Xin; Zhang, Xue-Ji

2014-12-01

In this work, the electrodeposition of pyrocatechol violet (PCV) was initially investigated by the electrochemical surface plasmon resonance (ESPR) technique. Subsequently, PCV was used as redox-mediator and was electrodeposited on the surface of pencil graphite electrode (PGE) modified with single-wall carbon nanotubes (SWCNTs). Owing to the remarkable synergistic effect of SWCNTs and PCV, PGE/SWCNTs/PCV exhibited excellent electrocatalytic activity towards dihydronicotinamide adenine dinucleotide (NADH) oxidation at low potential (0.2V vs. SCE) with fast amperometric response (<10s), broad linear range (1.3-280 μM), good sensitivity (146.2 μA mM(-1)cm(-2)) and low detection limit (1.3 μM) at signal-to-noise ratio of 3. Thus, this PGE/SWCNTs/PCV could be further used to fabricate a sensitive and economic ethanol biosensor using alcohol dehydrogenase (ADH) via a glutaraldehyde/BSA cross-linking procedure. Copyright © 2014 Elsevier B.V. All rights reserved.

Fabrication and Evaluation of a Micro(Bio)Sensor Array Chip for Multiple Parallel Measurements of Important Cell Biomarkers

PubMed Central

Pemberton, Roy M.; Cox, Timothy; Tuffin, Rachel; Drago, Guido A.; Griffiths, John; Pittson, Robin; Johnson, Graham; Xu, Jinsheng; Sage, Ian C.; Davies, Rhodri; Jackson, Simon K.; Kenna, Gerry; Luxton, Richard; Hart, John P.

2014-01-01

This report describes the design and development of an integrated electrochemical cell culture monitoring system, based on enzyme-biosensors and chemical sensors, for monitoring indicators of mammalian cell metabolic status. MEMS technology was used to fabricate a microwell-format silicon platform including a thermometer, onto which chemical sensors (pH, O2) and screen-printed biosensors (glucose, lactate), were grafted/deposited. Microwells were formed over the fabricated sensors to give 5-well sensor strips which were interfaced with a multipotentiostat via a bespoke connector box interface. The operation of each sensor/biosensor type was examined individually, and examples of operating devices in five microwells in parallel, in either potentiometric (pH sensing) or amperometric (glucose biosensing) mode are shown. The performance characteristics of the sensors/biosensors indicate that the system could readily be applied to cell culture/toxicity studies. PMID:25360580

Utilization of Diamine Oxidase Enzyme from Mung Bean Sprouts (Vigna radiata L) for Histamine biosensors

NASA Astrophysics Data System (ADS)

Karim, Abdul; Wahab, A. W.; Raya, I.; Natsir, H.; Arif, A. R.

2018-03-01

This research is aimed to utilize the diamine oxidase enzyme (DAO) which isolated from mung bean sprouts (Vigna radiata L) to develop histamine biosensors based on electode enzyme with the amperometric method (cyclic voltammetry).The DAO enzyme is trapped inside the membrane of chitin-cellulose acetate 2:1 and glutaraldehyde which super imposed on a Pt electrode. Histamine will be oxidized by DAO enzyme to produce aldehydes and H2O2 that acting as electron transfer mediators.The performance of biosensors will be measured at various concentrations of glutaraldehyde, temperature changes and different range of pH. Recently, it has been found that the optimal conditions obtained from the paramaters as follows; at 25% of glutaraldehyde, temperature of 37°C and pH of 7.4. Eventually, the results provided an expectation for applying histamine biosensors in determining the freshness and safety of fish specifically skombroidae families.

Nano interfaced biosensor for detection of choline in triple negative breast cancer cells.

PubMed

Thiagarajan, Vignesh; Madhurantakam, Sasya; Sethuraman, Swaminathan; Balaguru Rayappan, John Bosco; Maheswari Krishnan, Uma

2016-01-15

Choline, a type of Vitamin B, is an important nutrient in the human body and is involved in key metabolic pathways. Abnormal levels of choline leads to diseased conditions. The levels of choline and its associated compounds are found to be elevated in triple negative breast cancer (TNBC) patients. The choline level ranges from 0.4 to 4.9mmol/kg in TNBC. Thus the detection of choline levels in cells can aid in diagnosing breast cancer. The present work aims to develop a nano-interfaced electrochemical biosensor for the rapid detection of choline in cancer cells. For electrochemical detection, glassy carbon electrode coated with a zinc oxide nano-interface was used as the working electrode. Zinc oxide synthesized by hydrothermal method was characterized using SEM and XRD. The choline oxidase (ChOx) enzyme was immobilized on the nano-interface by drop-casting. Choline oxidase (ChOx) converts choline to betaine and H2O2 in the presence of oxygen. The H2O2 produced was determined amperometrically. The amount of H2O2 produced is directly proportional to concentration of choline present. The sensitivity, selectivity, stability and concentration studies were carried out and quantification of choline in TNBC was also carried out. The results demonstrate that this biosensor has the potential to be developed as a clinical tool for breast cancer detection. Copyright © 2015 Elsevier Inc. All rights reserved.

Disposable Amperometric Polymerase Chain Reaction-Free Biosensor for Direct Detection of Adulteration with Horsemeat in Raw Lysates Targeting Mitochondrial DNA.

PubMed

Ruiz-Valdepeñas Montiel, Víctor; Gutiérrez, María L; Torrente-Rodríguez, Rebeca M; Povedano, Eloy; Vargas, Eva; Reviejo, Á Julio; Linacero, Rosario; Gallego, Francisco J; Campuzano, Susana; Pingarrón, José M

2017-09-05

A novel electrochemical disposable nucleic acid biosensor for simple, rapid, and specific detection of adulterations with horsemeat is reported in this work. The biosensing platform involves immobilization of a 40-mer RNA probe specific for a characteristic fragment of the mitochondrial DNA D-loop region of horse onto the surface of magnetic microcarriers. In addition, signal amplification was accomplished by using a commercial antibody specific to RNA/DNA duplexes and a bacterial protein conjugated with a horseradish peroxidase homopolymer (ProtA-HRP40). Amperometric detection at -0.20 V vs Ag pseudoreference electrode was carried out at disposable screen-printed carbon electrodes. The methodology achieved a limit of detection (LOD) of 0.12 pM (3.0 attomoles) for the synthetic target and showed ability to discriminate between raw beef and horsemeat using just 50 ng of total extracted mitochondrial DNA (∼16 660 bp in length) without previous fragmentation. The biosensor also allowed discrimination between 100% raw beef and beef meat samples spiked with only 0.5% (w/w) horse meat (levels established by the European Commission) using raw mitochondrial lysates without DNA extraction or polymerase chain reaction (PCR) amplification in just 75 min. These interesting features made the developed methodology an extremely interesting tool for beef meat screening, and it can be easily adapted to the determination of other meat adulterations by selection of the appropriate specific fragments of the mitochondrial DNA region and capture probes.

A Multi-Technique Reconfigurable Electrochemical Biosensor: Enabling Personal Health Monitoring in Mobile Devices.

PubMed

Sun, Alexander; Venkatesh, A G; Hall, Drew A

2016-10-01

This paper describes the design and characterization of a reconfigurable, multi-technique electrochemical biosensor designed for direct integration into smartphone and wearable technologies to enable remote and accurate personal health monitoring. By repurposing components from one mode to the next, the biosensor's potentiostat is able reconfigure itself into three different measurements modes to perform amperometric, potentiometric, and impedance spectroscopic tests all with minimal redundant devices. A [Formula: see text] PCB prototype of the module was developed with discrete components and tested using Google's Project Ara modular smartphone. The amperometric mode has a ±1 nA to [Formula: see text] measurement range. When used to detect pH, the potentiometric mode achieves a resolution of < 0.08 pH units. In impedance measurement mode, the device can measure 50 Ω-10 [Formula: see text] and has been shown to have of phase error. This prototype was used to perform several point-of-care health tracking assays suitable for use with mobile devices: 1) Blood glucose tests were conducted and shown to cover the diagnostic range for Diabetic patients (  ∼  200 mg/dL). 2) Lactoferrin, a biomarker for urinary tract infections, was detected with a limit of detection of approximately 1 ng/mL. 3) pH tests of sweat were conducted to track dehydration during exercise. 4) EIS was used to determine the concentration of NeutrAvidin via a label-free assay.

Development of an amperometric sulfite biosensor based on SO(x)/PBNPs/PPY modified ITO electrode.

PubMed

Rawal, Rachna; Pundir, C S

2012-11-01

A sulfite oxidase (SO(x)) (EC 1.8.3.1) purified from Syzygium cumini leaves was immobilized onto prussian blue nanoparticles/polypyrrole composite (PBNPs/PPY) electrodeposited onto the surface of indium tin oxide (ITO) electrode. An amperometric sulfite biosensor was fabricated using SO(x)/PBNPs/PPY/ITO electrode as working electrode, Ag/AgCl as standard and Pt wire as auxiliary electrode connected through a potentiostat. The working electrode was characterized by Fourier transform infrared (FTIR) spectroscopy, cyclic voltammetry (CV), scanning electron microscopy (SEM) and electrochemical impedance spectroscopy (EIS) before and after immobilization of SO(x). The biosensor showed optimum response within 2s, when operated at 20 mV s⁻¹ in 0.1M Tris-HCl buffer, pH 8.5 and at 35 °C. Linear range and minimum detection limit were 0.5-1000 μM and 0.12 μM (S/N=3) respectively. There was good correlation (r=0.99) between red wine samples sulfite value by standard DTNB method and the present method. The sensor was evaluated with 97% recovery of added sulfite in red wine samples and 2.2% and 4.3% within and between batch coefficients of variation respectively. The sensor was employed for determination of sulfite level in red and white wine samples. The enzyme electrode was used 200 times over a period of 3 months when stored at 4 °C. Copyright © 2012 Elsevier B.V. All rights reserved.

Protein-mimicking nanowire-inspired electro-catalytic biosensor for probing acetylcholinesterase activity and its inhibitors.

PubMed

Zhang, Qingqing; Hu, Yufang; Wu, Di; Ma, Shaohua; Wang, Jiao; Rao, Jiajia; Xu, Lihua; Xu, Huan; Shao, Huili; Guo, Zhiyong; Wang, Sui

2018-06-01

A highly sensitive electrochemical biosensor based on the synthetized L-Cysteine-Ag(I) coordination polymer (L-Cys-Ag(I) CP), which looks like a protein-mimicking nanowire, was constructed to detect acetylcholinesterase (AChE) activity and screen its inhibitors. This sensing strategy involves the reaction of acetylcholine chloride (ACh) with acetylcholinesterase (AChE) to form choline that is in turn catalytically oxidized by choline oxidase (ChOx) to produce hydrogen peroxide (H 2 O 2 ), thus L-Cys-Ag(I) CP possesses the electro-catalytic property to H 2 O 2 reduction. Herein, the protein-mimicking nanowire-based platform was capable of investigating successive of H 2 O 2 effectively by amperometric i-t (current-time) response, and was further applied for the turn-on electrochemical detection of AChE activity. The proposed sensor is highly sensitive (limit of detection is 0.0006 U/L) and is feasible for screening inhibitors of AChE. The model for AChE inhibition was further established and two traditional AChE inhibitors (donepezil and tacrine) were employed to verify the feasibility of the system. The IC 5 0 of donepezil and tacrine were estimated to be 1.4 nM and 3.5 nM, respectively. The developed protocol provides a new and promising platform for probing AChE activity and screening its inhibitors with low cost, high sensitivity and selectivity. Copyright © 2018 Elsevier B.V. All rights reserved.

Simultaneous detection of creatine and creatinine using a sequential injection analysis/biosensor system.

PubMed

Stefan-van Staden, Raluca-Ioana; Bokretsion, Rahel Girmai; van Staden, Jacobus F; Aboul-Enein, Hassan Y

2006-01-01

Carbon paste based biosensors for the determination of creatine and creatinine have been integrated into a sequential injection system. Applying the multi-enzyme sequence of creatininase (CA), and/or creatinase (CI) and sarcosine oxidase (SO), hydrogen peroxide has been detected amperometrically. The linear concentration ranges are of pmol/L to nmol/L magnitude, with very low limits of detection. The proposed SIA system can be utilized reliably for the on-line simultaneous detection of creatine and creatinine in pharmaceutical products, as well as in serum samples, with a rate of 34 samples per hour and RSD values better than 0.16% (n=10).

Solution of non-steady-state substrate concentration in the action of biosensor response at mixed enzyme kinetics

NASA Astrophysics Data System (ADS)

Senthamarai, R.; Jana Ranjani, R.

2018-04-01

In this paper, a mathematical model of an amperometric biosensor at mixed enzyme kinetics and diffusion limitation in the case of substrate inhibition has been developed. The model is based on time dependent reaction diffusion equation containing a non -linear term related to non -Michaelis - Menten kinetics of the enzymatic reaction. Solution for the concentration of the substrate has been derived for all values of parameters using the homotopy perturbation method. All the approximate analytic expressions of substrate concentration are compared with simulation results using Scilab/Matlab program. Finally, we have given a satisfactory agreement between them.

Construction of an amperometric ascorbate biosensor using epoxy resin membrane bound Lagenaria siceraria fruit ascorbate oxidase.

PubMed

Pundir, C S; Chauhan, Nidhi; Jyoti

2011-06-01

Ascorbate oxidase purified from Lagenaria siceraria fruit was immobilized onto epoxy resin "Araldite" membrane with 79.4% retention of initial activity of free enzyme. The biosensor showed optimum response within 15s at pH 5.8 and 35°C, which was directly proportional to ascorbate concentration ranging from 1-100μM. There was a good correlation (R(2) = 0.99) between serum ascorbic acid values by standard enzymic colorimetric method and the present method. The enzyme electrode was used for 200 times without considerable loss of activity during the span of 90 days when stored at 4°C.

Immobilization of Glucose Oxidase on a Carbon Nanotubes/Dendrimer-Ferrocene Modified Electrode for Reagentless Glucose Biosensing.

PubMed

Zhou, Juan; Li, Huan; Yang, Huasong; Cheng, Hui; Lai, Guosong

2017-01-01

Ferrocene-grafted dendrimer was covalently linked to the surface of a carbon nanotubes (CNTs)-chitosan (CS) nanocomposite modified electrode for immobilizing high-content glucose oxidase (GOx), which resulted in the successful development a novel reagentless glucose biosensor. Electrochemical impedance spectroscopy, cyclic voltammetry, and amperometry were used to characterize the preparation process and the enzymatically catalytic response of this biosensor. Due to the excellent electron transfer acceleration of the CNTs and the high-content loading of the GOx biomolecule and ferrocene mediator on the electrode matrix, this biosensor showed excellent analytical performance such as fast response time less than 10 s, wide linear range from 0.02 to 2.91 mM and low detection limit down to 7.5 μM as well as satisfactory stability and reproducibility toward the amperometric glucose determination. In addition, satisfactory result was obtained when it was used for the glucose measurements in human blood samples. Thus this biosensor provides great potentials for practical applications.

On-line removal of redox-active interferents by a porous electrode before amperometric blood glucose determination.

PubMed

Deng, Chunyan; Peng, Yong; Su, Lei; Liu, You-Nian; Zhou, Feimeng

2012-03-16

A porous reticulated vitreous carbon (RVC) electrode and a disk electrode coupled in tandem in an electrochemical flow cell has been used for electrolytic removal of interferents before amperometric glucose detection. The electrolytic efficiency at the upstream RVC electrode is 100% at a flow rate of 0.1 mL min(-1) or lower. Potential interferents such as acetaminophen, ascorbic acid, and uric acid can be completely eliminated by electrolysis at the RVC electrode. A mixed monolayer comprising glucose oxidase (GOD) and ferrocenyl-1-undecanethiol preformed at the downstream gold disk electrode was used as a mediator-based amperometric glucose sensor. The dependence of the amperometric current on the glucose concentration exhibits good linearity across over three orders of magnitude. The glucose measurements were also found to be reproducible (RSD<3.5%) and accurate. Unlike the chemiluminescence method, this device obviates the use of carcinogenic substrates and the glucose sensor performance is independent of the oxygen present in sample. On the basis that the RVC electrode requires minimal cleanup and the GOD-modified electrode remains stable for a week, the electrochemical flow cell should be amenable for automated on-line removal of redox interferents for other types of enzyme-based biosensors. Copyright © 2012 Elsevier B.V. All rights reserved.

Bioelectrochemistry of heme peptide at seamless three-dimensional carbon nanotubes/graphene hybrid films for highly sensitive electrochemical biosensing.

PubMed

Komori, Kikuo; Terse-Thakoor, Trupti; Mulchandani, Ashok

2015-02-18

A seamless three-dimensional hybrid film consisting of carbon nanotubes grown at the graphene surface (CNTs/G) is a promising material for the application to highly sensitive enzyme-based electrochemical biosensors. The CNTs/G film was used as a conductive nanoscaffold for enzymes. The heme peptide (HP) was immobilized on the surface of the CNTs/G film for amperometric sensing of H2O2. Compared with flat graphene electrodes modified with HP, the catalytic current for H2O2 reduction at the HP-modified CNTs/G electrode increased due to the increase in the surface coverage of HP. In addition, microvoids in the CNTs/G film contributed to diffusion of H2O2 to modified HP, resulting in the enhancement of the catalytic cathodic currents. The kinetics of the direct electron transfer from the CNTs/G electrode to compound I and II of modified HP was also analyzed.

Modeling microelectrode biosensors: free-flow calibration can substantially underestimate tissue concentrations

PubMed Central

Wall, Mark J.

2016-01-01

Microelectrode amperometric biosensors are widely used to measure concentrations of analytes in solution and tissue including acetylcholine, adenosine, glucose, and glutamate. A great deal of experimental and modeling effort has been directed at quantifying the response of the biosensors themselves; however, the influence that the macroscopic tissue environment has on biosensor response has not been subjected to the same level of scrutiny. Here we identify an important issue in the way microelectrode biosensors are calibrated that is likely to have led to underestimations of analyte tissue concentrations. Concentration in tissue is typically determined by comparing the biosensor signal to that measured in free-flow calibration conditions. In a free-flow environment the concentration of the analyte at the outer surface of the biosensor can be considered constant. However, in tissue the analyte reaches the biosensor surface by diffusion through the extracellular space. Because the enzymes in the biosensor break down the analyte, a density gradient is set up resulting in a significantly lower concentration of analyte near the biosensor surface. This effect is compounded by the diminished volume fraction (porosity) and reduction in the diffusion coefficient due to obstructions (tortuosity) in tissue. We demonstrate this effect through modeling and experimentally verify our predictions in diffusive environments. NEW & NOTEWORTHY Microelectrode biosensors are typically calibrated in a free-flow environment where the concentrations at the biosensor surface are constant. However, when in tissue, the analyte reaches the biosensor via diffusion and so analyte breakdown by the biosensor results in a concentration gradient and consequently a lower concentration around the biosensor. This effect means that naive free-flow calibration will underestimate tissue concentration. We develop mathematical models to better quantify the discrepancy between the calibration and tissue environment and experimentally verify our key predictions. PMID:27927788

Modeling microelectrode biosensors: free-flow calibration can substantially underestimate tissue concentrations.

PubMed

Newton, Adam J H; Wall, Mark J; Richardson, Magnus J E

2017-03-01

Microelectrode amperometric biosensors are widely used to measure concentrations of analytes in solution and tissue including acetylcholine, adenosine, glucose, and glutamate. A great deal of experimental and modeling effort has been directed at quantifying the response of the biosensors themselves; however, the influence that the macroscopic tissue environment has on biosensor response has not been subjected to the same level of scrutiny. Here we identify an important issue in the way microelectrode biosensors are calibrated that is likely to have led to underestimations of analyte tissue concentrations. Concentration in tissue is typically determined by comparing the biosensor signal to that measured in free-flow calibration conditions. In a free-flow environment the concentration of the analyte at the outer surface of the biosensor can be considered constant. However, in tissue the analyte reaches the biosensor surface by diffusion through the extracellular space. Because the enzymes in the biosensor break down the analyte, a density gradient is set up resulting in a significantly lower concentration of analyte near the biosensor surface. This effect is compounded by the diminished volume fraction (porosity) and reduction in the diffusion coefficient due to obstructions (tortuosity) in tissue. We demonstrate this effect through modeling and experimentally verify our predictions in diffusive environments. NEW & NOTEWORTHY Microelectrode biosensors are typically calibrated in a free-flow environment where the concentrations at the biosensor surface are constant. However, when in tissue, the analyte reaches the biosensor via diffusion and so analyte breakdown by the biosensor results in a concentration gradient and consequently a lower concentration around the biosensor. This effect means that naive free-flow calibration will underestimate tissue concentration. We develop mathematical models to better quantify the discrepancy between the calibration and tissue environment and experimentally verify our key predictions. Copyright © 2017 the American Physiological Society.

Redox-active thionine-graphene oxide hybrid nanosheet: one-pot, rapid synthesis, and application as a sensing platform for uric acid.

PubMed

Sun, Zhoumin; Fu, Haiying; Deng, Liu; Wang, Jianxiu

2013-01-25

In this paper, we fabricate a sensitive and stable amperometric UA amperometric biosensor using nanobiocomposite derived from thionine modified graphene oxide in this study. A simple wet-chemical strategy for synthesis of thionine-graphene oxide hybrid nanosheets (T-GOs) through π-π stacking has been demonstrated. Various techniques, such as UV-vis absorption spectroscopy, X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), atomic force microscopy (AFM) and electrochemistry have been utilized to characterize the formation of the T-GOs. Due to the synergistic effect between thionine and graphene oxide, the nanosheets exhibited excellent performance toward H(2)O(2) reduction. The incorporation of thionine onto graphene oxide surface resulted in more than a twice increase in the amperometric response to H(2)O(2) of the thionine modified electrode. The as-formed T-GOs also served as a biocompatible matrix for enzyme assembly and a mediator to facilitate the electron transfer between the enzyme and the electrode. Using UOx as a model system, we have developed a simple and effective sensing platform for assay of uric acid at physiological levels. UA has been successfully detected at -0.1 V without any interference due to other electroactive compounds at physiological levels of glucose (5 mM), ascorbic acid (0.1 mM), noradrenalin (0.1 mM), and dopamine (0.1 mM). The response displays a good linear range from 0.02 to 4.5 mM with detection limit 7 μM. The application of this modified electrode in blood and urine UA exhibited a good performance. The robust and advanced hybrid materials might hold great promise in biosensing, energy conversion, and biomedical and electronic systems. Copyright © 2012 Elsevier B.V. All rights reserved.

Reagent-less amperometric glucose biosensor based on a graphite rod electrode layer-by-layer modified with 1,10-phenanthroline-5,6-dione and glucose oxidase.

PubMed

Kausaite-Minkstimiene, Asta; Simanaityte, Ruta; Ramanaviciene, Almira; Glumbokaite, Laura; Ramanavicius, Arunas

2017-08-15

A reagent-less amperometric glucose biosensor operating in not-stirred sample solution was developed. A working electrode of the designed biosensor was based on a graphite rod (GR) electrode, which was modified with 1,10-phenanthroline-5,6-dione (PD) and glucose oxidase (GOx). The PD and the GOx were layer-by-layer adsorbed on the GR electrode surface with subsequent drying followed by chemical cross-linking of the adsorbed GOx with glutaraldehyde (GA). Optimal preparation conditions of the working electrode (GR/PD/GOx) were achieved with 12.6μg and 0.24mg loading amount of PD and GOx, respectively and 25min lasting cross-linking of the GOx with GA. A current response to glucose of the GR/PD/GOx electrode was measured at +200mV potential vs Ag/AgCl reference electrode. Maximum current response was registered when the pH of the buffer solution was 6.0. The registered current response to glucose was linear in the concentration range of 0.1-76mmolL -1 (R 2 =0.9985) and a detection limit was 0.025mmolL -1 . The GR/PD/GOx electrode demonstrated good reproducibility and repeatability with the relative standard deviation of 6.2% and 1.8% (at 4.0mmolL -1 of glucose), respectively, high anti-interference ability to uric and ascorbic acids. It was highly selective to glucose and demonstrated good accuracy in the analysis of human serum samples. Copyright © 2017 Elsevier B.V. All rights reserved.

Ferrocene-functionalized 4-(2,5-Di(thiophen-2-yl)-1H-pyrrol-1-yl)aniline: a novel design in conducting polymer-based electrochemical biosensors.

PubMed

Ayranci, Rukiye; Demirkol, Dilek Odaci; Ak, Metin; Timur, Suna

2015-01-13

Herein, we report a novel ferrocenyldithiophosphonate functional conducting polymer and its use as an immobilization matrix in amperometric biosensor applications. Initially, 4-(2,5-di(thiophen-2-yl)-1H-pyrrol-1-yl)amidoferrocenyldithiophosphonate was synthesized and copolymerized with 4-(2,5-di(thiophen-2-yl)-1H-pyrrol-1-yl)benzenamine at graphite electrodes. The amino groups on the polymer were utilized for covalent attachment of the enzyme glucose oxidase. Besides, ferrocene on the backbone was used as a redox mediator during the electrochemical measurements. Prior to the analytical characterization, optimization studies were carried out. The changes in current signals at +0.45 V were proportional to glucose concentration from 0.5 to 5.0 mM. Finally, the resulting biosensor was applied for glucose analysis in real samples and the data were compared with the spectrophotometric Trinder method.

Ferrocene-Functionalized 4-(2,5-Di(thiophen-2-yl)-1H-pyrrol-1-yl)aniline: A Novel Design in Conducting Polymer-Based Electrochemical Biosensors

PubMed Central

Ayranci, Rukiye; Demirkol, Dilek Odaci; Ak, Metin; Timur, Suna

2015-01-01

Herein, we report a novel ferrocenyldithiophosphonate functional conducting polymer and its use as an immobilization matrix in amperometric biosensor applications. Initially, 4-(2,5-di(thiophen-2-yl)-1H-pyrrol-1-yl)amidoferrocenyldithiophosphonate was synthesized and copolymerized with 4-(2,5-di(thiophen-2-yl)-1H-pyrrol-1-yl)benzenamine at graphite electrodes. The amino groups on the polymer were utilized for covalent attachment of the enzyme glucose oxidase. Besides, ferrocene on the backbone was used as a redox mediator during the electrochemical measurements. Prior to the analytical characterization, optimization studies were carried out. The changes in current signals at +0.45 V were proportional to glucose concentration from 0.5 to 5.0 mM. Finally, the resulting biosensor was applied for glucose analysis in real samples and the data were compared with the spectrophotometric Trinder method. PMID:25591169

Electrochemical biosensor based on glucose oxidase encapsulated within enzymatically synthesized poly(1,10-phenanthroline-5,6-dione).

PubMed

Ciftci, Hakan; Oztekin, Yasemin; Tamer, Ugur; Ramanaviciene, Almira; Ramanavicius, Arunas

2014-11-01

This study is focused on the investigation of electrocatalytic effect of glucose oxidase (GOx) immobilized on the graphite rod (GR) electrode. The enzyme modified electrode was prepared by encapsulation of immobilized GOx within enzymatically formed poly(1,10-phenanthroline-5,6-dione) (pPD) film. The electrochemical responses of such enzymatic electrode (pPD/GOx/GR) vs. different glucose concentrations were examined chronoamperometrically in acetate-phosphate buffer solution (A-PBS), pH 6.0, under aerobic or anaerobic conditions. Amperometric signals of the pPD/GOx/GR electrode exhibited well-defined hyperbolic dependence upon glucose concentration. Amperometric signals at 100mM of glucose were 41.17 and 32.27 μA under aerobic and anaerobic conditions, respectively. Amperometric signals of the pPD/GOx/GR electrode decreased by 6% within seven days. The pPD/GOx/GR electrode showed excellent selectivity in the presence of dopamine and uric acid. Furthermore it had a good reproducibility and repeatability with standard deviation of 9.4% and 8.0%, respectively. Copyright © 2014 Elsevier B.V. All rights reserved.

A novel non-invasive electrochemical biosensing device for in situ determination of the alcohol content in blood by monitoring ethanol in sweat.

PubMed

Gamella, M; Campuzano, S; Manso, J; González de Rivera, G; López-Colino, F; Reviejo, A J; Pingarrón, J M

2014-01-02

A non-invasive, passive and simple to use skin surface based sensing device for determining the blood's ethanol content (BAC) by monitoring transdermal alcohol concentration (TAC) is designed and developed. The proposed prototype is based on bienzyme amperometric composite biosensors that are sensitive to the variation of ethanol concentration. The prototype correlates, through previous calibration set-up, the amperometric signal generated from ethanol in sweat with its content in blood in a short period of time. The characteristics of this sensor device permit determination of the ethanol concentration in isolated and in continuous form, giving information of the BAC of a subject either in a given moment or its evolution during long periods of time (8h). Moreover, as the measurements are performed in a biological fluid, the evaluated individual is not able to alter the result of the analysis. The maximum limit of ethanol in blood allowed by legislation is included within the linear range of the device (0.0005-0.6 g L(-1)). Moreover, the device shows higher sensitivity than the breathalyzers marketed at the moment, allowing the monitoring of the ethanol content in blood to be obtained just 5 min after ingestion of the alcoholic drink. The comparison of the obtained results using the proposed device in the analysis of 40 volunteers with those provided by the gas chromatographic reference method for determination of BAC pointed out that there were no significant differences between both methods. Copyright © 2013 Elsevier B.V. All rights reserved.

Alcohol oxidase protein mediated in-situ synthesized and stabilized gold nanoparticles for developing amperometric alcohol biosensor.

PubMed

Chinnadayyala, Somasekhar R; Santhosh, Mallesh; Singh, Naveen K; Goswami, Pranab

2015-07-15

A simple one step method for the alcohol oxidases (AOx) protein mediated synthesis of gold nano-particles (AuNPs) in alkaline (pH 8.5) condition with simultaneous stabilization of the nanoparticles on the AOx protein surface under native environment has been developed. The formation of the AOx conjugated AuNPs was confirmed by advanced analytical and spectroscopic techniques. The significant increase in zeta potential (ζ) value of -57mV for the synthesized AOx-AuNPs conjugate from the AOx (pI 4.5) protein (ζ, -30mV) implied good stability of the in-situ synthesized nano-conjugate. The AOx-AuNPs conjugate showed steady stability in alkaline (upto pH 8.5) and NaCl (up to 10(-1)M) solutions. The efficiency (Kcat/Km) of the AuNP conjugated AOx was increased by 18% from the free enzyme confirming the activating role of the surface stabilized AuNPs for the enzyme. The AuNPs-AOx conjugate was encapsulated with polyaniline (PANI) synthesized by oxidative polymerization of aniline using H2O2 generated in-situ from the AOx catalysed oxidation of alcohol. The PANI encapsulated AuNPs-AOx assembly was stabilized on a glassy carbon electrode (GCE) by chitosan-Nafion mixture and then utilized the fabricated bioelectrode for detection of alcohol amperometrically using H2O2 as redox indicator at +0.6V. The constructed biosensor showed high operational stability (6.3% loss after 25 measurements), wide linear detection range of 10µM-4.7mM (R(2)=0.9731), high sensitivity of 68.3±0.35µAmM(-1) and low detection limit of 7±0.027µM for ethanol. The fabricated bioelectrode was successfully used for the selective determination of alcohol in beverage samples. Copyright © 2015 Elsevier B.V. All rights reserved.

Stabilizing Acetylcholinesterase on Carbon Electrodes Using Peptide Nanotubes to Produce Effective Biosensors

DTIC Science & Technology

2012-03-22

of pesticide . Plans for the cleanup of nerve gas attacks involve hosing affected areas down with bleach and water, which may also lead to water...They have been widely used in agriculture as pesticides and are also used as deadly nerve agents in chemical weapons. Chromatography and...Amperometric Detection of Organophosphorus Pesticides and Nerve Agents ,” Electroanalysis 16, Nos. 1-2: 145-149 (2004). Norouzi, Parviz, Farnoush

Effect of Nanoparticles on Modified Screen Printed Inhibition Superoxide Dismutase Electrodes for Aluminum

PubMed Central

Barquero-Quirós, Miriam; Arcos-Martínez, María Julia

2016-01-01

A novel amperometric biosensor for the determination of Al(III) based on the inhibition of the enzyme superoxide dismutase has been developed. The oxidation signal of epinephrine substrate was affected by the presence of Al(III) ions leading to a decrease in its amperometric current. The immobilization of the enzyme was performed with glutaraldehyde on screen-printed carbon electrodes modifiedwith tetrathiofulvalene (TTF) and different types ofnanoparticles. Nanoparticles of gold, platinum, rhodium and palladium were deposited on screen printed carbon electrodes by means of two electrochemical procedures. Nanoparticles were characterized trough scanning electronic microscopy, X-rays fluorescence, and atomic force microscopy. Palladium nanoparticles showed lower atomic force microscopy parameters and higher slope of aluminum calibration curves and were selected to perform sensor validation. The developed biosensor has a detection limit of 2.0 ± 0.2 μM for Al(III), with a reproducibility of 7.9% (n = 5). Recovery of standard reference material spiked to buffer solution was 103.8% with a relative standard deviation of 4.8% (n = 5). Recovery of tap water spiked with the standard reference material was 100.5 with a relative standard deviation of 3.4% (n = 3). The study of interfering ions has also been carried out. PMID:27681735

One-step construction of reagentless biosensor based on chitosan-carbon nanotubes-nile blue-horseradish peroxidase biocomposite formed by electrodeposition.

PubMed

Xi, Fengna; Liu, Lijun; Chen, Zhichun; Lin, Xianfu

2009-05-15

A simple and controllable electrodeposition approach was established for one-step construction of novel reagentless biosensors by in situ formation of chitosan-carbon nanotubes-nile blue-horseradish peroxidase (CS-CNTs-NB-HRP) biocomposite film on electrode surface. The mediator effect of NB, conducting performance of CNTs and the biocompatible microenvironment of CS were combined by such one-step non-manual process. NB could interact with CNTs and resulted in good dispersion of CNTs-NB nanocomposites in aqueous solution. Cyclic voltammetry measurements demonstrated that electrons were efficiently shuttled between HRP and the electrode mediated by NB. The developed reagentless biosensor exhibited a fast amperometric response for the determination of H(2)O(2) and 95% of the steady-state current was obtained within 2s. The linear response of the reagentless biosensor for the determination of H(2)O(2) ranged from 1.0 x 10(-6) to 2.4 x 10(-4)mol l(-1) with a detection limit of 1.2 x 10(-7)mol l(-1). The biosensor exhibited high reproducibility and long-time storage stability. The as-prepared biosensor also showed effective anti-interference capability. The ease of the one-step non-manual technique and the promising feature of the biocomposite could serve as a versatile platform for fabricating electrochemical biosensors.

Ultrathin NiCo2O4 nanowalls supported on a 3D nanoporous gold coated needle for non-enzymatic amperometric sensing of glucose.

PubMed

Li, Weiwei; Qi, Hui; Wang, Baogang; Wang, Qiyu; Wei, Shuting; Zhang, Xiaolin; Wang, Ying; Zhang, Lei; Cui, Xiaoqiang

2018-01-24

A disposable needle-type of hybrid electrode was prepared from a core of stainless steel needle whose surface was modified with a 3D nanoporous gold/NiCo 2 O 4 nanowall hybrid structure for electrochemical non-enzymatic glucose detection. This hybrid electrode, best operated at 0.45 V (vs. SCE) in solutions of pH 13 has a linear response in the 0.01 to 21 mM glucose concentration range, a response time of <1 s, and a 1 μM detection limit (at an S/N ratio of 3). The remarkable enhancement compared to the solid gold/NiCo 2 O 4 and stainless steel/NiCo 2 O 4 hybrid electrodes in electrochemical performance is assumed to originate from the good electrical conductivity and large surface area of the hybrid electrode, which enhance the transport of mass and charge during electrochemical reactions. This biosensor was also applied to real sample analysis with little interferences. The electrode is disposable and considered to be a promising tool for non-enzymatic sensing of glucose in a variety of practical situations. Graphical abstract Ultrathin NiCo 2 O 4 nanowalls supported on nanoporous gold that is coated on a stainless steel needle was fabricated for sensitive non-enzymatic amperometric sensing of glucose.

Bienzyme bionanomultilayer electrode for glucose biosensing based on functional carbon nanotubes and sugar-lectin biospecific interaction.

PubMed

Chen, Huan; Xi, Fengna; Gao, Xia; Chen, Zhichun; Lin, Xianfu

2010-08-01

Bienzyme bionanomultilayer electrode for glucose biosensing was constructed based on functional carbon nanotubes and sugar-lectin biospecific interaction through layer-by-layer (LBL) assembly. After being functionalized by wrapping with polyelectrolyte, multiwalled carbon nanotubes (MCNTs) were water soluble and positively charged. MCNT-bienzyme bionanomultilayer electrode was then fabricated by LBL assembly of horseradish peroxidase (HRP) and glucose oxidase (GOD) on functional MCNT modified electrode. The attachment of the MCNT-bienzyme bionanomultilayer with the underlying electrode and each layer in the bionanomultilayer was based on reliably electrostatic or sugar-lectin biospecific interaction. The developed bienzyme biosensor exhibited fast amperometric response for the determination of glucose. The linear response of the developed biosensor for the determination of glucose ranged from 2.0 x 10(-6) to 1.7 x 10(-4) M with a detection limit of 2.5 x 10(-7) M. The biosensor can be used directly to determine glucose in serum. The construction of the bienzyme biosensor showed potential for the preparation of MCNT-enzyme nanocomposite with controllability and high performance. Copyright 2010 Elsevier Inc. All rights reserved.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cruz Vieira, I. da; Fatibello-Filho, O.

An amperometric biosensor for the determination of phenols is proposed using a crude extract of sweet potato (Ipomoea batatas (L.) Lam.) as an enzymatic source of polyphenol oxidase (PPO; tyrosinase; catechol oxidase; EC 1.14.18.1). The biosensor is constructed by the immobilization of sweet potato crude extract with glutaraldehyde and bovine serum albumin onto an oxygen membrane. This biosensor provides a linear response for catechol, pyrogallol, phenol and p-cresol in the concentration ranges of 2.0 x 10{sup -5} -4.3 x 10{sup -4} mol L{sup -1}, 2.0 x 10{sup -5} -4.3 x 10{sup -4} mol L{sup -1}, 2.0 x 10{sup -5} -4.5more » x 10{sup -4} mol L{sup -1} and 2.0 x 10{sup -5} -4.5 x 10{sup -4} mol L{sup -1}, respectively. The response time was about 3-5 min for the useful response range, and the lifetime of this electrode was excellent for fifteen days (over 220 determinations for each enzymatic membrane). Application of this biosensor for the determination of phenols in industrial wastewaters is presented.« less

Self-assembly of glucose oxidase on reduced graphene oxide-magnetic nanoparticles nanocomposite-based direct electrochemistry for reagentless glucose biosensor.

PubMed

Pakapongpan, Saithip; Poo-Arporn, Rungtiva P

2017-07-01

A novel approach of the immobilization of a highly selective and stable glucose biosensor based on direct electrochemistry was fabricated by a self-assembly of glucose oxidase (GOD) on reduced graphene oxide (RGO) covalently conjugated to magnetic nanoparticles (Fe 3 O 4 NPs) modified on a magnetic screen-printed electrode (MSPE). The RGO-Fe 3 O 4 nanocomposite has remarkable enhancement in large surface areas, is favorable environment for enzyme immobilization, facilitates electron transfer between enzymes and electrode surfaces and possesses superparamagnetism property. The morphology and electrochemical properties of RGO-Fe 3 O 4 /GOD were characterized by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, cyclic voltammetry (CV) and amperometry. The modified electrode was a fast, direct electron transfer with an apparent electron transfer rate constant (k s ) of 13.78s -1 . The proposed biosensor showed fast amperometric response (3s) to glucose with a wide linear range from 0.05 to 1mM, a low detection limit of 0.1μM at a signal to noise ratio of 3 (S/N=3) and good sensitivity (5.9μA/mM). The resulting biosensor has high stability, good reproducibility, excellent selectivity and successfully applied detection potential at -0.45V. This mediatorless glucose sensing used the advantages of covalent bonding and self-assembly as a new approach for immobilizing enzymes without any binder. It would be worth noting that it opens a new avenue for fabricating excellent electrochemical biosensors. This is a new approach that reporting the immobilization of glucose oxidase on reduced graphene oxide (RGO) covalently conjugated to magnetic nanoparticles (Fe 3 O 4 NPs) by electrostatic interaction and modified screen printed electrode. We propose the reagentless with fabrication method without binder and adhesive agents for immobilized enzyme. Fe 3 O 4 NPs increasing surface area to enhance the immobilization and prevent the leaching of enzymes at electrode surfaces by magnetic stickers which is improve the stability of the biosensor. Based on this synthesis technique, it is a good new strategy and simple used to fabrication of third-generation glucose biosensor and this nanocomposite could be used as a platform for disposable biosensor and biofuel cell applications. Copyright © 2017 Elsevier B.V. All rights reserved.

A novel H(2)O(2) amperometric biosensor based on gold nanoparticles/self-doped polyaniline nanofibers.

PubMed

Chen, Xiaojun; Chen, Zixuan; Zhu, Jinwei; Xu, Chenbin; Yan, Wei; Yao, Cheng

2011-10-01

A new kind of gold nanoparticles/self-doped polyaniline nanofibers (Au/SPAN) with grooves has been prepared for the immobilization of horseradish peroxidase (HRP) on the surface of glassy carbon electrode (GCE). The ratio of gold in the composite nanofibers was up to 64%, which could promote the conductivity and biocompatibility of SPAN and increase the immobilized amount of HRP molecules greatly. The electrode exhibits enhanced electrocatalytic activity in the reduction of H(2)O(2) in the presence of the mediator hydroquinone (HQ). The effects of concentration of HQ, solution pH and the working potential on the current response of the modified electrode toward H(2)O(2) were optimized to obtain the maximal sensitivity. The proposed biosensor exhibited a good linear response in the range from 10 to 2000 μM with a detection limit of 1.6 μM (S/N=3) under the optimum conditions. The response showed Michaelis-Menten behavior at larger H(2)O(2) concentrations, and the apparent Michaelis-Menten constant K(m) was estimated to be 2.21 mM. The detection of H(2)O(2) concentration in real sample showed acceptable accuracy with the traditional potassium permanganate titration. Copyright © 2011 Elsevier B.V. All rights reserved.

Development of amperometric lysine biosensors based on Au nanoparticles/multiwalled carbon nanotubes/polymers modified Au electrodes.

PubMed

Chauhan, Nidhi; Singh, Anamika; Narang, Jagriti; Dahiya, Swati; Pundir, C S

2012-11-07

The construction of two amperometric l-lysine biosensors is described in this study. The construction comprises the covalent immobilization of lysine oxidase (LOx) onto nanocomposite composed of gold nanoparticles (AuNPs) and carboxylated multiwalled carbon nanotubes (c-MWCNT), decorated on (i) polyaniline (PANI) and (ii) poly 1,2 diaminobenzene (DAB), electrodeposited on Au electrodes. The biosensors were characterized by scanning electron microscopy (SEM), Fourier transform infrared (FTIR) and electrochemical impedance spectroscopy (EIS) studies. The optimum response (current) was observed within 2 s at pH 7.0 and 25 °C for LOx/AuNPs/c-MWCNT/PANI/Au, and 4 s at pH 7.0 and 30 °C for LOx/AuNPs/c-MWCNT/DAB/Au electrodes. There was a linear relationship between current and lysine concentration ranging from 5.0 to 600 μM for LOx/AuNPs/c-MWCNT/PANI/Au with a detection limit of 5.0 μM, and 20 to 600 μM for the LOx/AuNPs/c-MWCNT/DAB/Au electrode with a detection limit of 20 μM. The PANI modified electrode was in good agreement with the standard HPLC method, with a better correlation (r = 0.992) compared to the DAB modified electrode (r = 0.986). These observations revealed that the PANI modified Au electrode was better than the DAB modified electrode, and hence it was employed for the determination of lysine in milk, pharmaceutical tablets and sera. The PANI modified electrode showed a half life of 120 days, compared to that of 90 days for the DAB modified electrode, after their 100 uses, when stored at 4 °C.

Enzyme-modified nanoporous gold-based electrochemical biosensors.

PubMed

Qiu, Huajun; Xue, Luyan; Ji, Guanglei; Zhou, Guiping; Huang, Xirong; Qu, Yinbo; Gao, Peiji

2009-06-15

On the basis of the unique physical and chemical properties of nanoporous gold (NPG), which was obtained simply by dealloying Ag from Au/Ag alloy, an attempt was made in the present study to develop NPG-based electrochemical biosensors. The NPG-modified glassy carbon electrode (NPG/GCE) exhibited high-electrocatalytic activity toward the oxidation of nicotinamide adenine dinucleotide (NADH) and hydrogen peroxide (H(2)O(2)), which resulted in a remarkable decrease in the overpotential of NADH and H(2)O(2) electro-oxidation when compared with the gold sheet electrode. The high density of edge-plane-like defective sites and large specific surface area of NPG should be responsible for the electrocatalytic behavior. Such electrocatalytic behavior of the NPG/GCE permitted effective low-potential amperometric biosensing of ethanol or glucose via the incorporation of alcohol dehydrogenase (ADH) or glucose oxidase (GOD) within the three-dimensional matrix of NPG. The ADH- and GOD-modified NPG-based biosensors showed good analytical performance for biosensing ethanol and glucose due to the clean, reproducible and uniformly distributed microstructure of NPG. The stabilization effect of NPG on the incorporated enzymes also made the constructed biosensors very stable. After 1 month storage at 4 degrees C, the ADH- and GOD-based biosensors lost only 5.0% and 4.2% of the original current response. All these indicated that NPG was a promising electrode material for biosensors construction.

Electrochemical Quantification of the Antioxidant Capacity of Medicinal Plants Using Biosensors

PubMed Central

Rodríguez-Sevilla, Erika; Ramírez-Silva, María-Teresa; Romero-Romo, Mario; Ibarra-Escutia, Pedro; Palomar-Pardavé, Manuel

2014-01-01

The working area of a screen-printed electrode, SPE, was modified with the enzyme tyrosinase (Tyr) using different immobilization methods, namely entrapment with water-soluble polyvinyl alcohol (PVA), cross-linking using glutaraldehyde (GA), and cross-linking using GA and human serum albumin (HSA); the resulting electrodes were termed SPE/Tyr/PVA, SPE/Tyr/GA and SPE/Tyr/HSA/GA, respectively. These biosensors were characterized by means of amperometry and EIS techniques. From amperometric evaluations, the apparent Michaelis-Menten constant, Km′, of each biosensor was evaluated while the respective charge transfer resistance, Rct, was assessed from impedance measurements. It was found that the SPE/Tyr/GA had the smallest Km′ (57 ± 7) μM and Rct values. This electrode also displayed both the lowest detection and quantification limits for catechol quantification. Using the SPE/Tyr/GA, the Trolox Equivalent Antioxidant Capacity (TEAC) was determined from infusions prepared with “mirto” (Salvia microphylla), “hHierba dulce” (Lippia dulcis) and “salve real” (Lippia alba), medicinal plants commonly used in Mexico. PMID:25111237

Electrochemical quantification of the antioxidant capacity of medicinal plants using biosensors.

PubMed

Rodríguez-Sevilla, Erika; Ramírez-Silva, María-Teresa; Romero-Romo, Mario; Ibarra-Escutia, Pedro; Palomar-Pardavé, Manuel

2014-08-08

The working area of a screen-printed electrode, SPE, was modified with the enzyme tyrosinase (Tyr) using different immobilization methods, namely entrapment with water-soluble polyvinyl alcohol (PVA), cross-linking using glutaraldehyde (GA), and cross-linking using GA and human serum albumin (HSA); the resulting electrodes were termed SPE/Tyr/PVA, SPE/Tyr/GA and SPE/Tyr/HSA/GA, respectively. These biosensors were characterized by means of amperometry and EIS techniques. From amperometric evaluations, the apparent Michaelis-Menten constant, Km', of each biosensor was evaluated while the respective charge transfer resistance, Rct, was assessed from impedance measurements. It was found that the SPE/Tyr/GA had the smallest Km' (57 ± 7) µM and Rct values. This electrode also displayed both the lowest detection and quantification limits for catechol quantification. Using the SPE/Tyr/GA, the Trolox Equivalent Antioxidant Capacity (TEAC) was determined from infusions prepared with "mirto" (Salvia microphylla), "hHierba dulce" (Lippia dulcis) and "salve real" (Lippia alba), medicinal plants commonly used in Mexico.

Recent advances in material science for developing enzyme electrodes.

PubMed

Sarma, Anil Kumar; Vatsyayan, Preety; Goswami, Pranab; Minteer, Shelley D

2009-04-15

The enzyme-modified electrode is the fundamental component of amperometric biosensors and biofuel cells. The selection of appropriate combinations of materials, such as: enzyme, electron transport mediator, binding and encapsulation materials, conductive support matrix and solid support, for construction of enzyme-modified electrodes governs the efficiency of the electrodes in terms of electron transfer kinetics, mass transport, stability, and reproducibility. This review investigates the varieties of materials that can be used for these purposes. Recent innovation in conductive electro-active polymers, functionalized polymers, biocompatible composite materials, composites of transition metal-based complexes and organometallic compounds, sol-gel and hydro-gel materials, nanomaterials, other nano-metal composites, and nano-metal oxides are reviewed and discussed here. In addition, the critical issues related to the construction of enzyme electrodes and their application for biosensor and biofuel cell applications are also highlighted in this article. Effort has been made to cover the recent literature on the advancement of materials sciences to develop enzyme electrodes and their potential applications for the construction of biosensors and biofuel cells.

A glucose biosensor based on direct electrochemistry of glucose oxidase immobilized on nitrogen-doped carbon nanotubes.

PubMed

Deng, Shengyuan; Jian, Guoqiang; Lei, Jianping; Hu, Zheng; Ju, Huangxian

2009-10-15

A novel biosensor for glucose was prepared by immobilizing glucose oxidase (GOx) on nitrogen-doped carbon nanotubes (CNx-MWNTs) modified electrode. The CNx-MWNTs membrane showed an excellent electrocatalytic activity toward the reduction of O(2) due to its diatomic side-on adsorption on CNx-MWNTs. The nitrogen doping accelerated the electron transfer from electrode surface to the immobilized GOx, leading to the direct electrochemistry of GOx. The biofunctional surface showed good biocompatibility, excellent electron-conductive network and large surface-to-volume ratio, which were characterized by scanning electron microscopy, contact angle and electrochemical impedance technique. The direct electron transfer of immobilized GOx led to stable amperometric biosensing for glucose with a linear range from 0.02 to 1.02 mM and a detection limit of 0.01 mM (S/N=3). These results indicated that CNx-MWNTs are good candidate material for construction of the third-generation enzyme biosensors based on the direct electrochemistry of immobilized enzymes.

A novel amperometric enzyme inhibition biosensor based on xanthine oxidase immobilised onto glassy carbon electrodes for bisphenol A determination.

PubMed

Ben Messaoud, Najib; Ghica, Mariana Emilia; Dridi, Cherif; Ben Ali, Mounir; Brett, Christopher M A

2018-07-01

A novel and simple biosensor for the determination of bisphenol A (BPA) based on xanthine oxidase (XOD) enzymatic inhibition has been developed. The biosensor was prepared from xanthine oxidase immobilised by crosslinking with glutaraldehyde, with hypoxanthine as enzyme substrate, and was successfully applied to the determination of BPA using fixed potential amperometry. Biosensor performance was optimised with respect to the applied potential, influence of pH of the electrolyte solution, XOD loading and the substrate concentration. The enzyme inhibition mechanism was evaluated from Cornish-Bowden plus Dixon plots and was found to be reversible and competitive with an apparent inhibition constant of 8.15 nM. Under optimised conditions, the determination of BPA can be achieved in the linear range up to 41 nM with a detection limit of 1.0 nM, which is equal to the lowest reported in the literature, with very good repeatability and reproducibility. The selectivity of the biosensor was evaluated by performing an interference study and found to be excellent; and stability was investigated. It was successfully applied to the detection of BPA in mineral water and in river water. Copyright © 2018 Elsevier B.V. All rights reserved.

Hydrogen peroxide biosensor based on a myoglobin/hydrophilic room temperature ionic liquid film.

PubMed

Safavi, Afsaneh; Farjami, Fatemeh

2010-07-01

The composite film based on Nafion and hydrophilic room temperature ionic liquid (RTIL) 1-butyl-3-methyl-imidazolium chloride ([bmim]Cl) was used as an immobilization matrix to entrap myoglobin (Mb). The study of ionic liquid (IL)-Mb interaction by ultraviolet-visible (UV-vis) spectroscopy showed that Mb retains its native conformation in the presence of IL. The immobilized Mb displayed a pair of well-defined cyclic voltammetric peaks with a formal potential (E(o)(')) of -0.35 V in a 0.1 M phosphate buffer solution (PBS) of pH 7.0. The immobilized Mb exhibited excellent electrocatalytic response to the reduction of hydrogen peroxide, based on which a mediator-free amperometric biosensor for hydrogen peroxide was designed. The linear range for the determination of hydrogen peroxide was from 1.0 to 180 microM with a detection limit of 0.14 microM at a signal/noise ratio of 3. The apparent Michaelis constant (K(m)(app)) for the electrocatalytic reaction was 22.6 microM. The stability, repeatability, and selectivity of the sensor were evaluated. The proposed biosensor has a lower detection limit than many other IL-heme protein-based biosensors and is free from common interference in hydrogen peroxide biosensors. 2010 Elsevier Inc. All rights reserved.

A novel amperometric biosensor based on artichoke (Cynara scolymus L.) tissue homogenate immobilized in gelatin for hydrogen peroxide detection.

PubMed

Oztürk, G; Ertaş, F N; Akyilmaz, E; Dinçkaya, E; Tural, H

2004-01-01

A biosensor for specific determination of hydrogen peroxide was developed by using homogenized artichoke (Cynara scolymus L.) tissue in combination with a dissolved oxygen probe and applied in determination of hydrogen peroxide in milk samples. Artichoke tissue, which has catalase activity, was immobilized with gelatine by means of glutaraldehyde and fixed on a pretreated teflon membrane. The electrode response was maximum when 0.05 M phosphate buffer was used at pH 7.0 and at 30 degrees C. Upon addition of hydrogen peroxide, the electrode gives a linear response in a concentration range of 5.0-50 x 10(-5) M with a response time of 3 min. The method was also applied to the determination of hydrogen peroxide in milk samples.

Immobilization techniques to avoid enzyme loss from oxidase-based biosensors: a one-year study.

PubMed

House, Jody L; Anderson, Ellen M; Ward, W Kenneth

2007-01-01

Continuous amperometric sensors that measure glucose or lactate require a stable sensitivity, and glutaraldehyde crosslinking has been used widely to avoid enzyme loss. Nonetheless, little data is published on the effectiveness of enzyme immobilization with glutaraldehyde. A combination of electrochemical testing and spectrophotometric assays was used to study the relationship between enzyme shedding and the fabrication procedure. In addition, we studied the relationship between the glutaraldehyde concentration and sensor performance over a period of one year. The enzyme immobilization process by glutaraldehyde crosslinking to glucose oxidase appears to require at least 24-hours at room temperature to reach completion. In addition, excess free glucose oxidase can be removed by soaking sensors in purified water for 20 minutes. Even with the addition of these steps, however, it appears that there is some free glucose oxidase entrapped within the enzyme layer which contributes to a decline in sensitivity over time. Although it reduces the ultimate sensitivity (probably via a change in the enzyme's natural conformation), glutaraldehyde concentration in the enzyme layer can be increased in order to minimize this instability. After exposure of oxidase enzymes to glutaraldehyde, effective crosslinking requires a rinse step and a 24-hour incubation step. In order to minimize the loss of sensor sensitivity over time, the glutaraldehyde concentration can be increased.

Amperometric glucose biosensor with remarkable acid stability based on glucose oxidase entrapped in colloidal gold-modified carbon ionic liquid electrode.

PubMed

Liu, Xiaoying; Zeng, Xiandong; Mai, Nannan; Liu, Yong; Kong, Bo; Li, Yonghong; Wei, Wanzhi; Luo, Shenglian

2010-08-15

A colloidal gold-modified carbon ionic liquid electrode was constructed by mixing colloidal gold-modified graphite powder with a solid room temperature ionic liquid n-octyl-pyridinium hexafluorophosphate (OPPF(6)). Glucose oxidase (GOD) was entrapped in this composite matrix and maintained its bioactivity well and displayed excellent stability. The effect conditions of pH, applied potential and GOD loading were examined. Especially, the glucose oxidase entrapped in this carbon ionic liquid electrode fully retained its activity upon stressing in strongly acidic conditions (pH 2.0) for over one hour. The proposed biosensor responds to glucose linearly over concentration range of 5.0x10(-6) to 1.2x10(-3) and 2.6x10(-3) to 1.3x10(-2) M, and the detection limit is 3.5x10(-6) M. The response time of the biosensor is fast (within 10s), and the life time is over two months. The effects of electroactive interferents, such as ascorbic acid, uric acid, can be significantly reduced by a Nafion film casting on the surface of resulting biosensor. Copyright 2010 Elsevier B.V. All rights reserved.

A disposable tear glucose biosensor--part 3: assessment of enzymatic specificity.

PubMed

Lan, Kenneth; McAferty, Kenyon; Shah, Pankti; Lieberman, Erica; Patel, Dharmendra R; Cook, Curtiss B; La Belle, Jeffrey T

2011-09-01

A concept for a tear glucose sensor based on amperometric measurement of enzymatic oxidation of glucose was previously presented, using glucose dehydrogenase flavin adenine dinucleotide (GDH-FAD) as the enzyme. Glucose dehydrogenase flavin adenine dinucleotide is further characterized in this article and evaluated for suitability in glucose-sensing applications in purified tear-like saline, with specific attention to the effect of interfering substances only. These interferents are specifically saccharides that could interact with the enzymatic activity seen in the sensor's performance. Bench top amperometric glucose assays were performed using an assay solution of GDH-FAD and ferricyanide redox mediator with samples of glucose, mannose, lactose, maltose, galactose, fructose, sucrose, and xylose at varying concentrations to evaluate specificity, linear dynamic range, signal size, and signal-to-noise ratio. A comparison study was done by substituting an equivalent activity unit concentration of glucose oxidase (GOx) for GDH-FAD. Glucose dehydrogenase flavin adenine dinucleotide was found to be more sensitive than GOx, producing larger oxidation currents than GOx on an identical glucose concentration gradient, and GDH-FAD exhibited larger slope response (-5.65 × 10(-7) versus -3.11 × 10(-7) A/mM), signal-to-noise ratio (18.04 versus 2.62), and linear dynamic range (0-30 versus 0-10 mM), and lower background signal (-7.12 versus -261.63 nA) than GOx under the same assay conditions. GDH-FAD responds equally to glucose and xylose but is otherwise specific for glucose. Glucose dehydrogenase flavin adenine dinucleotide compares favorably with GOx in many sensor-relevant attributes and may enable measurement of glucose concentrations both higher and lower than those measurable by GOx. GDH-FAD is a viable enzyme to use in the proposed amperometric tear glucose sensor system and perhaps also in detecting extreme hypoglycemia or hyperglycemia in blood. © 2011 Diabetes Technology Society.

Exploiting multi-function Metal-Organic Framework nanocomposite Ag@Zn-TSA as highly efficient immobilization matrixes for sensitive electrochemical biosensing.

PubMed

Dong, Sheying; Zhang, Dandan; Suo, Gaochao; Wei, Wenbo; Huang, Tinglin

2016-08-31

A novel multi-function Metal-Organic Framework composite Ag@Zn-TSA (zinc thiosalicylate, Zn(C7H4O2S), Zn-TSA) was synthesized as highly efficient immobilization matrixes of myoglobin (Mb)/glucose oxidase (GOx) for electrochemical biosensing. The electrochemical biosensors based on Ag@Zn-TSA composite and ionic liquid (IL) modified carbon paste electrode (CPE) were fabricated successfully. Furthermore, the properties of the sensors were discussed by cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and amperometric current-time curve, respectively. The results showed the proposed biosensors had wide linear response to hydrogen peroxide (H2O2) in the range of 0.3-20,000 μM, to nitrite (NO2(-)) for 1.3 μM-1660 μM and 2262 μM-1,33,000 μM, to glucose for 2.0-1022 μM, with a low detection limit of 0.08 μM for H2O2, 0.5 μM for NO2(-), 0.8 μM for glucose. The values of the apparent heterogeneous electron transfer rate constant (ks) for Mb and GOx were estimated as 2.05 s(-1) and 2.45 s(-1), respectively. Thus, Ag@Zn-TSA was a kind of ideal material as highly efficient immobilization matrixes for sensitive electrochemical biosensing. In addition, this work indicated that MOF nanocomposite had a great potential for constructing wide range of sensing interface. Copyright © 2016 Elsevier B.V. All rights reserved.

Graphene-metallic nanocomposites as modifiers in electrochemical glucose biosensor transducers

NASA Astrophysics Data System (ADS)

Altuntas, Derya Bal; Tepeli, Yudum; Anik, Ulku

2016-09-01

Graphene sheets and three different graphene-metallic nanocomposites including graphene-copper (graphene-Cu), graphene-nickel (graphene-Ni) and graphene-platinum (graphene-Pt) were prepared and characterized in the first place. Then the electrochemical performances of these nanocomposites were tested in glucose biosensor transducers, which were formed by combining these metallic nanocomposites with glucose oxidase enzyme and glassy carbon paste electrode (GCPE). This is the first work that includes the usage of these graphene-Me nanocomposites as a part of glucose biosensor transducer. Fabricated amperometric biosensors linear ranges were obtained as follow: For the plain graphene, the linear range was found in the concentration range between 50 μM and 800 μM with the RSD (n = 3 for 50 μM glucose) value of 12.86% and LOD value of 7.2 μM. For graphene-Pt modified glucose biosensor, the linear range was between 10 μM and 600 μM with the RSD (n = 3 for 50 μM glucose) value of 3.45% and LOD value of 3.06 μM. In the case of graphene-Ni modified glucose biosensor, the values were 25 μM to 600 μM with the RSD (n = 3 for 50 μM glucose) value of 8.76% and LOD value of 24.71 μM and for graphene-Cu modified glucose biosensor linear range was 25 μM to 400 μM with the RSD (n = 3 for 50 μM glucose) value of 3.93% and LOD value of 2.87 μM.

Determination of uric acid level by polyaniline and poly (allylamine): Based biosensor

PubMed Central

Wathoni, Nasrul; Hasanah, Aliya Nur; Gozali, Dolih; Wahyuni, Yeni; Fauziah, Lia Layusa

2014-01-01

The uric acid biosensor has been much developed by immobilizing uricase enzyme into the membrane of conductive polymer and the membrane of polyelectrolyte such as polyaniline (PANI) and poly (allylamine) (PAA) respectively. The purpose of this research was to create a new amperometric uric acid biosensor by immobilization of uricase in combination between PANI and PAA membranes. The working electrode was Pt plate (0.5 mm). The auxiliary and the reference electrode were Pt wire 0.4 mm and Ag/AgCl respectively. Uricase, uric acid, PAA, pyrrole and glutaraldehyde were supplied from Sigma. All other chemical was obtained from Merck. The biosensor was created by immobilizing of uricase by a glutaraldehyde crosslinking procedure on PANI composite film on the surface of a platinum electrode while the polyelectrolyte layer of PAA were prepared via layer-by-layer assembly on the electrode, functioning as H2O2-selective film. Standard of deviation, coefficient of variation (CV) and coefficient of correlation (r) analysis were used in this study. The biosensor had a good linearity with a correlation coefficient of 0.993 and it could be used up to 27 times with the CV value of 3.97%. The presence of other compounds such as glucose and ascorbic acid gave 1.3 ± 1.13% and 3.27 ± 2.29% respectively on the interference effect toward the current response of uric acid biosensor. The polymer combination of PANI and PAA can be used as a selective matrix of uric acid biosensor. PMID:24696812

Immobilization of glucose oxidase into a nanoporous TiO₂ film layered on metallophthalocyanine modified vertically-aligned carbon nanotubes for efficient direct electron transfer.

PubMed

Cui, Hui-Fang; Zhang, Kuan; Zhang, Yong-Fang; Sun, Yu-Long; Wang, Jia; Zhang, Wei-De; Luong, John H T

2013-08-15

Glucose oxidase (GOD) was adsorbed into a nanoporous TiO₂ film layered on the surface of an iron phthalocyanine (FePc) vertically-aligned carbon nanotube (CNT) modified electrode. A Nafion film was then dropcast on the electrode's surface to improve operational and storage stabilities of the GOD-based electrode. Scanning electron microscopy (SEM) micrographs revealed the formation of FePc and nanoporous TiO₂ nanoparticles along the sidewall and the tip of CNTs. Cyclic voltammograms of the GOD electrode in neutral PBS exhibited a pair of well-defined redox peaks, attesting the direct electron transfer of GOD (FAD/FADH₂) with the underlying electrode. The potential of glucose electro-oxidation under nitrogen was ∼+0.12 V with an oxidation current density of 65.3 μA cm(-2) at +0.77 V. Voltammetric and amperometric responses were virtually unaffected by oxygen, illustrating an efficient and fast direct electron transfer. The modification of the CNT surface with FePc resulted in a biosensor with remarkable detection sensitivity with an oxygen-independent bioelectrocatalysis. In deaerated PBS, the biosensor displayed average response time of 12 s, linearity from 50 μM to 4 mM, and a detection limit of 30 μM (S/N=3) for glucose. Copyright © 2013 Elsevier B.V. All rights reserved.

Controllable growth of Prussian blue nanostructures on carboxylic group-functionalized carbon nanofibers and its application for glucose biosensing.

PubMed

Wang, Li; Ye, Yinjian; Zhu, Haozhi; Song, Yonghai; He, Shuijian; Xu, Fugang; Hou, Haoqing

2012-11-16

Glucose detection is very important in biological analysis, clinical diagnosis and the food industry, and especially for the routine monitoring of diabetes. This work presents an electrochemical approach to the detection of glucose based on Prussian blue (PB) nanostructures/carboxylic group-functionalized carbon nanofiber (FCNF) nanocomposites. The hybrid nanocomposites were constructed by growing PB onto the FCNFs. The obtained PB-FCNF nanocomposites were characterized by scanning electron microscopy, x-ray diffraction and x-ray photoelectron spectroscopy. The mechanism of formation of PB-FCNF nanocomposites was investigated and is discussed in detail. The PB-FCNF modified glassy carbon electrode (PB-FCNF/GCE) shows good electrocatalysis toward the reduction of H(2)O(2), a product from the reduction of O(2) followed by glucose oxidase (GOD) catalysis of the oxidation of glucose to gluconic acid. Further immobilizing GOD on the PB-FCNF/GCE, an amperometric glucose biosensor was achieved by monitoring the generated H(2)O(2) under a relatively negative potential. The resulting glucose biosensor exhibited a rapid response of 5 s, a low detection limit of 0.5 μM, a wide linear range of 0.02-12 mM, a high sensitivity of 35.94 μA cm(-2) mM(-1), as well as good stability, repeatability and selectivity. The sensor might be promising for practical application.

An amperometric urea bisosensor based on covalent immobilization of urease on N2 incorporated diamond nanowire electrode.

PubMed

Shalini, Jayakumar; Sankaran, Kamatchi Jothiramalingam; Lee, Chi-Young; Tai, Nyan-Hwa; Lin, I-Nan

2014-06-15

N2 incorporated diamond nanowire (N-DNW) film electrochemical biosensor has utilized for the quantitative determination of urea in aqueous solution and urine sample. N-DNW electrode is wet-chemically cleaned (oxidation) by boiling in a mixture of H2SO4 and HNO3 (3:1) at 200°C for 2h to remove graphite. Urease (Urs) and glutamate dehydrogenase (GLDH) are covalently attached to the oxidized N-DNW electrode by activating the COOH group of N-DNW using ethyl(dimethylaminopropyl)carbodiimide as the coupling agent and N-hydroxysuccinimide as activator. Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy data reveal that carboxylic and hydroxyl functionalized nature of N-DNW electrodes Urs-GLDH immobilized N-DNW (Urs-GLDH/N-DNW) has been successfully utilized in urea biosensor which exhibits good performance in sensitivity (6.18 μA/mg dL/cm(2)), stability (~1 month), reproducibility, lower detection limit (3.87 mg/dL) and fast response time (>10s). Urs-GLDH/N-DNW also exhibits electrochemical response when tested for different concentration of human urine in buffer solution (from 1:9 to 4:6). In addition, Urs-GLDH/N-DNW bioelectrode retains 80% of its initial enzyme activity for <1 month, when stored at 4-6°C in a refrigerator. Copyright © 2013 Elsevier B.V. All rights reserved.

Development of amperometric glucose biosensor through immobilizing enzyme in a Pt nanoparticles/mesoporous carbon matrix.

PubMed

Yu, Jingjing; Yu, Donglei; Zhao, Tian; Zeng, Baizhao

2008-02-15

Pt nanoparticles were deposited on mesoporous carbon material CMK-3. Glucose oxidase (GOx) was immobilized in the resulting Pt nanoparticles/mesoporous carbon (Pt/CMK-3) matrix, and then the mixture was cast on a glassy carbon electrode (GCE) using gelatin as a binder. The glucose biosensor exhibited excellent current response to glucose after cross-linking with glutaraldehyde. At 0.6V (vs. SCE) the response current was linear to glucose concentration in the range of 0.04-12.2mM. The response time (time for achieving 95% of the maximum current) was 15s and the detection limit (S/N=3) was 1 microM. The Michaelis-Menten constant (K(m)(app)) and the maximum current density (i(max)) were 10.8 mM and 908 microAcm(-2), respectively. The activation energy of the enzymatic reaction was estimated to be 22.54 kJ mol(-1). The biosensor showed good stability. It achieved the maximum response current at about 52 degrees C and retained 95.1% of its initial response current after being stored for 30 days. In addition, some fabrication and operation parameters for the biosensor were optimized in this work. The biosensor was used to monitor the glucose levels of serum samples after being covered with an extra Nafion film to improve its anti-interferent ability and satisfied results were obtained.

BioMEMS for multiparameter clinical monitoring

NASA Astrophysics Data System (ADS)

Moser, Isabella

2003-01-01

For diabetes patients glucose monitoring means an important improvement of their life quality and additionally it is a $3-billion-a-year business. Continuous glucose monitoring provides gapless glucose level control, an early warning of hypoglycemia, and is intended to control insulin pumps. An upgrading to multi-parameter monitoring would not only benefit patients with severe metabolism defects but also the metabolism of diabetes patient could be better controlled by monitoring an additional parameter like lactate. Multi-parameter monitoring devices are not commercially available, one of the complications in the integration of different biosensors using the same detecting molecule for all analytes is chemical cross talk between adjacent amperometric biosensors. Recently some integrated biosensors were published but either they were not mass producible or they were realized in an expensive silicon based technology. In addition to it most of them were not tested under monitoring conditions but their integration principles will be discussed. As an example a low cost multi- parameter microsystem and some applications of it in clinical diagnosis will be presented. Also an overlook of non-invasive methods and (minimal) invasive methods will be given with a focus on microdialysis.

Construction, assembling and application of a trehalase-GOD enzyme electrode system.

PubMed

Antonelli, M L; Arduini, F; Laganà, A; Moscone, D; Siliprandi, V

2009-01-01

Trehalose is a disaccharide important in foods, serving as a glucose source in many and also as an additive in the food preparation. Because of its peculiar physico-chemical properties it plays an important role as preservative in drying and deep-freezing treatments. A new biosensor for trehalose determination has been realized by means of a flow system, based on a reactor in which the trehalase enzyme catalyses its hydrolysis into two alpha,d-glucose molecules, and a GOD (glucose oxidase) amperometric biosensor is employed for the glucose determination. The optimum operative conditions have been laid out and a particular attention has been paid to the immobilization procedure of the two enzymes. The electrode used is of the SPE (screen-printed electrode) type and has been activated with the Prussian Blue (PB) and then assembled using GOD immobilized with Nafion. The reactor has been prepared with the trehalase enzyme chemically immobilized on an Immunodyne ABC membrane. As demonstration of its utility, the biosensor has been tested on a real sample of Boletus edulis mushroom.

Polyphenols Determination in Olive Oil Samples Based on a Thick Film Voltammetric Sensor and a Tyrosinase Biosensor

NASA Astrophysics Data System (ADS)

Capannesi, Cecilia; Palchetti, Ilaria; Mascini, Marco

2000-12-01

The aim of the present work was to compare different techniques to evaluate the variation with the storage time and storage conditions in the phenolic content of an extra-virgin olive oil. A disposable screen-printed sensor (SPE) was coupled with differential pulse voltammetry (DPV) to determine the phenolic fractions after extraction with glycine buffer; DPV parameters were chosen in order to study oxidation peak of oleuropein, that was used as reference compound. Moreover a tyrosinase based biosensor operating in organic solvent (hexane) was assembled, using an amperometric oxygen probe as transducer. Calibration curves were realised in flow injection analysis (F.I.A.) using phenol as substrate. Both of these methods are easy to operate, require no extraction (biosensor) or a rapid extraction procedure (SPE), and the analysis time is short (min.). The results obtained with these two innovative procedures were compared with classical spectrophotometric assay using the Folin-Ciocalteau reagent. Other extra-virgin olive oil quality parameters were investigated with classical methods in order to better define the alteration process and results are reported.

Lipoxygenase-modified Ru-bpy/graphene oxide: Electrochemical biosensor for on-farm monitoring of non-esterified fatty acid.

PubMed

Veerapandian, Murugan; Hunter, Robert; Neethirajan, Suresh

2016-04-15

Elevated concentrations of non-esterified fatty acids (NEFA) in biological fluids are recognized as critical biomarkers for early diagnosis of dairy cow metabolic diseases. Herein, a cost-effective, electrochemically active, and bio-friendly sensor element based on ruthenium bipyridyl complex-modified graphene oxide nanosheets ([Ru(bpy)3](2+)-GO) is proposed as a biosensor platform for NEFA detection. Electrochemical analysis demonstrates that the [Ru(bpy)3](2+)-GO electrodes exhibit superior and durable redox properties compared to the pristine carbon and GO electrodes. Target specificity is accomplished through immobilization of the enzyme, lipoxygenase, which catalyzes the production of redox active species from NEFA. Lipoxygenases retain their catalytic ability upon immobilization and exhibit changes to amperometric signals upon interaction with various concentrations of standard NEFA and serum samples. Our study demonstrates that the [Ru(bpy)3](2+)-GO electrode has the potential to serve as a biosensor platform for developing a field deployable, rapid, and user-friendly detection tool for on-farm monitoring of dairy cow metabolic diseases. Copyright © 2015 Elsevier B.V. All rights reserved.

Monochloramine-sensitive amperometric microelectrode: optimization of gold, platinum, and carbon fiber sensing materials for removal of dissolved oxygen interference

EPA Science Inventory

Amperometric monochloramine detection using newly fabricated gold, platinum, and carbon-fiber microsensors was investigated to optimize sensor operation and eliminate oxygen interference. Gold and platinum microsensors exhibited no oxygen interference during monochloramine measu...

Plain to point network reduced graphene oxide - activated carbon composites decorated with platinum nanoparticles for urine glucose detection

NASA Astrophysics Data System (ADS)

Hossain, Mohammad Faruk; Park, Jae Y.

2016-02-01

In this study, a hydrothermal technique was applied to synthesize glucose-treated reduced graphene oxide-activated carbon (GRGO/AC) composites. Platinum nanoparticles (PtNP) were electrochemically deposited on the modified GRGO/AC surface, and chitosan-glucose oxidase (Chit-GOx) composites and nafion were integrated onto the modified surface of the working electrode to prepare a highly sensitive glucose sensor. The fabricated biosensor exhibited a good amperometric response to glucose in the detection range from 0.002 mM to 10 mM, with a sensitivity of 61.06 μA/mMcm2, a short response time (4 s) and a low detection limit of 2 μM (signal to noise ratio is 3). The glucose sensor exhibited a negligible response to interference and good stability. In addition, the glucose levels in human urine were tested in order to conduct a practical assessment of the proposed sensor, and the results indicate that the sensor had superior urine glucose recognition. These results thus demonstrate that the noble nano-structured electrode with a high surface area and electrocatalytic activity offers great promise for use in urine glucose sensing applications.

Plain to point network reduced graphene oxide - activated carbon composites decorated with platinum nanoparticles for urine glucose detection

PubMed Central

Hossain, Mohammad Faruk; Park, Jae Y.

2016-01-01

In this study, a hydrothermal technique was applied to synthesize glucose-treated reduced graphene oxide-activated carbon (GRGO/AC) composites. Platinum nanoparticles (PtNP) were electrochemically deposited on the modified GRGO/AC surface, and chitosan-glucose oxidase (Chit-GOx) composites and nafion were integrated onto the modified surface of the working electrode to prepare a highly sensitive glucose sensor. The fabricated biosensor exhibited a good amperometric response to glucose in the detection range from 0.002 mM to 10 mM, with a sensitivity of 61.06 μA/mMcm2, a short response time (4 s) and a low detection limit of 2 μM (signal to noise ratio is 3). The glucose sensor exhibited a negligible response to interference and good stability. In addition, the glucose levels in human urine were tested in order to conduct a practical assessment of the proposed sensor, and the results indicate that the sensor had superior urine glucose recognition. These results thus demonstrate that the noble nano-structured electrode with a high surface area and electrocatalytic activity offers great promise for use in urine glucose sensing applications. PMID:26876368

Electronically type-sorted carbon nanotube-based electrochemical biosensors with glucose oxidase and dehydrogenase.

PubMed

Muguruma, Hitoshi; Hoshino, Tatsuya; Nowaki, Kohei

2015-01-14

An electrochemical enzyme biosensor with electronically type-sorted (metallic and semiconducting) single-walled carbon nanotubes (SWNTs) for use in aqueous media is presented. This research investigates how the electronic types of SWNTs influence the amperometric response of enzyme biosensors. To conduct a clear evaluation, a simple layer-by-layer process based on a plasma-polymerized nano thin film (PPF) was adopted because a PPF is an inactive matrix that can form a well-defined nanostructure composed of SWNTs and enzyme. For a biosensor with the glucose oxidase (GOx) enzyme in the presence of oxygen, the response of a metallic SWNT-GOx electrode was 2 times larger than that of a semiconducting SWNT-GOx electrode. In contrast, in the absence of oxygen, the response of the semiconducting SWNT-GOx electrode was retained, whereas that of the metallic SWNT-GOx electrode was significantly reduced. This indicates that direct electron transfer occurred with the semiconducting SWNT-GOx electrode, whereas the metallic SWNT-GOx electrode was dominated by a hydrogen peroxide pathway caused by an enzymatic reaction. For a biosensor with the glucose dehydrogenase (GDH; oxygen-independent catalysis) enzyme, the response of the semiconducting SWNT-GDH electrode was 4 times larger than that of the metallic SWNT-GDH electrode. Electrochemical impedance spectroscopy was used to show that the semiconducting SWNT network has less resistance for electron transfer than the metallic SWNT network. Therefore, it was concluded that semiconducting SWNTs are more suitable than metallic SWNTs for electrochemical enzyme biosensors in terms of direct electron transfer as a detection mechanism. This study makes a valuable contribution toward the development of electrochemical biosensors that employ sorted SWNTs and various enzymes.

An electrochemical sulfite biosensor based on gold coated magnetic nanoparticles modified gold electrode.

PubMed

Rawal, Rachna; Chawla, Sheetal; Pundir, Chandra Shekhar

2012-01-15

A sulfite oxidase (SO(X)) (EC 1.8.3.1) purified from Syzygium cumini leaves was immobilized onto carboxylated gold coated magnetic nanoparticles (Fe(3)O(4)@GNPs) electrodeposited onto the surface of a gold (Au) electrode through N-ethyl-N'-(3-dimethylaminopropyl) carbodiimide (EDC)-N-hydroxy succinimide (NHS) chemistry. An amperometric sulfite biosensor was fabricated using SO(X)/Fe(3)O(4)@GNPs/Au electrode as working electrode, Ag/AgCl as standard and Pt wire as auxiliary electrode. The working electrode was characterized by Fourier Transform Infrared (FTIR) Spectroscopy, Cyclic Voltammetry (CV), Scanning Electron Microscopy (SEM) and Electrochemical Impedance Spectroscopy (EIS) before and after immobilization of SO(X). The biosensor showed optimum response within 2s when operated at 0.2V (vs. Ag/AgCl) in 0.1 M Tris-HCl buffer, pH 8.5 and at 35 °C. Linear range and detection limit were 0.50-1000 μM and 0.15 μM (S/N=3) respectively. Biosensor was evaluated with 96.46% recovery of added sulfite in red wine and 1.7% and 3.3% within and between batch coefficients of variation respectively. Biosensor measured sulfite level in red and white wines. There was good correlation (r=0.99) between red wines sulfite value by standard DTNB (5,5'-dithio-bis-(2-nitrobenzoic acid)) method and the present method. Enzyme electrode was used 300 times over a period of 4 months, when stored at 4 °C. Biosensor has advantages over earlier biosensors that it has excellent electrocatalysis towards sulfite, lower detection limit, higher storage stability and no interference by ascorbate, cysteine, fructose and ethanol. Copyright © 2011 Elsevier B.V. All rights reserved.

Development of a biosensor for caffeine.

PubMed

Babu, V R Sarath; Patra, S; Karanth, N G; Kumar, M A; Thakur, M S

2007-01-23

We have utilized a microbe, which can degrade caffeine to develop an Amperometric biosensor for determination of caffeine in solutions. Whole cells of Pseudomonas alcaligenes MTCC 5264 having the capability to degrade caffeine were immobilized on a cellophane membrane with a molecular weight cut off (MWCO) of 3000-6000 by covalent crosslinking method using glutaraledhyde as the bifunctional crosslinking agent and gelatin as the protein based stabilizing agent (PBSA). The biosensor system was able to detect caffeine in solution over a concentration range of 0.1 to 1 mg mL(-1). With read-times as short as 3 min, this caffeine biosensor acts as a rapid analysis system for caffeine in solutions. Interestingly, successful isolation and immobilization of caffeine degrading bacteria for the analysis of caffeine described here was enabled by a novel selection strategy that incorporated isolation of caffeine degrading bacteria capable of utilizing caffeine as the sole source of carbon and nitrogen from soils and induction of caffeine degrading capacity in bacteria for the development of the biosensor. This biosensor is highly specific for caffeine and response to interfering compounds such as theophylline, theobromine, paraxanthine, other methyl xanthines and sugars was found to be negligible. Although a few biosensing methods for caffeine are reported, they have limitations in application for commercial samples. The development and application of new caffeine detection methods remains an active area of investigation, particularly in food and clinical chemistry. The optimum pH and temperature of measurement were 6.8 and 30+/-2 degrees C, respectively. Interference in analysis of caffeine due to different substrates was observed but was not considerable. Caffeine content of commercial samples of instant tea and coffee was analyzed by the biosensor and the results compared well with HPLC analysis.

Immobilization Techniques to Avoid Enzyme Loss from Oxidase-Based Biosensors: A One-Year Study

PubMed Central

House, Jody L.; Anderson, Ellen M.; Ward, W. Kenneth

2007-01-01

Background Continuous amperometric sensors that measure glucose or lactate require a stable sensitivity, and glutaraldehyde crosslinking has been used widely to avoid enzyme loss. Nonetheless, little data is published on the effectiveness of enzyme immobilization with glutaraldehyde. Methods A combination of electrochemical testing and spectrophotometric assays was used to study the relationship between enzyme shedding and the fabrication procedure. In addition, we studied the relationship between the glutaraldehyde concentration and sensor performance over a period of one year. Results The enzyme immobilization process by glutaraldehyde crosslinking to glucose oxidase appears to require at least 24-hours at room temperature to reach completion. In addition, excess free glucose oxidase can be removed by soaking sensors in purified water for 20 minutes. Even with the addition of these steps, however, it appears that there is some free glucose oxidase entrapped within the enzyme layer which contributes to a decline in sensitivity over time. Although it reduces the ultimate sensitivity (probably via a change in the enzyme's natural conformation), glutaraldehyde concentration in the enzyme layer can be increased in order to minimize this instability. Conclusions After exposure of oxidase enzymes to glutaraldehyde, effective crosslinking requires a rinse step and a 24-hour incubation step. In order to minimize the loss of sensor sensitivity over time, the glutaraldehyde concentration can be increased. PMID:19888375

Nanostructured enzymatic biosensor based on fullerene and gold nanoparticles: preparation, characterization and analytical applications.

PubMed

Lanzellotto, C; Favero, G; Antonelli, M L; Tortolini, C; Cannistraro, S; Coppari, E; Mazzei, F

2014-05-15

In this work a novel electrochemical biosensing platform based on the coupling of two different nanostructured materials (gold nanoparticles and fullerenols) displaying interesting electrochemical features, has been developed and characterized. Gold nanoparticles (AuNPs) exhibit attractive electrocatalytic behavior stimulating in the last years, several sensing applications; on the other hand, fullerene and its derivatives are a very promising family of electroactive compounds although they have not yet been fully employed in biosensing. The methodology proposed in this work was finalized to the setup of a laccase biosensor based on a multilayer material consisting in AuNPs, fullerenols and Trametes versicolor Laccase (TvL) assembled layer by layer onto a gold (Au) electrode surface. The influence of different modification step procedures on the electroanalytical performance of biosensors has been evaluated. Cyclic voltammetry, chronoamperometry, surface plasmon resonance (SPR) and scanning tunneling microscopy (STM) were used to characterize the modification of surface and to investigate the bioelectrocatalytic biosensor response. This biosensor showed fast amperometric response to gallic acid, which is usually considered a standard for polyphenols analysis of wines, with a linear range 0.03-0.30 mmol L(-1) (r(2)=0.9998), with a LOD of 0.006 mmol L(-1) or expressed as polyphenol index 5.0-50 mg L(-1) and LOD 1.1 mg L(-1). A tentative application of the developed nanostructured enzyme-based biosensor was performed evaluating the detection of polyphenols either in buffer solution or in real wine samples. Copyright © 2013 Elsevier B.V. All rights reserved.

Ultra-miniaturization of a planar amperometric sensor targeting continuous intradermal glucose monitoring.

PubMed

Ribet, Federico; Stemme, Göran; Roxhed, Niclas

2017-04-15

An ultra-miniaturized electrochemical biosensor for continuous glucose monitoring (CGM) is presented. The aim of this work is to demonstrate the possibility of an overall reduction in sensor size to allow minimally invasive glucose monitoring in the interstitial fluid in the dermal region, in contrast to larger state-of-the-art systems, which are necessarily placed in the subcutaneous layer. Moreover, the reduction in size might be a key factor to improve the stability and reliability of transdermal sensors, due to the reduction of the detrimental foreign body reaction and of consequent potential failures. These advantages are combined with lower invasiveness and discomfort for patients. The realized device consists of a microfabricated three-electrode enzymatic sensor with a total surface area of the sensing portion of less than 0.04mm 2 , making it the smallest fully integrated planar amperometric glucose sensor area reported to date. The working electrode and counter electrode consist of platinum and are functionalized by drop casting of three polymeric membranes. The on-chip iridium oxide (IrOx) pseudo-reference electrode provides the required stability for measurements under physiological conditions. The device is able to dynamically and linearly measure glucose concentrations in-vitro over the relevant physiological range, while showing sufficient selectivity to known interfering species present in the interstitial fluid, with resolution and sensitivity (1.51nA/mM) comparable to that of state-of-art commercial CGM systems. This work can therefore enable less invasive and improved CGM in patients affected by diabetes. Copyright © 2016 Elsevier B.V. All rights reserved.

Electrochemical Detection in Stacked Paper Networks.

PubMed

Liu, Xiyuan; Lillehoj, Peter B

2015-08-01

Paper-based electrochemical biosensors are a promising technology that enables rapid, quantitative measurements on an inexpensive platform. However, the control of liquids in paper networks is generally limited to a single sample delivery step. Here, we propose a simple method to automate the loading and delivery of liquid samples to sensing electrodes on paper networks by stacking multiple layers of paper. Using these stacked paper devices (SPDs), we demonstrate a unique strategy to fully immerse planar electrodes by aqueous liquids via capillary flow. Amperometric measurements of xanthine oxidase revealed that electrochemical sensors on four-layer SPDs generated detection signals up to 75% higher compared with those on single-layer paper devices. Furthermore, measurements could be performed with minimal user involvement and completed within 30 min. Due to its simplicity, enhanced automation, and capability for quantitative measurements, stacked paper electrochemical biosensors can be useful tools for point-of-care testing in resource-limited settings. © 2015 Society for Laboratory Automation and Screening.

Superior long-term stability of a glucose biosensor based on inserted barrel plating gold electrodes.

PubMed

Hsu, Cheng-Teng; Hsiao, Hung-Chan; Fang, Mei-Yen; Zen, Jyh-Myng

2009-10-15

Disposable one shot usage blood glucose strips are routinely used in the diagnosis and management of diabetes mellitus and their performance can vary greatly. In this paper we critically evaluated the long-term stability of glucose strips made of barrel plating gold electrodes. Compared to other glucose biosensing platforms of vapor deposited palladium and screen printed carbon electrodes, the proposed glucose biosensor was found to show the best stability among the three biosensing platforms in thermal acceleration experiments at 40 degrees C for 6 months with an average bias of 3.4% at glucose concentrations of 5-20 mM. The precision test of this barrel plating gold glucose biosensor also showed the best performance (coefficients of variation in the range of 1.4-2.4%) in thermal acceleration experiments at 40 degrees C, 50 degrees C and 70 degrees C for 27 days. Error grid analysis revealed that all measurements fell in zone A and zone B. Regression analysis showed no significant difference between the proposed biosensor and the reference method at 99% confidence level. The amperometric glucose biosensor fabricated by inserting two barrel plating gold electrodes onto an injection-molding plastic base followed by immobilizing with a bio-reagent layer and membrane was very impressive with a long-term stability up to 2.5 years at 25 degrees C. Overall, these results indicated that the glucose oxidase/barrel plating gold biosensing platform is ideal for long-term accurate glycemic control.

Oxidative polymerization of 5-hydroxytryptamine to physically and chemically immobilize glucose oxidase for electrochemical biosensing.

PubMed

Huang, Ting; Liu, Zaichun; Li, Yunlong; Li, Yanqiu; Chao, Long; Chen, Chao; Tan, Yueming; Xie, Qingji; Yao, Shouzhuo; Wu, Yuping

2018-07-12

Poly(5-hydroxytryptamine) (poly(5-HT)) is exploited as a new and efficient enzyme-immobilization matrix for amperometric and biofuel cell (BFC)-based biosensing. A GOx-poly(5-HT)-Pd nanoparticles (PdNPs) bionanocomposite is prepared by Na 2 PdCl 4 -initiated oxidized polymerization of 5-hydroxytryptamine (5-HT) in a neutral aqueous solution containing glucose oxidase (GOx), and this bionanocomposite and then chitosan (CS) are cast-coated on a Pd-plated Au electrode to yield a CS/GOx-poly(5-HT)-PdNPs/Pd plate /Au enzyme electrode. Scanning/transmission electron microscopy, UV-vis spectrophotometry and electrochemical quartz crystal microbalance are employed for material characterization and/or process monitoring. Under optimized conditions, the amperometric response of the enzyme electrode is linear with glucose concentration from 2.0 μM to 6.66 mM with a sensitivity of 110 μA mM -1  cm -2 , a limit of detection of 0.2 μM, and excellent operation/storage stability in the first-generation biosensing mode. The sensitivity is larger than those of some conventional electrodes under identical conditions. The enzyme electrode also works well in the second-generation biosensing mode. By using the enzyme electrode as the anode for glucose oxidation and a Pd plate /Au electrode as the cathode for KMnO 4 reduction, a monopolar BFC is constructed as a self-powered biosensor, the current response of which is linear with glucose concentration from 50 μM to 34.5 mM. Experiments also show that poly(5-HT) is a physical and chemical dual-immobilization matrix of enzyme, since the abundant amino groups in poly(5-HT) can be used for chemical bonding of GOx. Copyright © 2018 Elsevier B.V. All rights reserved.

Direct metabolite detection with an n-type accumulation mode organic electrochemical transistor

PubMed Central

Maria, Iuliana Petruta; Uguz, Ilke

2018-01-01

The inherent specificity and electrochemical reversibility of enzymes poise them as the biorecognition element of choice for a wide range of metabolites. To use enzymes efficiently in biosensors, the redox centers of the protein should have good electrical communication with the transducing electrode, which requires either the use of mediators or tedious biofunctionalization approaches. We report an all-polymer micrometer-scale transistor platform for the detection of lactate, a significant metabolite in cellular metabolic pathways associated with critical health care conditions. The device embodies a new concept in metabolite sensing where we take advantage of the ion-to-electron transducing qualities of an electron-transporting (n-type) organic semiconductor and the inherent amplification properties of an ion-to-electron converting device, the organic electrochemical transistor. The n-type polymer incorporates hydrophilic side chains to enhance ion transport/injection, as well as to facilitate enzyme conjugation. The material is capable of accepting electrons of the enzymatic reaction and acts as a series of redox centers capable of switching between the neutral and reduced state. The result is a fast, selective, and sensitive metabolite sensor. The advantage of this device compared to traditional amperometric sensors is the amplification of the input signal endowed by the electrochemical transistor circuit and the design simplicity obviating the need for a reference electrode. The combination of redox enzymes and electron-transporting polymers will open up an avenue not only for the field of biosensors but also for the development of enzyme-based electrocatalytic energy generation/storage devices.

Direct metabolite detection with an n-type accumulation mode organic electrochemical transistor.

PubMed

Pappa, Anna Maria; Ohayon, David; Giovannitti, Alexander; Maria, Iuliana Petruta; Savva, Achilleas; Uguz, Ilke; Rivnay, Jonathan; McCulloch, Iain; Owens, Róisín M; Inal, Sahika

2018-06-01

The inherent specificity and electrochemical reversibility of enzymes poise them as the biorecognition element of choice for a wide range of metabolites. To use enzymes efficiently in biosensors, the redox centers of the protein should have good electrical communication with the transducing electrode, which requires either the use of mediators or tedious biofunctionalization approaches. We report an all-polymer micrometer-scale transistor platform for the detection of lactate, a significant metabolite in cellular metabolic pathways associated with critical health care conditions. The device embodies a new concept in metabolite sensing where we take advantage of the ion-to-electron transducing qualities of an electron-transporting (n-type) organic semiconductor and the inherent amplification properties of an ion-to-electron converting device, the organic electrochemical transistor. The n-type polymer incorporates hydrophilic side chains to enhance ion transport/injection, as well as to facilitate enzyme conjugation. The material is capable of accepting electrons of the enzymatic reaction and acts as a series of redox centers capable of switching between the neutral and reduced state. The result is a fast, selective, and sensitive metabolite sensor. The advantage of this device compared to traditional amperometric sensors is the amplification of the input signal endowed by the electrochemical transistor circuit and the design simplicity obviating the need for a reference electrode. The combination of redox enzymes and electron-transporting polymers will open up an avenue not only for the field of biosensors but also for the development of enzyme-based electrocatalytic energy generation/storage devices.

Long period fiber grating based sensor for the detection of triacylglycerides.

PubMed

Baliyan, Anjli; Sital, Shivani; Tiwari, Umesh; Gupta, Rani; Sharma, Enakshi K

2016-05-15

In this paper, stable, label free enzyme based sensor using long period fiber grating (LPG) is described for the detection of triacylglycerides. A stable covalent binding technique for lipase enzyme immobilization on an optical fiber is reported. An active and stable attachment of the functional group of the enzyme on the fiber surface is achieved using this method. Enzyme immobilization is confirmed by Scanning Electron Microscopy (SEM) and Raman Spectroscopy. The stability is confirmed by lipase p-nitrophenyl palmitate (PNP) assay. In contrast to widely used amperometric based biosensor, where a number of enzymes are required, only one enzyme, namely, lipase is required in our sensor. The sensor shows optimum response within one minute at a temperature of 37°C and pH of 7.4. The sensor is based on the shift in resonance wavelength of the LPG transmission spectrum due to the interaction of triacylglycerides with the enzyme. The biosensor is highly specific towards triacylglycerides and is unaffected by the presence of many other interfering substances in serum. Interaction between the bio-molecules and the long period grating surface is also modeled theoretically using a four layer model for the LPG fiber with the bio-recognition layer and the results obtained are consistent with experimentally obtained results. The sensor shows a high sensitivity of 0.5 nm/mM and a low detection limit of 17.71 mg/dl for the physiological range of triacylglycerides in human blood. Copyright © 2015 Elsevier B.V. All rights reserved.

A performance comparison of choline biosensors: anodic or cathodic detections of H2O2 generated by enzyme immobilized on a conducting polymer.

PubMed

Rahman, Md Aminur; Park, Deog-Soo; Shim, Yoon-Bo

2004-07-15

Amperometric choline biosensors were fabricated by the covalent immobilization of an enzyme of choline oxidase (ChO) and a bi-enzyme of ChO/horseradish peroxidase (ChO/HRP) onto poly-5,2':5',2"-terthiophene-3'-carboxylic acid (poly-TTCA) modified electrodes (CPMEs). A sensor modified with ChO utilized the oxidation process of enzymatically generated H(2)O(2) in a choline solution at +0.6V. The other one modified with ChO/HRP utilized the reduction process of H(2)O(2) in a choline solution at -0.2V. Experimental parameters affecting the sensitivity of sensors, such as pH, applied potential, and temperature were optimized. A performance comparison of two sensors showed that one based on ChO/HRP/CPME had a linear range from 1.0 x 10(-6) to 8.0 x 10(-5) M and the other based on ChO/CPME from 1.0 x 10(-6) to 5.0 x 10(-5) M. The detection limits for choline employing ChO/HRP/CPME and ChO/CPME were determined to be about 1.0 x 10(-7) and 4.0 x 10(-7) M, respectively. The response time of sensors was less than 5s. Sensors showed good selectivity to interfering species. The long-term storage stability of the sensor based on ChO/HRP/CPME was longer than that based on ChO/CPME.

Comparison between amperometric and true potentiometric end-point detection in the determination of water by the Karl Fischer method.

PubMed

Cedergren, A

1974-06-01

A rapid and sensitive method using true potentiometric end-point detection has been developed and compared with the conventional amperometric method for Karl Fischer determination of water. The effect of the sulphur dioxide concentration on the shape of the titration curve is shown. By using kinetic data it was possible to calculate the course of titrations and make comparisons with those found experimentally. The results prove that the main reaction is the slow step, both in the amperometric and the potentiometric method. Results obtained in the standardization of the Karl Fischer reagent showed that the potentiometric method, including titration to a preselected potential, gave a standard deviation of 0.001(1) mg of water per ml, the amperometric method using extrapolation 0.002(4) mg of water per ml and the amperometric titration to a pre-selected diffusion current 0.004(7) mg of water per ml. Theories and results dealing with dilution effects are presented. The time of analysis was 1-1.5 min for the potentiometric and 4-5 min for the amperometric method using extrapolation.

On the Accuracy of In Vivo Ethanol and Acetaldehyde Monitoring, a Key Tile in the Puzzle of Acetaldehyde as a Neuroactive Agent.

PubMed

Enrico, Paolo; Diana, Marco

2017-01-01

Over the last 20 years researchers have explored the postulated role of acetaldehyde (ACD) as a mediator of some of the actions of ethanol (EtOH) in the central nervous system (CNS). However, efforts have been hampered mainly by the difficulty of directly measuring in vivo EtOH and ACD levels in the CNS and thus, our knowledge is based on indirect evidences. Although technically challenging, the development of reliable methods for in vivo measurement of ACD and EtOH is of paramount importance to solve the " puzzle of acetaldehyde as a neuroactive agent. " In this short review we discuss the recent advances on brain EtOH pharmacokinetic and state-of-the-art available techniques that could be used for in vivo detect EtOH and ACD both non-invasively (magnetic resonance spectroscopy), and invasively (microdialysis and biosensors). Among the different in vivo sampling techniques described, particular emphasis is paid to the field of enzyme-based amperometric biosensors. Biosensors have gained much attention in recent years for their ability to online monitor biological signals in vivo , and several micro- and nano-structured devices have been successfully used for in vivo studies. Owing to their high temporal and spatial resolution, biosensors could provide the adequate technology for studying in vivo EtOH pharmacokinetic.

Amperometric L-glutamate biosensor based on bacterial cell-surface displayed glutamate dehydrogenase.

PubMed

Liang, Bo; Zhang, Shu; Lang, Qiaolin; Song, Jianxia; Han, Lihui; Liu, Aihua

2015-07-16

A novel L-glutamate biosensor was fabricated using bacteria surface-displayed glutamate dehydrogenase (Gldh-bacteria). Here the cofactor NADP(+)-specific dependent Gldh was expressed on the surface of Escherichia coli using N-terminal region of ice nucleation protein (INP) as the anchoring motif. The cell fractionation assay and SDS-PAGE analysis indicated that the majority of INP-Gldh fusion proteins were located on the surface of cells. The biosensor was fabricated by successively casting polyethyleneimine (PEI)-dispersed multi-walled carbon nanotubes (MWNTs), Gldh-bacteria and Nafion onto the glassy carbon electrode (Nafion/Gldh-bacteria/PEI-MWNTs/GCE). The MWNTs could not only significantly lower the oxidation overpotential towards NAPDH, which was the product of NADP(+) involving in the oxidation of glutamate by Gldh, but also enhanced the current response. Under the optimized experimental conditions, the current-time curve of the Nafion/Gldh-bacteria/PEI-MWNTs/GCE was performed at +0.52 V (vs. SCE) by amperometry varying glutamate concentration. The current response was linear with glutamate concentration in two ranges (10 μM-1 mM and 2-10 mM). The low limit of detection was estimated to be 2 μM glutamate (S/N=3). Moreover, the proposed biosensor is stable, specific, reproducible and simple, which can be applied to real samples detection. Copyright © 2015 Elsevier B.V. All rights reserved.

Amperometric biosensors for the determination of heavy metals

NASA Astrophysics Data System (ADS)

Compagnone, Dario; Palleschi, Giuseppe; Varallo, Giuseppe; Imperiali, PierLuigi

1995-10-01

A bioelectrochemical method for the determination of heavy metal ions has been developed. This method is based on the inhibition effect of metal ions on the enzymatic activity of oxidase enzymes. The enzymatic activity was determined with an amperometric hydrogen peroxide probe. The inhibition effect on enzymes in solution and covalently immobilized on polymeric supports has been evaluated. Hg(II) was the metal ion that inhibited almost all the enzymes, particularly glycerol-3-P oxidase. Hg(II) was detected in the 0.05/0.5 ppm range with the enzyme in solution. Calibration curves for Hg(II) were also obtained with the other oxidase enzymes in the 0.5/10 ppm range. The other metal ions tested inhibited the enzymes more specifically. The metal ion/enzyme systems which gave the best inhibition were Se(IV)/glutathione oxidase, Ni(II)/sarcosine oxidase, V(V)/glutathione oxidase, Cu(II)/alcohol oxidase from Pichia Pastoris and Cd(II)/D-aminoacid oxidase. All these metal ions were detected in the 0.1/10 ppm range using the enzymes in solution or covalently immobilized.

Enhancement in sensitivity of graphene-based zinc oxide assisted bimetallic surface plasmon resonance (SPR) biosensor

NASA Astrophysics Data System (ADS)

Kumar, Rajeev; Kushwaha, Angad S.; Srivastava, Monika; Mishra, H.; Srivastava, S. K.

2018-03-01

In the present communication, a highly sensitive surface plasmon resonance (SPR) biosensor with Kretschmann configuration having alternate layers, prism/zinc oxide/silver/gold/graphene/biomolecules (ss-DNA) is presented. The optimization of the proposed configuration has been accomplished by keeping the constant thickness of zinc oxide (32 nm), silver (32 nm), graphene (0.34 nm) layer and biomolecules (100 nm) for different values of gold layer thickness (1, 3 and 5 nm). The sensitivity of the proposed SPR biosensor has been demonstrated for a number of design parameters such as gold layer thickness, number of graphene layer, refractive index of biomolecules and the thickness of biomolecules layer. SPR biosensor with optimized geometry has greater sensitivity (66 deg/RIU) than the conventional (52 deg/RIU) as well as other graphene-based (53.2 deg/RIU) SPR biosensor. The effect of zinc oxide layer thickness on the sensitivity of SPR biosensor has also been analysed. From the analysis, it is found that the sensitivity increases significantly by increasing the thickness of zinc oxide layer. It means zinc oxide intermediate layer plays an important role to improve the sensitivity of the biosensor. The sensitivity of SPR biosensor also increases by increasing the number of graphene layer (upto nine layer).

How to Design a Biosensor

PubMed Central

Ward, W. Kenneth

2007-01-01

Amperometric sensors for continuous glucose monitoring could prevent acute and chronic complications of diabetes, but research is needed to improve accuracy and stability. In designing sensors, interference from non-glucose analytes can be minimized by use of filtration membranes or electron transfer mediators that allow polarization at low potentials. If oxygen is required for the enzymatic reaction with glucose, then the outer permselective membrane must have substantial oxygen permeability. For this reason, during development of permselective membranes, permeability studies (such as performed by Tipnis and colleagues in this issue) can be used to measure transport of glucose and oxygen and optimize membrane structure. Tipnis and colleagues present a novel biosensor based with separate layers for glucose-oxygen permselectivity, enzymatic conversion, and avoidance of interference. They also address sensor stability, in part by comparing sensor function during ascending vs descending glucose levels. By measuring the difference, they were able to minimize this aspect of instability (hysterisis), which assisted them in selecting a promising permselective membrane based on iron and humic acid. PMID:19888407

Cerium Oxide Nanoparticles Decorated Graphene Nanosheets for Selective Detection of Dopamine.

PubMed

Nayak, Pranati; Santhosh, P N; Ramaprabhu, S

2015-07-01

The fabrication of a novel amperometric biosensor based on selective determination of dopamine (DA) using nafion coated cerium oxide nanoparticles (NPs) decorated graphene nanosheets (CeO2-HEG-nafion) as a transducer candidate is reported. Graphene was synthesized by hydrogen exfoliation technique. Decoration of CeO2NPs over graphene nanosheets was done by chemical reduction method. The electrochemical impedance spectroscopy (EIS) study shows the enhanced electron transfer kinetics of the composite compared to HEG modified and bare glassy carbon electrode (GCE). The response of the composite towards dopamine displays a lower oxidation potential of 0.23 V and a high oxidation current. The sensor exhibits linearity from 10 µM to 780 µM with a detection limit of 1 µM. In the presence of nafion, it shows excellent selectivity for coexisting interference species like Ascorbic acid (AA) and Uric acid (UA). The excellent performance of the biosensor can be attributed to large active surface area, enhanced electron transfer kinetics and high catalytic activity of the composite.

How to design a biosensor.

PubMed

Ward, W Kenneth

2007-03-01

Amperometric sensors for continuous glucose monitoring could prevent acute and chronic complications of diabetes, but research is needed to improve accuracy and stability. In designing sensors, interference from non-glucose analytes can be minimized by use of filtration membranes or electron transfer mediators that allow polarization at low potentials. If oxygen is required for the enzymatic reaction with glucose, then the outer permselective membrane must have substantial oxygen permeability. For this reason, during development of permselective membranes, permeability studies (such as performed by Tipnis and colleagues in this issue) can be used to measure transport of glucose and oxygen and optimize membrane structure. Tipnis and colleagues present a novel biosensor based with separate layers for glucose-oxygen permselectivity, enzymatic conversion, and avoidance of interference. They also address sensor stability, in part by comparing sensor function during ascending vs descending glucose levels. By measuring the difference, they were able to minimize this aspect of instability (hysterisis), which assisted them in selecting a promising permselective membrane based on iron and humic acid.

Immobilization of glucose oxidase on graphene and cobalt phthalocyanine composite and its application for the determination of glucose.

PubMed

Mani, Veerappan; Devasenathipathy, Rajkumar; Chen, Shen-Ming; Huang, Sheng-Tung; Vasantha, V S

2014-11-01

We described a simple and facile chemical reduction strategy for the preparation of graphene (GR)-cobalt phthalocyanine (CoPc) composite and explored it for the enzymatic determination of glucose. CoPc is an active mediator and electrocatalysts for the immobilization of GOx and determination of glucose. However, it is not stable on the electrode surface and also suffers from lack of conductivity. Here, we have employed GR as the suitable support to stabilize CoPc through simple chemical reduction method and the resulting composite has been used for the glucose biosensor application. Scanning electron microscopy, X-ray diffraction and Energy-dispersive X-ray spectroscopy studies confirmed the successful formation of composite. Direct electron transfer of glucose oxidase (GOx) was observed with well defined redox peaks at the formal potential of -0.44 V. The amount of electroactive GOx (Г) and electron transfer rate constant (ks) were calculated to be 3.77×10(-10) mol cm(-2) and 3.57 s(-1), respectively. The fabricated amperometric biosensor detects glucose in wide linear concentration range from 10 μM to 14.8 mM with high sensitivity of 5.0 9μA mM(-1) cm(-2). The sensor offered very low detection limit (LOD) of 1.6 μM. In addition, practical feasibility of the sensor has been explored in screen printing carbon electrode with accurate determination of glucose present in human blood serum and urine samples. Furthermore, the sensor exhibited appreciable stability, repeatability and reproducibility results. Copyright © 2014 Elsevier Inc. All rights reserved.

Lab-on-a-bird: biophysical monitoring of flying birds.

PubMed

Gumus, Abdurrahman; Lee, Seoho; Ahsan, Syed S; Karlsson, Kolbeinn; Gabrielson, Richard; Guglielmo, Christopher G; Winkler, David W; Erickson, David

2015-01-01

The metabolism of birds is finely tuned to their activities and environments, and thus research on avian systems can play an important role in understanding organismal responses to environmental changes. At present, however, the physiological monitoring of bird metabolism is limited by the inability to take real-time measurements of key metabolites during flight. In this study, we present an implantable biosensor system that can be used for continuous monitoring of uric acid levels of birds during various activities including flight. The system consists of a needle-type enzymatic biosensor for the amperometric detection of uric acid in interstitial fluids. A lightweight two-electrode potentiostat system drives the biosensor, reads the corresponding output current and wirelessly transfers the data or records to flash memory. We show how the device can be used to monitor, in real time, the effects of short-term flight and rest cycles on the uric acid levels of pigeons. In addition, we demonstrate that our device has the ability to measure uric acid level increase in homing pigeons while they fly freely. Successful application of the sensor in migratory birds could open up a new way of studying birds in flight which would lead to a better understanding of the ecology and biology of avian movements.

Combination of cascade chemical reactions with graphene-DNA interaction to develop new strategy for biosensor fabrication.

PubMed

Zhu, Xiaoli; Sun, Liya; Chen, Yangyang; Ye, Zonghuang; Shen, Zhongming; Li, Genxi

2013-09-15

Graphene, a single atom thick and two dimensional carbon nano-material, has been proven to possess many unique properties, one of which is the recent discovery that it can interact with single-stranded DNA through noncovalent π-π stacking. In this work, we demonstrate that a new strategy to fabricate many kinds of biosensors can be developed by combining this property with cascade chemical reactions. Taking the fabrication of glucose sensor as an example, while the detection target, glucose, may regulate the graphene-DNA interaction through three cascade chemical reactions, electrochemical techniques are employed to detect the target-regulated graphene-DNA interaction. Experimental results show that in a range from 5μM to 20mM, the glucose concentration is in a natural logarithm with the logarithm of the amperometric response, suggesting a best detection limit and detection range. The proposed biosensor also shows favorable selectivity, and it has the advantage of no need for labeling. What is more, by controlling the cascade chemical reactions, detection of a variety of other targets may be achieved, thus the strategy proposed in this work may have a wide application potential in the future. Copyright © 2013 Elsevier B.V. All rights reserved.

Engineering the bioelectrochemical interface using functional nanomaterials and microchip technique toward sensitive and portable electrochemical biosensors.

PubMed

Jia, Xiaofang; Dong, Shaojun; Wang, Erkang

2016-02-15

Electrochemical biosensors have played active roles at the forefront of bioanalysis because they have the potential to achieve sensitive, specific and low-cost detection of biomolecules and many others. Engineering the electrochemical sensing interface with functional nanomaterials leads to novel electrochemical biosensors with improved performances in terms of sensitivity, selectivity, stability and simplicity. Functional nanomaterials possess good conductivity, catalytic activity, biocompatibility and high surface area. Coupled with bio-recognition elements, these features can amplify signal transduction and biorecognition events, resulting in highly sensitive biosensing. Additionally, microfluidic electrochemical biosensors have attracted considerable attention on account of their miniature, portable and low-cost systems as well as high fabrication throughput and ease of scaleup. For example, electrochemical enzymetic biosensors and aptamer biosensors (aptasensors) based on the integrated microchip can be used for portable point-of-care diagnostics and environmental monitoring. This review is a summary of our recent progress in the field of electrochemical biosensors, including aptasensors, cytosensors, enzymatic biosensors and self-powered biosensors based on biofuel cells. We presented the advantages that functional nanomaterials and microfluidic chip technology bring to the electrochemical biosensors, together with future prospects and possible challenges. Copyright © 2015 Elsevier B.V. All rights reserved.

Affinity Biosensors for Detection of Mycotoxins in Food.

PubMed

Evtugyn, Gennady; Subjakova, Veronika; Melikishvili, Sopio; Hianik, Tibor

2018-01-01

This chapter reviews recent achievements in methods of detection of mycotoxins in food. Special focus is on the biosensor technology that utilizes antibodies and nucleic acid aptamers as receptors. Development of biosensors is based on the immobilization of antibodies or aptamers onto various conventional supports like gold layer, but also on nanomaterials such as graphene oxide, carbon nanotubes, and quantum dots that provide an effective platform for achieving high sensitivity of detection using various physical methods, including electrochemical, mass sensitive, and optical. The biosensors developed so far demonstrate high sensitivity typically in subnanomolar limit of detection. Several biosensors have been validated in real samples. The sensitivity of biosensors is similar and, in some cases, even better than traditional analytical methods such as ELISA or chromatography. We believe that future trends will be focused on improving biosensor properties toward practical application in food industry. © 2018 Elsevier Inc. All rights reserved.

Chemistry integrated circuit: chemical system on a complementary metal oxide semiconductor integrated circuit.

PubMed

Nakazato, Kazuo

2014-03-28

By integrating chemical reactions on a large-scale integration (LSI) chip, new types of device can be created. For biomedical applications, monolithically integrated sensor arrays for potentiometric, amperometric and impedimetric sensing of biomolecules have been developed. The potentiometric sensor array detects pH and redox reaction as a statistical distribution of fluctuations in time and space. For the amperometric sensor array, a microelectrode structure for measuring multiple currents at high speed has been proposed. The impedimetric sensor array is designed to measure impedance up to 10 MHz. The multimodal sensor array will enable synthetic analysis and make it possible to standardize biosensor chips. Another approach is to create new functional devices by integrating molecular systems with LSI chips, for example image sensors that incorporate biological materials with a sensor array. The quantum yield of the photoelectric conversion of photosynthesis is 100%, which is extremely difficult to achieve by artificial means. In a recently developed process, a molecular wire is plugged directly into a biological photosynthetic system to efficiently conduct electrons to a gold electrode. A single photon can be detected at room temperature using such a system combined with a molecular single-electron transistor.

pH responsive label-assisted click chemistry triggered sensitivity amplification for ultrasensitive electrochemical detection of carbohydrate antigen 24-2.

PubMed

Zheng, Yun; Zhao, Lihua; Ma, Zhanfang

2018-05-15

Sensitivity amplification strategy by implementing click chemistry in the construction of biosensing interface can efficiently improve the performance of immunosensor. Herein, we developed a sandwich-type amperometric immunosensor for ultrasensitive detection of carbohydrate antigen 24-2 (CA 242) based on pH responsive label-assisted click chemistry triggered sensitivity amplification strategy. The sensitivity of amperometric immunosensor relies on the current response differences (ΔI) caused by per unit concentration target analyte. The pH responsive Cu 2+ -loaded polydopamine (CuPDA) particles conjugated with detection antibodies were employed as labels, which can release Cu(II) ions by regulating pH. In the presence of ascorbic acid (reductant), Cu(II) ions were reduced to Cu(I) ions. Azide-functionalized double-stranded DNA (dsDNA) as signal enhancer was immobilized on the substrate through Cu + -catalyzed azide/alkyne cycloaddition reaction. With the help of the click reaction, the ΔI caused by target was elevated prominently, resulting in sensitivity amplification of the immunosensor. Under optimal condition, the proposed immunosensor exhibited excellent performance with linear range from 0.0001 to 100 U mL -1 and ultralow detection limit of 20.74 μU mL -1 . This work successfully combines click chemistry with pH-responsive labels in sandwich-type amperometric immunosensor, providing a promising sensitivity amplification strategy to construct immunosensing platform for analysis of other tumor marker. Copyright © 2018 Elsevier B.V. All rights reserved.

Electrochemical Sensors and Biosensors Based on Nanomaterials and Nanostructures

DOE PAGES

Zhu, Chengzhou; Yang, Guohai; Li, He; ...

2014-10-29

We report that considerable attention has been devoted to the integration of recognition elements with electronic elements to develop electrochemical sensors and biosensors.Various electrochemical devices, such as amperometric sensors, electrochemical impedance sensors, and electrochemical luminescence sensors as well as photoelectrochemical sensors, provide wide applications in the detection of chemical and biological targets in terms of electrochemical change of electrode interfaces. Here, this review focuses on recent advances in electrochemical sensors and biosensors based on nanomaterials and nanostructures during 2013 to 2014. The aim of this effort is to provide the reader with a clear and concise view of new advancesmore » in areas ranging from electrode engineering, strategies for electrochemical signal amplification, and novel electroanalytical techniques used in the miniaturization and integration of the sensors. Moreover, the authors have attempted to highlight areas of the latest and significant development of enhanced electrochemical nanosensors and nanobiosensors that inspire broader interests across various disciplines. Electrochemical sensors for small molecules, enzyme-based biosensors, genosensors, immunosensors, and cytosensors are reviewed herein (Figure 1). Such novel advances are important for the development of electrochemical sensors that open up new avenues and methods for future research. In conclusion, we recommend readers interested in the general principles of electrochemical sensors and electrochemical methods to refer to other excellent literature for a broad scope in this area.(3, 4) However, due to the explosion of publications in this active field, we do not claim that this Review includes all of the published works in the past two years and we apologize to the authors of excellent work, which is unintentionally left out.« less

Comparative study of different alcohol sensors based on Screen-Printed Carbon Electrodes.

PubMed

Costa Rama, Estefanía; Biscay, Julien; González García, María Begoña; Julio Reviejo, A; Pingarrón Carrazón, José Manuel; Costa García, Agustín

2012-05-30

Different very simple single-use alcohol enzyme sensors were developed using alcohol oxidase (AOX) from three different yeast, Hansenula sp., Pichia pastoris and Candida boidinii, and employing three different commercial mediator-based Screen-Printed Carbon Electrodes as transducers. The mediators tested, Prussian Blue, Ferrocyanide and Co-phthalocyanine were included into the ink of the working electrode. The procedure to obtain these sensors consists of the immobilization of the enzyme on the electrode surface by adsorption. For the immobilization, an AOX solution is deposited on the working electrode and left until dried (1h) at room temperature. The best results were obtained with the biosensor using Screen-Printed Co-phthalocyanine/Carbon Electrode and AOX from Hansenula sp. The reduced cobalt-phthalocyanine form is amperometrically detected at +0.4V (vs. Ag pseudo reference electrode). This sensor shows good sensitivity (1211 nA mM(-1)), high precision (2.1% RSD value for the slope value of the calibration plot) and wide linear response (0.05-1.00 mM) for ethanol determination. The sensor provides also accurate results for ethanol quantification in alcoholic drinks. Copyright © 2012 Elsevier B.V. All rights reserved.

Portable amperometric immunosensor for histamine detection using Prussian blue-chitosan-gold nanoparticle nanocomposite films.

PubMed

Dong, Xiu-Xiu; Yang, Jin-Yi; Luo, Lin; Zhang, Yi-Feng; Mao, Chuanbin; Sun, Yuan-Ming; Lei, Hong-Tao; Shen, Yu-Dong; Beier, Ross C; Xu, Zhen-Lin

2017-12-15

Histamine (HA) is a biogenic amine that can accumulate to high concentration levels in food as a result of microbial activity and can cause toxic effects in consumers. In this work, a portable electrochemical immunosensor capable of detecting HA with high sensitivity and selectivity was developed. Prussian blue-chitosan-gold nanoparticle (PB-CS-AuNP) nanocomposite films with excellent biocompatibility were synthesized and characterized by scanning electron microscopy and energy dispersive X-ray analysis. The PB-CS-AuNP were coated onto a screen-printed electrode by one-step electrodeposition and used to conjugate the HA ovalbumin conjugate (HA-Ag). HA was determined by a competition between the coating HA-Ag and the HRP labeled HA antibody (HRP-HA-Ab). After careful optimization of assay conditions and Box-Behnken analysis, the developed immunosensor showed a linear range from 0.01 to 100μg/mL for HA in fish samples. The average recoveries from spiked samples ranged from 97.25% to 105%. The biosensor also showed good specificity, reproducibility, and stability, indicating its potential application in monitoring HA in a simple and low cost manner. Copyright © 2017 Elsevier B.V. All rights reserved.

Permselective and enzyme-entrapping behaviours of an electropolymerized, non-conducting, poly(o-aminophenol) thin film-modified electrode: a critical study.

PubMed

Guerrieri, Antonio; Ciriello, Rosanna; Centonze, Diego

2009-02-15

Non-conducting polymeric films synthesised by the electrooxidation of o-aminophenol on a platinum electrode in acetate or phosphate buffer displayed an interesting permselective behaviour, which proved valuable in minimising the electrochemical interferences from ascorbate, acetaminophen, cysteine and urate sample molecules in amperometric detection mode. The electrosynthesis of poly(o-aminophenol) (p(oAP)) film showed also useful as permselective membrane for enzyme immobilization as demonstrated by the production of an interference-free glucose oxidase biosensor. In this respect, the glucose response time, t(0.95), evaluated in batch addition experiments, was lower than 5s while the calibration curve was linear up to 10mM of glucose with a sensitivity of 69.7nA/mM. Both the permselective behaviour and the enzyme-entrapping property of the film were critically compared with the relevant studies until now reported. With respect to the sophisticated but complex approaches described elsewhere, this study shows that simply a proper optimization of p(oAP) electrosynthesis and its permselective behaviour is the key to improve significantly the selectivity of the resulting analytical devices.

A luminescent hybridoma-based biosensor for rapid detection of V. cholerae upon induction of calcium signaling pathway.

PubMed

Zamani, Parichehr; Sajedi, Reza H; Hosseinkhani, Saman; Zeinoddini, Mehdi; Bakhshi, Bita

2016-05-15

In this study, a hybridoma based biosensor was developed for rapid, sensitive and selective detection of Vibrio cholerae O1 which converts the antibody-antigen binding to bioluminescence light. After investigation on hybridoma performance, the biosensor was constructed by transfecting specific hybridoma cells with aequorin reporter gene and the bioluminescence activities of stable biosensor were measured. The sensitivity of biosensor was as few as 50 CFU/ml and it showed no responses to other entric bacteria. Moreover, the response time of biosensor was estimated in 7th second which means this method is considerably faster than many available detection assays. In addition, this biosensor was successfully applied to V. cholerae detection in environmental samples with no significant loss in sensitivity, demonstrating our proposed biosensor provides a sensitive and reliable method for detection of V. cholerae in natural samples. The application of whole hybridoma cell directly as a sensing element in biosensor construction which mentioned for the first time in present study suggests that hybridoma cells could provide a valuable tool for future studies in both basic and diagnostic sciences and could be considered as a fast and specific sensing element for detection of other pathogens in different applications. Copyright © 2015 Elsevier B.V. All rights reserved.

An ultra-sensitive Au nanoparticles functionalized DNA biosensor for electrochemical sensing of mercury ions.

PubMed

Zhang, Yanyan; Zhang, Cong; Ma, Rui; Du, Xin; Dong, Wenhao; Chen, Yuan; Chen, Qiang

2017-06-01

The present work describes an effective strategy to fabricate a highly sensitive and selective DNA-biosensor for the determination of mercury ions (Hg 2+ ). The DNA 1 was modified onto the surface of Au electrode by the interaction between sulfydryl group and Au electrode. DNA probe is complementary with DNA 1. In the presence of Hg 2+ , the electrochemical signal increases owing to that Hg 2+ -mediated thymine bases induce the conformation of DNA probe to change from line to hairpin and less DNA probes adsorb into DNA 1. Taking advantage of its reduction property, methylene blue is considered as the signal indicating molecule. For improving the sensitivity of the biosensor, Au nanoparticles (Au NPs) modified reporter DNA 3 is used to adsorb DNA 1. Electrochemical behaviors of the biosensor were evaluated by electrochemical impedance spectroscopy and cyclic voltammetry. Several important parameters which could affect the property of the biosensor were studied and optimized. Under the optimal conditions, the biosensor exhibits wide linear range, high sensitivity and low detection limit. Besides, it displays superior selectivity and excellent stability. The biosensor was also applied for water sample detection with satisfactory result. The novel strategy of fabricating biosensor provides a potential platform for fabricating a variety of metal ions biosensors. Copyright © 2017 Elsevier B.V. All rights reserved.

Graphene oxide-mediated electrochemistry of glucose oxidase on glassy carbon electrodes.

PubMed

Castrignanò, Silvia; Valetti, Francesca; Gilardi, Gianfranco; Sadeghi, Sheila J

2016-01-01

Glucose oxidase (GOD) was immobilized on glassy carbon electrodes in the presence of graphene oxide (GO) as a model system for the interaction between GO and biological molecules. Lyotropic properties of didodecyldimethylammonium bromide (DDAB) were used to stabilize the enzymatic layer on the electrode surface resulting in a markedly improved electrochemical response of the immobilized GOD. Transmission electron microscopy images of the GO with DDAB confirmed the distribution of the GO in a two-dimensional manner as a foil-like material. Although it is known that glassy carbon surfaces are not ideal for hydrogen peroxide detection, successful chronoamperometric titrations of the GOD in the presence of GO with β-d-glucose were performed on glassy carbon electrodes, whereas no current response was detected upon β-d-glucose addition in the absence of GO. The GOD-DDAB-GO system displayed a high turnover efficiency and substrate affinity as a glucose biosensor. The simplicity and ease of the electrode preparation procedure of this GO/DDAB system make it a good candidate for immobilizing other biomolecules for fabrication of amperometric biosensors. © 2015 International Union of Biochemistry and Molecular Biology, Inc.

The significance of amperometric detection of alkaline phosphatase in colorectal cancer diagnostics

NASA Astrophysics Data System (ADS)

Belkin, Anton; Freynd, Genrietta; Katsnelson, Mikhail

2016-08-01

Colorectal cancer (CRC) is one of the most common cancers in the world; it takes the second place in oncological morbidity. The ALP activity of intestinal epithelial differentiation marker (ALP) was investigated in surgical material and colon biopsies of 47 patients with the electrochemical method using biosensors (biochips). The average current obtained in the studies of colorectal cancer tissues was lower than in the studies of intact colon mucosa. Histology of tumors matched the differentiation types/stages of adenocarcinomas. The study of ALP activity in the surgical material and biopsies of colon tumors can become one of the most useful methods for evaluating the functional atypia in tumor tissue.

A reagentless amperometric biosensor for alcohol detection in column liquid chromatography based on co-immobilized peroxidase and alcohol oxidase in carbon paste.

PubMed

Johansson, K; Jönsson-Pettersson, G; Gorton, L; Marko-Varga, G; Csöregi, E

1993-12-01

A reagentless carbon paste electrode chemically modified with covalently bound alcohol oxidase and horse-radish peroxidase was examined as a selective sensor in flow injection and column liquid chromatography. A combination of carbodiimide, glutaraldehyde, and polyethyleneimine was used for immobilizing the enzymes in the paste. The surface of the electrodes was protected by first forming a layer of electropolymerized ortho-phenylenediamine followed by deposition of a cation exchange membrane (Eastman AQ 29D). The electrodes were used for detection of hydrogen peroxide, methanol, ethanol, propanol, isopropanol, and butanol. Preliminary investigations of the use of this sensor for bioprocess control are reported.

Influence of Thermal Modification and Morphology of TiO₂ Nanotubes on Their Electrochemical Properties for Biosensors Applications.

PubMed

Arkusz, Katarzyna; Paradowska, Ewa; Nycz, Marta; Krasicka-Cydzik, Elżzbieta

2018-05-01

The morphology of self-assembled TiO2 nanotubes layer plays a key role in electrical conductivity and biocompatibility properties in terms of cell proliferation, adhesion and mineralization. Many research studies have been reported in using a TiO2 nanotubes for different medical applications, there is a lack of unified correlation between TNT morphology and its electrochemical properties. The aim of this study was to examine the effects of diameter and annealing conditions on TiO2 nanotubes with identical height and their behaviour as biosensor platform. TiO2 nanotubes layer, 1000 nm thick with nanotubes of diameters in range: 25 ÷ 100 nm, was prepared by anodizing of the titanium foil in ethylene glycol solution. To change the crystal structure and improve the electrical conductivity of the semiconductive TiO2 nanotubes layer the thermal treatment by annealing in argon, nitrogen or air was used. Basing on the electrochemical tests, the XPS and scanning microscopy examinations, as well as the contact angle measurements and the amperometric detection of potassium ferricyanide, it was concluded that the 1000 nm thick TiO2 nanotubes layer with nanotubes of 50 nm diameter, annealed in argon, showed the best physicochemical properties, which helps investigate the adsorption immobilization mechanism. The possibility of using TNT as a biosensor platform was confirmed in hydrogen detection.

Hydrogen peroxide biosensor based on microperoxidase-11 immobilized in a silica cavity array electrode.

PubMed

Tian, Shu; Zhou, Qun; Gu, Zhuomin; Gu, Xuefang; Zhao, Lili; Li, Yan; Zheng, Junwei

2013-03-30

Hydrogen peroxide biosensor based on the silica cavity array modified indium-doped tin oxide (ITO) electrode was constructed. An array of silica microcavities was fabricated by electrodeposition using the assembled polystyrene particles as template. Due to the resistance gradient of the silica cavity structure, the silica cavity exhibits a confinement effect on the electrochemical reactions, making the electrode function as an array of "soft" microelectrodes. The covalently immobilized microperoxidase-11(MP-11) inside these SiO2 cavities can keep its physiological activities, the electron transfer between the MP-11 and electrode was investigated through electrochemical method. The cyclic voltammetric curve shows a quasi-reversible electrochemical redox behavior with a pair of well-defined redox peaks, the cathodic and anodic peaks are located at -0.26 and -0.15V. Furthermore, the modified electrode exhibits high electrocatalytic activity toward the reduction of hydrogen peroxide and also shows good analytical performance for the amperometric detection of H2O2 with a linear range from 2×10(-6) to 6×10(-4)M. The good reproducibility and long-term stability of this novel electrode not only offer an opportunity for the detection of H2O2 in low concentration, but also provide a platform to construct various biosensors based on many other enzymes. Copyright © 2013 Elsevier B.V. All rights reserved.

A Facile Electrochemical Preparation of Reduced Graphene Oxide@Polydopamine Composite: A Novel Electrochemical Sensing Platform for Amperometric Detection of Chlorpromazine

NASA Astrophysics Data System (ADS)

Palanisamy, Selvakumar; Thirumalraj, Balamurugan; Chen, Shen-Ming; Wang, Yi-Ting; Velusamy, Vijayalakshmi; Ramaraj, Sayee Kannan

2016-09-01

We report a novel and sensitive amperometric sensor for chlorpromazine (CPZ) based on reduced graphene oxide (RGO) and polydopamine (PDA) composite modified glassy carbon electrode. The RGO@PDA composite was prepared by electrochemical reduction of graphene oxide (GO) with PDA. The RGO@PDA composite modified electrode shows an excellent electro-oxidation behavior to CPZ when compared with other modified electrodes such as GO, RGO and GO@PDA. Amperometric i-t method was used for the determination of CPZ. Amperometry result shows that the RGO@PDA composite detects CPZ in a linear range from 0.03 to 967.6 μM. The sensor exhibits a low detection limit of 0.0018 μM with the analytical sensitivity of 3.63 ± 0.3 μAμM-1 cm-2. The RGO@PDA composite shows its high selectivity towards CPZ in the presence of potentially interfering drugs such as metronidazole, phenobarbital, chlorpheniramine maleate, pyridoxine and riboflavin. In addition, the fabricated RGO@PDA modified electrode showed an appropriate recovery towards CPZ in the pharmaceutical tablets.

Electrochemical detection of p-ethylguaiacol, a fungi infected fruit volatile using metal oxide nanoparticles.

PubMed

Fang, Yi; Umasankar, Yogeswaran; Ramasamy, Ramaraja P

2014-08-07

Nanoparticles of TiO(2) or SnO(2) on screen-printed carbon (SP) electrodes have been developed for evaluating their potential application in the electrochemical sensing of volatiles in fruits and plants. These metal oxide nanoparticle-modified electrodes possess high sensitivity and low detection limit for the detection of p-ethylguaiacol, a fingerprint compound present in the volatile signature of fruits and plants infected with a pathogenic fungus Phytophthora cactorum. The electroanalytical data obtained using cyclic voltammetry and differential pulse voltammetry showed that both SnO(2) and TiO(2) exhibited high sensitivity (174-188 μA cm(-2) mM(-1)) and low detection limits (35-62 nM) for p-ethylguaiacol detection. The amperometric detection was highly repeatable with RSD values ranging from 2.48 to 4.85%. The interference studies show that other common plant volatiles do not interfere in the amperometric detection signal of p-ethylguaiacol. The results demonstrate that metal oxides are a reasonable alternative to expensive electrode materials such as gold or platinum for amperometric sensor applications.

Flow injection amperometric sensor with a carbon nanotube modified screen printed electrode for determination of hydroquinone.

PubMed

Upan, Jantima; Reanpang, Preeyaporn; Chailapakul, Orawon; Jakmunee, Jaroon

2016-01-01

Flow injection amperometric (FI-Amp) sensor was developed for sensitive and selective determination of hydroquinone. A simple screen printed carbon electrode (SPCE) was modified with various nanomaterials for improvement of sensitivity on the determination of quinone. As a result, the appropriate sensitivity is obtained from the SPCE modified with carbon nanotube (CNT) which indicated that CNT contributed to the transfer of electron to quinone. The reproducibility (n=9) and repeatability (n=111) of SPCE-CNT were obtained at 4.4% and 3.6%RSD, respectively. The SPCE-CNT electrode and enzymatic column were incorporated to the FI-Amp system to determine hydroquinone. Laccase was immobilized on silica gel using a cross-linking method by glutaraldehyde modification and then packed in the column. The laccase column has high efficiency for catalytic oxidation of hydroquinone to quinone, which further detects by amperometric detection. Parameters affecting response of the proposed sensor, i.e., pH, ionic strength, and temperature have been optimized. The proposed system provided a wide linear range between 1 and 50 µM with detection limit of 0.1 µM. Satisfactory recoveries in the range of 91.2-103.8% were obtained for the analysis of water sample. Copyright © 2015 Elsevier B.V. All rights reserved.

Biocompatible electrochemiluminescent biosensor for choline based on enzyme/titanate nanotubes/chitosan composite modified electrode.

PubMed

Dai, Hong; Chi, Yuwu; Wu, Xiaoping; Wang, Youmei; Wei, Mingdeng; Chen, Guonan

2010-02-15

A new biocompatible ECL biosensor based on enzyme/titanate nanotubes/chitosan composite film was developed for the determination of analytes in biological samples. In the fabrication of the new ECL biosensor, biocompatible titanate nanotubes (TNTs) and a model enzyme, i.e., choline oxidase (ChOX), were immobilized on a chitosan modified glassy carbon electrode (GCE) via electrostatic adsorption and covalent interaction, respectively. By this ECL biosensor, choline was enzymatically oxidized to hydrogen peroxide and detected by a sensitive luminol ECL system. The use of TNTs not only provided a biocompatible microenvironment for the immobilized enzyme, which resulted in an excellent stability and long lifetime of the ECL biosensor, but also exhibited great enhancement towards luminol ECL and thus led to a significant improvement in sensitivity of ECL biosensor. Satisfactory results were obtained when employing this biosensor in assaying the total choline in milk samples. The work would provide a common platform to develop various sensitive, selective and biocompatible ECL biosensors based on using enzyme/TNTs/CHIT composite films. Copyright 2009 Elsevier B.V. All rights reserved.

Functionalization and Characterization of Nanomaterial Gated Field-Effect Transistor-Based Biosensors and the Design of a Multi-Analyte Implantable Biosensing Platform

NASA Astrophysics Data System (ADS)

Croce, Robert A., Jr.

Advances in semiconductor research and complementary-metal-oxide semiconductor fabrication allow for the design and implementation of miniaturized metabolic monitoring systems, as well as advanced biosensor design. The first part of this dissertation will focus on the design and fabrication of nanomaterial (single-walled carbon nanotube and quantum dot) gated field-effect transistors configured as protein sensors. These novel device structures have been functionalized with single-stranded DNA aptamers, and have shown sensor operation towards the protein Thrombin. Such advanced transistor-based sensing schemes present considerable advantages over traditional sensing methodologies in view of its miniaturization, low cost, and facile fabrication, paving the way for the ultimate realization of a multi-analyte lab-on-chip. The second part of this dissertation focuses on the design and fabrication of a needle-implantable glucose sensing platform which is based solely on photovoltaic powering and optical communication. By employing these powering and communication schemes, this design negates the need for bulky on-chip RF-based transmitters and batteries in an effort to attain extreme miniaturization required for needle-implantable/extractable applications. A complete single-sensor system coupled with a miniaturized amperometric glucose sensor has been demonstrated to exhibit reality of this technology. Furthermore, an optical selection scheme of multiple potentiostats for four different analytes (glucose, lactate, O 2 and CO2) as well as the optical transmission of sensor data has been designed for multi-analyte applications. The last part of this dissertation will focus on the development of a computational model for the amperometric glucose sensors employed in the aforementioned implantable platform. This model has been applied to single-layer single-enzyme systems, as well as multi-layer (single enzyme) systems utilizing glucose flux limiting layer-by-layer assembled outer membranes. The concentration of glucose and hydrogen peroxide within the sensor geometry, the transient response and the device response time has been simulated for both systems.

Amperometric Enzyme-based Gas Sensor for Formaldehyde: Impact of Possible Interferences

PubMed Central

Achmann, Sabine; Hämmerle, Martin; Moos, Ralf

2008-01-01

In this work, cross-sensitivities and environmental influences on the sensitivity and the functionality of an enzyme-based amperometric sensor system for the direct detection of formaldehyde from the gas phase are studied. The sensor shows a linear response curve for formaldehyde in the tested range (0 - 15 vppm) with a sensitivity of 1.9 μA/ppm and a detection limit of about 130 ppb. Cross-sensitivities by environmental gases like CO2, CO, NO, H2, and vapors of organic solvents like methanol and ethanol are evaluated as well as temperature and humidity influences on the sensor system. The sensor showed neither significant signal to CO, H2, methanol or ethanol nor to variations in the humidity of the test gas. As expected, temperature variations had the biggest influence on the sensor sensitivity with variations in the sensor signal of up to 10 % of the signal for 5 vppm CH2O in the range of 25 - 30 °C. PMID:27879770

Comparative analysis of microbial fuel cell based biosensors developed with a mixed culture and Shewanella loihica PV-4 and underlying biological mechanism.

PubMed

Yi, Yue; Xie, Beizhen; Zhao, Ting; Liu, Hong

2018-06-13

Microbial fuel cell based biosensors (MFC-biosensors) utilize anode biofilms as biological recognition elements to monitor biochemical oxygen demand (BOD) and biotoxicity. However, the relatively poor sensitivity constrains the application of MFC-biosensors. To address this limitation, this study provided a systematic comparison of sensitivity between the MFC-biosensors constructed with two inocula. Higher biomass density and viability were both observed in the anode biofilm of the mixed culture MFC, which resulted in better sensitivity for BOD assessment. Compared with using mixed culture as inoculum, the anode biofilm developed with Shewanella loihica PV-4 presented lower content of extracellular polymeric substances and poorer ability to secrete protein under toxic shocks. Moreover, the looser structure in the S. loihica PV-4 biofilm further facilitated its susceptibilities to toxic agents. Therefore, the MFC-biosensor with a pure culture of S. loihica PV-4 delivered higher sensitivity for biotoxicity monitoring. This study proposed a new perspective to enhance sensor performance. Copyright © 2018 Elsevier Ltd. All rights reserved.

Nano-machining of biosensor electrodes through gold nanoparticles deposition produced by femtosecond laser ablation

NASA Astrophysics Data System (ADS)

Della Ventura, B.; Funari, R.; Anoop, K. K.; Amoruso, S.; Ausanio, G.; Gesuele, F.; Velotta, R.; Altucci, C.

2015-06-01

We report an application of femtosecond laser ablation to improve the sensitivity of biosensors based on a quartz crystal microbalance device. The nanoparticles produced by irradiating a gold target with 527-nm, 300-fs laser pulses, in high vacuum, are directly deposited on the quartz crystal microbalance electrode. Different gold electrodes are fabricated by varying the deposition time, thus addressing how the nanoparticles surface coverage influences the sensor response. The modified biosensor is tested by weighting immobilized IgG antibody from goat and its analyte (IgG from mouse), and the results are compared with a standard electrode. A substantial increase of biosensor sensitivity is achieved, thus demonstrating that femtosecond laser ablation and deposition is a viable physical method to improve the biosensor sensitivity by means of nanostructured electrodes.

Application of recombinant fluorescent mammalian cells as a toxicity biosensor.

PubMed

Kim, E J; Lee, Y; Lee, J E; Gu, M B

2002-01-01

With respect to developing a more sensitive biosensor, a recombinant fluorescent Chinese Hamster Ovary cell line was used for the monitoring of various toxicants. Both cell lines, EFC-500 and KFC-A10, were able to detect toxicants sensitively. They were characterized with mitomycin C and gamma-ray as genotoxicants and bisphenol A, nonylphenol, ziram and methyl bromide as possible and known EDCs. When compared to each other, the response of KFC-A10 was generally more informative and sensitive. Compared to typical bacterial biosensor systems, these cell lines offered a sensitivity of 2- to 50-fold greater for the tested chemicals. Based on these results, the use of mammalian cells offers a sensitive biosensor system that is not only fast, cheap and reproducible but also capable of monitoring the endocrine-like characteristics of environmental toxicants.

On Chip Protein Pre-Concentration for Enhancing the Sensitivity of Porous Silicon Biosensors.

PubMed

Arshavsky-Graham, Sofia; Massad-Ivanir, Naama; Paratore, Federico; Scheper, Thomas; Bercovici, Moran; Segal, Ester

2017-12-22

Porous silicon (PSi) nanomaterials have been widely studied as label-free optical biosensors for protein detection. However, these biosensors' performance, specifically in terms of their sensitivity (which is typically in the micromolar range), is insufficient for many applications. Herein, we present a proof-of-concept application of the electrokinetic isotachophoresis (ITP) technique for real-time preconcentration of a target protein on a PSi biosensor. With ITP, a highly concentrated target zone is delivered to the sensing area, where the protein target is captured by immobilized aptamers. The detection of the binding events is conducted in a label-free manner by reflective interferometric Fourier transformation spectroscopy (RIFTS). Up to 1000-fold enhancement in local concentration of the protein target and the biosensor's sensitivity are achieved, with a measured limit of detection of 7.5 nM. Furthermore, the assay is successfully performed in complex media, such as bacteria lysate samples, while the selectivity of the biosensor is retained. The presented assay could be further utilized for other protein targets, and to promote the development of clinically useful PSi biosensors.

A highly sensitive magnetic biosensor for detection and quantification of anticancer drugs tagged to superparamagnetic nanoparticles

NASA Astrophysics Data System (ADS)

Wingo, J.; Devkota, J.; Mai, T. T. T.; Nguyen, X. P.; Mukherjee, P.; Srikanth, H.; Phan, M. H.; Vietnam Academy of Science and Technology Collaboration; University of South Florida Team

2014-03-01

A precise detection of low concentrations of biomolecules attached to magnetic nanoparticles in complex biological systems is a challenging task and requires biosensors with improved sensitivity. Here, we present a highly sensitive magnetic biosensor based on the magneto-reactance (MX) effect of a Co65Fe4Ni2Si15B14 amorphous ribbon with nanohole-patterned surface for detection and quantification of anticancer drugs (Curcumin) tagged to Fe3O4 nanoparticles. The detection and quantification of Curcumin were assessed by the change in MX of the ribbon subject to varying concentrations of the functionalized Fe3O4 nanoparticles. A high capacity of the MX-based biosensor in quantitative analysis of the nanoparticles was achieved in the range of 0 - 50 ng/ml, beyond which the detection sensitivity (η) remained unchanged. The η of the biosensor reached an extremely high value of 30%, which is about 4-5 times higher than that of a magneto-impedance (MI) based biosensor. This biosensor is well suited for detection of low-concentration magnetic biomarkers in biological systems. This work was supported by was supported by the Florida Cluster for Advanced Smart Sensor Technologies, USAMRMC (Grant # W81XWH-07-1-0708), and the NSF-funded REU program at the USF.

Concentric-electrode organic electrochemical transistors: case study for selective hydrazine sensing

NASA Astrophysics Data System (ADS)

Pecqueur, S.; Lenfant, S.; Guérin, D.; Alibart, F.; Vuillaume, D.

2017-12-01

We report on hydrazine-sensing organic electrochemical transistors (OECTs) with a design consisting in concentric annular electrodes. The design engineering of these OECTs was motivated by the great potential of using OECT sensing arrays in fields such as bioelectronics. In this work, PEDOT:PSS-based OECTs have been studied as aqueous sensors, specifically sensitive to the lethal hydrazine molecule. These amperometric sensors have many relevant features for the development of hydrazine sensors, such as a sensitivity down to 10-5 M of hydrazine in water, an order of magnitude higher selectivity for hydrazine than for 9 other water soluble common analytes, the capability to recover entirely its base signal after water flushing and a very low voltage operation. The specificity for hydrazine to be sensed by our OECTs is caused by its catalytic oxidation at the gate electrode and enables increasing the output current modulation of the devices. This has permitted the device-geometry study of the whole series of 80 micrometric OECT devices with sub-20-nm PEDOT:PSS layers, channel lengths down to 1 μm and a specific device geometry of coplanar and concentric electrodes. The numerous geometries unravel new aspects of the OECT mechanisms governing the electrochemical sensing behaviours of the device, more particularly the effect of the contacts which are inherent at the micro-scale. By lowering the device cross-talking, micrometric gate-integrated radial OECTs shall contribute to the diminishing of the readout invasiveness and therefore promotes further the development of OECT biosensors.

CMOS Amperometric ADC With High Sensitivity, Dynamic Range and Power Efficiency for Air Quality Monitoring.

PubMed

Li, Haitao; Boling, C Sam; Mason, Andrew J

2016-08-01

Airborne pollutants are a leading cause of illness and mortality globally. Electrochemical gas sensors show great promise for personal air quality monitoring to address this worldwide health crisis. However, implementing miniaturized arrays of such sensors demands high performance instrumentation circuits that simultaneously meet challenging power, area, sensitivity, noise and dynamic range goals. This paper presents a new multi-channel CMOS amperometric ADC featuring pixel-level architecture for gas sensor arrays. The circuit combines digital modulation of input currents and an incremental Σ∆ ADC to achieve wide dynamic range and high sensitivity with very high power efficiency and compact size. Fabricated in 0.5 [Formula: see text] CMOS, the circuit was measured to have 164 dB cross-scale dynamic range, 100 fA sensitivity while consuming only 241 [Formula: see text] and 0.157 [Formula: see text] active area per channel. Electrochemical experiments with liquid and gas targets demonstrate the circuit's real-time response to a wide range of analyte concentrations.

Development of mercury (II) ion biosensors based on mercury-specific oligonucleotide probes.

PubMed

Li, Lanying; Wen, Yanli; Xu, Li; Xu, Qin; Song, Shiping; Zuo, Xiaolei; Yan, Juan; Zhang, Weijia; Liu, Gang

2016-01-15

Mercury (II) ion (Hg(2+)) contamination can be accumulated along the food chain and cause serious threat to the public health. Plenty of research effort thus has been devoted to the development of fast, sensitive and selective biosensors for monitoring Hg(2+). Thymine was demonstrated to specifically combine with Hg(2+) and form a thymine-Hg(2+)-thymine (T-Hg(2+)-T) structure, with binding constant even higher than T-A Watson-Crick pair in DNA duplex. Recently, various novel Hg(2+) biosensors have been developed based on T-rich Mercury-Specific Oligonucleotide (MSO) probes, and exhibited advanced selectivity and excellent sensitivity for Hg(2+) detection. In this review, we explained recent development of MSO-based Hg(2+) biosensors mainly in 3 groups: fluorescent biosensors, colorimetric biosensors and electrochemical biosensors. Copyright © 2015 Elsevier B.V. All rights reserved.

Non-invasive screening for Alzheimer's disease by sensing salivary sugar using Drosophila cells expressing gustatory receptor (Gr5a) immobilized on an extended gate ion-sensitive field-effect transistor (EG-ISFET) biosensor.

PubMed

Lau, Hui-Chong; Lee, In-Kyu; Ko, Pan-Woo; Lee, Ho-Won; Huh, Jeung-Soo; Cho, Won-Ju; Lim, Jeong-Ok

2015-01-01

Body fluids are often used as specimens for medical diagnosis. With the advent of advanced analytical techniques in biotechnology, the diagnostic potential of saliva has been the focus of many studies. We recently reported the presence of excess salivary sugars, in patients with Alzheimer's disease (AD). In the present study, we developed a highly sensitive, cell-based biosensor to detect trehalose levels in patient saliva. The developed biosensor relies on the overexpression of sugar sensitive gustatory receptors (Gr5a) in Drosophila cells to detect the salivary trehalose. The cell-based biosensor was built on the foundation of an improved extended gate ion-sensitive field-effect transistor (EG-ISFET). Using an EG-ISFET, instead of a traditional ion-sensitive field-effect transistor (ISFET), resulted in an increase in the sensitivity and reliability of detection. The biosensor was designed with the gate terminals segregated from the conventional ISFET device. This design allows the construction of an independent reference and sensing region for simultaneous and accurate measurements of samples from controls and patients respectively. To investigate the efficacy of the cell-based biosensor for AD screening, we collected 20 saliva samples from each of the following groups: participants diagnosed with AD, participants diagnosed with Parkinson's disease (PD), and a control group composed of healthy individuals. We then studied the response generated from the interaction of the salivary trehalose of the saliva samples and the Gr5a in the immobilized cells on an EG-ISFET sensor. The cell-based biosensor significantly distinguished salivary sugar, trehalose of the AD group from the PD and control groups. Based on these findings, we propose that salivary trehalose, might be a potential biomarker for AD and could be detected using our cell-based EG-ISFET biosensor. The cell-based EG-ISFET biosensor provides a sensitive and direct approach for salivary sugar detection and may be used in the future as a screening method for AD.

Magnetic MoS2 on multiwalled carbon nanotubes for sulfide sensing.

PubMed

Li, Chunxiang; Zhang, Dan; Wang, Jiankang; Hu, Pingan; Jiang, Zhaohua

2017-07-04

A novel hybrid metallic cobalt insided in multiwalled carbon nanotubles/molybdenum disulfide (Co@CNT/MoS 2 ) modified glass carbon electrode (GCE) was fabricated with a adhesive of Nafion suspension and used as chemical sensors for sulfide detection. Single-layered MoS 2 was coated on CNTs through magnetic traction force between paramagnetic monolayer MoS 2 and Co particles in CNTs. Co particles faciliated the collection of paramagnetic monolayer MoS 2 exfoliated from bulk MoS 2 in solution. Amperometric analysis, cycle voltammetry, cathodic stripping analysis and linear sweep voltammetry results showed the Co@CNT/MoS 2 modified GCE exhibited excellent electrochemical activity to sulfide in buffer solutions, but amperometric analysis was found to be more sensitive than the other methods. The amperometric response result indicated the Co@CNT/MoS 2 -modified GCE electrode was an excellent electrochemical sensor for detecting S 2- with a detection limit of 7.6 nM and sensitivity of 0.23 mA/μM. The proposed electrode was used for the determination of sulfide levels in hydrogen sulfide-pretreated fruits, and the method was also verified with recovery studies. Copyright © 2017 Elsevier B.V. All rights reserved.

A Facile Electrochemical Preparation of Reduced Graphene Oxide@Polydopamine Composite: A Novel Electrochemical Sensing Platform for Amperometric Detection of Chlorpromazine

PubMed Central

Palanisamy, Selvakumar; Thirumalraj, Balamurugan; Chen, Shen-Ming; Wang, Yi-Ting; Velusamy, Vijayalakshmi; Ramaraj, Sayee Kannan

2016-01-01

We report a novel and sensitive amperometric sensor for chlorpromazine (CPZ) based on reduced graphene oxide (RGO) and polydopamine (PDA) composite modified glassy carbon electrode. The RGO@PDA composite was prepared by electrochemical reduction of graphene oxide (GO) with PDA. The RGO@PDA composite modified electrode shows an excellent electro-oxidation behavior to CPZ when compared with other modified electrodes such as GO, RGO and GO@PDA. Amperometric i-t method was used for the determination of CPZ. Amperometry result shows that the RGO@PDA composite detects CPZ in a linear range from 0.03 to 967.6 μM. The sensor exhibits a low detection limit of 0.0018 μM with the analytical sensitivity of 3.63 ± 0.3 μAμM–1 cm–2. The RGO@PDA composite shows its high selectivity towards CPZ in the presence of potentially interfering drugs such as metronidazole, phenobarbital, chlorpheniramine maleate, pyridoxine and riboflavin. In addition, the fabricated RGO@PDA modified electrode showed an appropriate recovery towards CPZ in the pharmaceutical tablets. PMID:27650697

Effect of chlorpyrifos on the inhibition of the enzyme acetylcholinesterase by cross-linking in water-supply samples and milk from dairy cattle.

PubMed

Catalina Rodríguez, Diana; Carvajal, Stephanie; Peñuela, Gustavo

2013-07-15

A methodology for the determination of chlorpyrifos in water-supply samples and in milk from dairy cattle was developed. An amperometric biosensor was used to inhibit the enzyme acetylcholinesterase (AChE), which was immobilized by the cross-linking method (crosslinks between the enzyme and the sensor). The potential applied, the amount of enzyme to be immobilized and the acetylthiocholine (ACTh) concentration were optimized before calibration and analysis of the samples was performed. The concentration of chlorpyrifos was determined in the range of 1.0×10(-6) M to 5.0×10(-2) M with a detection limit of 5.0×10(-6) M. Spiked water samples showed high recoveries (91.32% and 93.98% for low and high chlorpyrifos levels, respectively), while milk samples exhibited a matrix effect with recoveries of 82.81% and 79.77% for high and low chlorpyrifos levels, respectively. The average concentration of chlorpyrifos in the water supply samples (5.11×10(-6) M), determined using the biosensor, was compared using gas chromatography and gave an average value of 3.04×10(-6) M. The results allow it to be concluded that although chromatographic methods are still more exact, biosensors are promising tools for the determination of analytes in the field, as they have a low cost, a reduced analysis time and good reproducibility in the data. Copyright © 2013 Elsevier B.V. All rights reserved.

Immobilization of myoglobin on Au nanoparticle-decorated carbon nanotube/polytyramine composite as a mediator-free H2O2 and nitrite biosensor

PubMed Central

Vilian, A. T. Ezhil; Veeramani, Vediyappan; Chen, Shen-Ming; Madhu, Rajesh; Kwak, Cheol Hwan; Huh, Yun Suk; Han, Young-Kyu

2015-01-01

A novel composite film was designed for use as a highly selective mediator-free amperometric biosensor, and a method was created for accomplishing direct electrochemistry of myoglobin on a multi-walled carbon nanotube and tyramine-modified composite decorated with Au nanoparticles on a glassy carbon electrode. The ultraviolet-visible and electrochemical impedance spectroscopy results showed that myoglobin retained its native conformation in the interaction with Au-PTy-f-MWCNT. The surface coverage of Mb-heme-Fe(II)/(III) immobilized on Au-PTy-f-MWCNT and the heterogeneous electron-transfer rate constant were 2.12 × 10−9 mol cm−2 and 4.86 s−1, respectively, indicating a higher loading capacity of the nanocomposite for direct electron transfer of Mb onto the electrode surface. The proposed Mb/Au-PTy-f-MWCNT biofilm exhibited excellent electrocatalytic behavior toward the reduction of H2O2 and the oxidation of nitrite with linear ranges of 2 to 5000 μM and 1 to 8000 μM and lower detection limits of 0.01 μM and 0.002 μM, respectively. An apparent Michaelis-Menten constant of 0.12 mM indicated that the Mb immobilized on the Au-PTy-f-MWCNT film retained its native activity. This biosensor can be successfully applied to detect H2O2 and nitrite in disinfectant cream, eye drops, pickle juice, and milk samples. PMID:26672985

Characterization and application of a diamine oxidase from Lathyrus sativus as component of an electrochemical biosensor for the determination of biogenic amines in wine and beer.

PubMed

Di Fusco, Massimo; Federico, Rodolfo; Boffi, Alberto; Macone, Alberto; Favero, Gabriele; Mazzei, Franco

2011-08-01

In this work, we have characterized a diamine oxidase (DAO) from Lathyrus sativus and evaluated its use, for the first time, as biocatalytic component of an electrochemical biosensor for the determination of biogenic amines index in wine and beer samples. Firstly, DAO was electrokinetically characterized free in solution by means of a platinum electrode and then immobilized by using polyazetidine prepolimer on the surface of screen-printed electrodes constituted of two gold working electrodes. The amperometric measurements were carried out by using a flow system at a fixed potential of +600 mV vs the internal silver pseudo reference in phosphate buffer solution (0.1 mol l(-1), pH = 7.4). The analysis of wine and beer samples were performed in flow injection system using the dual channel transducer providing simultaneous detection of sample and blank signal, and the resulting signal (after subtraction of the blank signal) was referred to that of putrescine. The results were compared with those obtained using a modified reference method based on gas chromatography-mass spectrometry analysis on the same samples. The results obtained in the analysis of Italian wines shows the better suitability of DAO-based biosensor in the determination of the biogenic amines (BAs) index expressed as putrescine equivalent in both red and white wines, being less efficient in beer samples where it underestimates by about 50% the BAs content.

Immune biosensors based on the SPR and TIRE: efficiency of their application for bacteria determination

NASA Astrophysics Data System (ADS)

Starodub, N. F.; Ogorodniichuk, J.; Lebedeva, T.; Shpylovyy, P.

2013-11-01

In this work we have designed high-specific biosensors for Salmonella typhimurium detection based on the surface plasmon resonance (SPR) and total internal reflection ellipsometry (TIRE). It has been demonstrated high selectivity and sensitivity of analysis. As a registering part for our experiments the Spreeta (USA) and "Plasmonotest" (Ukraine) with flowing cell have been applied among of SPR device. Previous researches confirmed an efficiency of SPR biosensors using for detecting of specific antigen-antibody interactions therefore this type of reactions with some previous preparations of surface binding layer was used as reactive part. It has been defined that in case with Spreeta sensitivity was on the level 103 - 107 cells/ml. Another biosensor based on the SPR has shown the sensitivity within 101 - 106 cells/ml. Maximal sensitivity was on the level of several cells in 10 ml (up to the fact that less than 5 cells) which has been obtained using the biosensor based on TIRE.

Investigation of a Photoelectrochemical Passivated ZnO-Based Glucose Biosensor

PubMed Central

Lee, Ching-Ting; Chiu, Ying-Shuo; Ho, Shu-Ching; Lee, Yao-Jung

2011-01-01

A vapor cooling condensation system was used to deposit high quality intrinsic ZnO thin films and intrinsic ZnO nanorods as the sensing membrane of extended-gate field-effect-transistor (EGFET) glucose biosensors. The sensing sensitivity of the resulting glucose biosensors operated in the linear range was 13.4 μA mM−1 cm−2. To improve the sensing sensitivity of the ZnO-based glucose biosensors, the photoelectrochemical method was utilized to passivate the sidewall surfaces of the ZnO nanorods. The sensing sensitivity of the ZnO-based glucose biosensors with passivated ZnO nanorods was significantly improved to 20.33 μA mM−1 cm−2 under the same measurement conditions. The experimental results verified that the sensing sensitivity improvement was the result of the mitigation of the Fermi level pinning effect caused by the dangling bonds and the surface states induced on the sidewall surface of the ZnO nanorods. PMID:22163867

Recent Advances in Exosomal Protein Detection Via Liquid Biopsy Biosensors for Cancer Screening, Diagnosis, and Prognosis.

PubMed

Liu, Chang; Yang, Yunchen; Wu, Yun

2018-03-08

Current cancer diagnostic methods are challenged by low sensitivity, high false positive rate, limited tumor information, uncomfortable or invasive procedures, and high cost. Liquid biopsy that analyzes circulating biomarkers in body fluids represents a promising solution to these challenges. Exosomes are one of the promising cancer biomarkers for liquid biopsy because they are cell-secreted, nano-sized, extracellular vesicles that stably exist in all types of body fluids. Exosomes transfer DNAs, RNAs, proteins, and lipids from parent cells to recipient cells for intercellular communication and play important roles in cancer initiation, progression, and metastasis. Many liquid biopsy biosensors have been developed to offer non- or minimally-invasive, highly sensitive, simple, rapid, and cost-effective cancer diagnostics. This review summarized recent advances of liquid biopsy biosensors with a focus on the detection of exosomal proteins as biomarkers for cancer screening, diagnosis, and prognosis. We reviewed six major types of liquid biopsy biosensors including immunofluorescence biosensor, colorimetric biosensor, surface plasmon resonance (SPR) biosensor, surface-enhanced Raman scattering (SERS) biosensor, electrochemical biosensor, and nuclear magnetic resonance (NMR) biosensor. We shared our perspectives on future improvement of exosome-based liquid biopsy biosensors to accelerate their clinical translation.

Enzyme and microbial sensors for environmental monitoring

NASA Astrophysics Data System (ADS)

Wollenberger, U.; Neumann, B.; Scheller, Frieder W.

1993-03-01

Biosensors employing the biocatalyst on a different level of integration have been developed for monitoring environmental pollution. These probes range from laboratory specimen to commercial detectors applied to analyzers. This paper presents a selection of recent developments on amperometric enzyme and microbial biosensors. A monoenzymatic bulk type carbon electrode is described for biosensing organic hydroperoxides in aqueous solutions. Here, peroxidase is immobilized within the electrode body and the direct electron transfer between electrode and enzyme is measured. Both, reversible and irreversible inhibitors of acetylcholinesterase have been quantified by using a kinetically controlled acetylcholine enzyme sequence electrode. The inhibitory effect of pesticides such as butoxycarboxime, dimethoate, and trichlorfon could be quantified within 6 min in micrometers olar concentrations. Different multi-enzyme electrodes have been developed for the determination of inorganic phosphate. These sensors represent examples of sequentially acting enzymes in combination with enzymatic analyte recycling. Using this type of amplification nanomolar concentrations could be measured. A very fast responding microbial sensor for biological oxygen demand has been developed by immobilizing Trichosporon cutaneum onto an oxygen electrode. With this whole cell sensor waste water can be assayed with a sample frequency of 20 per hour and a working stability of more than 30 days.

A novel approach to construct a horseradish peroxidase|hydrophilic ionic liquids|Au nanoparticles dotted titanate nanotubes biosensor for amperometric sensing of hydrogen peroxide.

PubMed

Liu, Xiaoqiang; Feng, Heqing; Zhao, Ruoxia; Wang, Yanbing; Liu, Xiuhua

2012-01-15

The direct electrochemistry of horseradish peroxidase (HRP) on a novel sensing platform modified glassy carbon electrode (GCE) has been achieved. This sensing platform consists of Nafion, hydrophilic room-temperature ionic liquid (RTIL) and Au nanoparticles dotted titanate nanotubes (GNPs-TNTs). The composite of RTIL and GNPs-TNTs was immobilized on the electrode surface through the gelation of a small amount of HRP aqueous solution. The composite was characterized by transmission electron microscopy (TEM), powder X-ray diffraction (XRD) and infrared spectroscopy (IR). UV-Vis and IR spectroscopy demonstrated that HRP in the composite could retain its native secondary structure and biochemical activity. The HRP-immobilized electrode was investigated by cyclic voltammetry and chronoamperometry. The results from both techniques showed that the direct electron transfer between the nanocomposite modified electrodes and heme in HRP could be realized. The biosensor responded to H(2)O(2) in the linear range from 5×10(-6) to 1×10(-3) mol L(-1) with a detection limit of 2.1×10(-6) mol L(-1) (based on the S/N=3). Copyright © 2011 Elsevier B.V. All rights reserved.

A highly sensitive magnetic biosensor for detection and quantification of anticancer drugs tagged to superparamagnetic nanoparticles

NASA Astrophysics Data System (ADS)

Devkota, J.; Wingo, J.; Mai, T. T. T.; Nguyen, X. P.; Huong, N. T.; Mukherjee, P.; Srikanth, H.; Phan, M. H.

2014-05-01

We report on a highly sensitive magnetic biosensor based on the magneto-reactance (MX) effect of a Co65Fe4Ni2Si15B14 amorphous ribbon with a nanohole-patterned surface for detection and quantification of anticancer drugs (Curcumin) tagged to superparamagnetic (Fe3O4) nanoparticles. Fe3O4 nanoparticles (mean size, ˜10 nm) were first coated with Alginate, and Curcumin was then tagged to the nanoparticles. The detection and quantification of Curcumin were assessed by the change in MX of the ribbon subject to varying concentrations of the Fe3O4 nanoparticles to which Curcumin was tagged. A high capacity of the MX-based biosensor in quantitative analysis of Curcumin-loaded Fe3O4 nanoparticles was achieved in the range of 0-50 ng/ml, beyond which the detection sensitivity of the sensor remained unchanged. The detection sensitivity of the biosensor reached an extremely high value of 30%, which is about 4-5 times higher than that of a magneto-impedance (MI) based biosensor. This biosensor is well suited for detection of low-concentration magnetic biomarkers in biological systems.

Rapid electrochemical assessment of tumor suppressor gene methylations in raw human serum, and tumor cells and tissues using immuno-magnetic beads and selective DNA hybridization.

PubMed

Povedano, Eloy; Valverde, Alejandro; Ruiz-Valdepeñas Montiel, Víctor; Pedrero, María; Yáñez-Sedeño, Paloma; Barderas, Rodrigo; San Segundo-Acosta, Pablo; Peláez-García, Alberto; Mendiola, Marta; Hardisson, David; Campuzano, Susana; Pingarron, José Manuel

2018-05-09

We report a rapid and sensitive electrochemical strategy for the detection of gene-specific 5-methylcytosine DNA methylation. Magnetic beads (MBs) modified with an antibody specific for 5-methylcytosines (5-mC) are employed for the selective capture of any 5-mC methylated single-stranded (ss)DNA sequence. A flanking region next to the 5-mCs of the captured methylated ssDNA is recognized by selective hybridization with a synthetic biotinylated DNA sequence, further labeled with an HRP streptavidin conjugate. Amperometric transduction at disposable screen-printed carbon electrodes (SPCEs) is employed. The developed biosensor exhibits a dynamic range from 3.9 to 500 pM and a detection limit of 1.2 pM for the methylated synthetic sequence of the tumor suppressor gene O-6-methylguanine-DNA methyltransferase (MGMT) promoter region. The applicability of this strategy is demonstrated through the 45 min-analysis of specific methylation in the MGMT promoter region directly in raw spiked human serum samples and in genomic DNA extracted from U-87 glioblastoma cells and paraffin-embedded brain tumor tissues without any amplification and pretreatment step. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Eco-synthesis of graphene and its use in dihydronicotinamide adenine dinucleotide sensing.

PubMed

Amouzadeh Tabrizi, Mahmoud; Jalilzadeh Azar, Somayeh; Nadali Varkani, Javad

2014-09-01

In this paper, we report a green and eco-friendly approach to synthesize reduced graphene oxide (rGO) via a mild hydrothermal process using malt as a reduced agent. The proposed method is based on the reduction of graphene oxide (GO) in malt solution by making use of the reducing capability of phenolic compounds contained in malt solution. The obtained rGO was characterized by atomic force microscopy (AFM), ultraviolet-visible (UV-vis) absorption spectroscopy, X-ray diffraction spectroscopy (XRD), Raman spectroscopy, Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), and transmission electron microscopy (TEM). Electrochemical impedance spectroscopy analysis revealed that the charge transfer resistance of rGO modified glassy carbon (GC) electrode was much lower than that of the GC electrode. The electrochemical behavior of dihydronicotinamide adenine dinucleotide (NADH) on rGO modified GC electrode was investigated by cyclic voltammetry and amperometry. Electrochemical experiments indicated that rGO/GC electrode exhibited excellent electrocatalytic activity toward the NADH, which can be attributed to excellent electrical conductivity and high specific surface area of the rGO composite. The resulting biosensor showed highly sensitive amperometric response to NADH with a low detection limit (0.33μM). Copyright © 2014 Elsevier Inc. All rights reserved.

An amperometric enzyme electrode and its biofuel cell based on a glucose oxidase-poly(3-anilineboronic acid)-Pd nanoparticles bionanocomposite for glucose biosensing.

PubMed

Sun, Lingen; Ma, Yixuan; Zhang, Pei; Chao, Long; Huang, Ting; Xie, Qingji; Chen, Chao; Yao, Shouzhuo

2015-06-01

A new amperometric enzyme electrode and its biofuel cell were fabricated based on a glucose oxidase (GOx)-poly(3-anilineboronic acid) (PABA)-Pd nanoparticles (PdNPs) bionanocomposite for biosensing of glucose. Briefly, Pd was electroplated on a multiwalled carbon nanotubes (MWCNTs)-modified Au electrode, and the GOx-PABA-PdNPs bionanocomposite was prepared on the Pd(plate)/MWCNTs/Au electrode through the chemical oxidation of a GOx-3-anilineboronic acid adduct by Na2PdCl4, followed by electrode-modification with an outer-layer chitosan (CS) film. The thus-prepared CS/GOx-PABA-PdNPs/Pd(plate)/MWCNTs/Au electrode exhibited a linear amperometric response to glucose concentration from 2.0 μM to 4.5 mM with a sensitivity of 160 μA/mM/cm(2), sub-μM detection limit, and excellent operation/storage stability in the first-generation biosensing mode, as well as excellent analytical performance in the second-generation biosensing mode. The good recoveries of glucose obtained from spiked urine samples revealed the application potential of our amperometric enzyme electrode. In addition, a glucose/O2 biofuel cell was constructed using this enzyme electrode as the anode and a Pt/MWCNTs/Au electrode as the cathode, and this biofuel cell as a self-powered biosensing device showed a linear voltage response to glucose concentration from 100 μM to 13.5 mM with a sensitivity of 43.5 mV/mM/cm(2) and excellent operation/storage stability. Copyright © 2015 Elsevier B.V. All rights reserved.

Highly Sensitive and Reusable Membraneless Field-Effect Transistor (FET)-Type Tungsten Diselenide (WSe2) Biosensors.

PubMed

Lee, Hae Won; Kang, Dong-Ho; Cho, Jeong Ho; Lee, Sungjoo; Jun, Dong-Hwan; Park, Jin-Hong

2018-05-30

In recent years when the demand for high-performance biosensors has been aroused, a field-effect transistor (FET)-type biosensor (BioFET) has attracted great interest because of its high sensitivity, label-free detection, fast detection speed, and miniaturization. However, the insulating membrane in the conventional BioFET, which is essential in preventing the surface dangling bonds of typical semiconductors from nonspecific bindings, has limited the sensitivity of biosensors. Here, we present a highly sensitive and reusable membraneless BioFET based on a defect-free van der Waals material, tungsten diselenide (WSe 2 ). We intentionally generated a few surface defects that serve as extra binding sites for the bioreceptor immobilization through weak oxygen plasma treatment, consequently magnifying the sensitivity values to 2.87 × 10 5 A/A for 10 mM glucose. The WSe 2 BioFET also maintained its high sensitivity even after several cycles of rinsing and glucose application were repeated.

A new type of glucose biosensor based on surface acoustic wave resonator using Mn-doped ZnO multilayer structure.

PubMed

Luo, Jingting; Luo, Pingxiang; Xie, Min; Du, Ke; Zhao, Bixia; Pan, Feng; Fan, Ping; Zeng, Fei; Zhang, Dongping; Zheng, Zhuanghao; Liang, Guangxing

2013-11-15

This work reports a high-performance Mn-doped ZnO multilayer structure Love mode surface acoustic wave (SAW) biosensor for the detection of blood sugar. The biosensor was functionalized via immobilizing glucose oxidase onto a pH-sensitive polymer which was attached on Mn-doped ZnO biosensor. The fabricated SAW glucose biosensor is highly sensitive, accurate and fast with good anti-interference. The sensitivity of the SAW glucose biosensor is 7.184 MHz/mM and the accuracy is 6.96 × 10(-3)mM, which is sensitive and accurate enough for glucose monitoring. A good degree of reversibility and stability of the glucose sensor is also demonstrated, which keeps a constant differential frequency shift up to 32 days. Concerning the time response to human serum, the glucose sensor shows a value of 4.6 ± 0.4 min when increasing glucose concentrations and 7.1 ± 0.6 min when decreasing, which is less than 10 min and reach the fast response requirement for medical applications. The Mn-doped ZnO Love mode SAW biosensor can be fully integrated with CMOS Si chips and developed as a portable, passive and wireless real time detection system for blood sugar monitoring in human serum. Copyright © 2013 Elsevier B.V. All rights reserved.

New CNT/poly(brilliant green) and CNT/poly(3,4-ethylenedioxythiophene) based electrochemical enzyme biosensors.

PubMed

Barsan, Madalina M; Pifferi, Valentina; Falciola, Luigi; Brett, Christopher M A

2016-07-13

A combination of the electroactive polymer poly(brilliant green) (PBG) or conducting polymer poly(3,4-ethylenedioxythiophene) (PEDOT) with carbon nanotubes to obtain CNT/PBG and CNT/PEDOT modified carbon film electrodes (CFE) has been investigated as a new biosensor platform, incorporating the enzymes glucose oxidase (GOx) as test enzyme, alcohol oxidase (AlcOx) or alcohol dehydrogenase (AlcDH). The sensing parameters were optimized for all biosensors based on CNT/PBG/CFE, CNT/PEDOT/CFE platforms. Under optimized conditions, both GOx biosensors exhibited very similar sensitivities, while in the case of AlcOx and AlcDH biosensors, AlcOx/CNT/PBG/CFE was found to give a higher sensitivity and lower detection limit. The influence of dissolved O2 on oxidase-biosensor performance was investigated and was shown to be different for each enzyme. Comparisons were made with similar reported biosensors, showing the advantages of the new biosensors, and excellent selectivity against potential interferents was successfully demonstrated. Finally, alcohol biosensors were successfully used for the determination of ethanol in alcoholic beverages. Copyright © 2016 Elsevier B.V. All rights reserved.

Graphene oxide-based electrochemical label-free detection of glycoproteins down to aM level using a lectin biosensor

PubMed Central

Klukova, L.; Filip, J.; Belicky, S.; Vikartovska, A.; Tkac, J.

2017-01-01

A label-free ultrasensitive impedimetric biosensor with lectin immobilised on graphene oxide (GO) for the detection of glycoproteins from 1 aM is shown here. This is the first time a functional lectin biosensor with lectin directly immobilised on a graphene-based interface without any polymer modifier has been described. The study also shows that hydrophilic oxidative debris present on GO has a beneficial effect on the sensitivity of (8.46 ± 0.20)% per decade for the lectin biosensor compared to the sensitivity of (4.52 ± 0.23)% per decade for the lectin biosensor built up from GO with the oxidative debris washed out. PMID:27277703

Engineering the metal sensitive sites in Macrolampis sp2 firefly luciferase and use as a novel bioluminescent ratiometric biosensor for heavy metals.

PubMed

Gabriel, Gabriele V M; Viviani, Vadim R

2016-12-01

Most luminescent biosensors for heavy metals are fluorescent and rely on intensity measurements, whereas a few are ratiometric and rely on spectral changes. Bioluminescent biosensors for heavy metals are less common. Firefly luciferases have been coupled to responsive promoters for mercury and arsenium, and used as light on biosensors. Firefly luciferase bioluminescence spectrum is naturally sensitive to heavy metal cations such as zinc and mercury and to pH. Although pH sensitivity of firefly luciferases was shown to be useful for ratiometric estimation of intracellular pH, its potential use for ratiometric estimation of heavy metals was never considered. Using the yellow-emitting Macrolampis sp2 firefly luciferase and site-directed mutagenesis, we show that the residues H310 and E354 constitute two critical sites for metal sensitivity that can be engineered to increase sensitivity to zinc, nickel, and mercury. A linear relationship between cation concentration and the ratio of bioluminescence intensities at 550 and 610 nm allowed, for the first time, the ratiometric estimation of heavy metals concentrations down to 0.10 mM, demonstrating the potential applicability of firefly luciferases as enzymatic and intracellular ratiometric metal biosensors.

From dynamic measurements of photosynthesis in a living plant to sunlight transformation into electricity.

PubMed

Flexer, Victoria; Mano, Nicolas

2010-02-15

We propose here a new method for the direct and continuous measurement of O(2) and glucose generated during photosynthesis. Our system is based on amperometric enzyme biosensors comprising immobilized redox enzymes (glucose oxidase (GOx) and bilirubin oxidase (BOD)) and redox hydrogels "wiring" the enzyme reaction centers to electrodes. We found that these electrodes, implanted into a living plant, responded in real time to visible light as an external stimulus triggering photosynthesis. They proved to be highly selective and fast enough and may be a valuable tool in understanding photosynthesis kinetics. Furthermore, we demonstrate that with our electrodes we could harvest glucose and O(2) produced during photosynthesis to produce energy, transforming sunlight into electricity in a simple, green, renewable, and sustainable way.

Evaluation of biofilm performance as a protective barrier against biocorrosion using an enzyme electrode.

PubMed

Soleimani, S; Ormeci, B; Isgor, O B; Papavinasam, S

2011-01-01

Sulfide is known to be an important factor in microbiologically influenced corrosion (MIC) of metals and concrete deterioration in wastewater treatment structures and sewer pipelines. A sulfide biosensor was used to determine the effectiveness of Escherichia coli DH5 alpha biofilm as a protective barrier against MIC. The biofilm was shown to be effective in protecting surfaces from sulfide and helping to reduce MIC using amperometric measurements. The results also indicated that the growth conditions of E. coli DH5 alpha may have an impact on the performance of the biofilm as a sulfide barrier. The simple method provided in this work enables the comparison of several microbial biofilms and selection of the ones with potential to prevent MIC in a relatively short time.

A Glucose Biosensor Using CMOS Potentiostat and Vertically Aligned Carbon Nanofibers.

PubMed

Al Mamun, Khandaker A; Islam, Syed K; Hensley, Dale K; McFarlane, Nicole

2016-08-01

This paper reports a linear, low power, and compact CMOS based potentiostat for vertically aligned carbon nanofibers (VACNF) based amperometric glucose sensors. The CMOS based potentiostat consists of a single-ended potential control unit, a low noise common gate difference-differential pair transimpedance amplifier and a low power VCO. The potentiostat current measuring unit can detect electrochemical current ranging from 500 nA to 7 [Formula: see text] from the VACNF working electrodes with high degree of linearity. This current corresponds to a range of glucose, which depends on the fiber forest density. The potentiostat consumes 71.7 [Formula: see text] of power from a 1.8 V supply and occupies 0.017 [Formula: see text] of chip area realized in a 0.18 [Formula: see text] standard CMOS process.

A new amperometric glucose microsensor: in vitro and short-term in vivo evaluation.

PubMed

Ward, W Kenneth; Jansen, Lawrence B; Anderson, Ellen; Reach, Gerard; Klein, Jean-Claude; Wilson, George S

2002-03-01

For biosensor fabrication, it is important to optimize materials and methods in order to create predictable function in vitro and in vivo. For this reason, we designed a new glucose sensor ('revised protocol') that utilized an outer permselective membrane made of amphiphobic polyurethane which allows glucose passage through hydrophilic segments. An inner polyethersulfone membrane, stabilized with a trimethoxysilane, provided specificity. Before application of the inner membrane, it was necessary to etch the platinum electrode with a radio frequency oxygen plasma. The revised protocol sensors (n=185) were compared with sensors fabricated with an earlier ('original') protocol (n=204) which used an outer polyurethane without hydrophilic segments and a complex inner membrane of cellulose acetate and Nafion. The function of revised protocol sensors was more predictable in vitro as evidenced by a much lower variation of glucose sensitivity than the original protocol sensors. Revised and original protocol sensors were nearly linear up to a glucose concentration of 20 mM. In vitro interference from 0.1 mM acetaminophen was minimal in both groups of sensors and would be expected to represent about 2% of the total sensor response at normal glucose levels for revised protocol sensors. Prolonged testing of the revised protocol sensors for 11 days during immersion in buffer revealed stable sensitivities (day 1: 6.12+/-1.34 nA/mM; day 3: 6.33+/-1.40; day 8: 7.13+/-1.39; and day 11: 7.56+/-1.47; sensitivity for day 1 vs. each other day: not significant) and no critical loss of glucose oxidase activity. The response of the revised protocol sensors (n=7) to intraperitoneal glucose was tested in rats approximately one day after subcutaneous implantation and the sensors tracked glucose closely with a slight lag of 3-6 min.

Rapid, sensitive, and reusable detection of glucose by a robust radiofrequency integrated passive device biosensor chip.

PubMed

Kim, Nam-Young; Adhikari, Kishor Kumar; Dhakal, Rajendra; Chuluunbaatar, Zorigt; Wang, Cong; Kim, Eun-Soo

2015-01-15

Tremendous demands for sensitive and reliable label-free biosensors have stimulated intensive research into developing miniaturized radiofrequency resonators for a wide range of biomedical applications. Here, we report the development of a robust, reusable radiofrequency resonator based integrated passive device biosensor chip fabricated on a gallium arsenide substrate for the detection of glucose in water-glucose solutions and sera. As a result of the highly concentrated electromagnetic energy between the two divisions of an intertwined spiral inductor coupled with an interdigital capacitor, the proposed glucose biosensor chip exhibits linear detection ranges with high sensitivity at center frequency. This biosensor, which has a sensitivity of up to 199 MHz/mgmL(-1) and a short response time of less than 2 sec, exhibited an ultralow detection limit of 0.033 μM and a reproducibility of 0.61% relative standard deviation. In addition, the quantities derived from the measured S-parameters, such as the propagation constant (γ), impedance (Z), resistance (R), inductance (L), conductance (G) and capacitance (C), enabled the effective multi-dimensional detection of glucose.

Rapid, Sensitive, and Reusable Detection of Glucose by a Robust Radiofrequency Integrated Passive Device Biosensor Chip

PubMed Central

Kim, Nam-Young; Adhikari, Kishor Kumar; Dhakal, Rajendra; Chuluunbaatar, Zorigt; Wang, Cong; Kim, Eun-Soo

2015-01-01

Tremendous demands for sensitive and reliable label-free biosensors have stimulated intensive research into developing miniaturized radiofrequency resonators for a wide range of biomedical applications. Here, we report the development of a robust, reusable radiofrequency resonator based integrated passive device biosensor chip fabricated on a gallium arsenide substrate for the detection of glucose in water-glucose solutions and sera. As a result of the highly concentrated electromagnetic energy between the two divisions of an intertwined spiral inductor coupled with an interdigital capacitor, the proposed glucose biosensor chip exhibits linear detection ranges with high sensitivity at center frequency. This biosensor, which has a sensitivity of up to 199 MHz/mgmL−1 and a short response time of less than 2 sec, exhibited an ultralow detection limit of 0.033 μM and a reproducibility of 0.61% relative standard deviation. In addition, the quantities derived from the measured S-parameters, such as the propagation constant (γ), impedance (Z), resistance (R), inductance (L), conductance (G) and capacitance (C), enabled the effective multi-dimensional detection of glucose. PMID:25588958

Developing Highly Sensitive Micro-Biosensors for in-situ Monitoring Mercury and Chromium(IV) Contaminants by Genetically-evolving and Computer-designing Metal-binding Proteins

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang, Qinghong; Fang, Xiangdong; Goddard, William

2013-10-17

Mercury has been well known as an environmental pollutant to the environment and to cause serious effects on human health for several decades. To effectively control mercury pollution and reduce mercury damages, the sensitive determination of mercury is essential. Currently, many different types of sensor-based assays have been developed, while the whole-cell biosensor has been gaining increasingly attentions due to its easy reproducibility and the possibility to greatly reduce the cost. However, significant improvements on the specificity, sensitivity, stability and simplicity of the whole-cell biosensor are still needed prior to its eventual commercialization. Sponsored by US Department of Energy undermore » the contract agreement DE-FG02-07ER64410, we applied the special synthetic biology and directed evolution strategies to improve the effectiveness and performance of whole-cell biosensors. We have constructed different whole-cell biosensors for the mercuric ion and methylmercury detection with metalloregulator MerR, fluorescent protein mCherry and organomercurial lyase MerB. By introducing the mercuric transporter MerT, we were able to increase the detection sensitivity of whole-cell biosensors by at least one fold. By introducing the bio-amplification genetic circuit based on the gene cascade expression system of PRM-cI from bacteriophage l and Pm-XylS2 from Pseudomonas putida, we have increased the detection sensitivity of whole-cell biosensors by 1~2 folds in our tested conditions. With the directed evolution of MerR and subsequent high-throughput screening via color assay and microplate screening, we have dramatically increased the detection sensitivity by up to 10 folds at low concentration of mercury (II) of 1-10nM. Structural modeling and computational analysis of the mutated MerR showed that many mutations could cause the change of a loop to helix, which could be responsible for the increased mercury sensitivity.« less

Comparison of the efficiency control of mycotoxins by some optical immune biosensors

NASA Astrophysics Data System (ADS)

Slyshyk, N. F.; Starodub, N. F.

2013-11-01

It was compared the efficiency of patulin control at the application of such optical biosensors which were based on the surface plasmon resonance (SPR) and nano-porous silicon (sNPS). In last case the intensity of the immune reaction was registered by measuring level of chemiluminescence (ChL) or photocurrent of nPS. The sensitivity of this mycotoxin determination by first type of immune biosensor was 0.05-10 mg/L Approximately the same sensitivity as well as the overall time analysis were demonstrated by the immune biosensor based on the nPS too. Nevertheless, the last type of biosensor was simpler in technical aspect and the cost of analysis was cheapest. That is why, it was recommend the nPS based immune biosensor for wide screening application and SPR one for some additional control or verification of preliminary obtained results. In this article a special attention was given to condition of sample preparation for analysis, in particular, micotoxin extraction from potao and some juices. Moreover, it was compared the efficiency of the above mentioned immune biosensors with such traditional approach of mycotoxin determination as the ELISA-method. In the result of investigation and discussion of obtained data it was concluded that both type of the immune biosensors are able to fulfill modern practice demand in respect sensitivity, rapidity, simplicity and cheapness of analysis.

MOF-Bacteriophage Biosensor for Highly Sensitive and Specific Detection of Staphylococcus aureus.

PubMed

Bhardwaj, Neha; Bhardwaj, Sanjeev K; Mehta, Jyotsana; Kim, Ki-Hyun; Deep, Akash

2017-10-04

To produce a sensitive and specific biosensor for Staphylococcus aureus, bacteriophages have been interfaced with a water-dispersible and environmentally stable metal-organic framework (MOF), NH 2 -MIL-53(Fe). The conjugation of the MOF with bacteriophages has been achieved through the use of glutaraldehyde as cross-linker. Highly sensitive detection of S. aureus in both synthetic and real samples was realized by the proposed MOF-bacteriophage biosensor based on the photoluminescence quenching phenomena: limit of detection (31 CFU/mL) and range of detection (40 to 4 × 10 8 CFU/mL). This is the first report exploiting the use of an MOF-bacteriophage complex for the biosensing of S. aureus. The results of our study highlight that the proposed biosensor is more sensitive than most of the previous methods while exhibiting some advanced features like specificity, regenerability, extended range of linear detection, and stability for long-term storage (even at room temperature).

Goos-Hänchen effect in semiconductor metamaterial waveguide and its application as a biosensor

NASA Astrophysics Data System (ADS)

Tang, Tingting; Li, Chaoyang; Luo, Li; Zhang, Yanfen; Li, Jie

2016-06-01

We investigate Goos-Hänchen (GH) effect in a prism waveguide coupling structure with semiconductor metamaterial (SMM) of ZnGaO/ZnO multilayer and explore the possibility as a biosensor. The GH effect in three different waveguides and their performances as a refractive index sensor to detect glycerol concentration in water are analyzed. The SMM brings a periodic property of GH shift peaks which is not found in other waveguides. It is also verified that setting coupling layer of the prism waveguide coupling structure as sensing area is an effective method to significantly increase the sensitivity to refractive index variation. A schematic diagram for the biosensor configuration is designed, and the sensitivity distribution for different glycerol water index is given. Calculation results show that in the proposed biosensor the maximum sensitivity reaches 3.2 × 106 μm/RIU and resolution reaches 1.6 × 10-7 (around 1.33306) with high sensitive position sensitive detector.

Simple flow injection for determination of sulfite by amperometric detection using glassy carbon electrode modified with carbon nanotubes-PDDA-gold nanoparticles.

PubMed

Amatatongchai, Maliwan; Sroysee, Wongduan; Chairam, Sanoe; Nacapricha, Duangjai

2015-02-01

A new approach is presented for sensitive and selective measurement of sulfite (SO3(2-)) in beverages based on a simple flow injection system with amperometric detection. In this work, the sulfite sensor was a glassy carbon electrode modified with multiwall carbon nanotubes-poly(diallyldimethylammonium chloride)-gold nanoparticles composites (CNTs-PDDA-AuNPs/GC). Electrochemical oxidation of sulfite with this electrode was first studied in 0.1M phosphate buffer (pH 7.0) using cyclic voltammetry. The results indicated that the CNTs-PDDA-AuNPs/GC electrode possesses electrocatalytic activity for the oxidation of sulfite with high sensitivity and selectivity. Sulfite was quantified using amperometric measurement with the new sensor at +0.4V vs Ag/AgCl in conjunction with flow injection. The linear working range for the quantitation of sulfite was 2-200 mg L(-1) (r(2)=0.998) with a detection limit of 0.03 mg L(-1) (3σ of blank) and an estimated precision of 1.5%.The proposed method was successfully applied to the determination of sulfite in fruit juices and wines with a sample throughput of 23 samples per hour. Copyright © 2014 Elsevier B.V. All rights reserved.

Human salivary glucose analysis by high-performance ion-exchange chromatography and pulsed amperometric detection.

PubMed

Gough, H; Luke, G A; Beeley, J A; Geddes, D A

1996-02-01

The aim of this project was to develop an analytical procedure with the required level of sensitivity for the determination of glucose concentrations in small volumes of unstimulated fasting whole saliva. The technique involves high-performance ion-exchange chromatography at high pH and pulsed amperometric detection. It has a high level of reproducibility, a sensitivity as low as 0.1 mumol/l and requires only 50 microliters samples (sensitivity = 0.002 pmol). Inhibition of glucose metabolism, by procedures such as collection into 0.1% (w/v) sodium fluoride, was shown to be essential if accurate results are to be obtained. Collection on to ice followed by storage at -20 degrees C was shown to be unsuitable and resulted in glucose loss by degradation. There were inter- and intraindividual variations in the glucose concentration in unstimulated mixed saliva (range; 0.02-0.4 mmol/l). The procedure can be used for the analysis of other salivary carbohydrates and for monitoring the clearance of dietary carbohydrates from the mouth.

Highly sensitive assay for tyrosine hydroxylase activity by high-performance liquid chromatography.

PubMed

Nagatsu, T; Oka, K; Kato, T

1979-07-21

A highly sensitive assay for tyrosine hydroxylase (TH) activity by high-performance liquid chromatography (HPLC) with amperometric detection was devised based on the rapid isolation of enzymatically formed DOPA by a double-column procedure, the columns fitted together sequentially (the top column of Amberlite CG-50 and the bottom column of aluminium oxide). DOPA was adsorbed on the second aluminium oxide column, then eluted with 0.5 M hydrochloric acid, and assayed by HPLC with amperometric detection. D-Tyrosine was used for the control. alpha-Methyldopa was added to the incubation mixture as an internal standard after incubation. This assay was more sensitive than radioassays and 5 pmol of DOPA formed enzymatically could be measured in the presence of saturating concentrations of tyrosine and 6-methyltetrahydropterin. The TH activity in 2 mg of human putamen could be easily measured, and this method was found to be particularly suitable for the assay of TH activity in a small number of nuclei from animal and human brain.

Advanced glucose biosensing and nano-composite research

NASA Astrophysics Data System (ADS)

Uba, Humphreys Douglas I.

The fascinating and enhanced properties of carbon nanotubes (CNTs) have been of intense interest since their discovery. This is primarily due to their exceptional mechanical , electrical, and thermal properties , as well as their many and varied applications in modern industries such as in fuel cells, sensors, reinforced composites, electromagnetic interference shielding applications, actuators and fabrication of sophisticated nanostructures. During the production of CNTs, there are associated impurities such as metal nanoparticle and carbonaceous impurities. There are different types of CNTs such as single-walled nanotubes (SWNTs), double-walled nanotubes (DWNTs) and multi-walled nanotubes (MWNTs). In this study, XD-grade CNTs (XD) was used. XD is a mixture of SWNTs, DWNTs and MWNTs. The focus of this study was primarily geared toward the purification and application of CNTs. Two generally accepted cycles of purification were followed, purification under oxygen environment and purification under oxygen/argon mixture environment. XD was purified to different extents by oxidation and acid wash. The raw and purified CNTs were compounded into Epikote 862 and Epikure W epoxy resin to prepare composite materials and also in the biosensor studies. The CNTs and composite materials were characterized by means of thermal gravimetric analysis (TGA), differential scanning calorimetry (DSC), scanning electron microscopy (SEM) and transimssion electron microscopy (TEM). It was discovered that, excessive purification would not lead to further removal of metal residues; instead, it could result in disruption of the structure and property of CNTs. The use of CNTs as fillers was found to hinder the epoxy curing in general, and the removal of metal impurities seemed to worsen the situation. This would imply that the metal residue might catalyze the epoxy curing to a certain degree while the increased viscosity should be the primary reason for the slowed curing. An electrochemical biosensor is an analytical device that can convert a biological reaction into a current or voltage signal. A biosensor consists of a biological element that is immobilized on a film and connected to a transducer. The reaction occurs at the film where the substrate of interest is converted to a product that causes an electrical response. The response is measured by the transducer and then amplified, processed and displayed by a meter and a computer with laboratory data acquisition system. Amperometric biosensors function by monitoring the current when a constant potential is applied on the working electrode. The performances of the biosensor are evaluated by their response time, dynamic ranges and sensitivity. Response should be prompt, accurate, replicable, linear over a broad analytical range, with a reasonable recovery time, and a long working life time. Purification of the CNTs led to the opening and functionalization by oxidation of the nanotube array which may provide increased surface area for the immobilization of the enzyme, glucose oxidase. The platinum substrate provided the direct transduction platform for signal monitoring. GDI-modified (glutarate dialdehyde) chitosan played the role of an immobilization matrix. Hopefully, this research will further lead to the development of third generation biosensor system by using the CNT to directly link the electrode surface and the redox center in the enzyme molecule where superb selectivity and complete oxygen independence can be expected.

Oxygen sensing glucose biosensors based on alginate nano-micro systems

NASA Astrophysics Data System (ADS)

Chaudhari, Rashmi; Joshi, Abhijeet; Srivastava, Rohit

2014-04-01

Clinically glucose monitoring in diabetes management is done by point-measurement. However, an accurate, continuous glucose monitoring, and minimally invasive method is desirable. The research aims at developing fluorescence-mediated glucose detecting biosensors based on near-infrared radiation (NIR) oxygen sensitive dyes. Biosensors based on Glucose oxidase (GOx)-Rudpp loaded alginate microspheres (GRAM) and GOx-Platinum-octaethylporphyrin (PtOEP)-PLAalginate microsphere system (GPAM) were developed using air-driven atomization and characterized using optical microscopy, CLSM, fluorescence spectro-photometry etc. Biosensing studies were performed by exposing standard solutions of glucose. Uniform sized GRAM and GPAM with size 50+/-10μm were formed using atomization. CLSM imaging of biosensors suggests that Rudpp and PtOEP nanoparticles are uniformly distributed in alginate microspheres. The GRAM and GPAM showed a good regression constant of 0.974 and of 0.9648 over a range of 0-10 mM of glucose with a high sensitivity of 3.349%/mM (625 nm) and 2.38%/mM (645 nm) at 10 mM of glucose for GRAM and GPAM biosensor. GRAM and GPAM biosensors show great potential in development of an accurate and minimally invasive glucose biosensor. NIR dye based assays can aid sensitive, minimally-invasive and interference-free detection of glucose in diabetic patients.

Dual recognition unit strategy improves the specificity of the adenosine triphosphate (ATP) aptamer biosensor for cerebral ATP assay.

PubMed

Yu, Ping; He, Xiulan; Zhang, Li; Mao, Lanqun

2015-01-20

Adenosine triphosphate (ATP) aptamer has been widely used as a recognition unit for biosensor development; however, its relatively poor specificity toward ATP against adenosine-5'-diphosphate (ADP) and adenosine-5'-monophosphate (AMP) essentially limits the application of the biosensors in real systems, especially in the complex cerebral system. In this study, for the first time, we demonstrate a dual recognition unit strategy (DRUS) to construct a highly selective and sensitive ATP biosensor by combining the recognition ability of aptamer toward A nucleobase and of polyimidazolium toward phosphate. The biosensors are constructed by first confining the polyimidazolium onto a gold surface by surface-initiated atom transfer radical polymerization (SI-ATRP), and then the aptamer onto electrode surface by electrostatic self-assembly to form dual-recognition-unit-functionalized electrodes. The constructed biosensor based on DRUS not only shows an ultrahigh sensitivity toward ATP with a detection limit down to the subattomole level but also an ultrahigh selectivity toward ATP without interference from ADP and AMP. The constructed biosensor is used for selective and sensitive sensing of the extracellular ATP in the cerebral system by combining in vivo microdialysis and can be used as a promising neurotechnology to probing cerebral ATP concentration.

Double electrochemical covalent coupling method based on click chemistry and diazonium chemistry for the fabrication of sensitive amperometric immunosensor.

PubMed

Qi, Honglan; Li, Min; Zhang, Rui; Dong, Manman; Ling, Chen

2013-08-20

A double electrochemical covalent coupling method based on click chemistry and diazonium chemistry for the fabrication of sensitive amperometric immunosensor was developed. As a proof-of-concept, a designed alkyne functionalized human IgG was used as a capture antibody and a HRP-labeled rabbit anti-goat IgG was used as signal antibody for the determination of the anti-human IgG using the sandwich model. The immunosensor was fabricated by electrochemically grafting a phenylazide on the surface of a glassy carbon electrode, and then, by coupling the alkyne functionalized human IgG with the phenylazide group through an electro-click chemistry in the presence of Cu(II). The amperometric measurement for the determination of the anti-human IgG was performed after the fabricated immunosensor was incubated with the target anti-human IgG and then with the HRP-labeled anti-goat IgG at -0.25V in 0.10M PBS (pH 7.0) containing 0.1mM hydroquinone and 2.0mM H2O2. The results showed that the increased current was linear with the logarithm of the concentration of the anti-human IgG in the range from 1.0×10(-10)g mL(-1) to 1.0×10(-8)g mL(-1) with a detection limit of 3×10(-11)g mL(-1). Furthermore, the feasibility of the double electrochemical covalent coupling method proposed in this work for fabricating the amperometric immunosensor array was explored. This work demonstrates that the double electrochemical covalent coupling method is a promising approach for the fabrication of the immunosensor and immunosensor array. Copyright © 2013 Elsevier B.V. All rights reserved.

Sensitive detection of maltose and glucose based on dual enzyme-displayed bacteria electrochemical biosensor.

PubMed

Liu, Aihua; Lang, Qiaolin; Liang, Bo; Shi, Jianguo

2017-01-15

Glucoamylase-displayed bacteria (GA-bacteria) and glucose dehydrogenase-displayed bacteria (GDH-bacteria) were co-immobilized on multi-walled carbon nanotubes (MWNTs) modified glassy carbon electrode (GCE) to construct GA-bacteria/GDH-bacteria/MWNTs/GCE biosensor. The biosensor was developed by optimizing the loading amount and the ratio of GA-bacteria to GDH-bacteria. The as-prepared biosensor exhibited a wide dynamic range of 0.2-10mM and a low detection limit of 0.1mM maltose (S/N=3). The biosensor also had a linear response to glucose in the range of 0.1-2.0mM and a low detection limit of 0.04mM glucose (S/N=3). Interestingly, at the same concentration, glucose was 3.75-fold sensitive than that of maltose at the proposed biosensor. No interferences were observed for other possible mono- and disaccharides. The biosensor also demonstrated good long-term storage stability and repeatability. Further, using both GDH-bacteria/MWNTs/GCE biosensor and GA-bacteria/GDH-bacteria/MWNTs/GCE biosensor, glucose and maltose in real samples can be detected. Therefore, the proposed biosensor is capable of monitoring the food manufacturing and fermentation process. Copyright © 2016 Elsevier B.V. All rights reserved.

Graphene-based biosensors.

PubMed

Szunerits, Sabine; Boukherroub, Rabah

2018-06-06

Reliable data obtained from analysis of DNA, proteins, bacteria and other disease-related molecules or organisms in biological samples have become a fundamental and crucial part of human health diagnostics and therapy. The development of non-invasive tests that are rapid, sensitive, specific and simple would allow patient discomfort to be prevented, delays in diagnosis to be avoided and the status of a disease to be followed up. Bioanalysis is thus a progressive discipline for which the future holds many exciting opportunities. The use of biosensors for the early diagnosis of diseases has become widely accepted as a point-of-care diagnosis with appropriate specificity in a short time. To allow a reliable diagnosis of a disease at an early stage, highly sensitive biosensors are required as the corresponding biomarkers are generally expressed at very low concentrations. In the past 50 years, various biosensors have been researched and developed encompassing a wide range of applications. This contrasts the limited number of commercially available biosensors. When it comes to sensing of biomarkers with the required picomolar (pM) sensitivity for real-time sensing of biological samples, only a handful of sensing systems have been proposed, and these are often rather complex and costly. Lately, graphene-based materials have been considered as superior over other nanomaterials for the development of sensitive biosensors. The advantages of graphene-based sensor interfaces are numerous, including enhanced surface loading of the desired ligand due to the high surface-to-volume ratio, excellent conductivity and a small band gap that is beneficial for sensitive electrical and electrochemical read-outs, as well as tunable optical properties for optical read-outs such as fluorescence and plasmonics. In this paper, we review the advances made in recent years on graphene-based biosensors in the field of medical diagnosis.

Photoelectrochemical enzymatic biosensors.

PubMed

Zhao, Wei-Wei; Xu, Jing-Juan; Chen, Hong-Yuan

2017-06-15

Enzymatic biosensors have been valuable bioanalytical devices for analysis of diverse targets in disease diagnosis, biological and biomedical research, etc. Photoelectrochemical (PEC) bioanalysis is a recently emerged method that promptly becoming a subject of new research interests due to its attractive potential for future bioanalysis with high sensitivity and specificity. PEC enzymatic biosensors integrate the inherent sensitivities of PEC bioanalysis and the selectivity of enzymes and thus share their both advantages. Currently, PEC enzymatic biosensors have become a hot topic of significant research and the recent impetus has grown rapidly as demonstrated by increased research papers. Given the pace of advances in this area, this review will make a thorough discussion and survey on the fundamentals, sensing strategies, applications and the state of the art in PEC enzymatic biosensors, followed by future prospects based on our own opinions. We hope this work could provide an accessible introduction to PEC enzymatic biosensors for any scientist. Copyright © 2016 Elsevier B.V. All rights reserved.

Theoretical analysis of the performance of glucose sensors with layer-by-layer assembled outer membranes.

PubMed

Croce, Robert A; Vaddiraju, Santhisagar; Papadimitrakopoulos, Fotios; Jain, Faquir C

2012-10-01

The performance of implantable electrochemical glucose sensors is highly dependent on the flux-limiting (glucose, H(2)O(2), O(2)) properties of their outer membranes. A careful understanding of the diffusion profiles of the participating species throughout the sensor architecture (enzyme and membrane layer) plays a crucial role in designing a robust sensor for both in vitro and in vivo operation. This paper reports the results from the mathematical modeling of Clark's first generation amperometric glucose sensor coated with layer-by-layer assembled outer membranes in order to obtain and compare the diffusion profiles of various participating species and their effect on sensor performance. Devices coated with highly glucose permeable (HAs/Fe(3+)) membranes were compared with devices coated with PSS/PDDA membranes, which have an order of magnitude lower permeability. The simulation showed that the low glucose permeable membrane (PSS/PDDA) sensors exhibited a 27% higher amperometric response than the high glucose permeable (HAs/Fe(3+)) sensors. Upon closer inspection of H(2)O(2)diffusion profiles, this non-typical higher response from PSS/PDDA is not due to either a larger glucose flux or comparatively larger O(2) concentrations within the sensor geometry, but rather is attributed to a 48% higher H(2)O(2) concentration in the glucose oxidase enzyme layer of PSS/PDDA coated sensors as compared to HAs/Fe(3+) coated ones. These simulated results corroborate our experimental findings reported previously. The high concentration of H(2)O(2) in the PSS/PDDA coated sensors is due to the low permeability of H(2)O(2) through the PSS/PDDA membrane, which also led to an undesired increase in sensor response time. Additionally, it was found that this phenomenon occurs for all enzyme thicknesses investigated (15, 20 and 25 nm), signifying the need for a holistic approach in designing outer membranes for amperometric biosensors.

Photonic crystal fiber-based plasmonic biosensor with external sensing approach

NASA Astrophysics Data System (ADS)

Rifat, Ahmmed A.; Hasan, Md. Rabiul; Ahmed, Rajib; Butt, Haider

2018-01-01

We propose a simple photonic crystal fiber (PCF) biosensor based on the surface plasmon resonance effect. The sensing properties are characterized using the finite element method. Chemically stable gold material is deposited on the outer surface of the PCF to realize the practical sensing approach. The performance of the modeled biosensor is investigated in terms of wavelength sensitivity, amplitude sensitivity, sensor resolution, and linearity of the resonant wavelength with the variation of structural parameters. In the sensing range of 1.33 to 1.37, maximum sensitivities of 4000 nm/RIU and 478 are achieved with the high sensor resolutions of 2.5×10-5 and 2.1×10-5 RIU using wavelength and amplitude interrogation methods, respectively. The designed biosensor will reduce fabrication complexity due to its simple and realistic hexagonal lattice structure. It is anticipated that the proposed biosensor may find possible applications for unknown biological and biochemical analyte detections with a high degree of accuracy.

Portable evanescent wave fiber biosensor for highly sensitive detection of Shigella

NASA Astrophysics Data System (ADS)

Xiao, Rui; Rong, Zhen; Long, Feng; Liu, Qiqi

2014-11-01

A portable evanescent wave fiber biosensor was developed to achieve the rapid and highly sensitive detection of Shigella. In this study, a DNA probe was covalently immobilized onto fiber-optic biosensors that can hybridize with a fluorescently labeled complementary DNA. The sensitivity of detection for synthesized oligonucleotides can reach 10-10 M. The surface of the sensor can be regenerated with 0.5% sodium dodecyl sulfate solution (pH 1.9) for over 30 times without significant deterioration of performance. The total analysis time for a single sample, including the time for measurement and surface regeneration, was less than 6 min. We employed real-time polymerase chain reaction (PCR) and compared the results of both methods to investigate the actual Shigella DNA detection capability of the fiber-optic biosensor. The fiber-optic biosensor could detect as low as 102 colony-forming unit/mL Shigella. This finding was comparable with that by real-time PCR, which suggests that this method is a potential alternative to existing detection methods.

Simple Fabrication of a Highly Sensitive and Fast Glucose Biosensor using Enzyme Immobilized in Mesocellular Carbon Foam

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lee, Dohoon; Lee, Jinwoo; Kim, Jungbae

2005-12-05

We fabricated a highly sensitive and fast glucose biosensor by simply immobilizing glucose oxidase in mesocellular carbon foam. Due to its unique structure, the MSU-F-C enabled high enzyme loading without serious mass transfer limitation, resulting in high catalytic efficiency. As a result, the glucose biosensor fabricated with MSU-F-C/GOx showed a high sensitivity and fast response. Given these results and the inherent electrical conductivity, we anticipate that MSU-F-C will make a useful matrix for enzyme immobilization in various biocatalytic and electrobiocatalytic applications.

On the origin of enhanced sensitivity in nanoscale FET-based biosensors

PubMed Central

Shoorideh, Kaveh; Chui, Chi On

2014-01-01

Electrostatic counter ion screening is a phenomenon that is detrimental to the sensitivity of charge detection in electrolytic environments, such as in field-effect transistor-based biosensors. Using simple analytical arguments, we show that electrostatic screening is weaker in the vicinity of concave curved surfaces, and stronger in the vicinity of convex surfaces. We use this insight to show, using numerical simulations, that the enhanced sensitivity observed in nanoscale biosensors is due to binding of biomolecules in concave corners where screening is reduced. We show that the traditional argument, that increased surface area-to-volume ratio for nanoscale sensors is responsible for their increased sensitivity, is incorrect. PMID:24706861

Slow light Mach-Zehnder interferometer as label-free biosensor with scalable sensitivity

DOE PAGES

Qin, Kun; Hu, Shuren; Retterer, Scott T.; ...

2016-02-05

Our design, fabrication, and characterization of a label-free Mach–Zehnder interferometer (MZI) optical biosensor that incorporates a highly dispersive one-dimensional (1D) photonic crystal in one arm are presented. The sensitivity of this slow light MZI-based sensor scales with the length of the slow light photonic crystal region. The numerically simulated sensitivity of a MZI sensor with a 16 μm long slow light region is 115,000 rad/RIU-cm, which is sevenfold higher than traditional MZI biosensors with millimeter-length sensing regions. Moreover, the experimental bulk refractive index detection sensitivity of 84,000 rad/RIU-cm is realized and nucleic acid detection is also demonstrated.

Hall effect biosensors with ultraclean graphene film for improved sensitivity of label-free DNA detection.

PubMed

Loan, Phan Thi Kim; Wu, Dongqin; Ye, Chen; Li, Xiaoqing; Tra, Vu Thanh; Wei, Qiuping; Fu, Li; Yu, Aimin; Li, Lain-Jong; Lin, Cheng-Te

2018-01-15

The quality of graphene strongly affects the performance of graphene-based biosensors which are highly demanded for the sensitive and selective detection of biomolecules, such as DNA. This work reported a novel transfer process for preparing a residue-free graphene film using a thin gold supporting layer. A Hall effect device made of this gold-transferred graphene was demonstrated to significantly enhance the sensitivity (≈ 5 times) for hybridization detection, with a linear detection range of 1pM to 100nM for DNA target. Our findings provide an efficient method to boost the sensitivity of graphene-based biosensors for DNA recognition. Copyright © 2017 Elsevier B.V. All rights reserved.

Graphene oxide-based optical biosensor functionalized with peptides for explosive detection.

PubMed

Zhang, Qian; Zhang, Diming; Lu, Yanli; Yao, Yao; Li, Shuang; Liu, Qingjun

2015-06-15

A label-free optical biosensor was constructed with biofunctionalized graphene oxide (GO) for specific detection of 2,4,6-trinitrotoluene (TNT). By chemically binding TNT-specific peptides with GO, the biosensor gained unique optoelectronic properties and high biological sensitivity, with transducing bimolecular bonding into optical signals. Through UV absorption detection, increasing absorbance responses could be observed in presence of TNT at different concentrations, as low as 4.40×10(-9) mM, and showed dose-dependence and stable behavior. Specific responses of the biosensor were verified with the corporation of 2,6-dinitrotoluene (DNT), which had similar molecular structure to TNT. Thus, with high sensitivity and selectivity, the biosensor provided a convenient approach for detection of explosives as miniaturizing and integrating devices. Copyright © 2015 Elsevier B.V. All rights reserved.

Film bulk acoustic resonators (FBARs) as biosensors: A review.

PubMed

Zhang, Yi; Luo, Jikui; Flewitt, Andrew J; Cai, Zhiqiang; Zhao, Xiubo

2018-09-30

Biosensors play important roles in different applications such as medical diagnostics, environmental monitoring, food safety, and the study of biomolecular interactions. Highly sensitive, label-free and disposable biosensors are particularly desired for many clinical applications. In the past decade, film bulk acoustic resonators (FBARs) have been developed as biosensors because of their high resonant frequency and small base mass (hence greater sensitivity), lower cost, label-free capability and small size. This paper reviews the piezoelectric materials used for FBARs, the optimisation of device structures, and their applications as biosensors in a wide range of biological applications such as the detection of antigens, DNAs and small biomolecules. Their integration with microfluidic devices and high-throughput detection are also discussed. Copyright © 2018 Elsevier B.V. All rights reserved.

Targeted Molecular Imaging of Cancer Cells Using MS2-Based 129 Xe NMR

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jeong, Keunhong; Netirojjanakul, Chawita; Munch, Henrik K.

Targeted, selective, and highly sensitive 129Xe NMR nanoscale biosensors have been synthesized using a spherical MS2 viral capsid, Cryptophane A molecules, and DNA aptamers. The biosensors showed strong binding specificity toward targeted lymphoma cells (Ramos line). Hyperpolarized 129Xe NMR signal contrast and hyper-CEST 129Xe MRI image contrast indicated its promise as highly sensitive hyperpolarized 129Xe NMR nanoscale biosensor for future applications in cancer detection in vivo.

A green synthetic strategy of nickel hexacyanoferrate nanoparticals supported on the graphene substrate and its non-enzymatic amperometric sensing application

NASA Astrophysics Data System (ADS)

xue, Zhonghua; He, Nan; Rao, Honghong; Hu, Chenxian; Wang, Xiaofen; Wang, Hui; Liu, Xiuhui; Lu, Xiaoquan

2017-02-01

Rapid glucose detection is a key requirement for both diagnosis and treatment of diabetes. A facile and green strategy to achieve spherical-shaped nickel hexacyanoferrate (NiHCF) nanoparticals supported on electrochemical reduction graphene oxide by using electrochemical cyclic voltammetry is explored. As a sensing substrate, electrochemical reduction graphene oxide deposited on a glassy carbon electrode surface exhibited obvious positive effect on the electrodeposition of NiHCF nanoparticals with spherical structure and thus effectively improved the electrical conductivity and electrochemical sensing of the proposed amperometric sensor. Proof-concept experiments demonstrated that the proposed nanocomposites modified electrode exhibited excellent sensitivity toward glucose oxidation as well as with a satisfying detection limit of 0.11 μM. More importantly, we also explore that as a simple, green and facile method, electrochemical technology can be employed and provide a new strategy for developing GO and metal hexacyanoferrate based amperometric sensing platform toward glucose and other biomolecules.

A Reagentless Amperometric Formaldehyde-Selective Chemosensor Based on Platinized Gold Electrodes

PubMed Central

Demkiv, Olha; Smutok, Oleh; Gonchar, Mykhailo; Nisnevitch, Marina

2017-01-01

Fabrication and characterization of a new amperometric chemosensor for accurate formaldehyde analysis based on platinized gold electrodes is described. The platinization process was performed electrochemically on the surface of 4 mm gold planar electrodes by both electrolysis and cyclic voltamperometry. The produced electrodes were characterized using scanning electron microscopy and X-ray spectral analysis. Using a low working potential (0.0 V vs. Ag/AgCl) enabled an essential increase in the chemosensor’s selectivity for the target analyte. The sensitivity of the best chemosensor prototype to formaldehyde is uniquely high (28180 A·M−1·m−2) with a detection limit of 0.05 mM. The chemosensor remained stable over a one-year storage period. The formaldehye-selective chemosensor was tested on samples of commercial preparations. A high correlation was demonstrated between the results obtained by the proposed chemosensor, chemical and enzymatic methods (R = 0.998). The developed formaldehyde-selective amperometric chemosensor is very promising for use in industry and research, as well as for environmental control. PMID:28772868

A Reagentless Amperometric Formaldehyde-Selective Chemosensor Based on Platinized Gold Electrodes.

PubMed

Demkiv, Olha; Smutok, Oleh; Gonchar, Mykhailo; Nisnevitch, Marina

2017-05-06

Fabrication and characterization of a new amperometric chemosensor for accurate formaldehyde analysis based on platinized gold electrodes is described. The platinization process was performed electrochemically on the surface of 4 mm gold planar electrodes by both electrolysis and cyclic voltamperometry. The produced electrodes were characterized using scanning electron microscopy and X-ray spectral analysis. Using a low working potential (0.0 V vs. Ag/AgCl) enabled an essential increase in the chemosensor's selectivity for the target analyte. The sensitivity of the best chemosensor prototype to formaldehyde is uniquely high (28180 A·M -1 ·m -2 ) with a detection limit of 0.05 mM. The chemosensor remained stable over a one-year storage period. The formaldehye-selective chemosensor was tested on samples of commercial preparations. A high correlation was demonstrated between the results obtained by the proposed chemosensor, chemical and enzymatic methods ( R = 0.998). The developed formaldehyde-selective amperometric chemosensor is very promising for use in industry and research, as well as for environmental control.

Flexure-FET biosensor to break the fundamental sensitivity limits of nanobiosensors using nonlinear electromechanical coupling

PubMed Central

Jain, Ankit; Nair, Pradeep R.; Alam, Muhammad A.

2012-01-01

In this article, we propose a Flexure-FET (flexure sensitive field effect transistor) ultrasensitive biosensor that utilizes the nonlinear electromechanical coupling to overcome the fundamental sensitivity limits of classical electrical or mechanical nanoscale biosensors. The stiffness of the suspended gate of Flexure-FET changes with the capture of the target biomolecules, and the corresponding change in the gate shape or deflection is reflected in the drain current of FET. The Flexure-FET is configured to operate such that the gate is biased near pull-in instability, and the FET-channel is biased in the subthreshold regime. In this coupled nonlinear operating mode, the sensitivity (S) of Flexure-FET with respect to the captured molecule density (Ns) is shown to be exponentially higher than that of any other electrical or mechanical biosensor. In other words, while , classical electrical or mechanical biosensors are limited to Sclassical ∼ γ3NS or γ4 ln(NS), where γi are sensor-specific constants. In addition, the proposed sensor can detect both charged and charge-neutral biomolecules, without requiring a reference electrode or any sophisticated instrumentation, making it a potential candidate for various low-cost, point-of-care applications. PMID:22623527

Development of an acoustic wave based biosensor for vapor phase detection of small molecules

NASA Astrophysics Data System (ADS)

Stubbs, Desmond

For centuries scientific ingenuity and innovation have been influenced by Mother Nature's perfect design. One of her more elusive designs is that of the sensory olfactory system, an array of highly sensitive receptors responsible for chemical vapor recognition. In the animal kingdom this ability is magnified among canines where ppt (parts per trillion) sensitivity values have been reported. Today, detection dogs are considered an essential part of the US drug and explosives detection schemes. However, growing concerns about their susceptibility to extraneous odors have inspired the development of highly sensitive analytical detection tools or biosensors known as "electronic noses". In general, biosensors are distinguished from chemical sensors in that they use an entity of biological origin (e.g. antibody, cell, enzyme) immobilized onto a surface as the chemically-sensitive film on the device. The colloquial view is that the term "biosensors" refers to devices which detect the presence of entities of biological origin, such as proteins or single-stranded DNA and that this detection must take place in a liquid. Our biosensor utilizes biomolecules, specifically IgG monoclonal antibodies, to achieve molecular recognition of relatively small molecules in the vapor phase.

Highly sensitive nano-porous lattice biosensor based on localized surface plasmon resonance and interference.

PubMed

Yeom, Se-Hyuk; Kim, Ok-Geun; Kang, Byoung-Ho; Kim, Kyu-Jin; Yuan, Heng; Kwon, Dae-Hyuk; Kim, Hak-Rin; Kang, Shin-Won

2011-11-07

We propose a design for a highly sensitive biosensor based on nanostructured anodized aluminum oxide (AAO) substrates. A gold-deposited AAO substrate exhibits both optical interference and localized surface plasmon resonance (LSPR). In our sensor, application of these disparate optical properties overcomes problems of limited sensitivity, selectivity, and dynamic range seen in similar biosensors. We fabricated uniform periodic nanopore lattice AAO templates by two-step anodizing and assessed their suitability for application in biosensors by characterizing the change in optical response on addition of biomolecules to the AAO template. To determine the suitability of such structures for biosensing applications, we immobilized a layer of C-reactive protein (CRP) antibody on a gold coating atop an AAO template. We then applied a CRP antigen (Ag) atop the immobilized antibody (Ab) layer. The shift in reflectance is interpreted as being caused by the change in refractive index with membrane thickness. Our results confirm that our proposed AAO-based biosensor is highly selective toward detection of CRP antigen, and can measure a change in CRP antigen concentration of 1 fg/ml. This method can provide a simple, fast, and sensitive analysis for protein detection in real-time.

An ATP sensitive light addressable biosensor for extracellular monitoring of single taste receptor cell.

PubMed

Wu, Chunsheng; Du, Liping; Zou, Ling; Zhao, Luhang; Wang, Ping

2012-12-01

Adenosine triphosphate (ATP) is considered as the key neurotransmitter in taste buds for taste signal transmission and processing. Measurements of ATP secreted from single taste receptor cell (TRC) with high sensitivity and specificity are essential for investigating mechanisms underlying taste cell-to-cell communications. In this study, we presented an aptamer-based biosensor for the detection of ATP locally secreted from single TRC. ATP sensitive DNA aptamer was used as recognition element and its DNA competitor was served as signal transduction element that was covalently immobilized on the surface of light addressable potentiometric sensor (LAPS). Due to the light addressable capability of LAPS, local ATP secretion from single TRC can be detected by monitoring the working potential shifts of LAPS. The results show this biosensor can detect ATP with high sensitivity and specificity. It is demonstrated this biosensor can effectively detect the local ATP secretion from single TRC responding to tastant mixture. This biosensor could provide a promising new tool for the research of taste cell-to-cell communications as well as for the detection of local ATP secretion from other types of ATP secreting individual cells.

A highly sensitive monoclonal antibody based biosensor for quantifying 3-5 ring polycyclic aromatic hydrocarbons (PAHs) in aqueous environmental samples.

PubMed

Li, Xin; Kaattari, Stephen L; Vogelbein, Mary A; Vadas, George G; Unger, Michael A

2016-03-01

Immunoassays based on monoclonal antibodies (mAbs) are highly sensitive for the detection of polycyclic aromatic hydrocarbons (PAHs) and can be employed to determine concentrations in near real-time. A sensitive generic mAb against PAHs, named as 2G8, was developed by a three-step screening procedure. It exhibited nearly uniformly high sensitivity against 3-ring to 5-ring unsubstituted PAHs and their common environmental methylated PAHs, with IC 50 values between 1.68-31 μg/L (ppb). 2G8 has been successfully applied on the KinExA Inline Biosensor system for quantifying 3-5 ring PAHs in aqueous environmental samples. PAHs were detected at a concentration as low as 0.2 μg/L. Furthermore, the analyses only required 10 min for each sample. To evaluate the accuracy of the 2G8-based biosensor, the total PAH concentrations in a series of environmental samples analyzed by biosensor and GC-MS were compared. In most cases, the results yielded a good correlation between methods. This indicates that generic antibody 2G8 based biosensor possesses significant promise for a low cost, rapid method for PAH determination in aqueous samples.

Synthesis of functional carbon nanospheres by a composite-molten-salt method and amperometric sensing of hydrogen peroxide.

PubMed

Wang, Xue; Hu, Chenguo; Xiong, Yufeng; Zhang, Cuiling

2013-02-01

Functional carbon nanospheres have been synthesized from analytically pure glucose by a composite-molten-salt (CMS) method. Field emission scanning electron microscopy, transmission electron microscopy, Raman and Fourier transformation infra-red spectroscopy indicate the carbon nanospheres are solid, bond hybridisation (sp2/sp3) and with many functional groups on their surfaces. Amperometric sensor based on the synthesized carbon nanospheres have been fabricated without pretreatment or modification. The detection of hydrogen peroxide exhibits high sensitivity and good selectivity. The electrochemical measurement of these nanospheres demonstrates much superior performance to those of the carbon nanospheres synthesized by hydrothermal method.

Mesoporous carbon nitride based biosensor for highly sensitive and selective analysis of phenol and catechol in compost bioremediation.

PubMed

Zhou, Yaoyu; Tang, Lin; Zeng, Guangming; Chen, Jun; Cai, Ye; Zhang, Yi; Yang, Guide; Liu, Yuanyuan; Zhang, Chen; Tang, Wangwang

2014-11-15

Herein, we reported here a promising biosensor by taking advantage of the unique ordered mesoporous carbon nitride material (MCN) to convert the recognition information into a detectable signal with enzyme firstly, which could realize the sensitive, especially, selective detection of catechol and phenol in compost bioremediation samples. The mechanism including the MCN based on electrochemical, biosensor assembly, enzyme immobilization, and enzyme kinetics (elucidating the lower detection limit, different linear range and sensitivity) was discussed in detail. Under optimal conditions, GCE/MCN/Tyr biosensor was evaluated by chronoamperometry measurements and the reduction current of phenol and catechol was proportional to their concentration in the range of 5.00 × 10(-8)-9.50 × 10(-6)M and 5.00 × 10(-8)-1.25 × 10(-5)M with a correlation coefficient of 0.9991 and 0.9881, respectively. The detection limits of catechol and phenol were 10.24 nM and 15.00 nM (S/N=3), respectively. Besides, the data obtained from interference experiments indicated that the biosensor had good specificity. All the results showed that this material is suitable for load enzyme and applied to the biosensor due to the proposed biosensor exhibited improved analytical performances in terms of the detection limit and specificity, provided a powerful tool for rapid, sensitive, especially, selective monitoring of catechol and phenol simultaneously. Moreover, the obtained results may open the way to other MCN-enzyme applications in the environmental field. Copyright © 2014 Elsevier B.V. All rights reserved.

Porous silicon photoluminescence biosensor for rapid and sensitive detection of toxins

NASA Astrophysics Data System (ADS)

Melnyk, Yulia; Pavlova, Karyna; Myndrul, Valerii; Viter, Roman; Smyntyna, Valentyn; Iatsunskyi, Igor

2017-08-01

A rapid and low cost photoluminescence (PL) immunosensor for the determination of low concentrations of Ochratoxin A(OTA) and Aflatoxine B1 (AfB1) has been developed. This biosensor was based on porous silicon (PSi) fabricated by metal-assisted chemical etching (MACE) and modified by antibodies against OTA/AfB1 (anti-OTA/anti-AfB1). Biofunctionalization method of the PSi surface by anti-OTA/ anti-AfB1 was developed. The changes of the PL intensity after interaction of the immobilized anti-OTA/anti-AfB1with OTA/AfB1 antigens were used as biosensor signal, allowing sensitive and selective detection of OTA/AfB1 antigens in BSA solution. The sensitivity of the reported optical biosensor towards OTA/AfB1 antigens is in the range from 10-3 to 102 ng/ml.

Optical biosensors.

PubMed

Damborský, Pavel; Švitel, Juraj; Katrlík, Jaroslav

2016-06-30

Optical biosensors represent the most common type of biosensor. Here we provide a brief classification, a description of underlying principles of operation and their bioanalytical applications. The main focus is placed on the most widely used optical biosensors which are surface plasmon resonance (SPR)-based biosensors including SPR imaging and localized SPR. In addition, other optical biosensor systems are described, such as evanescent wave fluorescence and bioluminescent optical fibre biosensors, as well as interferometric, ellipsometric and reflectometric interference spectroscopy and surface-enhanced Raman scattering biosensors. The optical biosensors discussed here allow the sensitive and selective detection of a wide range of analytes including viruses, toxins, drugs, antibodies, tumour biomarkers and tumour cells. © 2016 The Author(s). Published by Portland Press Limited on behalf of the Biochemical Society.

Rapid detection of Salmonella Typhimurium in chicken carcass using a SPR biosensor

NASA Astrophysics Data System (ADS)

Wang, Shizhou; Lan, Yubin; Yin, Yongguang; Dasari, Thirumala R.

2005-11-01

The SPR biosensor was sensitive to the presence of Salmonella Typhimurium in chicken carcass. The selectivity of the SPR biosensor was assayed using a series of antibody concentrations and dilution series of the organism. The SPR biosensor was specific to Salmonella Typhimurium at concentrations of 106 CFU/ml. Initial results show potential for its application for pathogenic bacteria monitoring.

Recent Advances in Bioprinting and Applications for Biosensing

PubMed Central

Dias, Andrew D.; Kingsley, David M.; Corr, David T.

2014-01-01

Future biosensing applications will require high performance, including real-time monitoring of physiological events, incorporation of biosensors into feedback-based devices, detection of toxins, and advanced diagnostics. Such functionality will necessitate biosensors with increased sensitivity, specificity, and throughput, as well as the ability to simultaneously detect multiple analytes. While these demands have yet to be fully realized, recent advances in biofabrication may allow sensors to achieve the high spatial sensitivity required, and bring us closer to achieving devices with these capabilities. To this end, we review recent advances in biofabrication techniques that may enable cutting-edge biosensors. In particular, we focus on bioprinting techniques (e.g., microcontact printing, inkjet printing, and laser direct-write) that may prove pivotal to biosensor fabrication and scaling. Recent biosensors have employed these fabrication techniques with success, and further development may enable higher performance, including multiplexing multiple analytes or cell types within a single biosensor. We also review recent advances in 3D bioprinting, and explore their potential to create biosensors with live cells encapsulated in 3D microenvironments. Such advances in biofabrication will expand biosensor utility and availability, with impact realized in many interdisciplinary fields, as well as in the clinic. PMID:25587413

An acetylcholinesterase biosensor based on graphene-gold nanocomposite and calcined layered double hydroxide.

PubMed

Zhai, Chen; Guo, Yemin; Sun, Xia; Zheng, Yuhe; Wang, Xiangyou

2014-05-10

In this study, a novel acetylcholinesterase-based biosensor was fabricated. Acetylcholinesterase (AChE) was immobilized onto a glassy carbon electrode (GCE) with the aid of Cu-Mg-Al calcined layered double hydroxide (CLDH). CLDH can provide a bigger effective surface area for AChE loading, which could improve the precision and stability of AChE biosensor. However, the poor electroconductibility of CLDHs could lead to the low sensitivity of AChE biosensor. In order to effectively compensate the disadvantages of CLDHs, graphene-gold nanocomposites were used for improving the electron transfer rate. Thus, the graphene-gold nanocomposite (GN-AuNPs) was firstly modified onto the GCE, and then the prepared CLDH-AChE composite was immobilized onto the modified GCE to construct a sensitive AChE biosensor for pesticides detection. Relevant parameters were studied in detail and optimized, including the pH of the acetylthiocholine chloride (ATCl) solution, the amount of AChE immobilized on the biosensor and the inhibition time governing the analytical performance of the biosensor. The biosensor detected chlorpyrifos at concentrations ranging from 0.05 to 150μg/L. The detection limit for chlorpyrifos was 0.05μg/L. Copyright © 2014 Elsevier Inc. All rights reserved.

Recent advances in transition-metal dichalcogenides based electrochemical biosensors: A review.

PubMed

Wang, Yi-Han; Huang, Ke-Jing; Wu, Xu

2017-11-15

Layered transition metal dichalcogenides (TMDCs) comprise a category of two-dimensional (2D) materials that offer exciting properties, including large surface area, metallic and semi-conducting electrical capabilities, and intercalatable morphologies. Biosensors employ biological molecules to recognize the target and utilize output elements which can translate the biorecognition event into electrical, optical or mass-sensitive signals to determine the quantities of the target. TMDCs nanomaterials have been widely applied in various electrochemical biosensors with high sensitivity and selectivity. The marriage of TMDCs and electrochemical biosensors has created many productive sensing strategies for applications in the areas of clinical diagnosis, environmental monitoring and food safety. In recent years, an increasing number of TMDCs-based electrochemical biosensors are reported, suggesting TMDCs offers new possibilities of improving the performance of electrochemical biosensors. This review summarizes recent advances in electrochemical biosensors based on TMDCs for detection of various inorganic and organic analytes in the last five years, including glucose, proteins, DNA, heavy metal, etc. In addition, we also point out the challenges and future perspectives related to the material design and development of TMDCs-based electrochemical biosensors. Copyright © 2017 Elsevier B.V. All rights reserved.

Enzyme-linked, aptamer-based, competitive biolayer interferometry biosensor for palytoxin.

PubMed

Gao, Shunxiang; Zheng, Xin; Hu, Bo; Sun, Mingjuan; Wu, Jihong; Jiao, Binghua; Wang, Lianghua

2017-03-15

In this study, we coupled biolayer interferometry (BLI) with competitive binding assay through an enzyme-linked aptamer and developed a real-time, ultra-sensitive, rapid quantitative method for detection of the marine biotoxin palytoxin. Horseradish peroxidase-labeled aptamers were used as biorecognition receptors to competitively bind with palytoxin, which was immobilized on the biosensor surface. The palytoxin: horseradish peroxidase-aptamer complex was then submerged in a 3,3'-diaminobenzidine solution, which resulted in formation of a precipitated polymeric product directly on the biosensor surface and a large change in the optical thickness of the biosensor layer. This change could obviously shift the interference pattern and generate a response profile on the BLI biosensor. The biosensor showed a broad linear range for palytoxin (200-700pg/mL) with a low detection limit (0.04pg/mL). Moreover, the biosensor was applied to the detection of palytoxin in spiked extracts and showed a high degree of selectivity for palytoxin, good reproducibility, and stability. This enzyme-linked, aptamer-based, competitive BLI biosensor offers a promising method for rapid and sensitive detection of palytoxin and other analytes. Copyright © 2016 Elsevier B.V. All rights reserved.

Superior Sensitivity of Copper-Based Plasmonic Biosensors.

PubMed

Stebunov, Yury V; Yakubovsky, Dmitry I; Fedyanin, Dmitry Yu; Arsenin, Aleksey V; Volkov, Valentyn S

2018-04-17

Plasmonic biosensing has been demonstrated to be a powerful technique for quantitative determination of molecular analytes and kinetic analysis of biochemical reactions. However, interfaces of most plasmonic biosensors are made of noble metals, such as gold and silver, which are not compatible with industrial production technologies. This greatly limits biosensing applications beyond biochemical and pharmaceutical research. Here, we propose and investigate copper-based biosensor chips fully fabricated with a standard complementary metal-oxide-semiconductor (CMOS) process. The protection of thin copper films from oxidation is achieved with SiO 2 and Al 2 O 3 dielectric films deposited onto the metal surface. In addition, the deposition of dielectric films with thicknesses of only several tens of nanometers significantly improves the biosensing sensitivity, owing to better localization of electromagnetic field above the biosensing surface. According to surface plasmon resonance (SPR) measurements, the copper biosensor chips coated with thin films of SiO 2 (25 nm) and Al 2 O 3 (15 nm) show 55% and 75% higher sensitivity to refractive index changes, respectively, in comparison to pure gold sensor chips. To test biomolecule immobilization, the copper-dielectric biosensor chips are coated with graphene oxide linking layers and used for the selective analysis of oligonucleotide hybridization. The proposed plasmonic biosensors make SPR technology more affordable for various applications and provide the basis for compact biosensors integrated with modern electronic devices.

An InN/InGaN Quantum Dot Electrochemical Biosensor for Clinical Diagnosis

PubMed Central

Alvi, Naveed ul Hassan; Gómez, Victor J.; Rodriguez, Paul E.D. Soto; Kumar, Praveen; Zaman, Saima; Willander, Magnus; Nötzel, Richard

2013-01-01

Low-dimensional InN/InGaN quantum dots (QDs) are demonstrated for realizing highly sensitive and efficient potentiometric biosensors owing to their unique electronic properties. The InN QDs are biochemically functionalized. The fabricated biosensor exhibits high sensitivity of 97 mV/decade with fast output response within two seconds for the detection of cholesterol in the logarithmic concentration range of 1 × 10−6 M to 1 × 10−3 M. The selectivity and reusability of the biosensor are excellent and it shows negligible response to common interferents such as uric acid and ascorbic acid. We also compare the biosensing properties of the InN QDs with those of an InN thin film having the same surface properties, i.e., high density of surface donor states, but different morphology and electronic properties. The sensitivity of the InN QDs-based biosensor is twice that of the InN thin film-based biosensor, the EMF is three times larger, and the response time is five times shorter. A bare InGaN layer does not produce a stable response. Hence, the superior biosensing properties of the InN QDs are governed by their unique surface properties together with the zero-dimensional electronic properties. Altogether, the InN QDs-based biosensor reveals great potential for clinical diagnosis applications. PMID:24132228

Dependence of seed layer thickness on sensitivity of nano-ZnO cholesterol biosensor

NASA Astrophysics Data System (ADS)

Lu, Yang-Ming; Wang, Po-Chin; Tang, Jian-Fu; Chu, Sheng-Yuan

2017-01-01

The anemone-like ZnO nanostructures have been synthesized by hydrothermal method and were further adsorbed immobilized cholesterol oxidase (ChOx) as a nano-biosensor. In this study, the sensitivity of biosensor were improved by varying the thickness of the ZnO seed layer. The SEM analysis showed changes in thickness of seed layer will not affect the morphologies of anemone-like ZnO nanostructures. The X-ray Diffraction patterns showed that the (002) plane of anemone-like ZnO grown on various thickness of the seed layer was more prouded than other crystal plane. Abioelectrode (ChOx/ZnO/ITO/glass) grown on the 30nm of ZnO seed layer with high sensitivity of 57.533μAmM-1cm-2 (1.488 μA (mg/dl) -1cm-2), a wide sensitive range from 25 to 500 mg/dl. It is concluded that the thinner sputtered ZnO seed layer for growing anemone-like ZnO nanostructure can effectively improve the sensitivity of the ZnO biosensor.

Environmental Stability of Plasmonic Biosensors Based on Natural versus Artificial Antibody.

PubMed

Luan, Jingyi; Xu, Ting; Cashin, John; Morrissey, Jeremiah J; Kharasch, Evan D; Singamaneni, Srikanth

2018-06-13

Plasmonic biosensors based on the refractive index sensitivity of localized surface plasmon resonance (LSPR) are considered to be highly promising for on-chip and point-of-care biodiagnostics. However, most of the current plasmonic biosensors employ natural antibodies as biorecognition elements, which can easily lose their biorecognition ability upon exposure to environmental stressors (e.g., temperature and humidity). Plasmonic biosensors relying on molecular imprints as recognition elements (artificial antibodies) are hypothesized to be an attractive alternative for applications in resource-limited settings due to their excellent thermal, chemical, and environmental stability. In this work, we provide a comprehensive comparison of the stability of plasmonic biosensors based on natural and artificial antibodies. Although the natural antibody-based plasmonic biosensors exhibit superior sensitivity, their stability (temporal, thermal, and chemical) was found to be vastly inferior to those based on artificial antibodies. Our results convincingly demonstrate that these novel classes of artificial antibody-based plasmonic biosensors are highly attractive for point-of-care and resource-limited conditions where tight control over transport, storage, and handling conditions is not possible.

A flow cytometry-optimized assay using an SOS-green fluorescent protein (SOS-GFP) whole-cell biosensor for the detection of genotoxins in complex environments.

PubMed

Norman, Anders; Hansen, Lars Hestbjerg; Sørensen, Søren J

2006-02-28

Whole-cell biosensors have become popular tools for detection of ecotoxic compounds in environmental samples. We have developed an assay optimized for flow cytometry with detection of genotoxic compounds in mind. The assay features extended pre-incubation and a cell density of only 10(6)-10(7) cells/mL, and proved far more sensitive than a previously published assay using the same biosensor strain. By applying the SOS-green fluorescent protein (GFP) whole-cell biosensor directly to soil microcosms we were also able to evaluate both the applicability and sensitivity of a biosensor based on SOS-induction in whole soil samples. Soil microcosms were spiked with a dilution-series of crude broth extract from the mitomycin C-producing streptomycete Streptomyces caespitosus. Biosensors extracted from these microcosms after 1 day of incubation at 30 degrees C were easily distinguished from extracts of non-contaminated soil particles when using flow cytometry, and induction of the biosensor by mitomycin C was detectable at concentrations as low as 2.5 ng/g of soil.

A Highly Sensitive Nonenzymatic Glucose Biosensor Based on the Regulatory Effect of Glucose on Electrochemical Behaviors of Colloidal Silver Nanoparticles on MoS₂†.

PubMed

Anderson, Kash; Poulter, Benjamin; Dudgeon, John; Li, Shu-En; Ma, Xiang

2017-08-05

A novel and highly sensitive nonenzymatic glucose biosensor was developed by nucleating colloidal silver nanoparticles (AgNPs) on MoS₂. The facile fabrication method, high reproducibility (97.5%) and stability indicates a promising capability for large-scale manufacturing. Additionally, the excellent sensitivity (9044.6 μA mM -1 cm -2 ), low detection limit (0.03 μM), appropriate linear range of 0.1-1000 μM, and high selectivity suggests that this biosensor has a great potential to be applied for noninvasive glucose detection in human body fluids, such as sweat and saliva.

Biomolecule detection based on Si single-electron transistors for practical use

NASA Astrophysics Data System (ADS)

Nakajima, Anri; Kudo, Takashi; Furuse, Sadaharu

2013-07-01

Experimental and theoretical analyses demonstrated that ultra-sensitive biomolecule detection can be achieved using a Si single-electron transistor (SET). A multi-island channel structure was used to enable room-temperature operation. Coulomb oscillation increases transconductance without increasing channel width, which increases detection sensitivity to a charged target. A biotin-modified SET biosensor was used to detect streptavidin at a dilute concentration. In addition, an antibody-functionalized SET biosensor was used for immunodetection of prostate-specific antigen, demonstrating its suitability for practical use. The feasibility of ultra-sensitive detection of biomolecules for practical use by using a SET biosensor was clearly proven through this systematic study.

Nanomolar detection of methylparaben by a cost-effective hemoglobin-based biosensor.

PubMed

Hajian, A; Ghodsi, J; Afraz, A; Yurchenko, O; Urban, G

2016-12-01

This work describes the development of a new biosensor for methylparaben determination using electrocatalytic properties of hemoglobin in the presence of hydrogen peroxide. The voltammetric oxidation of methylparaben by the proposed biosensor in phosphate buffer (pH=7.0), a physiological pH, was studied and it was confirmed that methylparaben undergoes a one electron-one proton reaction in a diffusion-controlled process. The biosensor was fabricated by carbon paste electrode modified with hemoglobin and multiwalled carbon nanotube. Based on the excellent electrochemical properties of the modified electrode, a sensitive voltammetric method was used for determination of methylparaben within a linear range from 0.1 to 13μmolL(-1) and detection limit of 25nmolL(-1). The developed biosensor possessed accurate and rapid response to methylparaben and showed good sensitivity, stability, and repeatability. Finally, the applicability of the proposed biosensor was verified by methylparaben evaluation in various real samples. Copyright © 2016 Elsevier B.V. All rights reserved.

A low-cost photonic biosensor built on a polymer platform

NASA Astrophysics Data System (ADS)

Wang, Linghua; Kodeck, Valérie; Van Vlierberghe, Sandra; Ren, Jun; Teng, Jie; Han, Xiuyou; Jian, Xigao; Baets, Roel; Morthier, Geert; Zhao, Mingshan

2011-12-01

Planar integrated optical biosensors are becoming more and more important as they facilitate label-free and real time monitoring biosensing with high sensitivity. In this paper, the systematic research on one kind of optical biosensor, based on a resonant principle in a polymer ring resonator, will be presented. Reduced footprint and high sensitivity are advantages of this kind of biosensor. Rather than expensive CMOS fabrication, the device with high performance is fabricated through a simple UV based soft imprint technique utilizing self-developed low loss polymer material. The measurement results for the bulk sensing of a NaCl solution and the surface sensing of a minimal amount of avidin molecules in a buffered solution will be presented.

Open Loop Structure Low Cost Integrated Differential Inductive Micro Magnetic Volumetric Bio-Sensors

NASA Astrophysics Data System (ADS)

Khodadadi, Mohammad; Chang, Long; Litvinov, Dimitri

This investigation proposes a study, model, simulate and experiment innovative very low cost Magnetic induction biosensor for point of care diagnostics. The biosensor consists of 2 ``semi-loops'' in a micro fluidic channel, one as a sensor and one as a reference, the design takes advantage of microfabrication processes to produce more precise structures to improve sensitivity. Besides the attractively low cost, this biosensor has many advantages. Since the detector is basically a shaped wire, it is inherently robust and reliable. Typical errors in fabricating the wires will not affect its performance and it is sensing volumetric, unlike GMR-based sensors used in biosensor systems that boast single particle detection. Due to small dimensions the sensors do not need to be calibrated. This sensor also has a large range of detection since its sensitivity is proportional to the excitation frequency. Being able to sense Magnetic nano particles in the volume is an advantage in term of trapping MNPs and sensitivity and functionality. Basically, this new brilliant design, fill the gap between the fabricated sensors and hand wounded sensors.

Ternary Surface Monolayers for Ultrasensitive (Zeptomole) Amperometric Detection of Nucleic-Acid Hybridization without Signal Amplification

PubMed Central

Wu, Jie; Campuzano, Susana; Halford, Colin; Haake, David A.; Wang, Joseph

2010-01-01

A ternary surface monolayer, consisting of co-assembled thiolated capture probe (SHCP) mercaptohexanol (MCH) and dithiothreitol (DTT), is shown to offer dramatic improvements in the signal-to-noise characteristics of electrochemical DNA hybridization biosensors based on common self-assembled monolayers (SAMs). Remarkably low detection limits down to 40 zmole (in 4 μL samples) as well as only 1 CFU E. coli per sensor are thus obtained without any additional amplification step in connection to the commonly used horseradish peroxidase/3,3′,5,5′-tetramethylbenzidine (HRP/TMB) system. Such dramatic improvements in the detection limits (compared to common binary alkanethiol interfaces and to most electrochemical DNA sensing strategies without target or signal amplification) are attributed primarily to the remarkably higher resistance to non-specific adsorption. This reflects the highly compact layer (with lower pinhole density) produced by the coupling of the cyclic- and linear-configuration ‘backfillers’ that leads to a remarkably low background noise even in the presence of complex sample matrices. A wide range of surface compositions have been investigated and the ternary mixed monolayer has been systematically optimized. Detailed impedance spectroscopy and cyclic voltammetric studies shed useful insights into the surface coverage. The impressive sensitivity and high specificity of the simple developed methodology indicate great promise for a wide range of nucleic acid testing, including clinical diagnostics, biothreat detection, food safety and forensic analysis. PMID:20883023

Ternary surface monolayers for ultrasensitive (zeptomole) amperometric detection of nucleic acid hybridization without signal amplification.

PubMed

Wu, Jie; Campuzano, Susana; Halford, Colin; Haake, David A; Wang, Joseph

2010-11-01

A ternary surface monolayer, consisting of coassembled thiolated capture probe, mercaptohexanol and dithiothreitol, is shown to offer dramatic improvements in the signal-to-noise characteristics of electrochemical DNA hybridization biosensors based on common self-assembled monolayers. Remarkably low detection limits down to 40 zmol (in 4 μL samples) as well as only 1 CFU Escherichia coli per sensor are thus obtained without any additional amplification step in connection to the commonly used horseradish peroxidase/3,3',5,5'-tetramethylbenzidine system. Such dramatic improvements in the detection limits (compared to those of common binary alkanethiol interfaces and to those of most electrochemical DNA sensing strategies without target or signal amplification) are attributed primarily to the remarkably higher resistance to nonspecific adsorption. This reflects the highly compact layer (with lower pinhole density) produced by the coupling of the cyclic- and linear-configuration "backfillers" that leads to a remarkably low background noise even in the presence of complex sample matrixes. A wide range of surface compositions have been investigated, and the ternary mixed monolayer has been systematically optimized. Detailed impedance spectroscopy and cyclic voltammetric studies shed useful insights into the surface coverage. The impressive sensitivity and high specificity of the simple developed methodology indicate great promise for a wide range of nucleic acid testing, including clinical diagnostics, biothreat detection, food safety, and forensic analysis.

Biosensing of glucose in flow injection analysis system based on glucose oxidase-quantum dot modified pencil graphite electrode.

PubMed

Sağlam, Özlem; Kızılkaya, Bayram; Uysal, Hüseyin; Dilgin, Yusuf

2016-01-15

A novel amperometric glucose biosensor was proposed in flow injection analysis (FIA) system using glucose oxidase (GOD) and Quantum dot (ZnS-CdS) modified Pencil Graphite Electrode (PGE). After ZnS-CdS film was electrochemically deposited onto PGE surface, GOD was immobilized on the surface of ZnS-CdS/PGE through crosslinking with chitosan (CT). A pair of well-defined reversible redox peak of GOD was observed at GOD/CT/ZnS-CdS/PGE based on enzyme electrode by direct electron transfer between the protein and electrode. Further, obtained GOD/CT/ZnS-CdS/PGE offers a disposable, low cost, selective and sensitive electrochemical biosensing of glucose in FIA system based on the decrease of the electrocatalytic response of the reduced form of GOD to dissolved oxygen. Under optimum conditions (flow rate, 1.3mL min(-1); transmission tubing length, 10cm; injection volume, 100μL; and constant applied potential, -500mV vs. Ag/AgCl), the proposed method displayed a linear response to glucose in the range of 0.01-1.0mM with detection limit of 3.0µM. The results obtained from this study would provide the basis for further development of the biosensing using PGE based FIA systems. Copyright © 2015 Elsevier B.V. All rights reserved.

Fabricating an Amperometric Cholesterol Biosensor by a Covalent Linkage between Poly(3-thiopheneacetic acid) and Cholesterol Oxidase.

PubMed

Nien, Po-Chin; Chen, Po-Yen; Ho, Kuo-Chuan

2009-01-01

In this study, use of the covalent enzyme immobilization method was proposed to attach cholesterol oxidase (ChO) on a conducting polymer, poly(3-thiopheneacetic acid), [poly(3-TPAA)]. Three red-orange poly(3-TPAA) films, named electrodes A, B and C, were electropolymerized on a platinum electrode by applying a constant current of 1.5 mA, for 5, 20 and 100 s, respectively. Further, 1-ethyl-3-(3-dimethylamiopropyl)carbodiimide hydrochloride (EDC · HCl) and N-hydroxysuccinimide (NHS) were used to activate the free carboxylic groups of the conducting polymer. Afterwards, the amino groups of the cholesterol oxidase were linked on the activated groups to form peptide bonds. The best sensitivity obtained for electrode B is 4.49 mA M(-1) cm(-2), with a linear concentration ranging from 0 to 8 mM, which is suitable for the analysis of cholesterol in humans. The response time (t(95)) is between 70 and 90 s and the limit of detection is 0.42 mM, based on the signal to noise ratio equal to 3. The interference of species such as ascorbic acid and uric acid increased to 5.2 and 10.3% of the original current response, respectively, based on the current response of cholesterol (100%). With respect to the long-term stability, the sensing response retains 88% of the original current after 13 days.

Melt quenched vanadium oxide embedded in graphene oxide sheets as composite electrodes for amperometric dopamine sensing and lithium ion battery applications

NASA Astrophysics Data System (ADS)

Sreejesh, M.; Shenoy, Sulakshana; Sridharan, Kishore; Kufian, D.; Arof, A. K.; Nagaraja, H. S.

2017-07-01

Electrochemical sensors and lithium-ion batteries are two important topics in electrochemistry that have attracted much attention owing to their extensive applications in enzyme-free biosensors and portable electronic devices. Herein, we report a simple hydrothermal approach for synthesizing composites of melt quenched vanadium oxide embedded on graphene oxide of equal proportion (MVGO50) for the fabrication of electrodes for nonenzymatic amperometic dopamine sensor and lithium-ion battery applications. The sensing performance of MVGO50 electrodes through chronoamperometry studies in 0.1 M PBS solution (at pH 7) over a wide range of dopamine concentration exhibited a highest sensitivity of 25.02 μA mM-1 cm-2 with the lowest detection limit of 0.07 μM. In addition, the selective sensing capability of MVGO50 was also tested through chronoamperometry studies by the addition of a very small concentration of dopamine (10 μM) in the presence of a fairly higher concentration of uric acid (10 mM) as the interfering species. Furthermore, the reversible lithium cycling properties of MVGO50 are evaluated by galvanostatic charge-discharge cycling studies. MVGO50 electrodes exhibited enhanced rate capacity of up to 200 mAhg-1 at a current of 0.1C rate and remained stable during cycling. These results indicate that MVGO composites are potential candidates for electrochemical device applications.

Microwave annealing effect for highly reliable biosensor: dual-gate ion-sensitive field-effect transistor using amorphous InGaZnO thin-film transistor.

PubMed

Lee, In-Kyu; Lee, Kwan Hyi; Lee, Seok; Cho, Won-Ju

2014-12-24

We used a microwave annealing process to fabricate a highly reliable biosensor using amorphous-InGaZnO (a-IGZO) thin-film transistors (TFTs), which usually experience threshold voltage instability. Compared with furnace-annealed a-IGZO TFTs, the microwave-annealed devices showed superior threshold voltage stability and performance, including a high field-effect mobility of 9.51 cm(2)/V·s, a low threshold voltage of 0.99 V, a good subthreshold slope of 135 mV/dec, and an outstanding on/off current ratio of 1.18 × 10(8). In conclusion, by using the microwave-annealed a-IGZO TFT as the transducer in an extended-gate ion-sensitive field-effect transistor biosensor, we developed a high-performance biosensor with excellent sensing properties in terms of pH sensitivity, reliability, and chemical stability.

Detection of Sub-fM DNA with Target Recycling and Self-Assembly Amplification on Graphene Field-Effect Biosensors

PubMed Central

2018-01-01

All-electronic DNA biosensors based on graphene field-effect transistors (GFETs) offer the prospect of simple and cost-effective diagnostics. For GFET sensors based on complementary probe DNA, the sensitivity is limited by the binding affinity of the target oligonucleotide, in the nM range for 20 mer targets. We report a ∼20 000× improvement in sensitivity through the use of engineered hairpin probe DNA that allows for target recycling and hybridization chain reaction. This enables detection of 21 mer target DNA at sub-fM concentration and provides superior specificity against single-base mismatched oligomers. The work is based on a scalable fabrication process for biosensor arrays that is suitable for multiplexed detection. This approach overcomes the binding-affinity-dependent sensitivity of nucleic acid biosensors and offers a pathway toward multiplexed and label-free nucleic acid testing with high accuracy and selectivity. PMID:29768011

Detection of Sub-fM DNA with Target Recycling and Self-Assembly Amplification on Graphene Field-Effect Biosensors.

PubMed

Gao, Zhaoli; Xia, Han; Zauberman, Jonathan; Tomaiuolo, Maurizio; Ping, Jinglei; Zhang, Qicheng; Ducos, Pedro; Ye, Huacheng; Wang, Sheng; Yang, Xinping; Lubna, Fahmida; Luo, Zhengtang; Ren, Li; Johnson, Alan T Charlie

2018-06-13

All-electronic DNA biosensors based on graphene field-effect transistors (GFETs) offer the prospect of simple and cost-effective diagnostics. For GFET sensors based on complementary probe DNA, the sensitivity is limited by the binding affinity of the target oligonucleotide, in the nM range for 20 mer targets. We report a ∼20 000× improvement in sensitivity through the use of engineered hairpin probe DNA that allows for target recycling and hybridization chain reaction. This enables detection of 21 mer target DNA at sub-fM concentration and provides superior specificity against single-base mismatched oligomers. The work is based on a scalable fabrication process for biosensor arrays that is suitable for multiplexed detection. This approach overcomes the binding-affinity-dependent sensitivity of nucleic acid biosensors and offers a pathway toward multiplexed and label-free nucleic acid testing with high accuracy and selectivity.

A novel amperometric immunosensor based on acetone-extracted propolis for the detection of the HIV-1 p24 antigen.

PubMed

Kheiri, F; Sabzi, R E; Jannatdoust, E; Shojaeefar, E; Sedghi, H

2011-07-15

A novel amperometric immunosensor for the detection of the p24 antigen (p24Ag) from HIV-1 was constructed using gold nanoparticles (GNP), multi-walled carbon nanotubes (MWCNTs), and an acetone-extracted propolis film (AEP). First, amino-functionalized MWCNTs (MWCNTNH₂) were prepared and dispersed in an HAuCl₄ solution to synthesize GNPs in situ. Next, the GNP/CNT/AEP nanocomposite was prepared by mixing an AEP solution and the GNP/CNT powder. The nanocomposite was dripped onto a gold electrode (GE), and then p24 antibody (anti-p24 Ab) was immobilized on the resulting modified gold electrode to construct the immunosensor. The assembly process was characterized using cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The factors that were likely to influence the performance of the proposed immunosensor were studied in detail. Under optimal conditions, the proposed immunosensor exhibited good electrochemical sensitivity to the presence of p24 in a concentration range of 0.01 to 60.00 ng/mL, with a relatively low detection limit of 0.0064 ng/mL (S/N = 3). Moreover, the proposed immunosensor showed a rapid (≤ 18 s) and highly sensitive amperometric response (0.018 and 1.940 μA/ng/mL) to p24 with acceptable stability and reproducibility. Copyright © 2011 Elsevier B.V. All rights reserved.

Construction of titanium dioxide nanorod/graphite microfiber hybrid electrodes for a high performance electrochemical glucose biosensor

NASA Astrophysics Data System (ADS)

Zhang, Jian; Yu, Xin; Guo, Weibo; Qiu, Jichuan; Mou, Xiaoning; Li, Aixue; Liu, Hong

2016-04-01

The demand for a highly sensitive and selective glucose biosensor which can be used for implantable or on-time monitoring is constantly increasing. In this work, TiO2 nanorods were synthesized in situ on the surface of graphite microfibers to yield TiO2 nanorod/graphite microfiber hybrid electrodes. The TiO2 nanorods not only retain the high activity of the immobilized glucose molecule, but also promote the direct electron transfer process on the electrode surface. As a working electrode in an electrochemical glucose biosensor in a flowing system, the microfiber hybrid electrodes exhibit high sensitivity, selectivity and stability. Due to its simplicity, low cost, high stability, and unique morphology, the TiO2 nanorod/graphite microfiber hybrid electrode is expected to be an excellent candidate for an implantable biosensor or for in situ flow monitoring.The demand for a highly sensitive and selective glucose biosensor which can be used for implantable or on-time monitoring is constantly increasing. In this work, TiO2 nanorods were synthesized in situ on the surface of graphite microfibers to yield TiO2 nanorod/graphite microfiber hybrid electrodes. The TiO2 nanorods not only retain the high activity of the immobilized glucose molecule, but also promote the direct electron transfer process on the electrode surface. As a working electrode in an electrochemical glucose biosensor in a flowing system, the microfiber hybrid electrodes exhibit high sensitivity, selectivity and stability. Due to its simplicity, low cost, high stability, and unique morphology, the TiO2 nanorod/graphite microfiber hybrid electrode is expected to be an excellent candidate for an implantable biosensor or for in situ flow monitoring. Electronic supplementary information (ESI) available. See DOI: 10.1039/c6nr01360k

Design of surface modifications for nanoscale sensor applications.

PubMed

Reimhult, Erik; Höök, Fredrik

2015-01-14

Nanoscale biosensors provide the possibility to miniaturize optic, acoustic and electric sensors to the dimensions of biomolecules. This enables approaching single-molecule detection and new sensing modalities that probe molecular conformation. Nanoscale sensors are predominantly surface-based and label-free to exploit inherent advantages of physical phenomena allowing high sensitivity without distortive labeling. There are three main criteria to be optimized in the design of surface-based and label-free biosensors: (i) the biomolecules of interest must bind with high affinity and selectively to the sensitive area; (ii) the biomolecules must be efficiently transported from the bulk solution to the sensor; and (iii) the transducer concept must be sufficiently sensitive to detect low coverage of captured biomolecules within reasonable time scales. The majority of literature on nanoscale biosensors deals with the third criterion while implicitly assuming that solutions developed for macroscale biosensors to the first two, equally important, criteria are applicable also to nanoscale sensors. We focus on providing an introduction to and perspectives on the advanced concepts for surface functionalization of biosensors with nanosized sensor elements that have been developed over the past decades (criterion (iii)). We review in detail how patterning of molecular films designed to control interactions of biomolecules with nanoscale biosensor surfaces creates new possibilities as well as new challenges.

Design of Surface Modifications for Nanoscale Sensor Applications

PubMed Central

Reimhult, Erik; Höök, Fredrik

2015-01-01

Nanoscale biosensors provide the possibility to miniaturize optic, acoustic and electric sensors to the dimensions of biomolecules. This enables approaching single-molecule detection and new sensing modalities that probe molecular conformation. Nanoscale sensors are predominantly surface-based and label-free to exploit inherent advantages of physical phenomena allowing high sensitivity without distortive labeling. There are three main criteria to be optimized in the design of surface-based and label-free biosensors: (i) the biomolecules of interest must bind with high affinity and selectively to the sensitive area; (ii) the biomolecules must be efficiently transported from the bulk solution to the sensor; and (iii) the transducer concept must be sufficiently sensitive to detect low coverage of captured biomolecules within reasonable time scales. The majority of literature on nanoscale biosensors deals with the third criterion while implicitly assuming that solutions developed for macroscale biosensors to the first two, equally important, criteria are applicable also to nanoscale sensors. We focus on providing an introduction to and perspectives on the advanced concepts for surface functionalization of biosensors with nanosized sensor elements that have been developed over the past decades (criterion (iii)). We review in detail how patterning of molecular films designed to control interactions of biomolecules with nanoscale biosensor surfaces creates new possibilities as well as new challenges. PMID:25594599

A highly sensitive monoclonal antibody based biosensor for quantifying 3-5 ring polycyclic aromatic hydrocarbons (PAHs) in aqueous environmental samples

PubMed Central

Li, Xin; Kaattari, Stephen L.; Vogelbein, Mary A.; Vadas, George G.; Unger, Michael A.

2016-01-01

Immunoassays based on monoclonal antibodies (mAbs) are highly sensitive for the detection of polycyclic aromatic hydrocarbons (PAHs) and can be employed to determine concentrations in near real-time. A sensitive generic mAb against PAHs, named as 2G8, was developed by a three-step screening procedure. It exhibited nearly uniformly high sensitivity against 3-ring to 5-ring unsubstituted PAHs and their common environmental methylated PAHs, with IC50 values between 1.68–31 μg/L (ppb). 2G8 has been successfully applied on the KinExA Inline Biosensor system for quantifying 3-5 ring PAHs in aqueous environmental samples. PAHs were detected at a concentration as low as 0.2 μg/L. Furthermore, the analyses only required 10 min for each sample. To evaluate the accuracy of the 2G8-based biosensor, the total PAH concentrations in a series of environmental samples analyzed by biosensor and GC-MS were compared. In most cases, the results yielded a good correlation between methods. This indicates that generic antibody 2G8 based biosensor possesses significant promise for a low cost, rapid method for PAH determination in aqueous samples. PMID:26925369

Magnetron sputtered diamond-like carbon microelectrodes for on-chip measurement of quantal catecholamine release from cells

PubMed Central

Gao, Yuanfang; Chen, Xiaohui; Gupta, Sanju; Gillis, Kevin D.; Gangopadhyay, Shubhra

2008-01-01

Carbon electrodes are widely used in electrochemistry due to their low cost, wide potential window, and low and stable background noise. Carbon-fiber electrodes (CFE) are commonly used to electrochemically measure “quantal” catecholamine release via exocytosis from individual cells, but it is difficult to integrate CFEs into lab-on-a-chip devices. Here we report the development of nitrogen doped diamond-like carbon (DLC:N) microelectrodes on a chip to monitor quantal release of catecholamines from cells. Advantages of DLC:N microelectrodes are that they are batch producible at low cost, and are harder and more durable than graphite films. The DLC:N microelectrodes were prepared by a magnetron sputtering process with nitrogen doping. The 30 μm by 40 μm DLC:N microelectrodes were patterned onto microscope glass slides by photolithography and lift-off technology. The properties of the DLC:N microelectrodes were characterized by AFM, Raman spectroscopy and cyclic voltammetry. Quantal catecholamine release was recorded amperometrically from bovine adrenal chromaffin cells on the DLC:N microelectrodes. Amperometric spikes due to quantal release of catecholamines were similar in amplitude and area as those recorded using CFEs and the background current and noise levels of microchip DLC:N electrodes were also comparable to CFEs. Therefore, DLC:N microelectrodes are suitable for microchip-based high-throughput measurement of quantal exocytosis with applications in basic research, drug discovery and cell-based biosensors. PMID:18493856

Biosensing Technologies for Mycobacterium tuberculosis Detection: Status and New Developments

PubMed Central

Zhou, Lixia; He, Xiaoxiao; He, Dinggeng; Wang, Kemin; Qin, Dilan

2011-01-01

Biosensing technologies promise to improve Mycobacterium tuberculosis (M. tuberculosis) detection and management in clinical diagnosis, food analysis, bioprocess, and environmental monitoring. A variety of portable, rapid, and sensitive biosensors with immediate “on-the-spot” interpretation have been developed for M. tuberculosis detection based on different biological elements recognition systems and basic signal transducer principles. Here, we present a synopsis of current developments of biosensing technologies for M. tuberculosis detection, which are classified on the basis of basic signal transducer principles, including piezoelectric quartz crystal biosensors, electrochemical biosensors, and magnetoelastic biosensors. Special attention is paid to the methods for improving the framework and analytical parameters of the biosensors, including sensitivity and analysis time as well as automation of analysis procedures. Challenges and perspectives of biosensing technologies development for M. tuberculosis detection are also discussed in the final part of this paper. PMID:21437177

1-D grating based SPR biosensor for the detection of lung cancer biomarkers using Vroman effect

NASA Astrophysics Data System (ADS)

Teotia, Pradeep Kumar; Kaler, R. S.

2018-01-01

Grating based surface plasmon resonance waveguide biosensor have been reported for the detection of lung cancer biomarkers using Vroman effect. The proposed grating based multilayered biosensor is designed with high detection accuracy for Epidermal growth factor receptor (EGFR) and also analysed to show high detection accuracy with acceptable sensitivity for both cancer biomarkers. The introduction of periodic grating with multilayer metals generates a good resonance that make it possible for early detection of cancerous cells. Using finite difference time domain method, it is observed wavelength of biosensor get red-shifted on variations of the refractive index due to the presence of both the cancerous bio-markers. The reported detection accuracy and sensitivity of proposed biosensor is quite acceptable for both lung cancer biomarkers i.e. Carcinoembryonic antigen (CEA) and Epidermal growth factor receptor (EGFR) which further offer us label free early detection of lung cancer using these biomarkers.

Highly sensitive electrochemical biosensor for bisphenol A detection based on a diazonium-functionalized boron-doped diamond electrode modified with a multi-walled carbon nanotube-tyrosinase hybrid film.

PubMed

Zehani, Nedjla; Fortgang, Philippe; Saddek Lachgar, Mohamed; Baraket, Abdoullatif; Arab, Madjid; Dzyadevych, Sergei V; Kherrat, Rochdi; Jaffrezic-Renault, Nicole

2015-12-15

A highly sensitive electrochemical biosensor for the detection of Bisphenol A (BPA) in water has been developed by immobilizing tyrosinase onto a diazonium-functionalized boron doped diamond electrode (BDD) modified with multi-walled carbon nanotubes (MWCNTs). The fabricated biosensor exhibits excellent electroactivity towards o-quinone, a product of this enzymatic reaction of BPA oxidation catalyzed by tyrosinase. The developed BPA biosensor displays a large linear range from 0.01 nM to 100 nM, with a detection limit (LOD) of 10 pM. The feasibility of the proposed biosensor has been demonstrated on BPA spiked water river samples. Therefore, it could be a promising and reliable analytical tool for on-site monitoring of BPA in waste water. Copyright © 2015 Elsevier B.V. All rights reserved.

Amperometric detector designs for capillary electrophoresis microchips.

PubMed

Castaño-Alvarez, Mario; Fernández-Abedul, M Teresa; Costa-García, Agustín

2006-03-24

Electrochemical (EC) detection is a sensitive and miniaturisable detection mode for capillary electrophoresis (CE) microchips. Detection cell design is very important in order to ensure electrical isolation from the high separation voltage. Amperometric detectors with different designs have been developed for coupling EC detection to CE-microchips. Different working electrode alignment: in-channel or end-channel has been tested in conjunction with several materials: gold, platinum or carbon. The end-channel detector was based on a platinum or gold wire manually aligned at the exit of the separation channel. Thick- (screen-printed carbon electrode) and thin-film (sputtered gold film) electrodes have also been employed with this configuration, but with a different design that allowed the rapid replacement of the electrode. The in-channel detector was based on a gold film within the separation channel. A gold-based dual electrode detector, which combined for the first time in- and end-channel detection, has been also tested. These amperometric detectors have been evaluated in combination to poly(methylmethacrylate) (PMMA) and Topas (thermoplastic olefin polymer of amorphous structure) CE-microchips. Topas is a new and promising cyclic olefin copolymer with high chemical resistance. Relevant parameters of the polymer microchip separation such as precision, efficiency or resolution and amperometric detection were studied with the different detector designs using p-aminophenol and L-ascorbic acid as model analytes in Tris-based buffer pH 9.0.

Capacitive Biosensors and Molecularly Imprinted Electrodes.

PubMed

Ertürk, Gizem; Mattiasson, Bo

2017-02-17

Capacitive biosensors belong to the group of affinity biosensors that operate by registering direct binding between the sensor surface and the target molecule. This type of biosensors measures the changes in dielectric properties and/or thickness of the dielectric layer at the electrolyte/electrode interface. Capacitive biosensors have so far been successfully used for detection of proteins, nucleotides, heavy metals, saccharides, small organic molecules and microbial cells. In recent years, the microcontact imprinting method has been used to create very sensitive and selective biorecognition cavities on surfaces of capacitive electrodes. This chapter summarizes the principle and different applications of capacitive biosensors with an emphasis on microcontact imprinting method with its recent capacitive biosensor applications.

An interferometric imaging biosensor using weighted spectrum analysis to confirm DNA monolayer films with attogram sensitivity.

PubMed

Fu, Rongxin; Li, Qi; Wang, Ruliang; Xue, Ning; Lin, Xue; Su, Ya; Jiang, Kai; Jin, Xiangyu; Lin, Rongzan; Gan, Wupeng; Lu, Ying; Huang, Guoliang

2018-05-01

Interferometric imaging biosensors are powerful and convenient tools for confirming the existence of DNA monolayer films on silicon microarray platforms. However, their accuracy and sensitivity need further improvement because DNA molecules contribute to an inconspicuous interferometric signal both in thickness and size. Such weaknesses result in poor performance of these biosensors for low DNA content analyses and point mutation tests. In this paper, an interferometric imaging biosensor with weighted spectrum analysis is presented to confirm DNA monolayer films. The interferometric signal of DNA molecules can be extracted and then quantitative detection results for DNA microarrays can be reconstructed. With the proposed strategy, the relative error of thickness detection was reduced from 88.94% to merely 4.15%. The mass sensitivity per unit area of the proposed biosensor reached 20 attograms (ag). Therefore, the sample consumption per unit area of the target DNA content was only 62.5 zeptomoles (zm), with the volume of 0.25 picolitres (pL). Compared with the fluorescence resonance energy transfer (FRET), the measurement veracity of the interferometric imaging biosensor with weighted spectrum analysis is free to the changes in spotting concentration and DNA length. The detection range was more than 1µm. Moreover, single nucleotide mismatch could be pointed out combined with specific DNA ligation. A mutation experiment for lung cancer detection proved the high selectivity and accurate analysis capability of the presented biosensor. Copyright © 2017 Elsevier B.V. All rights reserved.

Piezoelectric detection of bilirubin based on bilirubin-imprinted titania film electrode.

PubMed

Yang, Zhengpeng; Yan, Jinlong; Zhang, Chunjing

2012-02-01

A novel quartz crystal microbalance (QCM) sensor with a high selectivity and sensitivity has been developed for bilirubin determination, based on the modification of bilirubin-imprinted titania film onto a quartz crystal by molecular imprinting and surface sol-gel techniques. The performance of the developed bilirubin biosensor was evaluated and the results indicated that a sensitive bilirubin biosensor could be fabricated. The obtained bilirubin biosensor presents high-selectivity monitoring of bilirubin, better reproducibility, shorter response time (30 min), wider linear range (0.1-50 μM), and lower detection limit (0.05 μM). The analytical application of the bilirubin biosensor confirms the feasibility of bilirubin determination in serum sample. Copyright © 2011 Elsevier Inc. All rights reserved.

Progress in chemical luminescence-based biosensors: A critical review.

PubMed

Roda, Aldo; Mirasoli, Mara; Michelini, Elisa; Di Fusco, Massimo; Zangheri, Martina; Cevenini, Luca; Roda, Barbara; Simoni, Patrizia

2016-02-15

Biosensors are a very active research field. They have the potential to lead to low-cost, rapid, sensitive, reproducible, and miniaturized bioanalytical devices, which exploit the high binding avidity and selectivity of biospecific binding molecules together with highly sensitive detection principles. Of the optical biosensors, those based on chemical luminescence detection (including chemiluminescence, bioluminescence, electrogenerated chemiluminescence, and thermochemiluminescence) are particularly attractive, due to their high-to-signal ratio and the simplicity of the required measurement equipment. Several biosensors based on chemical luminescence have been described for quantitative, and in some cases multiplex, analysis of organic molecules (such as hormones, drugs, pollutants), proteins, and nucleic acids. These exploit a variety of miniaturized analytical formats, such as microfluidics, microarrays, paper-based analytical devices, and whole-cell biosensors. Nevertheless, despite the high analytical performances described in the literature, the field of chemical luminescence biosensors has yet to demonstrate commercial success. This review presents the main recent advances in the field and discusses the approaches, challenges, and open issues, with the aim of stimulating a broader interest in developing chemical luminescence biosensors and improving their commercial exploitation. Copyright © 2015 Elsevier B.V. All rights reserved.

Attomolar electrochemical detection of the BCR/ABL fusion gene based on an amplifying self-signal metal nanoparticle-conducting polymer hybrid composite.

PubMed

Avelino, Karen Y P S; Frias, Isaac A M; Lucena-Silva, Norma; Gomes, Renan G; de Melo, Celso P; Oliveira, Maria D L; Andrade, César A S

2016-12-01

In the last ten years, conjugated polymers started to be used in the immobilization of nucleic acids via non-covalent interactions. In the present study, we describe the construction and use of an electrochemical DNA biosensor based on a nanostructured polyaniline-gold composite, specifically developed for the detection of the BCR/ABL chimeric oncogene. This chromosome translocation is used as a biomarker to confirm the clinical diagnosis of both chronic myelogenous leukemia (CML) and acute lymphocytic leukemia (ALL). The working principle of the biosensor rests on measuring the conductivity resulting from the non-covalent interactions between the hybrid nanocomposite and the DNA probe. The nanostructured platform exhibits a large surface area that enhances the conductivity. Positive cases, which result from the hybridization between DNA probe and targeted gene, induce changes in the amperometric current and in the charge transfer resistance (R CT ) responses. Atomic force microscopy (AFM) images showed changes in the genosensor surface after exposure to cDNA sample of patient with leukemia, evidencing the hybridization process. This new hybrid sensing-platform displayed high specificity and selectivity, and its detection limit is estimated to be as low as 69.4 aM. The biosensor showed excellent analytical performance for the detection of the BCR/ABL oncogene in clinical samples of patients with leukemia. Hence, this electrochemical sensor appears as a simple and attractive tool for the molecular diagnosis of the BCR/ABL oncogene even in early-stage cases of leukemia and for the monitoring of minimum levels of residual disease. Copyright © 2016 Elsevier B.V. All rights reserved.

Sense and sensitivity in bioprocessing-detecting cellular metabolites with biosensors.

PubMed

Dekker, Linda; Polizzi, Karen M

2017-10-01

Biosensors use biological elements to detect or quantify an analyte of interest. In bioprocessing, biosensors are employed to monitor key metabolites. There are two main types: fully biological systems or biological recognition coupled with physical/chemical detection. New developments in chemical biosensors include multiplexed detection using microfluidics. Synthetic biology can be used to engineer new biological biosensors with improved characteristics. Although there have been few biosensors developed for bioprocessing thus far, emerging trends can be applied in the future. A range of new platform technologies will enable rapid engineering of new biosensors based on transcriptional activation, riboswitches, and Förster Resonance Energy Transfer. However, translation to industry remains a challenge and more research into the robustness biosensors at scale is needed. Copyright © 2017 Elsevier Ltd. All rights reserved.

Development of a multilayered polymeric DNA biosensor using radio frequency technology with gold and magnetic nanoparticles.

PubMed

Yang, Cheng-Hao; Kuo, Long-Sheng; Chen, Ping-Hei; Yang, Chii-Rong; Tsai, Zuo-Min

2012-01-15

This study utilized the radio frequency (RF) technology to develop a multilayered polymeric DNA sensor with the help of gold and magnetic nanoparticles. The flexible polymeric materials, poly (p-xylylene) (Parylene) and polyethylene naphtholate (PEN), were used as substrates to replace the conventional rigid substrates such as glass and silicon wafers. The multilayered polymeric RF biosensor, including the two polymer layers and two copper transmission structure layers, was developed to reduce the total sensor size and further enhance the sensitivity of the biochip in the RF DNA detection. Thioglycolic acid (TGA) was used on the surface of the proposed biochip to form a thiolate-modified sensing surface for DNA hybridization. Gold nanoparticles (AuNPs) and magnetic nanoparticles (MNPs) were used to immobilize on the surface of the biosensor to enhance overall detection sensitivity. In addition to gold nanoparticles, the magnetic nanoparticles has been demonstrated the applicability for RF DNA detection. The performance of the proposed biosensor was evaluated by the shift of the center frequency of the RF biosensor because the electromagnetic characteristic of the biosensors can be altered by the immobilized multilayer nanoparticles on the biosensor. The experimental results show that the detection limit of the DNA concentration can reach as low as 10 pM, and the largest shift of the center frequency with triple-layer AuNPs and MNPs can approach 0.9 and 0.7 GHz, respectively. Such the achievement implies that the developed biosensor can offer an alternative inexpensive, disposable, and highly sensitive option for application in biomedicine diagnostic systems because the price and size of each biochip can be effectively reduced by using fully polymeric materials and multilayer-detecting structures. Copyright © 2011 Elsevier B.V. All rights reserved.

Label-free detection of glycoproteins by the lectin biosensor down to attomolar level using gold nanoparticles

PubMed Central

Bertok, Tomas; Sediva, Alena; Katrlik, Jaroslav; Gemeiner, Pavol; Mikula, Milan; Nosko, Martin; Tkac, Jan

2016-01-01

We present here an ultrasensitive electrochemical biosensor based on a lectin biorecognition capable to detect concentrations of glycoproteins down to attomolar (aM) level by investigation of changes in the charge transfer resistance (Rct) using electrochemical impedance spectroscopy (EIS). On polycrystalline gold modified by an aminoalkanethiol linker layer, gold nanoparticles were attached. A Sambucus nigra agglutinin was covalently immobilised on a mixed self-assembled monolayer formed on gold nanoparticles and finally, the biosensor surface was blocked by poly(vinylalcohol). The lectin biosensor was applied for detection of sialic acid containing glycoproteins fetuin and asialofetuin. Building of a biosensing interface was carefully characterised by a broad range of techniques such as electrochemistry, EIS, atomic force microscopy, scanning electron microscopy and surface plasmon resonance with the best performance of the biosensor achieved by application of HS-(CH2)11-NH2 linker and gold nanoparticles with a diameter of 20 nm. The lectin biosensor responded to an addition of fetuin (8.7% of sialic acid) with sensitivity of (338 ± 11) Ω decade-1 and to asialofetuin (≤ 0.5% of sialic acid) with sensitivity of (109 ± 10) Ω decade-1 with a blank experiment with oxidised asialofetuin (without recognisable sialic acid) revealing sensitivity of detection of (79 ± 13) Ω decade-1. These results suggest the lectin biosensor responded to changes in the glycan amount in a quantitative way with a successful validation by a lectin microarray. Such a biosensor device has a great potential to be employed in early biomedical diagnostics of diseases such as arthritis or cancer, which are connected to aberrant glycosylation of protein biomarkers in biological fluids. PMID:23601864

A reduced graphene oxide based electrochemical biosensor for tyrosine detection

NASA Astrophysics Data System (ADS)

Wei, Junhua; Qiu, Jingjing; Li, Li; Ren, Liqiang; Zhang, Xianwen; Chaudhuri, Jharna; Wang, Shiren

2012-08-01

In this paper, a ‘green’ and safe hydrothermal method has been used to reduce graphene oxide and produce hemin modified graphene nanosheet (HGN) based electrochemical biosensors for the determination of l-tyrosine levels. The as-fabricated HGN biosensors were characterized by UV-visible absorption spectra, fluorescence spectra, Fourier transform infrared spectroscopy (FTIR) spectra and thermogravimetric analysis (TGA). The experimental results indicated that hemin was successfully immobilized on the reduced graphene oxide nanosheet (rGO) through π-π interaction. TEM images and EDX results further confirmed the attachment of hemin on the rGO nanosheet. Cyclic voltammetry tests were carried out for the bare glass carbon electrode (GCE), the rGO electrode (rGO/GCE), and the hemin-rGO electrode (HGN/GCE). The HGN/GCE based biosensor exhibits a tyrosine detection linear range from 5 × 10-7 M to 2 × 10-5 M with a detection limitation of 7.5 × 10-8 M at a signal-to-noise ratio of 3. The sensitivity of this biosensor is 133 times higher than that of the bare GCE. In comparison with other works, electroactive biosensors are easily fabricated, easily controlled and cost-effective. Moreover, the hemin-rGO based biosensors demonstrate higher stability, a broader detection linear range and better detection sensitivity. Study of the oxidation scheme reveals that the rGO enhances the electron transfer between the electrode and the hemin, and the existence of hemin groups effectively electrocatalyzes the oxidation of tyrosine. This study contributes to a widespread clinical application of nanomaterial based biosensor devices with a broader detection linear range, improved stability, enhanced sensitivity and reduced costs.

A reduced graphene oxide based electrochemical biosensor for tyrosine detection.

PubMed

Wei, Junhua; Qiu, Jingjing; Li, Li; Ren, Liqiang; Zhang, Xianwen; Chaudhuri, Jharna; Wang, Shiren

2012-08-24

In this paper, a 'green' and safe hydrothermal method has been used to reduce graphene oxide and produce hemin modified graphene nanosheet (HGN) based electrochemical biosensors for the determination of l-tyrosine levels. The as-fabricated HGN biosensors were characterized by UV-visible absorption spectra, fluorescence spectra, Fourier transform infrared spectroscopy (FTIR) spectra and thermogravimetric analysis (TGA). The experimental results indicated that hemin was successfully immobilized on the reduced graphene oxide nanosheet (rGO) through π-π interaction. TEM images and EDX results further confirmed the attachment of hemin on the rGO nanosheet. Cyclic voltammetry tests were carried out for the bare glass carbon electrode (GCE), the rGO electrode (rGO/GCE), and the hemin-rGO electrode (HGN/GCE). The HGN/GCE based biosensor exhibits a tyrosine detection linear range from 5 × 10(-7) M to 2 × 10(-5) M with a detection limitation of 7.5 × 10(-8) M at a signal-to-noise ratio of 3. The sensitivity of this biosensor is 133 times higher than that of the bare GCE. In comparison with other works, electroactive biosensors are easily fabricated, easily controlled and cost-effective. Moreover, the hemin-rGO based biosensors demonstrate higher stability, a broader detection linear range and better detection sensitivity. Study of the oxidation scheme reveals that the rGO enhances the electron transfer between the electrode and the hemin, and the existence of hemin groups effectively electrocatalyzes the oxidation of tyrosine. This study contributes to a widespread clinical application of nanomaterial based biosensor devices with a broader detection linear range, improved stability, enhanced sensitivity and reduced costs.

ORGANOPHOSPHORUS HYDROLASE-BASED AMPEROMETRIC SENSOR: MODULATION OF SENSITIVITY AND SUBSTRATE SELECTIVITY

EPA Science Inventory

The detection of organophosphate (OP) insecticides with nitrophenyl substituents is reported using an enzyme electrode composed of Organophosphorus Hydrolase (OPH) and albumin co-immobilized to a nylon net and attached to a carbon paste electrode. The mechanism for this biosen...

Amperometric Gas Sensors as a Low Cost Emerging Technology Platform for Air Quality Monitoring Applications: A Review.

PubMed

Baron, Ronan; Saffell, John

2017-11-22

This review examines the use of amperometric electrochemical gas sensors for monitoring inorganic gases that affect urban air quality. First, we consider amperometric gas sensor technology including its development toward specifically designed air quality sensors. We then review recent academic and research organizations' studies where this technology has been trialed for air quality monitoring applications: early studies showed the potential of electrochemical gas sensors when colocated with reference Air Quality Monitoring (AQM) stations. Spatially dense networks with fast temporal resolution provide information not available from sparse AQMs with longer recording intervals. We review how this technology is being offered as commercial urban air quality networks and consider the remaining challenges. Sensors must be sensitive, selective, and stable; air quality monitors/nodes must be electronically and mechanically well designed. Data correction is required and models with differing levels of sophistication are being designed. Data analysis and validation is possibly the biggest remaining hurdle needed to deliver reliable concentration readings. Finally, this review also considers the roles of companies, urban infrastructure requirements, and public research in the development of this technology.

A ratiometric electrochemical biosensor for the exosomal microRNAs detection based on bipedal DNA walkers propelled by locked nucleic acid modified toehold mediate strand displacement reaction.

PubMed

Zhang, Jing; Wang, Liang-Liang; Hou, Mei-Feng; Xia, Yao-Kun; He, Wen-Hui; Yan, An; Weng, Yun-Ping; Zeng, Lu-Peng; Chen, Jing-Hua

2018-04-15

Sensitive and selective detection of microRNAs (miRNAs) in cancer cells derived exosomes have attracted rapidly growing interest owing to their potential in diagnostic and prognostic applications. Here, we design a ratiometric electrochemical biosensor based on bipedal DNA walkers for the attomolar detection of exosomal miR-21. In the presence of miR-21, DNA walkers are activated to walk continuously along DNA tracks, resulting in conformational changes as well as considerable increases of the signal ratio produced by target-respond and target-independent reporters. With the signal cascade amplification of DNA walkers, the biosensor exhibits ultrahigh sensitivity with the limit of detection (LOD) down to 67 aM. Furthermore, owing to the background-correcting function of target-independent reporters termed as reference reporters, the biosensor is robust and stable enough to be applied in the detection of exosomal miR-21 extracted from breast cancer cell lines and serums. In addition, because locked nucleic acid (LNA) modified toehold mediate strand displacement reaction (TMSDR) has extraordinary discriminative ability, the biosensor displays excellent selectivity even against the single-base-mismatched target. It is worth mentioning that our sensor is regenerative and stable for at least 5 cycles without diminution in sensitivity. In brief, the high sensitivity, selectivity and reproducibility, together with cheap, make the proposed biosensor a promising approach for exosomal miRNAs detection, in conjunction with early point-of-care testing (POCT) of cancer. Copyright © 2017 Elsevier B.V. All rights reserved.

Electrochemical Quartz Crystal Nanobalance (EQCN) Based Biosensor for Sensitive Detection of Antibiotic Residues in Milk.

PubMed

Bhand, Sunil; Mishra, Geetesh K

2017-01-01

An electrochemical quartz crystal nanobalance (EQCN), which provides real-time analysis of dynamic surface events, is a valuable tool for analyzing biomolecular interactions. EQCN biosensors are based on mass-sensitive measurements that can detect small mass changes caused by chemical binding to small piezoelectric crystals. Among the various biosensors, the piezoelectric biosensor is considered one of the most sensitive analytical techniques, capable of detecting antigens at picogram levels. EQCN is an effective monitoring technique for regulation of the antibiotics below the maximum residual limit (MRL). The analysis of antibiotic residues requires high sensitivity, rapidity, reliability and cost effectiveness. For analytical purposes the general approach is to take advantage of the piezoelectric effect by immobilizing a biosensing layer on top of the piezoelectric crystal. The sensing layer usually comprises a biological material such as an antibody, enzymes, or aptamers having high specificity and selectivity for the target molecule to be detected. The biosensing layer is usually functionalized using surface chemistry modifications. When these bio-functionalized quartz crystals are exposed to a particular substance of interest (e.g., a substrate, inhibitor, antigen or protein), binding interaction occurs. This causes a frequency or mass change that can be used to determine the amount of material interacted or bound. EQCN biosensors can easily be automated by using a flow injection analysis (FIA) setup coupled through automated pumps and injection valves. Such FIA-EQCN biosensors have great potential for the detection of different analytes such as antibiotic residues in various matrices such as water, waste water, and milk.

Fiber optic choline biosensor

NASA Astrophysics Data System (ADS)

Wang, Hong; Cao, Xiaojian; Jia, Ke; Chai, Xueting; Lu, Hua; Lu, Zuhong

2001-10-01

A fiber optic fluorescence biosensor for choline is introduced in this paper. Choline is an important neurotransmitter in mammals. Due to the growing needs for on-site clinical monitoring of the choline, much effect has been devoted to develop choline biosensors. Fiber-optic fluorescence biosensors have many advantages, including miniaturization, flexibility, and lack of electrical contact and interference. The choline fiber-optic biosensor we designed implemented a bifurcated fiber to perform fluorescence measurements. The light of the blue LED is coupled into one end of the fiber as excitation and the emission spectrum from sensing film is monitored by fiber-spectrometer (S2000, Ocean Optics) through the other end of the fiber. The sensing end of the fiber is coated with Nafion film dispersed with choline oxidase and oxygen sensitive luminescent Ru(II) complex (Tris(2,2'-bipyridyl)dichlororuthenium(II), hexahydrate). Choline oxidase catalyzes the oxidation of choline to betaine and hydrogen peroxide while consuming oxygen. The fluorescence intensity of oxygen- sensitive Ru(II) are related to the choline concentration. The response of the fiber-optic sensor in choline solution is represented and discussed. The result indicates a low-cost, high-performance, portable choline biosensor.

Effect of platinum nanoparticle deposition parameters on hydrogen peroxide transduction for applications in wearable electrochemical glucose biosensors

NASA Astrophysics Data System (ADS)

Cargill, Allison A.; Neil, Kathrine M.; Hondred, John A.; McLamore, Eric S.; Claussen, Jonathan C.

2016-05-01

Enhanced interest in wearable biosensor technology over the past decade is directly related to the increasing prevalence of diabetes and the associated requirement of daily blood glucose monitoring. In this work we investigate the platinum-carbon transduction element used in traditional first-generation glucose biosensors which rely on the concentration of hydrogen peroxide produced by the glucose-glucose oxidase binding scheme. We electrodeposit platinum nanoparticles on a commercially-available screen printed carbon electrode by stepping an applied current between 0 and 7.12 mA/cm2 for a varying number of cycles. Next, we examine the trends in deposition and the effect that the number of deposition cycles has on the sensitivity of electrochemical glucose sensing. Results from this work indicate that applying platinum nanoparticles to screen printed carbon via electrodeposition from a metal salt solution improves overall biosensor sensitivity. This work also pinpoints the amount of platinum (i.e., number of deposition cycles) that maximizes biosensor sensitivity in an effort to minimize the use of the precious metals, viz., platinum, in electrode fabrication. In summary, this work quantifies the relationship between platinum electrodeposition and sensor performance, which is crucial in designing and producing cost-effective sensors.

Current trends in nanomaterial embedded field effect transistor-based biosensor.

PubMed

Nehra, Anuj; Pal Singh, Krishna

2015-12-15

Recently, as metal-, polymer-, and carbon-based biocompatible nanomaterials have been increasingly incorporated into biosensing applications, with various nanostructures having been used to increase the efficacy and sensitivity of most of the detecting devices, including field effect transistor (FET)-based devices. These nanomaterial-based methods also became the ideal for the amalgamation of biomolecules, especially for the fabrication of ultrasensitive, low-cost, and robust FET-based biosensors; these are categorically very successful at binding the target specified entities in the confined gated micro-region for high functionality. Furthermore, the contemplation of nanomaterial-based FET biosensors to various applications encompasses the desire for detection of many targets with high selectivity, and specificity. We assess how such devices have empowered the achievement of elevated biosensor performance in terms of high sensitivity, selectivity and low detection limits. We review the recent literature here to illustrate the diversity of FET-based biosensors, based on various kinds of nanomaterials in different applications and sum up that graphene or its assisted composite based FET devices are comparatively more efficient and sensitive with highest signal to noise ratio. Lastly, the future prospects and limitations of the field are also discussed. Copyright © 2015 Elsevier B.V. All rights reserved.

Detection and quantification of new psychoactive substances (NPSs) within the evolved "legal high" product, NRG-2, using high performance liquid chromatography-amperometric detection (HPLC-AD).

PubMed

Zuway, Khaled Y; Smith, Jamie P; Foster, Christopher W; Kapur, Nikil; Banks, Craig E; Sutcliffe, Oliver B

2015-09-21

The global increase in the production and abuse of cathinone-derived New Psychoactive Substances (NPSs) has developed the requirement for rapid, selective and sensitive protocols for their separation and detection. Electrochemical sensing of these compounds has been demonstrated to be an effective method for the in-field detection of these substances, either in their pure form or in the presence of common adulterants, however, the technique is limited in its ability to discriminate between structurally related cathinone-derivatives (for example: (±)-4′-methylmethcathinone (4-MMC, 2a) and (±)-4′-methyl-N-ethylmethcathinone (4-MEC, 2b) when they are both present in a mixture. In this paper we demonstrate, for the first time, the combination of HPLC-UV with amperometric detection (HPLC-AD) for the qualitative and quantitative analysis of 4-MMC and 4-MEC using either a commercially available impinging jet (LC-FC-A) or custom-made iCell channel (LC-FC-B) flow-cell system incorporating embedded graphite screen-printed macroelectrodes. The protocol offers a cost-effective, reproducible and reliable sensor platform for the simultaneous HPLC-UV and amperometric detection of the target analytes. The two systems have similar limits of detection, in terms of amperometric detection [LC-FC-A: 14.66 μg mL(-1) (2a) and 9.35 μg mL(-1) (2b); LC-FC-B: 57.92 μg mL(-1) (2a) and 26.91 μg mL(-1) (2b)], to the previously reported oxidative electrochemical protocol [39.8 μg mL(-1) (2a) and 84.2 μg mL(-1) (2b)], for two synthetic cathinones, prevalent on the recreational drugs market. Though not as sensitive as standard HPLC-UV detection, both flow cells show a good agreement, between the quantitative electroanalytical data, thereby making them suitable for the detection and quantification of 4-MMC and 4-MEC, either in their pure form or within complex mixtures. Additionally, the simultaneous HPLC-UV and amperometric detection protocol detailed herein shows a marked improvement and advantage over previously reported electroanalytical methods, which were either unable to selectively discriminate between structurally related synthetic cathinones (e.g. 4-MMC and 4-MEC) or utilised harmful and restrictive materials in their design.

Rapid amplification/detection of nucleic acid targets utilizing a HDA/thin film biosensor.

PubMed

Jenison, Robert; Jaeckel, Heidi; Klonoski, Joshua; Latorra, David; Wiens, Jacinta

2014-08-07

Thin film biosensors exploit a flat, optically coated silicon-based surface whereupon formation of nucleic acid hybrids are enzymatically transduced in a molecular thin film that can be detected by the unaided human eye under white light. While the limit of sensitivity for detection of nucleic acid targets is at sub-attomole levels (60 000 copies) many clinical specimens containing bacterial pathogens have much lower levels of analyte present. Herein, we describe a platform, termed HDA/thin film biosensor, which performs helicase-dependant nucleic acid amplification on a thin film biosensor surface to improve the limit of sensitivity to 10 copies of the mecA gene present in methicillin-resistant strains of Staphylococcus. As double-stranded DNA is unwound by helicase it was either bound by solution-phase DNA primers to be copied by DNA polymerase or hybridized to surface immobilized probe on the thin film biosensor surface to be detected. Herein, we show that amplification reactions on the thin film biosensor are equivalent to in standard thin wall tubes, with detection at the limit of sensitivity of the assay occurring after 30 minutes of incubation time. Further we validate the approach by detecting the presence of the mecA gene in methicillin-resistant Staphylococcus aureus (MRSA) from positive blood culture aliquots with high specificity (signal/noise ratio of 105).

Label-free colorimetric sensor for sensitive detection of choline based on DNAzyme-choline oxidase coupling.

PubMed

Nikzad, Nasrin; Karami, Zahra

2018-04-14

Changes in choline levels can be associated with diseases such as Alzheimer, Parkinson, Huntington, fatty liver, interstitial lung abnormalities, autism and so on. Therefore, quantitative determination of choline is important in the biological and clinical analysis. So far, several methods have been investigated for measuring choline in the body fluids, each of which has disadvantages such as the need for specialist ability, complexity, and high cost. For this purpose, a facile and sensitive colorimetric biosensor based on DNAzyme-choline oxidase coupling used for the determination of choline. In this method, the first, choline oxidase produces H 2 O 2 and betaine in the presence of choline and oxygen, then, the DNAzyme converts colorless ABTS into green ABTS + radicals. Compared to the previous methods, the linear range and the limit of detection of this talented biosensor were 0.1-25 μM and 22 nM. Choline measurement using this biosensor has shown satisfactory selectivity and repeatability. Its recovery was 96.9-103.7%, which shows the reliability of biosensor assay in biological samples. Simplicity, low cost, naked eye, high sensitivity, and precision are the benefits of this biosensor. Taken to gather, the proposed system can be considered as a great biosensor for measuring choline levels especially in point of care diagnostic. Copyright © 2018 Elsevier B.V. All rights reserved.

Thickness dependence of polydopamine thin films on detection sensitivity of surface plasmon-enhanced fluorescence biosensors

NASA Astrophysics Data System (ADS)

Toma, Mana; Tawa, Keiko

2018-03-01

A bioinspired polydopamine (PDA) coating is a good candidate for the rapid and cheap chemical modification of biosensor surfaces. Herein, we report the effect of PDA thickness on the detection sensitivity of a fluorescence biosensor utilizing surface plasmon-enhanced fluorescence. The thickness of PDA films was tuned by the incubation time of the dopamine solution and varied from 1 to 17 nm. The detection sensitivity was evaluated as the limit of detection (LOD) of a fluorescently labelled target analyte by a model immunoassay. The LOD was determined to be 1.6 pM for the thickest PDA film and was improved to 1.0 pM by reducing the thickness to the range from 1 to 5 nm, corresponding to the incubation time of 10 to 60 min. The experimental results indicate that the PDA coating is suitable for the surface functionalization of biosensors in mass production as it does not require precise control of the incubation time.

Light-addressable amperometric electrodes for enzyme sensors based on direct quantum dot-electrode contacts

NASA Astrophysics Data System (ADS)

Riedel, M.; Göbel, G.; Parak, W. J.; Lisdat, F.

2014-03-01

Quantum dots allow the generation of charge carriers upon illumination. When these particles are attached to an electrode a photocurrent can be generated. This allows their use as a light-switchable layer on the surface. The QDs can not only exchange electronics with the electrode, but can also interact with donor or acceptor compounds in solution providing access to the construction of signal chains starting from an analytic molecule. The magnitude and the direction of the photocurrent depend on several factors such as electrode polarization, solution pH and composition. These defined dependencies have been evaluated with respect to the combination of QD-electrodes with enzyme reactions for sensorial purpose. CdSe/ZnS-QD-modified electrodes can be used to follow enzymatic reactions in solution based on the oxygen sensitivity. In order to develop a photoelectrochemical biosensor, e.g. glucose oxidase is immobilized on the CdSe/ZnS-electrode. One immobilization strategy applies the layer-by-layer-technique of GOD and a polyelectrolyte. Photocurrent measurements of such a sensor show a clear concentration dependent behavior. The principle of combing QD oxidase. The sensitivity of quantum dot electrodes can be influenced by additional nanoparticles, but also by multiple layers of the QDs. In another direction of research it can be influenced by additional nanoparticles, but also by multiple layers of the QDs. In another direction of research it can be demonstrated that direct electron transfer from excited quantum dots can be achieved with the redox protein cytochrome c. This allows the detection of the protein, but also interaction partners such as a enzymes or superoxide.

An amperometric bienzymatic cholesterol biosensor based on functionalized graphene modified electrode and its electrocatalytic activity towards total cholesterol determination.

PubMed

Manjunatha, Revanasiddappa; Shivappa Suresh, Gurukar; Melo, Jose Savio; D'Souza, Stanislaus F; Venkatesha, Thimmappa Venkatarangaiah

2012-09-15

Cholesterol oxidase (ChOx) and cholesterol esterase (ChEt) have been covalently immobilized onto functionalized graphene (FG) modified graphite electrode. Enzymes modified electrodes were characterized using cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). FG accelerates the electron transfer from electrode surface to the immobilized ChOx, achieving the direct electrochemistry of ChOx. A well defined redox peak was observed, corresponding to the direct electron transfer of the FAD/FADH(2) of ChOx. The electron transfer coefficient (α) and electron transfer rate constant (K(s)) were calculated and their values are found to be 0.31 and 0.78 s(-1), respectively. For the free cholesterol determination, ChOx-FG/Gr electrode exhibits a sensitive response from 50 to 350 μM (R=-0.9972) with a detection limit of 5 μM. For total cholesterol determination, co-immobilization of ChEt and ChOx on modified electrode, i.e. (ChEt/ChOx)-FG/Gr electrode showed linear range from 50 to 300 μM (R=-0.9982) with a detection limit of 15 μM. Some common interferents like glucose, ascorbic acid and uric acid did not cause any interference, due to the use of a low operating potential. The FG/Gr electrode exhibits good electrocatalytic activity towards hydrogen peroxide (H(2)O(2)). A wide linear response to H(2)O(2) ranging from 0.5 to 7 mM (R=-0.9967) with a sensitivity of 443.25 μA mM(-1) cm(-2) has been obtained. Copyright © 2012 Elsevier B.V. All rights reserved.

Handheld Chem/Biosensor Using Extreme Conformational Changes in Designed Binding Proteins to Enhance Surface Plasmon Resonance (SPR)

DTIC Science & Technology

2016-04-01

AFCEC-CX-TY-TR-2016-0007 HANDHELD CHEM/ BIOSENSOR USING EXTREME CONFORMATIONAL CHANGES IN DESIGNED BINDING PROTEINS TO ENHANCE SURFACE PLASMON...Include area code) 03/24/2016 Abstract 08/14/2015--03/31/2016 Handheld chem/ biosensor using extreme conformational changes in designed binding...Baltimore, Maryland on 17-21 April 2016. We propose the development of a highly sensitive handheld chem/ biosensor device using a novel class of engineered

Surface stress-based biosensors.

PubMed

Sang, Shengbo; Zhao, Yuan; Zhang, Wendong; Li, Pengwei; Hu, Jie; Li, Gang

2014-01-15

Surface stress-based biosensors, as one kind of label-free biosensors, have attracted lots of attention in the process of information gathering and measurement for the biological, chemical and medical application with the development of technology and society. This kind of biosensors offers many advantages such as short response time (less than milliseconds) and a typical sensitivity at nanogram, picoliter, femtojoule and attomolar level. Furthermore, it simplifies sample preparation and testing procedures. In this work, progress made towards the use of surface stress-based biosensors for achieving better performance is critically reviewed, including our recent achievement, the optimally circular membrane-based biosensors and biosensor array. The further scientific and technological challenges in this field are also summarized. Critical remark and future steps towards the ultimate surface stress-based biosensors are addressed. Copyright © 2013 Elsevier B.V. All rights reserved.

A comparative study of enzyme immobilization strategies for multi-walled carbon nanotube glucose biosensors

NASA Astrophysics Data System (ADS)

Shi, Jin; Claussen, Jonathan C.; McLamore, Eric S.; Haque, Aeraj ul; Jaroch, David; Diggs, Alfred R.; Calvo-Marzal, Percy; Rickus, Jenna L.; Porterfield, D. Marshall

2011-09-01

This work addresses the comparison of different strategies for improving biosensor performance using nanomaterials. Glucose biosensors based on commonly applied enzyme immobilization approaches, including sol-gel encapsulation approaches and glutaraldehyde cross-linking strategies, were studied in the presence and absence of multi-walled carbon nanotubes (MWNTs). Although direct comparison of design parameters such as linear range and sensitivity is intuitive, this comparison alone is not an accurate indicator of biosensor efficacy, due to the wide range of electrodes and nanomaterials available for use in current biosensor designs. We proposed a comparative protocol which considers both the active area available for transduction following nanomaterial deposition and the sensitivity. Based on the protocol, when no nanomaterials were involved, TEOS/GOx biosensors exhibited the highest efficacy, followed by BSA/GA/GOx and TMOS/GOx biosensors. A novel biosensor containing carboxylated MWNTs modified with glucose oxidase and an overlying TMOS layer demonstrated optimum efficacy in terms of enhanced current density (18.3 ± 0.5 µA mM - 1 cm - 2), linear range (0.0037-12 mM), detection limit (3.7 µM), coefficient of variation (2%), response time (less than 8 s), and stability/selectivity/reproducibility. H2O2 response tests demonstrated that the most possible reason for the performance enhancement was an increased enzyme loading. This design is an excellent platform for versatile biosensing applications.

Electrochemical Aptamer Scaffold Biosensors for Detection of Botulism and Ricin Proteins.

PubMed

Daniel, Jessica; Fetter, Lisa; Jett, Susan; Rowland, Teisha J; Bonham, Andrew J

2017-01-01

Electrochemical DNA (E-DNA) biosensors enable the detection and quantification of a variety of molecular targets, including oligonucleotides, small molecules, heavy metals, antibodies, and proteins. Here we describe the design, electrode preparation and sensor attachment, and voltammetry conditions needed to generate and perform measurements using E-DNA biosensors against two protein targets, the biological toxins ricin and botulinum neurotoxin. This method can be applied to generate E-DNA biosensors for the detection of many other protein targets, with potential advantages over other systems including sensitive detection limits typically in the nanomolar range, real-time monitoring, and reusable biosensors.

Tear glucose detection combining microfluidic thread based device, amperometric biosensor and microflow injection analysis.

PubMed

Agustini, Deonir; Bergamini, Márcio F; Marcolino-Junior, Luiz Humberto

2017-12-15

The tear glucose analysis is an important alternative for the indirect, simple and less invasive monitoring of blood glucose levels. However, the high cost and complex manufacturing process of tear glucose analyzers combined with the need to exchange the sensor after each analysis in the disposable tests prevent widespread application of the tear in glucose monitoring. Here, we present the integration of a biosensor made by the electropolymerization of poly(toluidine blue O) (PTB) and glucose oxidase (GOx) with an electroanalytical microfluidic device of easy assembly based on cotton threads, low cost materials and measurements by microflow injection analysis (µFIA) through passive pumping for performing tear glucose analyses in a simple, rapid and inexpensive way. A high stability between the analyses (RSD = 2.54%) and among the different systems (RSD = 3.13%) was obtained for the determination of glucose, in addition to a wide linear range between 0.075 and 7.5mmolL -1 and a limit of detection of 22.2µmolL -1 . The proposed method was efficiently employed in the determination of tear glucose in non-diabetic volunteers, obtaining a close correlation with their blood glucose levels, simplifying and reducing the costs of the analyses, making the tear glucose monitoring more accessible for the population. Copyright © 2017 Elsevier B.V. All rights reserved.

Ratiometric Matryoshka biosensors from a nested cassette of green- and orange-emitting fluorescent proteins.

PubMed

Ast, Cindy; Foret, Jessica; Oltrogge, Luke M; De Michele, Roberto; Kleist, Thomas J; Ho, Cheng-Hsun; Frommer, Wolf B

2017-09-05

Sensitivity, dynamic and detection range as well as exclusion of expression and instrumental artifacts are critical for the quantitation of data obtained with fluorescent protein (FP)-based biosensors in vivo. Current biosensors designs are, in general, unable to simultaneously meet all these criteria. Here, we describe a generalizable platform to create dual-FP biosensors with large dynamic ranges by employing a single FP-cassette, named GO-(Green-Orange) Matryoshka. The cassette nests a stable reference FP (large Stokes shift LSSmOrange) within a reporter FP (circularly permuted green FP). GO- Matryoshka yields green and orange fluorescence upon blue excitation. As proof of concept, we converted existing, single-emission biosensors into a series of ratiometric calcium sensors (MatryoshCaMP6s) and ammonium transport activity sensors (AmTryoshka1;3). We additionally identified the internal acid-base equilibrium as a key determinant of the GCaMP dynamic range. Matryoshka technology promises flexibility in the design of a wide spectrum of ratiometric biosensors and expanded in vivo applications.Single fluorescent protein biosensors are susceptible to expression and instrumental artifacts. Here Ast et al. describe a dual fluorescent protein design whereby a reference fluorescent protein is nested within a reporter fluorescent protein to control for such artifacts while preserving sensitivity and dynamic range.

Biosensors and their applications in detection of organophosphorus pesticides in the environment.

PubMed

Hassani, Shokoufeh; Momtaz, Saeideh; Vakhshiteh, Faezeh; Maghsoudi, Armin Salek; Ganjali, Mohammad Reza; Norouzi, Parviz; Abdollahi, Mohammad

2017-01-01

This review discusses the past and recent advancements of biosensors focusing on detection of organophosphorus pesticides (OPs) due to their exceptional use during the last decades. Apart from agricultural benefits, OPs also impose adverse toxicological effects on animal and human population. Conventional approaches such as chromatographic techniques used for pesticide detection are associated with several limitations. A biosensor technology is unique due to the detection sensitivity, selectivity, remarkable performance capabilities, simplicity and on-site operation, fabrication and incorporation with nanomaterials. This study also provided specifications of the most OPs biosensors reported until today based on their transducer system. In addition, we highlighted the application of advanced complementary materials and analysis techniques in OPs detection systems. The availability of these new materials associated with new sensing techniques has led to introduction of easy-to-use analytical tools of high sensitivity and specificity in the design and construction of OPs biosensors. In this review, we elaborated the achievements in sensing systems concerning innovative nanomaterials and analytical techniques with emphasis on OPs.

An improved biosensor for acetaldehyde determination using a bienzymatic strategy at poly(neutral red) modified carbon film electrodes.

PubMed

Ghica, Mariana Emilia; Pauliukaite, Rasa; Marchand, Nicolas; Devic, Eric; Brett, Christopher M A

2007-05-15

Improved biosensors for acetaldehyde determination have been developed using a bienzymatic strategy, based on a mediator-modified carbon film electrode and co-immobilisation of NADH oxidase and aldehyde dehydrogenase. Modification of the carbon film electrode with poly(neutral red) mediator resulted in a sensitive, low-cost and reliable NADH detector. Immobilisation of the enzymes was performed using encapsulation in a sol-gel matrix or cross-linking with glutaraldehyde. The bienzymatic biosensors were characterized by studying the influence of pH, applied potential and co-factors. The sol-gel and glutaraldehyde biosensors showed a linear response up to 60 microM and 100 microM, respectively, with detection limits of 2.6 microM and 3.3 microM and sensitivities were 1.7 microA mM(-1) and 5.6 microA mM(-1). The optimised biosensors showed good stability and good selectivity and have been tested for application for the determination of acetaldehyde in natural samples such as wine.

Highly sensitive graphene biosensor by monomolecular self-assembly of receptors on graphene surface

NASA Astrophysics Data System (ADS)

Kim, Ji Eun; No, Young Hyun; Kim, Joo Nam; Shin, Yong Seon; Kang, Won Tae; Kim, Young Rae; Kim, Kun Nyun; Kim, Yong Ho; Yu, Woo Jong

2017-05-01

Graphene has attracted a great deal of interest for applications in bio-sensing devices because of its ultra-thin structure, which enables strong electrostatic coupling with target molecules, and its excellent electrical mobility promising for ultra-fast sensing speeds. However, thickly stacked receptors on the graphene's surface interrupts electrostatic coupling between graphene and charged biomolecules, which can reduce the sensitivity of graphene biosensors. Here, we report a highly sensitive graphene biosensor by the monomolecular self-assembly of designed peptide protein receptors. The graphene channel was non-covalently functionalized using peptide protein receptors via the π-π interaction along the graphene's Bravais lattice, allowing ultra-thin monomolecular self-assembly through the graphene lattice. In thickness dependent characterization, a graphene sensor with a monomolecular receptor (thickness less than 3 nm) showed five times higher sensitivity and three times higher voltage shifts than graphene sensors with thick receptor stacks (thicknesses greater than 20 nm), which is attributed to excellent gate coupling between graphene and streptavidin via an ultrathin receptor insulator. In addition to having a fast-inherent response time (less than 0.6 s) based on fast binding speed between biotin and streptavidin, our graphene biosensor is a promising platform for highly sensitive real-time monitoring of biomolecules with high spatiotemporal resolution.

Progress in utilisation of graphene for electrochemical biosensors.

PubMed

Lawal, Abdulazeez T

2018-05-30

This review discusses recent graphene (GR) electrochemical biosensor for accurate detection of biomolecules, including glucose, hydrogen peroxide, dopamine, ascorbic acid, uric acid, nicotinamide adenine dinucleotide, DNA, metals and immunosensor through effective immobilization of enzymes, including glucose oxidase, horseradish peroxidase, and haemoglobin. GR-based biosensors exhibited remarkable performance with high sensitivities, wide linear detection ranges, low detection limits, and long-term stabilities. Future challenges for the field include miniaturising biosensors and simplifying mass production are discussed. Copyright © 2018 Elsevier B.V. All rights reserved.

Guided-Wave Optical Biosensors

PubMed Central

Passaro, Vittorio M. N.; Dell'Olio, Francesco; Casamassima, Biagio; De Leonardis, Francesco

2007-01-01

Guided-wave optical biosensors are reviewed in this paper. Advantages related to optical technologies are presented and integrated architectures are investigated in detail. Main classes of bio receptors and the most attractive optical transduction mechanisms are discussed. The possibility to use Mach-Zehnder and Young interferometers, microdisk and microring resonators, surface plasmon resonance, hollow and antiresonant waveguides, and Bragg gratings to realize very sensitive and selective, ultra-compact and fast biosensors is discussed. Finally, CMOS-compatible technologies are proved to be the most attractive for fabrication of guided-wave photonic biosensors.

Printed Graphene Electrochemical Biosensors Fabricated by Inkjet Maskless Lithography for Rapid and Sensitive Detection of Organophosphates.

PubMed

Hondred, John A; Breger, Joyce C; Alves, Nathan J; Trammell, Scott A; Walper, Scott A; Medintz, Igor L; Claussen, Jonathan C

2018-04-04

Solution phase printing of graphene-based electrodes has recently become an attractive low-cost, scalable manufacturing technique to create in-field electrochemical biosensors. Here, we report a graphene-based electrode developed via inkjet maskless lithography (IML) for the direct and rapid monitoring of triple-O linked phosphonate organophosphates (OPs); these constitute the active compounds found in chemical warfare agents and pesticides that exhibit acute toxicity as well as long-term pollution to soils and waterways. The IML-printed graphene electrode is nano/microstructured with a 1000 mW benchtop laser engraver and electrochemically deposited platinum nanoparticles (dia. ∼25 nm) to improve its electrical conductivity (sheet resistance decreased from ∼10 000 to 100 Ω/sq), surface area, and electroactive nature for subsequent enzyme functionalization and biosensing. The enzyme phosphotriesterase (PTE) was conjugated to the electrode surface via glutaraldehyde cross-linking. The resulting biosensor was able to rapidly measure (5 s response time) the insecticide paraoxon (a model OP) with a low detection limit (3 nM), and high sensitivity (370 nA/μM) with negligible interference from similar nerve agents. Moreover, the biosensor exhibited high reusability (average of 0.3% decrease in sensitivity per sensing event), stability (90% anodic current signal retention over 1000 s), longevity (70% retained sensitivity after 8 weeks), and the ability to selectively sense OP in actual soil and water samples. Hence, this work presents a scalable printed graphene manufacturing technique that can be used to create OP biosensors that are suitable for in-field applications as well as, more generally, for low-cost biosensor test strips that could be incorporated into wearable or disposable sensing paradigms.

Design of highly sensitive multichannel bimetallic photonic crystal fiber biosensor

NASA Astrophysics Data System (ADS)

Hameed, Mohamed Farhat O.; Alrayk, Yassmin K. A.; Shaalan, Abdelhamid A.; El Deeb, Walid S.; Obayya, Salah S. A.

2016-10-01

A design of a highly sensitive multichannel biosensor based on photonic crystal fiber is proposed and analyzed. The suggested design has a silver layer as a plasmonic material coated by a gold layer to protect silver oxidation. The reported sensor is based on detection using the quasi transverse electric (TE) and quasi transverse magnetic (TM) modes, which offers the possibility of multichannel/multianalyte sensing. The numerical results are obtained using a finite element method with perfect matched layer boundary conditions. The sensor geometrical parameters are optimized to achieve high sensitivity for the two polarized modes. High-refractive index sensitivity of about 4750 nm/RIU (refractive index unit) and 4300 nm/RIU with corresponding resolutions of 2.1×10-5 RIU, and 2.33×10-5 RIU can be obtained according to the quasi TM and quasi TE modes of the proposed sensor, respectively. Further, the reported design can be used as a self-calibration biosensor within an unknown analyte refractive index ranging from 1.33 to 1.35 with high linearity and high accuracy. Moreover, the suggested biosensor has advantages in terms of compactness and better integration of microfluidics setup, waveguide, and metallic layers into a single structure.

Anomalous resonance in a nanomechanical biosensor

PubMed Central

Gupta, Amit K.; Nair, Pradeep R.; Akin, Demir; Ladisch, Michael R.; Broyles, Steve; Alam, Muhammad A.; Bashir, Rashid

2006-01-01

The decrease in resonant frequency (−Δωr) of a classical cantilever provides a sensitive measure of the mass of entities attached on its surface. This elementary phenomenon has been the basis of a new class of bio-nanomechanical devices as sensing components of integrated microsystems that can perform rapid, sensitive, and selective detection of biological and biochemical entities. Based on classical analysis, there is a widespread perception that smaller sensors are more sensitive (sensitivity ≈ −0.5ωr/mC, where mC is the mass of the cantilever), and this notion has motivated scaling of biosensors to nanoscale dimensions. In this work, we show that the response of a nanomechanical biosensor is far more complex than previously anticipated. Indeed, in contrast to classical microscale sensors, the resonant frequencies of the nanosensor may actually decrease or increase after attachment of protein molecules. We demonstrate theoretically and experimentally that the direction of the frequency change arises from a size-specific modification of diffusion and attachment kinetics of biomolecules on the cantilevers. This work may have broad impact on microscale and nanoscale biosensor design, especially when predicting the characteristics of bio-nanoelectromechanical sensors functionalized with biological capture molecules. PMID:16938886

A fluorescent graphitic carbon nitride nanosheet biosensor for highly sensitive, label-free detection of alkaline phosphatase.

PubMed

Xiang, Mei-Hao; Liu, Jin-Wen; Li, Na; Tang, Hao; Yu, Ru-Qin; Jiang, Jian-Hui

2016-02-28

Graphitic C3N4 (g-C3N4) nanosheets provide an attractive option for bioprobes and bioimaging applications. Utilizing highly fluorescent and water-dispersible ultrathin g-C3N4 nanosheets, a highly sensitive, selective and label-free biosensor has been developed for ALP detection for the first time. The developed approach utilizes a natural substrate of ALP in biological systems and thus affords very high catalytic efficiency. This novel biosensor is demonstrated to enable quantitative analysis of ALP in a wide range from 0.1 to 1000 U L(-1) with a low detection limit of 0.08 U L(-1), which is among the most sensitive assays for ALP. It is expected that the developed method may provide a low-cost, convenient, rapid and highly sensitive platform for ALP-based clinical diagnostics and biomedical applications.

Fabrication of an electrochemical DNA-based biosensor for Bacillus cereus detection in milk and infant formula.

PubMed

Izadi, Zahra; Sheikh-Zeinoddin, Mahmoud; Ensafi, Ali A; Soleimanian-Zad, Sabihe

2016-06-15

This paper describes fabrication of a DNA-based Au-nanoparticle modified pencil graphite electrode (PGE) biosensor for detection of Bacillus cereus, causative agent of two types of food-borne disease, i.e., emetic and diarrheal syndrome. The sensing element of the biosensor was comprised of gold nanoparticles (GNPs) self-assembled with single-stranded DNA (ssDNA) of nheA gene immobilized with thiol linker on the GNPs modified PGE. The size, shape and dispersion of the GNPs were characterized by field emission scanning electron microscope (FESEM). Detection of B. cereus was carried out based on an increase in the charge transfer resistance (Rct) of the biosensor due to hybridization of the ss-DNA with target DNA. An Atomic force microscope (AFM) was used to confirm the hybridization. The biosensor sensitivity in pure cultures of B. cereus was found to be 10(0) colony forming units per milliliter (CFU/mL) with a detection limit of 9.4 × 10(-12) mol L(-1). The biosensor could distinguish complementary from mismatch DNA sequence. The proposed biosensor exhibited a rapid detection, low cost, high sensitivity to bacterial contamination and could exclusively and specifically detect the target DNA sequence of B. cereus from other bacteria that can be found in dairy products. Moreover, the DNA biosensor exhibited high reproducibility and stability, thus it may be used as a suitable biosensor to detect B. cereus and to become a portable system for food quality control. Copyright © 2016 Elsevier B.V. All rights reserved.

The whispering gallery mode biosensor: label-free detection from virus to single protein

NASA Astrophysics Data System (ADS)

Holler, S.; Dantham, V. R.; Keng, D.; Kolchenko, V.; Arnold, S.; Mulroe, Brigid; Paspaley-Grbavac, M.

2014-08-01

The whispering gallery mode (WGM) biosensor is a micro-optical platform capable of sensitive label-free detection of biological particles. Described by the reactive sensing principle (RSP), this analytic formulation quantifies the response of the system to the adsorption of bioparticles. Guided by the RSP, the WGM biosensor enabling from detection of virus (e.g., Human Papillomavirus, HPV) to the ultimate goal of single protein detection. The latter was derived from insights into the RSP, which resulted in the development of a hybrid plasmonic WGM biosensor, which has recently demonstrated detection of individual protein cancer markers. Enhancements from bound gold nanoparticles provide the sensitivity to detect single protein molecules (66 kDa) with good signal-to-noise (S/N > 10), and project that detection of proteins as small as 5 kDa.

Electro-Immobilization of Acetylcholinesterase Using Polydopamine for Carbaryl Microsensor

NASA Astrophysics Data System (ADS)

Ha, Trung B.; Le, Huyen T.; Cao, Ha H.; Binh, Nguyen Thanh; Nguyen, Huy L.; Dang, Le Hai; Do, Quan P.; Nguyen, Dzung T.; Lam, Tran Dai; Nguyen, Vân-Anh

2018-02-01

A simple and sensitive electrochemical acetylcholinesterase (AChE) biosensor for determination of carbaryl, one of the most commonly used carbamate pesticides, is described. The AChE enzyme was successfully entrapped by a polydopamine-graphene composite on polypyrrole nanowires that modified interdigitated planar platinum-film microelectrodes . The influence of different parameters on the operation of the biosensor was also studied. The selected parameters for the biosensor performance in detecting carbaryl were as follows: applied potential + 0.7 V, pH 7.4 at 25°C. The inhibition of carbaryl was proportional to its concentrations ranging from 0.05 to 1.5 μg/mL with the detection limit of 0.008 μg/mL using chronoamperometry. This study provides a promising approach in fabrication of sensitive biosensors for the analysis of carbamate pesticides as well as other hazardous compounds.

H2O2 sensing using HRP modified catalyst-free ZnO nanorods synthesized by RF sputtering

NASA Astrophysics Data System (ADS)

Srivastava, Amit; Kumar, Naresh; Singh, Priti; Singh, Sunil Kumar

2017-06-01

Catalyst-free ( 00 l) oriented ZnO nanorods (NRs) -based biosensor for the H2O2 sensing has been reported. The (002) oriented ZnO NRs as confirmed by X-ray diffraction were successfully grown on indium tin oxide (ITO) coated glass substrate by radio frequency (RF) sputtering technique without using any catalyst. Horseradish peroxidase (HRP) enzyme was immobilized on ZnO NRs by physical adsorption technique to prepare the biosensor. In this HRP/ZnO NR/ITO bioelectrode, nafion solution was added to form a tight membrane on surface. The prepared bioelectrode has been used for biosensing measurements by electrochemical analyzer. The electrochemical studies reveal that the prepared HRP/ZnO NR/ITO biosensor is highly sensitive to the detection of H2O2 over a linear range of 0.250-10 μM. The ZnO NR-based biosensor showed lower value of detection limit (0.125 μM) and higher sensitivity (13.40 µA/µM cm2) towards H2O2. The observed value of higher sensitivity attributed to larger surface area of ZnO nanostructure for effective loading of HRP besides its high electron communication capability. In addition, the biosensor also shows lower value of enzyme's kinetic parameter (Michaelis-Menten constant, K m) of 0.262 μM which indicates enhanced enzyme affinity of HRP to H2O2. The reported biosensor may be useful for various applications in biosensing, clinical, food, and beverage industry.

MRI biosensor for lead detection based on the DNAzyme-induced catalytic reaction.

PubMed

Xu, Liguang; Yin, Honghong; Ma, Wei; Wang, Libing; Kuang, Hua; Xu, Chuanlai

2013-11-21

A MRI biosensor for sensitive and specific detection of lead ions (Pb(2+)) was developed based on DNAzyme-induced cleavage of magnetic nanoparticles (MNPs). A low limit of detection (LOD) of 0.05 ng mL(-1) was obtained. This biosensor has the potential to serve as a general platform for the detection of heavy metal ions.

PEGylation of a Maltose Biosensor Promotes Enhanced Signal Response

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dattelbaum, Andrew; Baker, Gary A; Fox, John M

2009-01-01

A robust method to immobilize a maltose biosensor is described using an engineered maltose periplasmic binding protein (PBP) covalently coupled to NBDamide, an environmentally sensitive fluorophore. A mesoporous silica sol-gel derived from diglycerylsilane (DGS) was constructed to embed the maltose biosensor, and the ligand reporting fluorescence properties were meas red. When sequestered in the DGS-derived silica matrix, the biosensor retained maltose-dependent fluorescence sensing capability with micromolar affinity, which is consistent with the protein free in solution. The MBP-NBD conjugate was further modified by covalent conjugation with poly(ethylene glycol)-5000 (PEG) to promote the retention of water molecules around the protein andmore » to reduce possible steric effects between the silica matrix and protein. Bioconjugation with PEG molecules does not significantly affect the signaling response of the protein in solution. When immobilized in the DGS polymer, a consistent increase in fluorescence intensity was observed as compared to the protein not functionalized with PEG. To our knowledge, this report presents the first successful method to embed a PBP biosensor in a polymerized matrix and retain signaling response using an environmentally sensitive probe. The immobilization method presented here should be easily adaptable to all conformation-dependent biosensors.« less

Nanomaterial-Based Electrochemical Immunosensors for Clinically Significant Biomarkers

PubMed Central

Ronkainen, Niina J.; Okon, Stanley L.

2014-01-01

Nanotechnology has played a crucial role in the development of biosensors over the past decade. The development, testing, optimization, and validation of new biosensors has become a highly interdisciplinary effort involving experts in chemistry, biology, physics, engineering, and medicine. The sensitivity, the specificity and the reproducibility of biosensors have improved tremendously as a result of incorporating nanomaterials in their design. In general, nanomaterials-based electrochemical immunosensors amplify the sensitivity by facilitating greater loading of the larger sensing surface with biorecognition molecules as well as improving the electrochemical properties of the transducer. The most common types of nanomaterials and their properties will be described. In addition, the utilization of nanomaterials in immunosensors for biomarker detection will be discussed since these biosensors have enormous potential for a myriad of clinical uses. Electrochemical immunosensors provide a specific and simple analytical alternative as evidenced by their brief analysis times, inexpensive instrumentation, lower assay cost as well as good portability and amenability to miniaturization. The role nanomaterials play in biosensors, their ability to improve detection capabilities in low concentration analytes yielding clinically useful data and their impact on other biosensor performance properties will be discussed. Finally, the most common types of electroanalytical detection methods will be briefly touched upon. PMID:28788700

Integration of a highly ordered gold nanowires array with glucose oxidase for ultra-sensitive glucose detection.

PubMed

Cui, Jiewu; Adeloju, Samuel B; Wu, Yucheng

2014-01-27

A highly sensitive amperometric nanobiosensor has been developed by integration of glucose oxidase (GO(x)) with a gold nanowires array (AuNWA) by cross-linking with a mixture of glutaraldehyde (GLA) and bovine serum albumin (BSA). An initial investigation of the morphology of the synthesized AuNWA by field emission scanning electron microscopy (FESEM) and field emission transmission electron microscopy (FETEM) revealed that the nanowires array was highly ordered with rough surface, and the electrochemical features of the AuNWA with/without modification were also investigated. The integrated AuNWA-BSA-GLA-GO(x) nanobiosensor with Nafion membrane gave a very high sensitivity of 298.2 μA cm(-2) mM(-1) for amperometric detection of glucose, while also achieving a low detection limit of 0.1 μM, and a wide linear range of 5-6000 μM. Furthermore, the nanobiosensor exhibited excellent anti-interference ability towards uric acid (UA) and ascorbic acid (AA) with the aid of Nafion membrane, and the results obtained for the analysis of human blood serum indicated that the device is capable of glucose detection in real samples. Copyright © 2013 Elsevier B.V. All rights reserved.

Determination of mutagenic amines in water and food samples by high pressure liquid chromatography with amperometric detection using a multiwall carbon nanotubes-glassy carbon electrode.

PubMed

Bueno, Ana María; Marín, Miguel Ángel; Contento, Ana María; Ríos, Ángel

2016-02-01

A chromatographic method, using amperometric detection, for the sensitive determination of six representative mutagenic amines was developed. A glassy carbon electrode (GCE), modified with multiwall carbon nanotubes (GCE-CNTs), was prepared and its response compared to a conventional glassy carbon electrode. The chromatographic method (HPLC-GCE-CNTs) allowed the separation and the determination of heterocyclic aromatic amines (HAAs) classified as mutagenic amines by the International Agency for Research of Cancer. The new electrode was systematically studied in terms of stability, sensitivity, and reproducibility. Statistical analysis of the obtained data demonstrated that the modified electrode provided better sensitivity than the conventional unmodified ones. Detection limits were in the 3.0 and 7.5 ng/mL range, whereas quantification limits ranged between 9.5 and 25.0 ng/mL were obtained. The applicability of the method was demonstrated by the determination of the amines in several types of samples (water and food samples). Recoveries indicate very good agreement between amounts added and those found for all HAAs (recoveries in the 92% and 105% range). Copyright © 2015 Elsevier Ltd. All rights reserved.

A hydrogel biosensor for high selective and sensitive detection of amyloid-beta oligomers.

PubMed

Sun, Liping; Zhong, Yong; Gui, Jie; Wang, Xianwu; Zhuang, Xiaorong; Weng, Jian

2018-01-01

Alzheimer's disease (AD) is a neurodegenerative disorder characterized by progressive cognitive and memory impairment. It is the most common neurological disease that causes dementia. Soluble amyloid-beta oligomers (AβO) in blood or cerebrospinal fluid (CSF) are the pathogenic biomarker correlated with AD. A simple electrochemical biosensor using graphene oxide/gold nanoparticles (GNPs) hydrogel electrode was developed in this study. Thiolated cellular prion protein (PrP C ) peptide probe was immobilized on GNPs of the hydrogel electrode to construct an AβO biosensor. Electrochemical impedance spectroscopy was utilized for AβO analysis. The specific binding between AβO and PrP C probes on the hydrogel electrode resulted in an increase in the electron-transfer resistance. The biosensor showed high specificity and sensitivity for AβO detection. It could selectively differentiate AβO from amyloid-beta (Aβ) monomers or fibrils. Meanwhile, it was highly sensitive to detect as low as 0.1 pM AβO in artificial CSF or blood plasma. The linear range for AβO detection is from 0.1 pM to 10 nM. This biosensor could be used as a cost-effective tool for early diagnosis of AD due to its high electrochemical performance and bionic structure.

Two-dimensional Layered MoS2 Biosensors Enable Highly Sensitive Detection of Biomolecules

NASA Astrophysics Data System (ADS)

Lee, Joonhyung; Dak, Piyush; Lee, Yeonsung; Park, Heekyeong; Choi, Woong; Alam, Muhammad A.; Kim, Sunkook

2014-12-01

We present a MoS2 biosensor to electrically detect prostate specific antigen (PSA) in a highly sensitive and label-free manner. Unlike previous MoS2-FET-based biosensors, the device configuration of our biosensors does not require a dielectric layer such as HfO2 due to the hydrophobicity of MoS2. Such an oxide-free operation improves sensitivity and simplifies sensor design. For a quantitative and selective detection of PSA antigen, anti-PSA antibody was immobilized on the sensor surface. Then, introduction of PSA antigen, into the anti-PSA immobilized sensor surface resulted in a lable-free immunoassary format. Measured off-state current of the device showed a significant decrease as the applied PSA concentration was increased. The minimum detectable concentration of PSA is 1 pg/mL, which is several orders of magnitude below the clinical cut-off level of ~4 ng/mL. In addition, we also provide a systematic theoretical analysis of the sensor platform - including the charge state of protein at the specific pH level, and self-consistent channel transport. Taken together, the experimental demonstration and the theoretical framework provide a comprehensive description of the performance potential of dielectric-free MoS2-based biosensor technology.

Sensitivity control of optical fiber biosensors utilizing turnaround point long period gratings with self-assembled polymer coatings

NASA Astrophysics Data System (ADS)

Gifford, Erika; Wang, Z.; Ramachandran, S.; Heflin, J. R.

2007-09-01

Ionic self-assembled multilayers (ISAMs) adsorbed on long period fiber gratings (LPGs) can serve as an inexpensive, robust, portable, biosensor platform. The ISAM technique is a layer-by-layer deposition technique that creates thin films on the nanoscale level. The combination of ISAMs with LPGs yields exceptional sensitivity of the optical fiber transmission spectrum. We have shown theoretically that the resonant wavelength shift for a thin-film coated LPG can be caused by the variation of the film's refractive index and/or the variation of the thickness of the film. We have experimentally demonstrated that the deposition of nm-thick ISAM films on LPGs induces shifts in the resonant wavelength of > 1.6 nm per nm of thin film. It has also been shown that the sensitivity of the LPG to the thickness of the ISAM film increases with increased film thickness. We have further demonstrated that ISAM-coated LPGs can function effectively as biosensors by using the biotin-streptavidin system and by using the Bacillus anthracis (Anthrax) antibody- PA (Protective Antigen) system. Experiments have been successfully performed in both air and solution, which illustrates the versatility of the biosensor. The results confirm that ISAM-LPGs yield a reusable, thermally-stable, and robust platform for designing and building efficient optical biosensors.

Prediction of the limit of detection of an optical resonant reflection biosensor.

PubMed

Hong, Jongcheol; Kim, Kyung-Hyun; Shin, Jae-Heon; Huh, Chul; Sung, Gun Yong

2007-07-09

A prediction of the limit of detection of an optical resonant reflection biosensor is presented. An optical resonant reflection biosensor using a guided-mode resonance filter is one of the most promising label-free optical immunosensors due to a sharp reflectance peak and a high sensitivity to the changes of optical path length. We have simulated this type of biosensor using rigorous coupled wave theory to calculate the limit of detection of the thickness of the target protein layer. Theoretically, our biosensor has an estimated ability to detect thickness change approximately the size of typical antigen proteins. We have also investigated the effects of the absorption and divergence of the incident light on the detection ability of the biosensor.

Disease-Related Detection with Electrochemical Biosensors: A Review.

PubMed

Huang, Ying; Xu, Jin; Liu, Junjie; Wang, Xiangyang; Chen, Bin

2017-10-17

Rapid diagnosis of diseases at their initial stage is critical for effective clinical outcomes and promotes general public health. Classical in vitro diagnostics require centralized laboratories, tedious work and large, expensive devices. In recent years, numerous electrochemical biosensors have been developed and proposed for detection of various diseases based on specific biomarkers taking advantage of their features, including sensitivity, selectivity, low cost and rapid response. This article reviews research trends in disease-related detection with electrochemical biosensors. Focus has been placed on the immobilization mechanism of electrochemical biosensors, and the techniques and materials used for the fabrication of biosensors are introduced in details. Various biomolecules used for different diseases have been listed. Besides, the advances and challenges of using electrochemical biosensors for disease-related applications are discussed.

A SERS biosensor with magnetic substrate CoFe2O4@Ag for sensitive detection of Hg2+

NASA Astrophysics Data System (ADS)

Yang, Xia; He, Yi; Wang, Xueling; Yuan, Ruo

2017-09-01

Mercuric ion (Hg2+) is one toxic metal ion existed in aquatic ecosystems which would seriously damage human central nervous system and other organs. So developing an approach to sensitively detect Hg2+ in our living environment is urgent and important. In this work, a novel surface enhancement Raman spectrum(SERS) sensor is fabricated for high selective and ultrasensitive detection of Hg2+ in aqueous solution, based on a stable thymine-Hg2+-thymine (T-Hg2+-T) structure and the π-π interaction between single-stranded DNA (ssDNA) and single walled carbon nanotubes (SWCNTs). Herein, SWCNTs act as Raman labels to produce characteristic Raman peaks which can be a beacon to quantitative detect Hg2+. In the presence of Hg2+, the ssDNA can capture Hg2+ forming T-Hg2+-T structure, which makes SWCNTs leave the hot spots of the SERS-based biosensor. With this design, the Raman intensity of SWCNTs decreased with the increasing concentration of Hg2+. At the same time, CoFe2O4@Ag as active SERS substrates can effectively enhance sensitivity and uniformity of the biosensor through aggregation by magnet. Under optimal conditions, this proposed biosensor can detect Hg2+ at a range from 1 pM to 100 nM with a detection limit of 0.84 pM. With the advantages of good sensitivity, selectivity, simplicity and rapidity, the biosensor is potentially suitable for monitoring of Hg2+ in environmental applications.

Development of a Sensitive Electrochemical Enzymatic Reaction-Based Cholesterol Biosensor Using Nano-Sized Carbon Interdigitated Electrodes Decorated with Gold Nanoparticles

PubMed Central

Sharma, Deepti; Lee, Jongmin; Seo, Junyoung; Shin, Heungjoo

2017-01-01

We developed a versatile and highly sensitive biosensor platform. The platform is based on electrochemical-enzymatic redox cycling induced by selective enzyme immobilization on nano-sized carbon interdigitated electrodes (IDEs) decorated with gold nanoparticles (AuNPs). Without resorting to sophisticated nanofabrication technologies, we used batch wafer-level carbon microelectromechanical systems (C-MEMS) processes to fabricate 3D carbon IDEs reproducibly, simply, and cost effectively. In addition, AuNPs were selectively electrodeposited on specific carbon nanoelectrodes; the high surface-to-volume ratio and fast electron transfer ability of AuNPs enhanced the electrochemical signal across these carbon IDEs. Gold nanoparticle characteristics such as size and morphology were reproducibly controlled by modulating the step-potential and time period in the electrodeposition processes. To detect cholesterol selectively using AuNP/carbon IDEs, cholesterol oxidase (ChOx) was selectively immobilized via the electrochemical reduction of the diazonium cation. The sensitivity of the AuNP/carbon IDE-based biosensor was ensured by efficient amplification of the redox mediators, ferricyanide and ferrocyanide, between selectively immobilized enzyme sites and both of the combs of AuNP/carbon IDEs. The presented AuNP/carbon IDE-based cholesterol biosensor exhibited a wide sensing range (0.005–10 mM) and high sensitivity (~993.91 µA mM−1 cm−2; limit of detection (LOD) ~1.28 µM). In addition, the proposed cholesterol biosensor was found to be highly selective for the cholesterol detection. PMID:28914766

Biosensors based on enzyme field-effect transistors for determination of some substrates and inhibitors.

PubMed

Dzyadevych, Sergei V; Soldatkin, Alexey P; Korpan, Yaroslav I; Arkhypova, Valentyna N; El'skaya, Anna V; Chovelon, Jean-Marc; Martelet, Claude; Jaffrezic-Renault, Nicole

2003-10-01

This paper is a review of the authors' publications concerning the development of biosensors based on enzyme field-effect transistors (ENFETs) for direct substrates or inhibitors analysis. Such biosensors were designed by using immobilised enzymes and ion-selective field-effect transistors (ISFETs). Highly specific, sensitive, simple, fast and cheap determination of different substances renders them as promising tools in medicine, biotechnology, environmental control, agriculture and the food industry. The biosensors based on ENFETs and direct enzyme analysis for determination of concentrations of different substrates (glucose, urea, penicillin, formaldehyde, creatinine, etc.) have been developed and their laboratory prototypes were fabricated. Improvement of the analytical characteristics of such biosensors may be achieved by using a differential mode of measurement, working solutions with different buffer concentrations and specific agents, negatively or positively charged additional membranes, or genetically modified enzymes. These approaches allow one to decrease the effect of the buffer capacity influence on the sensor response in an aim to increase the sensitivity of the biosensors and to extend their dynamic ranges. Biosensors for the determination of concentrations of different toxic substances (organophosphorous pesticides, heavy metal ions, hypochlorite, glycoalkaloids, etc.) were designed on the basis of reversible and/or irreversible enzyme inhibition effect(s). The conception of an enzymatic multibiosensor for the determination of different toxic substances based on the enzyme inhibition effect is also described. We will discuss the respective advantages and disadvantages of biosensors based on the ENFETs developed and also demonstrate their practical application.

Biosensors Based on Urease Adsorbed on Nickel, Platinum, and Gold Conductometric Transducers Modified with Silicalite and Nanozeolites

NASA Astrophysics Data System (ADS)

Kucherenko, Ivan S.; Soldatkin, Oleksandr O.; Kasap, Berna Ozansoy; Kurç, Burcu Akata; Melnyk, Volodymir G.; Semenycheva, Lyudmila M.; Dzyadevych, Sergei V.; Soldatkin, Alexei P.

This work describes urease-based conductometric biosensors that were created using nontypical method of urease immobilization via adsorption on micro- and nanoporous particles: silicalite and nanocrystalline zeolites Beta (BEA) and L. Conductometric transducers with nickel, gold, and platinum interdigitated electrodes were used. Active regions of the nickel transducers were modified with microparticles using two procedures—spin coating and drop coating. Gold and platinum transducers were modified with silicalite using drop coating since it was more effective. Scanning electron microscopy was used to evaluate effectiveness of these procedures. The procedure of spin coating produced more uniform layers of particles (and biosensors had good reproducibility of preparation), but it was more complicated, drop coating was easier and led to formation of a bulk of particles; thus, biosensors had bigger sensitivity but worse reproducibility of preparation. Urease was immobilized onto transducers modified with particles by physical adsorption. Analytical characteristics of the obtained biosensors for determination of urea (calibration curves, sensitivity, limit of detection, linear concentration range, noise of responses, reproducibility of signal during a day, and operational stability during 3 days) were compared. Biosensors with all three particles deposited by spin coating showed similar characteristics; however, silicalite was a bit more effective. Biosensors based on nickel transducers modified by drop coating had better characteristics in comparison with modification by spin coating (except reproducibility of preparation). Transducers with gold electrodes showed best characteristics while creating biosensors, platinum electrodes were slightly inferior to them, and nickel electrodes were the worst.

Genetically engineered microbial biosensors for in situ monitoring of environmental pollution.

PubMed

Shin, Hae Ja

2011-02-01

Microbial biosensors are compact, portable, cost effective, and simple to use, making them seem eminently suitable for the in situ monitoring of environmental pollution. One promising approach for such applications is the fusion of reporter genes with regulatory genes that are dose-dependently responsive to the target chemicals or physiological signals. Their biosensor capabilities, such as target range and sensitivity, could be improved by modification of regulatory genes. Recent uses of such genetically engineered microbial biosensors include the development of portable biosensor kits and high-throughput cell arrays on chips, optic fibers, or other platforms for on-site and on-line monitoring of environmental pollution. This mini-review discusses recent advances in microbial biosensors and their future prospects, with a focus on the development and application of genetically modified microbial biosensors for in situ environmental monitoring.

Experimental demonstration and theoretical explanation of the efficiency of the nano-structured silicon as the transducer for optical immune biosensors

NASA Astrophysics Data System (ADS)

Starodub, Nickolaj F.; Slyshyk, Nelya F.; Shavanova, Kateryna E.; Karpyuk, Andrij; Mel'nichenko, Mykola M.; Zherdev, Anatolij V.; Dzantiev, Boris B.

2014-10-01

It is presented the experimental results about the investigations of the efficiency of the structured nano-pourous silicon (sNPS) application as transducer in the immune biosensors designed for the control of retroviral bovine leucosis (RBL) and the determination of the level such mycotoxins as T2 and patulin among environmental objects. Today, there is an arsenal of the traditional immunological methods that allow for the biochemical diagnostics of the above diseases and control of toxins but they are deeply routine and can not provide the requirements of practice for express analysis, its low cost and simplicity. Early to provide practical demands we developed immune biosensors based on SPR, TIRE and thermistors. To find more simple variant of the assay we studied the efficiency sNPS as trasducer in immune biosensor. The registration of the specific signals was made by measuremets of level of chemiluminescence (ChL) or photocurrent. The sensitivity of biosensor for both variants of the specific signal registration at the determination of T2 and patulin was about 10-20 ng/ml. Sensitivity analysis of RBL by this immune biosensors exceeds traditionally used approaches including the ELISA-method too. The optimal serum dilution of blood at the screening leukemia should be no less than 1:100, or even 1:500. The immune biosensor may be applied too for express screening leucosis through analysis of milk. In this case the optimal serum dilution of milk should be about 1:20. The total time of analysis including all steps (immobilization of specific Ab or antigens on the transducer surface and measurements) was about 40 min and it may be a sharp decline if the above mentione sensitive elements will be immobilized preliminary measurements. It is concluded that the proposed type of transducer for immune biosensor is effective for analysis of mycotoxins in screening regime.

Enzyme-coated microelectrodes to monitor lactate production in a nanoliter microfluidic cell culture device

PubMed Central

Ges, Igor A.; Baudenbacher, Franz

2015-01-01

Monitoring the degree of anaerobic respiration of cells in high density microscale culture systems is an enabling key technology and essential for cell-based biosensors. We have fabricated and incorporated miniature amperometric lactate sensing electrodes with working areas from 3 to 5×10−2 mm2 into a microfluidic-based microscale cell culture system to measure the lactate production rate of fibroblasts in nanoliter volumes. Planar thin film platinum electrode arrays on glass substrates were spin coated with lactate oxidase and a protective Nafion layer. The lactate electrodes had a high enzymatic activity described by a Michaelis-Menten constant of 2.6±0.1 mM, a linear response in the range 0.01÷2.5mM and a sensitivity of 7.3×10−2mA/mM·cm2. A replica-molded polydimethylsiloxane (PDMS) microfluidic device with nanoliter sensing volumes was aligned and sealed to a glass substrate with the sensing electrodes. We trapped fibroblasts in the cell culture volume and measured the lactate production rate using a stop and flow protocol. The average lactate production rate was 0.011±0.0049mM/min. The lactate production was suppressed with the addition of 2-deoxy-D-glucose, which binds to hexokinase. The blocking of hexokinase prevents the generation of pyruvate, the intermittent substrate required for lactate production even in the presence of glucose. PMID:20566279

Bubble electrodeposition of gold porous nanocorals for the enzymatic and non-enzymatic detection of glucose.

PubMed

Sanzó, Gabriella; Taurino, Irene; Antiochia, Riccarda; Gorton, Lo; Favero, Gabriele; Mazzei, Franco; De Micheli, Giovanni; Carrara, Sandro

2016-12-01

Au nanocorals are grown on gold screen-printed electrodes (SPEs) by using a novel and simple one-step electrodeposition process. Scanning electron microscopy was used for the morphological characterization. The devices were assembled on a three-electrode SPE system, which is flexible and mass producible. The electroactive surface area, determined by cyclic voltammetry in sulphuric acid, was found to be 0.07±0.01cm(2) and 35.3±2.7cm(2) for bare Au and nanocoral Au, respectively. The nanocoral modified SPEs were used to develop an enzymatic glucose biosensor based on H2O2 detection. Au nanocoral electrodes showed a higher sensitivity of 48.3±0.9μA/(mMcm(2)) at +0.45V vs Ag|AgCl compared to a value of 24.6±1.3μA/(mMcm(2)) at +0.70V vs Ag|AgCl obtained with bare Au electrodes. However, the modified electrodes have indeed proven to be extremely powerful for the direct detection of glucose with a non-enzymatic approach. The results confirmed a clear peak observed by using nanocoral Au electrode even in the presence of chloride ions at physiological concentration. Amperometric study carried out at +0.15V vs Ag|AgCl in the presence of 0.12M NaCl showed a linear range for glucose between 0.1 and 13mM. Copyright © 2016. Published by Elsevier B.V.

A novel paper-based device coupled with a silver nanoparticle-modified boron-doped diamond electrode for cholesterol detection.

PubMed

Nantaphol, Siriwan; Chailapakul, Orawon; Siangproh, Weena

2015-09-03

A novel paper-based analytical device (PAD) coupled with a silver nanoparticle-modified boron-doped diamond (AgNP/BDD) electrode was first developed as a cholesterol sensor. The AgNP/BDD electrode was used as working electrode after modification by AgNPs using an electrodeposition method. Wax printing was used to define the hydrophilic and hydrophobic areas on filter paper, and then counter and reference electrodes were fabricated on the hydrophilic area by screen-printing in house. For the amperometric detection, cholesterol and cholesterol oxidase (ChOx) were directly drop-cast onto the hydrophilic area, and H2O2 produced from the enzymatic reaction was monitored. The fabricated device demonstrated a good linearity (0.39 mg dL(-1) to 270.69 mg dL(-1)), low detection limit (0.25 mg dL(-1)), and high sensitivity (49.61 μA mM(-1) cm(-2)). The precision value for ten replicates was 3.76% RSD for 1 mM H2O2. In addition, this biosensor exhibited very high selectivity for cholesterol detection and excellent recoveries for bovine serum analysis (in the range of 99.6-100.8%). The results showed that this new sensing platform will be an alternative tool for cholesterol detection in routine diagnosis and offers the advantages of low sample/reagent consumption, low cost, portability, and short analysis time. Copyright © 2015 Elsevier B.V. All rights reserved.