Effects of the surface chemistry and structure of carbon nanotubes on the coating of glucose oxidase and electrochemical biosensors performance

González-Gaitán, Carolina; Ruiz-Rosas, Ramiro; Morallón, Emilia; Cazorla‐Amorós, Diego

doi:10.1039/c7ra02380d

Cited by 36 publications

(30 citation statements)

References 52 publications

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“…Glycerol reacts with the glycerol-3-kinase (GK) and gets converted to to glycerol-3-phosphate which then serves as the substrate for glycerol-3-phosphate oxidase to form dihydroxyacetonephosphate and H 2 O 2 ( Figure 5B). The redox potential of H 2 O 2 is about 0.4 V. [4,26,31] The other potential contributor to the redox signal is FAD whose redox potential also has been reported between 0.4-0.5 V. [46] We did not observe any redox peak at that potential in the present study. Instead, we have observed a redox peak between 0.2 to 0.3 V which is attributed to the redox potential of FAD.…”

Section: Electrochemical Measurementssupporting

confidence: 46%

Fabrication of a Nano‐Interfaced Electrochemical Triglyceride Biosensor and its Potential Application towards Distinguishing Cancer and Normal Cells

et al. 2020

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Hypertriglyceridemia, a condition characterized by elevated levels of triglycerides is considered a major risk factor of metabolic syndrome. The present work aims to develop a hybrid nano-interfaced enzymatic sensor that employs three enzymes to hydrolyze the triglycerides, phosphorylate glycerol and finally oxidize it to generate the electrochemical signal. Triolein, a common long chained triglyceride found in biological systems was employed as the substrate. The sensor displayed an excellent response time of 3 s and a linear range of 0.5 to 5.5 mM. The sensor was stable under both wet and dry conditions for 25 days. The capability of the sensor to detect triglycerides in biological samples was assessed by employing it to estimate total triglyceride levels in normal and cancer cells. Cancer cells displayed triglyceride levels distinctly higher than normal cells suggesting that this sensor can be employed for screening normal and cancer tissues apart from routine serum analysis to screen individuals with triglyceridemia and metabolic syndrome.

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Section: Electrochemical Measurementssupporting

confidence: 46%

Fabrication of a Nano‐Interfaced Electrochemical Triglyceride Biosensor and its Potential Application towards Distinguishing Cancer and Normal Cells

et al. 2020

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“…The larger electrochemical flow cell is shown in Figure 3A, where the VACNT sensor was held between two, size- the O 2 reduction current. 45 However, at low potentials the PNU-VACNTs produced a very large negative current from the reduction of oxygen, making it unreasonable to operate at low potentials in the presence of oxygen (oxygen is required for the GOx reaction).…”

Section: Flow Cell Configurationsmentioning

confidence: 99%

“…Also shown inFigure 4is current density with flow rate for 10 µM of ascorbic acid (AA, Fisher Scientific) at a potential of 0.55 V vs. Ag/AgCl (same as GOx tests),as tested with each of the GOx sensors (Pt only, EDC/NHS, and PEDOT). The current density from this interfering species was rather large because AA oxidizes readily at this potential 45. This was especially significant for the low current densities of EDC/NHS and PEDOT sensors at high flow rates, which is the main reason to operate the functionalized sensors at a low flow rate (1 mL/min).…”

mentioning

confidence: 99%

Electrochemical Glucose Sensors Enhanced by Methyl Viologen and Vertically Aligned Carbon Nanotube Channels

Brownlee

Bahari

Harb

et al. 2018

ACS Appl. Mater. Interfaces

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Freestanding, vertically aligned carbon nanotubes (VACNTs) were patterned into 16 μm diameter microchannel arrays for flow-through electrochemical glucose sensing. Non-enzymatic sensing of glucose was achieved by the chemical reaction of glucose with methyl viologen (MV) at an elevated temperature and pH (0.1 M NaOH), followed by the electrochemical reaction of reduced-MV with the VACNT surface. The MV sensor required no functionalization (including no metal) and was able to produce on average 3.4 electrons per glucose molecule. The current density of the MV sensor was linear with both flow rate and glucose concentration. Challenges with interference chemicals were mitigated by operating at a low potential of -0.2 V vs Ag/AgCl. As a comparison, enzymatic VACNT sensors with platinum nano-urchins were functionalized with glucose oxidase by covalent binding (1-ethyl-3-(-3-dimethylaminopropyl)carbodiimide/ N-hydroxysuccinimide) or by polymer entrapment [poly(3,4-ethylene-dioxythiophene)] and operated in phosphate buffered saline. With normalization by the overall cross-sectional area of the flow (0.713 cm), the sensitivity of the MV, enzyme-in-solution, and covalent sensors were 45.93, 18.77, and 1.815 mA cm mM, respectively. Corresponding limits of detection were 100, 194, and 311 nM glucose. The linear sensing ranges for the sensors were 250 nM to 200 μM glucose for the MV sensor, 500 nM to 200 μM glucose for the enzyme-in-solution sensor, and 1 μM to 6 mM glucose for the covalent sensor. The flow cell and sensor cross-sectional area were scaled down (0.020 cm) to enable detection from 200 μL of glucose with MV by flow injection analysis. The sensitivity of the small MV sensor was 5.002 mA cm mM, with a limit of detection of 360 nM glucose and a linear range up to at least 150 μM glucose. The small MV sensor has the potential to measure glucose levels found in 200 μL of saliva.

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“…Material science and protein engineering develop approaches to overcome those limitations. Material science focuses on the modification of the enzyme–electrode interface for improved electrochemical communication (du Toit & Di Lorenzo, ; Gonzalez‐Gaitan et al, ; Haghighi, Hallaj, & Salimi, ; Husain, ; Li et al, ; Mano et al, ; M. Zhang et al, ; Pourasl et al, ; Sağlam et al, ; Shrestha et al, ; Suganthi et al, ; Tian et al, ; Zhu et al, ). Protein engineering aims to optimize the enzyme toward specific needs and to gain knowledge about the involved mechanisms on a molecular level.…”

Section: Introductionmentioning

confidence: 99%

“…First generation glucose sensors were able to detect either a pH-shift caused by gluconic acid formation, oxygen consumption (Clark & Lyons, 1962), or hydrogen peroxide formation (Clark & Clark, 1973). Since then, intensive research on the direct electrochemical communication between redox enzyme and electrode took place (González-Gaitán, Ruiz-Rosas, Morallón, & Cazorla-Amorós, 2017;Mano et al, 2002;Pourasl et al, 2014;Zhu et al, 2012). These third generation biosensors are composed of electrodes (e.g., glassy carbon electrode, porous gold electrode, etc.)…”

Section: Introductionmentioning

confidence: 99%

How to engineer glucose oxidase for mediated electron transfer

Gutierrez

Wallraf

Balaceanu

et al. 2018

Biotech & Bioengineering

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Glucose oxidase (GOx) is of high industrial interest for glucose sensing because of its high β-d-glucose specificity. The efficient and specific electrochemical communication between the redox center and electrodes is crucial to ensure accurate glucose determination. The efficiency of the electron transfer rates (ETR) with GOx, together with quinone diamine based mediators, is low and differs even among mediator derivatives. To design optimized enzyme-mediator couples and to describe a mediator binding model, a joint experimental and computational study was performed based on an oxygen-independent GOx variant V7 and two quinone diimine based electron mediators (QDM-1 and QDM-2), which differ in polarity and size, and ferrocenemethanol (FM). A site saturation library at position 414 was screened with all three mediators and yielded four beneficial substitutions Tyr, Met, Leu, and Val. The variants showed increased mediator activity for the more polar QDM-2 with a simultaneously decreased activity for the less polar and smaller QDM-1 and for FM. The variant GOx V7-I414Y exhibited the biggest change for the quinone diimine derivatives compared with V7 (QDM-1: 55.9 U/mg V7, 33.2 U/mg V7-I414Y; QDM-2: 2.7 U/mg V7, 12.9 U/mg V7-I414Y). Theoretical ETR calculated based on the Marcus theory were in good agreement with the experimental results. Molecular docking studies revealed a preferable binding of the two QD mediators directly in the active site, 3.5 Å away from the N5 atom of the flavin adenine dinucleotide (FAD) and in direct vicinity to position 414. In summary, position 414 in the active site was identified to modulate the electron shuttling from the FAD of the GOx to small water-soluble mediators dependent on the polarity and size of residue 414 and on the polarity and size of the mediator. The presented mediator binding model offers a promising possibility for the design of optimized enzyme-mediator couples.

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Effects of the surface chemistry and structure of carbon nanotubes on the coating of glucose oxidase and electrochemical biosensors performance

Abstract: Glucose oxidase has been immobilized on multiwall and herringbone carbon nanotubes for glucose biosensing.

Cited by 36 publications

References 52 publications

Fabrication of a Nano‐Interfaced Electrochemical Triglyceride Biosensor and its Potential Application towards Distinguishing Cancer and Normal Cells

Fabrication of a Nano‐Interfaced Electrochemical Triglyceride Biosensor and its Potential Application towards Distinguishing Cancer and Normal Cells

Electrochemical Glucose Sensors Enhanced by Methyl Viologen and Vertically Aligned Carbon Nanotube Channels

How to engineer glucose oxidase for mediated electron transfer

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