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Article

Metal Oxide Nanoparticle Based Electrochemical Sensor for Total Antioxidant Capacity (TAC) Detection in Wine Samples

by
Cristina Tortolini
,
Paolo Bollella
,
Rosaceleste Zumpano
,
Gabriele Favero
,
Franco Mazzei
and
Riccarda Antiochia
*
Department of Chemistry and Drug Technologies, Sapienza University of Rome—P.le Aldo Moro 5, 00185 Rome, Italy
*
Author to whom correspondence should be addressed.
Biosensors 2018, 8(4), 108; https://doi.org/10.3390/bios8040108
Submission received: 13 September 2018 / Revised: 31 October 2018 / Accepted: 9 November 2018 / Published: 14 November 2018
(This article belongs to the Special Issue Enzymatic Electrochemical Biosensors)
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Abstract

:
A single-use electrochemical screen-printed electrode is reported based on biomimetic properties of nanoceria particles (CeNPs). The developed tool showed an easy approach compared to the classical spectrophotometric methods reported in literature in terms of ease of use, cost, portability, and unnecessary secondary reagents. The sensor allowed the detection of the total antioxidant capacity (TAC) in wine samples. The sensor has been optimized and characterized electrochemically and then tested with antioxidant compounds occurred in wine samples. The electrochemical CeNPs modified sensor has been used for detection of TAC in white and red commercial wines and the data compared to the 2,2′-azino-bis(3-ethylbenzthiazoline-6-sulphonic acid (ABTS)-based spectrophotometric method. Finally, the obtained results have demonstrated that the proposed sensor was suitable for the simple and quick evaluation of TAC in beverage samples.

1. Introduction

Antioxidant capacity is an ability of organisms or food to catch free radicals and prevent their harmful effects. Substances with antioxidative properties are called antioxidants and have received much attention in recent years. They have ability to fight against the oxidative processes [1], to promote health and to prevent a wide variety of diseases: atherosclerosis, type 2 diabetes, neurodegeneration (Alzheimer’s and Parkinson’s diseases) [2,3] and cancer [4]. Epidemiological studies recommend to introduce in the diet substances as fruits, vegetables and less processed staple foods ensure the best protection against possible diseases caused by oxidative stress, such as coronary heart disease, obesity, hypertension, and cataracts [5]. The explanation consists in the beneficial health effect, due to antioxidants present in fruit and vegetables [6]. In particular, polyphenols are naturally-occurring antioxidants found widely in the fruits, vegetables, cereals, dry legumes, chocolate and beverages, such as tea, coffee, or wine. Polyphenols and other food phenolics are the subject of increasing scientific interest because offer a great hope for the prevention of human diseases [7].
Total antioxidant capacity (TAC) is the measure of the quantity of free radicals scavenged by a test solution [8], for evaluating the antioxidant capacity in samples of different nature. Several methods have been proposed for the determination of the TAC of body fluids [9,10,11,12,13], of biological samples [14,15], and food extracts [16,17]. Usually, the antioxidant capacity is given as the Trolox (6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid) equivalent antioxidant capacity (TEAC) [18,19], as the ferric reducing antioxidant power (FRAP) [20,21], as the cupric reducing antioxidant capacity (CUPRAC) [22,23,24], as the oxygen radical absorption capacity method (ORAC) [25,26], as the 2,2′-azino-bis(3-ethylbenzthiazoline-6-sulphonic acid (ABTS) [25], and as the DPPH (2,2-diphenyl-1-picrylhydrazyl) method [27], respectively based on the different spectrophotometric methods which have been used to estimated it.
Recently, also electrochemical methods have greatly contributed to measure of TAC based on biosensors [28,29,30,31] and sensors [32,33]. They offer sensitivity, inexpensive instrumentation, fast response, small volumes [34,35,36,37].
In the last years, the application of nanomaterials resulted in many advantages for the sensing systems, including the observation of enhanced electrocatalytic phenomena with benefits in chemical and biosensing and improving analytical performance of classical sensing platforms [37,38,39,40,41,42,43,44,45,46]. Some authors reported nanomaterial based sensor for determination of polyphenols in foodstuffs [47,48,49,50,51,52,53,54,55].
Different kinds of nanomaterials have been used as stable and low-cost alternatives to biomolecules in (bio)analytical methods. The materials comprise metal/metal oxides, metal complexes, nanocomposites, porphyrins, phthalocyanines, smart polymers, and carbon nanomaterials [56,57]. Cerium oxide nanoparticles (CeNPs) or nanoceria particles have attractive catalytic and electrochemical features [58]. Moreover, ceria is an excellent co-immobilization material for a variety of oxidase and peroxidase enzymes such as horseradish peroxidase [59,60], glutamate oxidase [61]. Its catalytic activity can be exploited to develop highly sensitive, enzymeless H2O2 sensors [62] and for the fabrication of third generation biosensors [63]. Ceria has high oxygen mobility at its surface [64,65] and a large oxygen diffusion coefficient, which facilitates the conversion between valance states Ce4+/Ce3+ [66] that allow oxygen to be released or stored in its crystalline structure [67,68].
Recently, CeNPs have also been reported to have multienzyme, including superoxide oxidase, catalase and oxidase, and mimetic properties [69,70,71], and have emerged as a fascinating material in biological fields, such as in bioanalysis [72,73,74], biomedicine [75,76,77], and drug delivery [78,79]. Catalytically active nanoceria offer several advantages over natural enzymes, such as controlled synthesis at low cost, tunable catalytic activities and high stability against severe physiological conditions [80].
In the present work, we developed an electrochemical disposable sensor modified with nanoceria particles for determination of total antioxidant capacity (TAC) in real samples. Firstly, the sensor was characterized electrochemically and then has been tested for some common antioxidants present in wines, such as gallic acid, caffeic acid, ascorbic acid, quercetin, trans-resveratrol and, finally, for the detection of TAC in six white and red commercial wine samples. The results relative to wine samples obtained with the electrochemical method were compared to those carried out with the spectrophotometric method (ABTS-based method). The modification procedure was demonstrated to be very simple and the developed sensor resulted to be easy-to-use, robust and cheap without involving labeled reagents.

2. Materials and Methods

2.1. Chemicals and Reagents

All chemicals used were analytical grade and were used as received without any further purification. In particular: sodium monobasic phosphate (Na2HPO4), sodium dibasic phosphate NaH2PO4, potassium chloride (KCl), potassium ferricyanide (III) (K3[Fe(CN)6]), cerium (IV) oxide NPs (20 wt% colloidal dispersion in acetic acid 2.5 wt%, d = 30–60 nm), gallic acid (GA), caffeic acid (CA), quercetin (Q), trans-resveratrol (t-R), ascorbic acid (AA), and dimethyl sulfoxide were purchased from Sigma-Aldrich (Buchs, Switzerland). For the TEAC assay: 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid (ABTS) and potassium persulfate (K2S2O8) were also supplied by Sigma-Aldrich (Buchs, Switzerland).
All the solutions were prepared in phosphate buffer 0.1 M, KCl 0.1 M, pH 7.4 (PBS buffer) high-purity deionized water (resistance: 18.2 MΩ × cm at 25 °C; TOC < 10 µg L−1) obtained from Millipore (Molsheim, France) has been used to prepare all the solutions.
A solution of 1.1 mM K3[Fe(CN)6] in PBS buffer was used in cyclic voltammetric experiments for determination of electroactive area using the Randles–Ševćik equation. Stock solutions of 10 mM of several phenolic (GA, CA, Q and t-R) and not phenolic antioxidants (AA) were prepared daily before use: all substances in PBS buffer only the quercitin had need of few drops of DMSO.
The value of pH 7.4 was chosen because from early studies in literature was reported that at this value the particles have the highest oxidase-like activity against phenolic compounds [81]. Moreover, all the experiments were carried out at room temperature, approximately 25 °C.

2.2. Electrochemical Measurements

Electrochemical measurements were performed using a portable PalmSens potentiostat (PalmSens, Houten, The Netherlands) controlled by means of the PSTrace 4 program (Vers. 4.4 PalmSens BV). All the experiments were conducted using a three screen-printed electrodes system from Orion High Technologies S.L. (Parla, Madrid, Spain). In particular: Nanostructured carbon (OHT-000), carboxylic acid functionalized multi-walled carbon nanotubes (OHT-069) and Carboxylic acid functionalized multi-walled carbon nanotubes-Fe3O4 superparamagnetic nanoparticles (OHT-102) screen printed electrodes, respectively. The working electrodes were different for each sensor (with a surface diameter of 4 mm) but the counter electrode (graphite) and the reference one (Ag/AgCl) were the same for all the SPEs.
All absorbance measurements were made at the specified wavelength (731 nm) of the selected spectrophotometric method (ABTS-based method) using a T60U Spectrometer PG Instruments Ltd. (Wibtoft Leicestershire, Lutterworth, UK).

2.3. Electrochemical Method

The procedure of square wave voltammetry (SWV) was carried out as analytical technique to develop the calibration curve of GA used as standard and to test the selected wine samples and for the other antioxidant compounds. The frequency (f) and pulse amplitude at 25 Hz and 50 mV, respectively. The OHT-069 modified SPE was used as sensor.

2.4. Sensor Modification by Using CeNPs

The surface modification procedure was realized by two steps: first, a colloidal NPs suspension of 2% (w/v) nanoceria was prepared by dispersing particles in distilled water, then 5 µL of the solution were dropped onto the working electrode surface of the SPE and let it dry for two days at room temperature until use. Electrodes were stored at room temperature.

2.5. ABTS-Based Method

The ABTS antioxidant assay was slightly modified and carried out as described in literature [82]. Briefly, 7 mM ABTS solution prepared in 2.5 mM K2S2O8 was incubated in the dark for about 15 h at room temperature to generate ABTS radicals. Then, the solution was diluted 400 times with distilled water. The white wines and the red ones were diluted 10 and 100 times respectively with distilled water. Next 100 µL of each sample were mixed with 2.5 mL of ABTS radical solution and 0.4 mL H2O and the absorbance has read after 3 min at 731 nm. The phenolic antioxidant gallic acid (GA) was used as standard, and triplicates were analysed for each sample.

3. Results and Discussion

3.1. Electrochemical Characterization

3.1.1. Comparison of Electrochemical Performances before and after CeNPs Sensor Modification

Firstly, the improvement of the electrochemical performances by the simple modification of the electrode surface using CeNPs has been demonstrated by calculating the electroactive area (Ae) of three different SPE sensors.
The Ae for the electrodes were obtained by cyclic voltammetry (CV) using a solution of 1.1 mM K3[Fe(CN)6] in PBS buffer solution as probe at different scan rates. For a reversible process, the Randles–Ševćik equation has been used:
Ip = 2.686 105 n 3/2 Ae D01/2 C0 v1/2
where Ip is peak current in ampere (A), n is number of electrons transferred of K3[Fe(CN)6] by CV in the redox event (usually 1), Ae is electroactive area (cm2), D0 is diffusion coefficient (7.6 × 10−6 cm2 s−1), C0 is the concentration (mol cm−3), and v is the scan rate (Vs−1) [83]. By using the slope of the plot of Ip vs v1/2, the electroactive areas were calculated and the results are shown in Table 1. In bare OHT-000, OHT-102, and OHT-069 SPEs, the electrode surface was found to be: 2.42, 6.26, and 8.50 mm2 respectively. For the same modified SPEs the surface was nearly 7, 3, and 2.5 times greater. The presence of the MWCNTs in both OHT-102 and OHT-069 bare sensors resulted in a higher Ae value in comparison to OHT-000 bare sensor, due to the well-known peculiarities of nanomaterials (e.g., large surface-to-volume ratios, their physicochemical properties, composition, and shape and their robustness, etc.) [39,40]. Moreover, the modification procedure of the different working electrode surface by the presence of cerium nanoparticles increased quite notable the peak current signal and consequently the surface activity. This was attributed to their capability to facilitate the electron transfer [60] and to improve the biocatalytic signals [84].
In addition, the comparison was also observed in function of PBS buffer solution (Figure 1) and one of the selected antioxidants, the caffeic acid (Figure 2). The modified electrode had no electrochemical activity in phosphate buffer solution (Figure 1A,B, black lines) and showed a similar CV profile to the bare electrodes, respectively (Figure 1A,B, red lines). Conversely, for the OHT-102 a couple of peaks was observed (Figure 1C, black line), probably due to Fe3O4 nanoparticles redox behaviour, which are directly reduced at the electrode surface according to the following reaction:
(1)
Fe3O4 (s) + 2 e− + 6H+ (aq) → 2Fe2+ (aq) + 3H2O + FeO (s)
Then, Fe2+ ions produced could combine with phosphate ions in the buffer solution:
(2)
Fe2+ (aq) + HPO42− (aq) → FePO4(s) + e− + H+ (aq)
Here after, the solid FePO4 at the surface of electrode could be responsible for observed redox behaviour [85,86]. For all the three modified sensors the background current becomes larger, due to the CeNPs can increase the surface activity remarkably. The CeNPs-induced oxidation of CA was studied in the potential range between −0.4 and 0 V, as example in Figure 2 is reported the electrochemical performance of the OHT-069 SPE sensor. The CVs of bare and modified SPE carried out in PBS buffer solution showed a similar voltammogram, but in the case of the CeNPs modified sensor the area was broader and it showed no peaks in PBS indicating lack of electrochemical activity of these cerium particles in the potential range tested (Figure 2, red line). Observing the electrochemical behaviour of the bare OHT-069 SPE (Figure 2, green line) and the modified one (Figure 2, blue line) in the presence of 0.8 μM CA solution a similar profile is recorded. Anodic and catodic peaks were observed in both cases. In the CV of the CeNPs/SPE the peaks are wider and shifted to higher potential values compared to those observed for the bare/SPE. In identical experimental conditions, sensors in presence of nanoparticles showed a more evident response in the same potential range comparing to bare carbon electrode. This difference demonstrates the role of CeNPs to catalytically form reducible quinones onto the electrode surface and, moreover, to be better able to quantitatively detect antioxidants.
The reduction current was proportional with the amount of CA added on the electrode, as illustrated in Figure 3. By increasing CA concentration from 5.5 to 550 µM, the oxidation/reduction peak potential is constant at 0.130 and 0.050 V, respectively. These results suggest that diffusional barriers are not present for the oxidized/reduced CA to/from nanoceria surface. Figure 4 shows the effect of scan rate on the intensity of the oxidation/reduction current. In the inset of Figure 4 is reported the reduction current vs. the square root of scan rate. The current increased proportionally with the square root of scan rate with a correlation coefficient of 0.99 (N = 3) with a slight shift towards negative potentials, suggesting a quasi-reversible process, which is diffusion-controlled.

3.1.2. Analytical Characteristic: Sensitivity, LOD, Linear Range, and Response Time of Phenolic and Non-Phenolic Antioxidants

The CeNPs modified sensors have been tested for the detection of some common antioxidant compounds contained in wines: gallic acid (GA), caffeic acid (CA), quercetin (Q), t-resveratrol (t-R), and ascorbic acid (AA).
Figure 5 displays the calibration curves of the three different sensors for the selected antioxidant compounds. After the addition of the antioxidant compound a response proportional with the concentration was observed.
The sensitivity of the different sensors towards the same antioxidant was studied and the results reported in Figure 5A–E. The order OHT-069 > OHT-102 > OHT-000 was observed.
The analytical parameters of the antioxidants have been reported by applying the CeNPs modified OHT-069 sensor (Table 2).

3.2. Spectrophotometric Characterization

The ABTS-based assay described here involves the direct production of the blue/green ABTS•+ chromophore. This has absorption maxima at 731 nm. The addition of antioxidant compounds quenches the colour and produce a decolouration of the solution which is proportional to their amount (Scheme 1). This reaction is rapid and the end point, which is stable, is taken as a measure of the antioxidative efficiency.
The phenolic antioxidant Gallic Acid (GA) was used as standard and the values of real samples expressed as mg L−1 of GA.
In Table 3 we have reported a comparison with some enzyme-based biosensors and nanomaterial-based sensors for the determination of some common antioxidants, present in the literature [50,57,87,88,89,90,91,92]. The linear range of our developed sensor is similar and, in some cases, better than ones proposed by other authors. In terms of storage, our sensor is superior respect to the enzyme biosensors because no needs of storage conditions, on the contrary enzyme-based biosensors need of particular conditions (e.g., buffer and low temperature) and one of their drawbacks is protein instability [50,88,90]. Furthermore, in comparison to the nanomaterial CeNP-modified electrode for GA and AA compounds our linear range is broader [57]. Additionally, our LOD value is lower for CA and Q antioxidants [57]. In terms of response time, we have recorded a response time of 30 s. Lastly, these advantages make our sensor as a useful tool for a quick screening to detect antioxidants in beverages sample.

3.3. Real Sample Analysis

Real samples (common antioxidants and white/red commercial wines) were tested for their antioxidant activity. The real samples were analysed both by the OHT-069-modified sensor and the ABTS-based assay.
By the first method, the antioxidant activity of the wine sample was reported as mg L−1 of GA, obtained by interpolation of the current signal of the sample into the calibration curve of the GA. The wine white sample were diluted 10 times before analysis and the red ones 100.
For comparison purpose, the same samples were also analysed by the spectrophotometric method involving the use of the ABTS to calculate the total antioxidant capacity (TAC).
As reported in Table 4, the data obtained with the two methods are in good agreement despite the electrochemical and the spectrophotometric methods are based on a completely different mechanism. The results relative to white and red wines are in very close agreement with the data obtained with the spectrophotometric test. Finally, we can conclude that the nanoceria modified sensor could be employed as first tool for the determination of TAC in wine samples. It can be considered as a valid alternative to commercially available spectrophotometric kits thanks to several advantages such as ease of use, rapidity, cost-effectiveness, and portability.

Author Contributions

Conceptualization, C.T. and P.B.; Formal Analysis, R.Z.; Investigation, C.T.; Resources, F.M.; Data Curation, G.F.; Writing-Original Draft Preparation, C.T.; Writing-Review & Editing, P.B. and R.A.; Visualization, G.F.; Supervision, F.M.

Funding

This research received no external funding.

Conflicts of Interest

The authors declare no conflict of interest.

References

  1. Pisoschi, A.M.; Pop, A. The role of antioxidants in the chemistry of oxidative stress: A review. Eur. J. Med. Chem. 2015, 97, 55–74. [Google Scholar] [CrossRef] [PubMed]
  2. Uttara, B.; Singh, A.V.; Zamboni, P.; Mahajan, R.T. Oxidative stress and neurodegenerative diseases: A review of upstream and downstream antioxidant therapeutic options. Curr. Neuropharmacol. 2009, 7, 65–74. [Google Scholar] [CrossRef] [PubMed]
  3. D’Angelo, B.; Santucci, S.; Benedetti, E.; Di Loreto, S.; Phani, R.A.; Falone, S.; Amicarelli, F.; Ceru, M.P.; Cimini, A. Cerium oxide nanoparticles trigger neuronal survival in a human Alzheimer disease model by modulating BDNF pathway. Curr. Nanosci. 2009, 5, 167–176. [Google Scholar] [CrossRef]
  4. Tian, Z.; Li, J.; Zhang, Z.; Gao, W.; Zhou, X.; Qu, Y. Highly sensitive and robust peroxidase-like activity of porous nanorods of ceria and their application for breast cancer detection. Biomaterials 2015, 59, 116–124. [Google Scholar] [CrossRef] [PubMed]
  5. Halvorsen, B.L.; Holte, K.; Myhrstad, M.C.W.; Barikmo, I.; Hvattum, E.; Remberg, S.F.; Wold, A.B.; Haffner, K.; Baugerød, H.; Andersen, L.F.; et al. A systematic screening of total antioxidants in dietary plants. J. Nutr. 2002, 132, 461–471. [Google Scholar] [CrossRef] [PubMed]
  6. Halvorsen, B.L.; Carlsen, M.H.; Phillips, K.M.; Bohn, S.K.; Holte, K.; Jacobs, D.R., Jr.; Blomhoff, R. Content of redox-active compounds (ie, antioxidants) in foods consumed in the United States. Am. J. Clin. Nutr. 2006, 84, 95–135. [Google Scholar] [CrossRef] [PubMed]
  7. Scalbert, A.; Manach, C.; Morand, C.; Rémésy, C.; Jiménez, L. Dietary polyphenols and the prevention of diseases. Crit. Rev. Food Sci. Nutr. 2005, 45, 287–306. [Google Scholar] [CrossRef] [PubMed]
  8. Ghiselli, A.; Serafini, M.; Natella, F.; Scaccini, C. Total antioxidant capacity as a tool to assess redox status: Critical view and experimental data. Free Radic. Biol. Med. 2000, 29, 1106–1114. [Google Scholar] [CrossRef]
  9. Miller, N.J.; Rice-Evans, C.A.; Davies, M.J.; Gopinathan, V.; Milner, A. A novel method for measuring antioxidant capacity and its application to monitoring the antioxidant status in premature neonates. Clin. Sci. 1993, 84, 407–412. [Google Scholar] [CrossRef] [PubMed]
  10. Ghiselli, A.; Serafini, M.; Maiani, G.; Azzini, E.; Ferro-Luzzi, A. A fluorescence-based method for measuring total plasma antioxidant capability. Free Radic. Biol. Med. 1995, 18, 29–36. [Google Scholar] [CrossRef]
  11. Lonnrot, K.; Metsa-Ketela, T.; Molnar, G.; Ahonen, J.-P.; Latvala, M.; Peltola, J.; Pietila, T.; Alho, H. The effect of ascorbate and ubiquinone supplementation on plasma and CSF total antioxidant capacity. Free Radic. Biol. Med. 1996, 21, 211–217. [Google Scholar] [CrossRef]
  12. Koracevic, D.; Koracevic, G.; Djordjevic, V.; Andrejevic, S.; Cosic, V. Method for the measurement of antioxidant activity in human fluids. J. Clin. Pathol. 2001, 54, 356–361. [Google Scholar] [CrossRef] [PubMed] [Green Version]
  13. Cao, G.; Prior, R.L. Comparison of different analytical methods for assessing total antioxidant capacity of human serum. Clin. Chem. 1998, 44, 1309–1315. [Google Scholar] [PubMed]
  14. Marques, S.S.; Magalhães, L.M.; Tóth, I.V.; Segundo, M.A. Insights on antioxidant assays for biological samples based on the reduction of copper complexes—The importance of analytical conditions. Int. J. Mol. Sci. 2014, 15, 11387–11402. [Google Scholar] [CrossRef] [PubMed]
  15. Bartosz, G. Non-enzymatic antioxidant capacity assays: Limitations of use in biomedicine. Free Radic. Res. 2010, 44, 711–720. [Google Scholar] [CrossRef] [PubMed]
  16. Pinchuk, I.; Shoval, H.; Dotan, Y.; Lichtenberg, D. Evaluation of antioxidants: Scope, limitations and relevance of assays. Chem. Phys. Lipids 2012, 165, 638–647. [Google Scholar] [CrossRef] [PubMed]
  17. Rice-Evans, C.A.; Miller, N.J. Antioxidant activities of flavonoids as bioactive components of food. Biochem. Soc. Trans. 1996, 24, 790–795. [Google Scholar] [CrossRef] [PubMed] [Green Version]
  18. Zulueta, A.; Esteve, M.J.; Frigola, A. ORAC and TEAC assays comparison to measure the antioxidant capacity of food products. Food Chem. 2009, 114, 310–316. [Google Scholar] [CrossRef]
  19. Re, R.; Pellegrini, N.; Proteggente, A.; Pannala, A.; Yang, M.; Rice-Evans, C. Antioxidant activity applying an improved ABTS radical cation decolorization assay. Free Radic. Biol. Med. 1999, 26, 1231–1237. [Google Scholar] [CrossRef]
  20. Pellegrini, N.; Serafini, M.; Colombi, B.; Del Rio, D.; Salvatore, S.; Bianchi, M.; Brighenti, F. Total antioxidant capacity of plant foods, beverages and oils consumed in Italy assessed by three different in vitro assays. J. Nutr. 2003, 133, 2812–2819. [Google Scholar] [CrossRef] [PubMed]
  21. Benzie, I.F.; Strain, J.J. The ferric reducing ability of plasma (FRAP) as a measure of “antioxidant power”: The FRAP assay. Anal. Biochem. 1996, 239, 70–76. [Google Scholar] [CrossRef] [PubMed]
  22. Ou, B.; Huang, D.; Hampsch-Woodill, M.; Flanagan, J.A.; Deemer, E.K. Analysis of antioxidant activities of common vegetables employing oxygen radical absorbance capacity (ORAC) and ferric reducing antioxidant power (FRAP) assays: A comparative study. J. Agric. Food Chem. 2002, 50, 3122–3128. [Google Scholar] [CrossRef] [PubMed]
  23. Meng, J.; Fang, Y.; Zhang, A.; Chen, S.; Xu, T.; Ren, Z.; Han, G.; Liu, J.; Li, H.; Zhang, Z.; et al. Phenolic content and antioxidant capacity of Chinese raisins produced in Xinjiang Province. Food Res. Int. 2011, 44, 2830–2836. [Google Scholar] [CrossRef]
  24. Apak, R.; Guculu, K.G.; Ozyurek, M.; Karademir, S.E. Novel total antioxidant capacity index for dietary polyphenols and vitamins C and E, using their cupric iron reducing capability in the presence of neocuproine: CUPRAC method. J. Agric. Food Chem. 2004, 52, 7970–7981. [Google Scholar] [CrossRef] [PubMed]
  25. Thaipong, K.; Boonprakob, U.; Crosby, K.; Cisneros-Zevallos, L.; Byrne, D.H. Comparison of ABTS, DPPH, FRAP, and ORAC assays for estimating antioxidant activity from guava fruit extracts. J. Food Compost. Anal. 2006, 19, 669–675. [Google Scholar] [CrossRef]
  26. Denev, P.; Ciz, M.; Ambrozova, G.; Lojek, A.; Yanakieva, I.; Kratchanova, M. Solid phase extraction of berries’ anthocyanins and evaluation of their antioxidative properties. Food Chem. 2010, 123, 1055–1061. [Google Scholar] [CrossRef]
  27. Molyneux, P. The use of the stable free radical diphenylpicrylhydrazyl (DPPH) for estimating antioxidant activity. Songklanakarin J. Sci. Technol. 2004, 26, 211–219. [Google Scholar]
  28. Gil, D.M.A.; Rebelo, M.J.F. Evaluating the antioxidant capacity of wines: A laccase-based biosensor approach. Eur. Food Res. Technol. 2010, 231, 303–308. [Google Scholar] [CrossRef]
  29. Wang, X.; Jiao, C.; Yu, Z. Electrochemical biosensor for assessment of the total antioxidant capacity of orange juice beverage based on the immobilizing DNA on a poly l-glutamic acid doped silver hybridized membrane. Sens. Actuators B Chem. 2014, 192, 628–633. [Google Scholar] [CrossRef]
  30. Barroso, M.F.; de-los-Santos-Álvarez, N.; Lobo-Castañón, M.J.; Miranda-Ordieres, A.J.; Delerue-Matos, C.; Oliveira, M.B.P.P.; Tuñón-Blanco, P. DNA-based biosensor for the electrocatalytic determination of antioxidant capacity in beverages. Biosens. Bioelectron. 2011, 26, 2396–2401. [Google Scholar] [CrossRef] [PubMed] [Green Version]
  31. Barroso, M.F.; Delerue-Matos, C.; Oliveira, M.B.P.P. Electrochemical evaluation of total antioxidant capacity of beverages using a purine-biosensor. Food Chem. 2012, 132, 1055–1062. [Google Scholar] [CrossRef] [Green Version]
  32. Blasco, A.J.; Crevillén, A.G.; González, M.C.; Escarpa, A. Direct electrochemical sensing and detection of natural antioxidants and antioxidant capacity in vitro systems. Electroanalysis 2007, 19, 2275–2286. [Google Scholar] [CrossRef]
  33. Wang, Y.; Calas-Blanchard, C.; Cortina-Puig, M.; Baohong, L.; Marty, J.L. An electrochemical method for sensitive determination of antioxidant capacity. Electroanalysis 2009, 21, 1395–1400. [Google Scholar] [CrossRef]
  34. Bhalla, N.; Jolly, P.; Formisano, N.; Estrela, P. Introduction to biosensors. Essays Biochem. 2016, 60, 1–8. [Google Scholar] [CrossRef] [PubMed] [Green Version]
  35. Kimmel, D.W.; LeBlanc, G.; Meschievitz, M.E.; Cliffel, D.E. Electrochemical Sensors and Biosensors. Anal. Chem. 2012, 84, 685–707. [Google Scholar] [CrossRef] [PubMed]
  36. Turner, A.P.F. Biosensors: Sense and sensibility. Chem.Soc. Rev. 2013, 42, 3184–3196. [Google Scholar] [CrossRef] [PubMed]
  37. Bollella, P.; Fusco, G.; Tortolini, C.; Sanzò, G.; Favero, G.; Gorton, L.; Antiochia, R. Beyond graphene: Electrochemical sensors and biosensors for biomarkers detection. Biosens. Bioelectron. 2017, 89, 152–166. [Google Scholar] [CrossRef] [PubMed]
  38. Mazzei, F.; Favero, G.; Bollella, P.; Tortolini, C.; Mannina, L.; Conti, M.E.; Antiochia, R. Recent trends in electrochemical nanobiosensors for environmental analysis. Int. J. Environ. Health 2015, 7, 267–291. [Google Scholar] [CrossRef]
  39. Holzinger, M.; Le Goff, A.; Cosnier, S. Nanomaterials for biosensing applications: A review. Front. Chem. 2014, 2, 63. [Google Scholar] [CrossRef] [PubMed]
  40. Taurino, I.; Sanzò, G.; Antiochia, R.; Tortolini, C.; Mazzei, F.; Favero, G.; De Micheli, G.; Carrara, S. Recent advances in third generation biosensors based on Au and Pt nanostructured electrodes. Trends in Anal. Chem. 2016, 79, 151–159. [Google Scholar] [CrossRef]
  41. Maduraiveeran, G.; Sasidharan, M.; Ganesan, V. Electrochemical sensor and biosensor platforms based on advanced nanomaterials for biological and biomedical applications. Biosens. Bioelectron. 2018, 103, 113–129. [Google Scholar] [CrossRef] [PubMed]
  42. Jariwala, D.; Sangwan, V.K.; Lauhon, L.J.; Marks, T.J.; Hersam, M.C. Carbon nanomaterials for electronics, optoelectronics, photovoltaics, and sensing. Chem. Soc. Rev. 2013, 42, 2824–2860. [Google Scholar] [CrossRef] [PubMed] [Green Version]
  43. Wang, Q.; Yang, Y.; Gao, F.; Ni, J.; Zhang, Y.; Lin, Z. Graphene oxide directed one-step synthesis of flowerlike graphene@HKUST-1 for enzyme-free detection of hydrogen peroxide in biological samples. ACS Appl. Mater. Interfaces 2016, 8, 32477–32487. [Google Scholar] [CrossRef] [PubMed]
  44. Wang, X.; Wang, Q.; Wang, Q.; Gao, F.; Gao, F.; Yang, Y.; Guo, H. Highly dispersible and stable copper terephthalate metal–organic framework–graphene oxide nanocomposite for an electrochemical sensing application. ACS Appl. Mater. Interfaces 2014, 6, 11573–11580. [Google Scholar] [CrossRef] [PubMed]
  45. Yang, Y.; Wang, Q.; Qiu, W.; Guo, H.; Gao, F. Covalent immobilization of Cu3(btc)2 at chitosan–electroreduced graphene oxide hybrid film and its application for simultaneous detection of dihydroxybenzene isomers. J. Phys. Chem. C 2016, 120, 9794–9803. [Google Scholar] [CrossRef]
  46. Gao, F.; Cai, X.; Wang, X.; Gao, C.; Liu, S.; Gao, F.; Wang, Q. Highly sensitive and selective detection of dopamine in the presence of ascorbic acid at graphene oxide modified electrode. Sens. Actuators B Chem. 2013, 186, 380–387. [Google Scholar] [CrossRef]
  47. Pérez-Lópeza, B.; Merkoçi, A. Nanomaterials based biosensors for food analysis applications. Trends Food Sci. Technol. 2011, 22, 625–639. [Google Scholar] [CrossRef] [Green Version]
  48. Della Pelle, F.; Compagnone, D. Nanomaterial-based sensing and biosensing of phenolic compounds and related antioxidant capacity in food. Sensors 2018, 18, 462. [Google Scholar] [CrossRef] [PubMed]
  49. Diaconu, M.; Litescu, S.C.; Radu, G.L. Laccase–MWCNT–chitosan biosensor—A new tool for total polyphenolic content evaluation from in vitro cultivated plants. Sens. Actuators B Chem. 2010, 145, 800–806. [Google Scholar] [CrossRef]
  50. Diaconu, M.; Litescu, S.C.; Radu, G.L. Bienzymatic sensor based on the use of redox enzymes and chitosan–MWCNT nanocomposite. Evaluation of total phenolic content in plant extracts. Microchim. Acta 2010, 172, 177–184. [Google Scholar] [CrossRef]
  51. Chawla, S.; Rawal, R.; Sharma, S.; Pundir, C.S. An amperometric biosensor based on laccase immobilized onto nickel nanoparticles/carboxylated multiwalled carbon nanotubes/polyaniline modified gold electrode for determination of phenolic content in fruit juices. Biochem. Eng. J. 2012, 68, 76–84. [Google Scholar] [CrossRef]
  52. Li, Y.; Zhang, L.; Li, M.; Pan, Z.; Li, D. A disposable biosensor based on immobilization of laccase with silica spheres on the MWCNTs-doped screen-printed electrode. Chem. Cent. J. 2012, 6, 103–110. [Google Scholar] [CrossRef] [PubMed]
  53. Rawal, R.; Chawla, S.; Devender Pundir, C.S. An amperometric biosensor based on laccase immobilized onto Fe3O4NPs/cMWCNT/PANI/Au electrode for determination of phenolic content in tea leaves extract. Enzyme Microb. Technol. 2012, 51, 179–185. [Google Scholar] [CrossRef]
  54. Lanzellotto, C.; Favero, G.; Antonelli, M.L.; Tortolini, C.; Cannistraro, S.; Coppari, E.; Mazzei, F. Nanostructured enzymatic biosensor based on fullerene and gold nanoparticles: Preparation, characterization and analytical applications. Biosens. Bioelectron. 2014, 55, 430–437. [Google Scholar] [CrossRef] [PubMed]
  55. Zappi, D.; Nasci, G.; Sadun, C.; Tortolini, C.; Antonelli, M.L.; Bollella, P. Evaluation of new cholinium-amino acids based room temperature ionic liquids (RTILs) as immobilization matrix for electrochemical biosensor development: Proof-of-concept with Trametes Versicolor laccase. Microchem. J. 2018, 141, 346–352. [Google Scholar] [CrossRef]
  56. Nasir, M.; Nawaz, M.H.; Latif, U.; Yaqub, M.; Hayat, A.; Rahim, A. An overview on enzyme-mimicking nanomaterials for use in electrochemical and optical assays. Microchim. Acta 2017, 184, 323–342. [Google Scholar] [CrossRef]
  57. Andrei, V.; Sharpe, E.; Vasilescu, A.; Andreescu, S. A single use electrochemical sensor based on biomimetic nanoceria for the detection of wine antioxidants. Talanta 2016, 156–157, 112–118. [Google Scholar] [CrossRef] [PubMed]
  58. Das, M.; Patil, S.; Bhargava, N.; Kang, J.F.; Riedel, L.M.; Seal, S.; Hickman, J.J. Auto-catalytic ceria nanoparticles offer neuroprotection to adult rat spinal cord neurons. Biomaterials 2007, 28, 1918–1925. [Google Scholar] [CrossRef] [PubMed] [Green Version]
  59. Ansari, A.A.; Solanki, P.R.; Malhotra, B.D. Hydrogen peroxide sensor based on horseradish peroxidase immobilized nanostructured cerium oxide film. J. Biotechnol. 2009, 142, 179–184. [Google Scholar] [CrossRef] [PubMed]
  60. Xiao, X.L.; Luan, Q.F.; Yao, X.; Zhou, K.B. Single-crystal CeO2 nanocubes used for the direct electron transfer and electrocatalysis of horseradish peroxidase. Biosens. Bioelectron. 2010, 24, 2447–2451. [Google Scholar] [CrossRef] [PubMed]
  61. Özel, R.E.; Ispas, C.; Ganesana, M.; Leiter, J.C.; Andreescu, S. Glutamate oxidase biosensor based on mixed ceria and titania nanoparticles for the detection of glutamate in hypoxic environments. Biosens. Bioelectron. 2014, 52, 397–402. [Google Scholar] [CrossRef] [PubMed] [Green Version]
  62. Yang, X.; Ouyang, Y.; Wu, F.; Hu, Y.; Zhang, H.; Wu, Z. In situ & controlled preparation of platinum nanoparticles dopping into graphene sheets @cerium oxide nanocomposites sensitized screen printed electrode for nonenzymatic electrochemical sensing of hydrogen peroxide. J. Electroanal. Chem. 2016, 777, 85–91. [Google Scholar] [CrossRef]
  63. Ispas, C.; Njagi, J.; Cates, M.; Andreescu, S. Electrochemical Studies of Ceria as Electrode Material for Sensing and Biosensing Applications. J. Electrochem. Soc. 2008, 155, F169–F176. [Google Scholar] [CrossRef]
  64. Zhang, M.; Wang, H.L.; Wang, X.D.; Li, W.C. Complex impedance study on nano-CeO2 coating TiO2. Mater. Design 2006, 27, 489–493. [Google Scholar] [CrossRef]
  65. Preda, G.; Migani, A.; Neyman, K.M.; Bromley, S.T.; Illas, F.; Pacchioni, G. Formation of superoxide anions on ceria nanoparticles by interaction of molecular oxygen with Ce3+ sites. J. Phys. Chem. C 2011, 115, 5817–5822. [Google Scholar] [CrossRef]
  66. Dutta, P.; Pal, S.; Seehra, M.S.; Shi, Y.; Eyring, E.M.; Ernst, R.D. Concentration of Ce3+ and oxygen vacancies in cerium oxide nanoparticles. Chem. Mater. 2006, 18, 5144–5146. [Google Scholar] [CrossRef]
  67. Wang, D.; Kang, Y.; Doan-Nguyen, V.; Chen, J.; Küngas, R.; Wieder, N.L.; Bakhmutsky, K.; Gorte, R.J.; Murray, C.B. Synthesis and oxygen storage capacity of two-dimensional ceria nanocrystals. Angew. Chem. Int. Ed. Engl. 2011, 50, 4378–4381. [Google Scholar] [CrossRef] [PubMed]
  68. Xu, J.; Harmer, J.; Li, G.; Chapman, T.; Collier, P.; Longworth, S.; Tsang, S.C. Size dependent oxygen buffering capacity of ceria nanocrystals. Chem. Commun. 2010, 46, 1887–1889. [Google Scholar] [CrossRef] [PubMed]
  69. Heckert, E.G.; Karakoti, A.S.; Seal, S.; Self, W.T. The role of cerium redox state in the SOD mimetic activity of nanoceria. Biomaterials 2008, 29, 2705–2709. [Google Scholar] [CrossRef] [PubMed] [Green Version]
  70. Pirmohamed, T.; Dowding, J.M.; Singh, S.; Wasserman, B.; Heckert, E.G.; Karakoti, A.S.; King, J.E.S.; Seal, S.; Self, W.T. Nanoceria exhibit redox state-dependent catalase mimetic activity. Chem. Commun. 2010, 46, 2736–2738. [Google Scholar] [CrossRef] [PubMed]
  71. Asati, A.; Santra, S.; Kaittanis, C.; Nath, S.; Perez, J.M. Oxidase-like activity of polymer-coated cerium oxide nanoparticles. Angew. Chem. Int. Ed. Engl. 2009, 48, 2308–2312. [Google Scholar] [CrossRef] [PubMed]
  72. Asati, A.; Kaittanis, C.; Santra, S.; Perez, J.M. The pH-tunable oxidase-like activity of cerium oxide nanoparticles achieves sensitive fluorigenic detection of cancer biomarkers at neutral pH. Anal. Chem. 2011, 83, 2547–2553. [Google Scholar] [CrossRef] [PubMed]
  73. Li, X.; Sun, L.; Ge, A.; Guo, Y. Enhanced chemiluminescence detection of thrombin based on cerium oxide nanoparticles. Chem. Commun. 2011, 47, 947–949. [Google Scholar] [CrossRef] [PubMed]
  74. Kaittanis, C.; Santra, S.; Asati, A.; Perez, J.M. A cerium oxide nanoparticle based device for the detection of chronic inflammation via optical and magnetic resonance imaging. Nanoscale 2012, 4, 2117–2123. [Google Scholar] [CrossRef] [PubMed]
  75. Ornatska, M.; Sharpe, E.; Andreescu, D.; Andreescu, S. Paper bioassay based on ceria nanoparticles as colorimetric probes. Anal. Chem. 2011, 83, 4273–4280. [Google Scholar] [CrossRef] [PubMed]
  76. Lin, Y.; Xu, C.; Ren, J.; Qu, X. Using thermally regenerable cerium oxide nanoparticles in biocomputing to perform label-free, resettable, and colorimetric logic operations. Angew. Chem. Int. Ed. Engl. 2012, 51, 12579–12583. [Google Scholar] [CrossRef] [PubMed]
  77. Celardo, I.; Pedersen, J.Z.; Traversa, E.; Ghibelli, L. Pharmacological potential of cerium oxide nanoparticles. Nanoscale 2011, 3, 1411–1420. [Google Scholar] [CrossRef] [PubMed]
  78. Li, M.; Shi, P.; Xu, C.; Ren, J.; Qu, X. Cerium oxide caged metal chelator: Anti-aggregation and anti-oxidation integrated H2O2-responsive controlled drug release for potential Alzheimer’s disease treatment. Chem. Sci. 2013, 4, 2536–2542. [Google Scholar] [CrossRef]
  79. Xu, C.; Lin, Y.; Wang, J.; Wu, L.; Wei, W.; Ren, J.; Qu, X. Nanoceria-triggered synergetic drug release based on CeO(2)-capped mesoporous silica host–guest interactions and switchable enzymatic activity and cellular effects of CeO(2). Adv. Healthc. Mater. 2013, 2, 1591–1599. [Google Scholar] [CrossRef] [PubMed]
  80. Singh, S. Cerium oxide based nanozymes: Redox phenomenon at biointerfaces. Biointerphases 2016, 11, 04B202. [Google Scholar] [CrossRef] [PubMed] [Green Version]
  81. Hayat, A.; Cunningham, J.; Bulbul, G.; Andreescu, S. Evaluation of the oxidase like activity of nanoceria and its application in colorimetric assays. Anal. Chim. Acta 2015, 885, 140–147. [Google Scholar] [CrossRef] [PubMed] [Green Version]
  82. Pellegrini, N.; Re, R.; Yang, M.; Rice-Evans, C. Screening of dietary carotenoids and carotenoid-rich fruit extracts for antioxidant activities applying 2,20-azinobis (3-ethylenebenzothiazoline-6-sulfonic acid) radical cation decolourisation assay. Methods Enzymol. 1999, 299, 379–389. [Google Scholar]
  83. Bard, A.J.; Faulkner, L.R. Electrochemical Methods: Fundamentals and Applications; John Wiley & Sons: New York, NY, USA, 2001. [Google Scholar]
  84. Njagi, J.; Chernov, M.M.; Leiter, J.C.; Andreescu, S. Amperometric detection of dopamine in vivo with an enzyme based carbon fiber microbiosensor. Anal. Chem. 2010, 82, 989–996. [Google Scholar] [CrossRef] [PubMed]
  85. McKenzie, K.J.; Marken, F. Direct electrochemistry of nanoparticulate Fe2O3 in aqueous solution and adsorbed onto tin-doped indium oxide. Pure Appl. Chem. 2001, 73, 1885–1894. [Google Scholar] [CrossRef]
  86. Teymourian, H.; Salimi, A.; Khezrian, S. Fe3O4 magnetic nanoparticles/reduced graphene oxide nanosheets as a novel electrochemical and bioeletrochemical sensing platform. Biosens. Bioelectron. 2013, 49, 1–8. [Google Scholar] [CrossRef] [PubMed]
  87. Gomes, S.A.S.S.; Nogueira, J.M.F.; Rebelo, M.J.F. A New Laccase biosensor for polyphenols determination. Sensors 2003, 3, 166–175. [Google Scholar] [CrossRef]
  88. Di Fusco, M.; Tortolini, C.; Deriu, D.; Mazzei, F. Laccase-based biosensor for the determination of polyphenol index in wine. Talanta 2010, 81, 235–240. [Google Scholar] [CrossRef] [PubMed]
  89. Odaci, D.; Timur, S.; Pazarlioglu, N.; Montereali, M.R.; Vastarella, W.; Pilloton, R.; Telefoncu, A. Determination of phenolic acids using Trametes versicolor laccase. Talanta 2007, 71, 312–317. [Google Scholar] [CrossRef] [PubMed]
  90. Montereali, M.R.; Vastarella, W.; Della Seta, L.; Pilloton, R. Tyrosinase biosensor based on modified screen printed electrodes: Measurements of total phenol content. Int. J. Environ. Anal. Chem. 2005, 85, 795–806. [Google Scholar] [CrossRef]
  91. Granero, A.M.; Fernández, H.; Agostini, E.; Zón, M.A. An amperometric biosensor based on peroxidases from Brassica napus for the determination of the total polyphenolic content in wine and tea samples. Talanta 2012, 83, 249–255. [Google Scholar] [CrossRef] [PubMed]
  92. Amatatongchai, M.; Laosing, S.; Chailapakul, O.; Nacapricha, D. Simple flow injection for screening of total antioxidant capacity by amperometric detection of DPHH radical on carbon nanotube modified-glassy carbon electrode. Talanta 2012, 97, 267–272. [Google Scholar] [CrossRef] [PubMed]
Biosensors 08 00108 g001 550
Figure 1. CVs of OHT-000 (A), OHT-069 (B), and OHT-102 (C) bare sensors (red line) and after modification by CeNPs (black line) in PBS buffer solution, ν = 100 mV s−1.
Figure 1. CVs of OHT-000 (A), OHT-069 (B), and OHT-102 (C) bare sensors (red line) and after modification by CeNPs (black line) in PBS buffer solution, ν = 100 mV s−1.
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Biosensors 08 00108 g002 550
Figure 2. CVs of OHT-069 bare SPE (black line) and modified SPE by CeNPs (red line) in PBS buffer solution and the same sensors OHT-069 bare SPE (green line) and modified SPE by CeNPs (blue line) in the presence of 0.8 μM di CA at ν = 10 mV s−1.
Figure 2. CVs of OHT-069 bare SPE (black line) and modified SPE by CeNPs (red line) in PBS buffer solution and the same sensors OHT-069 bare SPE (green line) and modified SPE by CeNPs (blue line) in the presence of 0.8 μM di CA at ν = 10 mV s−1.
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Figure 3. CVs of modified OHT-069 SPE in presence of different CA concentrations: 5.5, 45, 120, 270, and 550 μM, at ν = 10 mV s−1.
Figure 3. CVs of modified OHT-069 SPE in presence of different CA concentrations: 5.5, 45, 120, 270, and 550 μM, at ν = 10 mV s−1.
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Figure 4. CVs of CA 550 μM using the modified OHT-069 SPE recorded in PBS buffer solution at scan rates of: 5, 25, 50, 100, 200, 300, and 500 mV s−1, respectively. Inset: plot of reduction current vs. the square root of scan rate.
Figure 4. CVs of CA 550 μM using the modified OHT-069 SPE recorded in PBS buffer solution at scan rates of: 5, 25, 50, 100, 200, 300, and 500 mV s−1, respectively. Inset: plot of reduction current vs. the square root of scan rate.
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Figure 5. Calibration curves for antioxidant compounds employing SWV technique: gallic acid, GA (A), caffeic acid, CA (B), quercetin, Q (C), t-resveratrol, t-R (D), and ascorbic acid, AA (E) at different concentrations. The modified SPE-sensors are: OHT-069 (red circle), OHT-102 (blue circle), and OHT-000 (red circle), respectively.
Figure 5. Calibration curves for antioxidant compounds employing SWV technique: gallic acid, GA (A), caffeic acid, CA (B), quercetin, Q (C), t-resveratrol, t-R (D), and ascorbic acid, AA (E) at different concentrations. The modified SPE-sensors are: OHT-069 (red circle), OHT-102 (blue circle), and OHT-000 (red circle), respectively.
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Biosensors 08 00108 sch001 550
Scheme 1. Formation of radical ABTS and its reaction with antioxidants (AOH).
Scheme 1. Formation of radical ABTS and its reaction with antioxidants (AOH).
Biosensors 08 00108 sch001
Table
Table 1. Comparison of the electroactive area (Ae) before and after CeNPs modification.
Table 1. Comparison of the electroactive area (Ae) before and after CeNPs modification.
SensorAe a (mm2)Ae b (mm2)ρ aρ b
OHT-0002.42 ± 0.0216.82 ± 0.040.191.34
OHT-1026.26 ± 0.0218.74 ± 0.020.501.49
OHT-0698.50 ± 0.0321.93 ± 0.010.681.74
a Bare sensor; b modified sensor by using 5 µL CeNPs solution on the electrode surface.
Table
Table 2. Analytical characterization of antioxidant compounds by using CeNPs modified OHT-069 sensor by SWV method.
Table 2. Analytical characterization of antioxidant compounds by using CeNPs modified OHT-069 sensor by SWV method.
Antioxidant CompoundLinear Range (mM)Slope (µA mM−1)RLOD (mM)
GALLR0.025–0.056.550.9900.007
HLR0.5–5.00.570.9870.151
CALLR0.033–0.10.7930.9990.010
HLR0.25–5.00.1800.9980.083
QLLR0.025–0.13.9780.9780.009
HLR1.0–5.00.1200.9940.303
t-RLLR0.025–0.054.7910.9820.008
HLR0.1–1.00.2620.9990.033
AALLR0.025–11.6670.9990.007
HLR1.0–5.00.1800.9960.334
LLR: Low Linear Range; HLR: High Linear Range.
Table
Table 3. Comparison of some analytical characteristics for antioxidants detection of some enzyme-based biosensors and nanomaterial-based sensors.
Table 3. Comparison of some analytical characteristics for antioxidants detection of some enzyme-based biosensors and nanomaterial-based sensors.
SensorAntioxidant CompoundLR (µM)LOD (µM)Storage/Response TimeRef.
Lac/pESm/Pt electrodeCA10–80--[87]
Lac/PAP/SWCNTs/SPEGA0.53–96-10 d at 4 °C/-[88]
Lac/oxygen electrodeCA0.10–1.000.06-[89]
Lac/Fc/SPE2.0–30.01.6-
Tyr/BSA/GA/Fc/SPEGA30.0–3005730 d at 4 °C/-[90]
CA10.6–26610.5
ITO/Lac/Tyr/CS/MWCNTs electrodeGA1.6–8.11.58 d at 4 °C dry atmosphere/-[50]
CA0.4–7.40.3
POx/Fc/MWCNTs/ MO electrodeCA0.3–3830.1-[91]
t-R0.2–2280.1
GC/MWCNTs/PEI/electrodeGA0.6–120.04
CA0.6–120.08-[92]
Q0.3–60.03
CeNPs/C/SPEGA2–201.5RT/40 s[57]
CA50–10015.3
Q20–2008.6
AA0.5–200.4
CeNPs/MWCNTs-COOH/SPEGA25–507 Our work
CA33–10010
Q25–1008RT/30 s
t-R25–508
AA25–1007
Lac: Laccase; pESm: polyether sulphone membrane; PAP: polyazetidine prepolymer; Fc: ferrocene; Tyr: tyrosinase; CS: chitosan; BSA: bovine serum albumine; GA: glutaraldehyde; PEI: polyethylenimine; POx; peroxidase; MO: mineral oil; C: carbon.
Table
Table 4. TAC of several white and red wines assessed in parallel by the nanoceria-based electrochemical assay and by the classic TEAC assay.
Table 4. TAC of several white and red wines assessed in parallel by the nanoceria-based electrochemical assay and by the classic TEAC assay.
Wine SampleCeNPs-SPE aABTS-Based Method a
white 1204 ± 10208 ± 17
white 2183 ± 11187 ± 9
white 3212 ± 18209 ± 15
red 12067 ± 2072078 ± 187
red 22340 ± 2102538 ± 228
red 33938 ± 2364172 ± 292
a Expressed as mg L−1 of GA.

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Tortolini, C.; Bollella, P.; Zumpano, R.; Favero, G.; Mazzei, F.; Antiochia, R. Metal Oxide Nanoparticle Based Electrochemical Sensor for Total Antioxidant Capacity (TAC) Detection in Wine Samples. Biosensors 2018, 8, 108. https://doi.org/10.3390/bios8040108

AMA Style

Tortolini C, Bollella P, Zumpano R, Favero G, Mazzei F, Antiochia R. Metal Oxide Nanoparticle Based Electrochemical Sensor for Total Antioxidant Capacity (TAC) Detection in Wine Samples. Biosensors. 2018; 8(4):108. https://doi.org/10.3390/bios8040108

Chicago/Turabian Style

Tortolini, Cristina, Paolo Bollella, Rosaceleste Zumpano, Gabriele Favero, Franco Mazzei, and Riccarda Antiochia. 2018. "Metal Oxide Nanoparticle Based Electrochemical Sensor for Total Antioxidant Capacity (TAC) Detection in Wine Samples" Biosensors 8, no. 4: 108. https://doi.org/10.3390/bios8040108

APA Style

Tortolini, C., Bollella, P., Zumpano, R., Favero, G., Mazzei, F., & Antiochia, R. (2018). Metal Oxide Nanoparticle Based Electrochemical Sensor for Total Antioxidant Capacity (TAC) Detection in Wine Samples. Biosensors, 8(4), 108. https://doi.org/10.3390/bios8040108

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