Home Physical Sciences A novel lactose biosensor based on electrochemically synthesized 3,4-ethylenedioxythiophene/thiophene (EDOT/Th) copolymer
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A novel lactose biosensor based on electrochemically synthesized 3,4-ethylenedioxythiophene/thiophene (EDOT/Th) copolymer

  • Songul Sen Gursoy , Abdulkerim Yildiz , Gamze Celik Cogal and Oguz Gursoy EMAIL logo
Published/Copyright: August 11, 2020
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Open Chemistry
From the journal Open Chemistry Volume 18 Issue 1

Abstract

In this study, a new lactose biosensor has been developed in which the 3,4-ethylenedioxythiophene/thiophene (EDOT/Th) copolymer is used as a transducer. The EDOT/Th copolymer was deposited on the glassy carbon electrode to be used as the working electrode. In addition to the working electrode, the three-electrode system was used in both the electrochemical synthesis and in the biosensor measurements. Lactase (β-galactosidase) that catalyzes the breakdown of lactose into monosaccharides (glucose and galactose) and galactose oxidase that catalyzes the oxidation of the resulting galactose were attached to the copolymer by a cross-linker on the modified working electrode. The response of the enzyme electrode to lactose was determined by cyclic voltammetry (CV) at +0.12 V. Enzyme electrode optimization parameters (pH, temperature, enzyme concentration, etc.) were performed. Fourier transform infrared spectroscopy, scanning electron microscopy and CV methods were used to support copolymer formation. In addition, the characteristics of the enzyme electrode prepared in this study (Km, 0.02 mM; activation energy Ea, 38 kJ/mol; linear working range, up to 1.72 mM; limit of detection, 1.9 × 10−5 M and effects of interferents [uric acid and ascorbic acid]) were determined.

Keywords: copolymerization; 3,4-ethylenedioxythiophene; lactose; polythiophene; sensor

1 Introduction

In recent years, electrochemical sensors have an increasing attention due to their excellent properties, especially in electroanalytical determination of important analytes. Electrochemical sensors are relatively new technologies due to their ability to be highly sensitive to small changes in analyte concentrations [1]. Various electrode materials have been used in the construction of electrochemical sensors. Among them conductive polymers, which were first discovered in 1977 by Shirakawa and co-workers, have found special attention due to their excellent characteristics such as low cost, environmental stability, ease of synthesis, high surface area, long-term stability and high electron affinity [2,3,4]. Polythiophenes are an attractive class of conducting polymers, which are thermally stable and environmentally friendly. The discovery of electrical conductivity in polythiophenes was reported in 1980 by Yamamoto et al. [5] and Lin and Dudek [6]. There are few studies on the synthesis of copolymers of thiophene and their derivatives with physical properties that are different from those of homopolymers prepared by electrochemical methods [7,8]. Further functionalization of polythiophenes could enable its sensing selectivity and improve electrocatalytic properties. Polythiophenes could be fabricated as the recognition units of biosensors by the direct polymerization of monomers or the substitution of the prepared polythiophene backbones [9]. Polythiophenes have a lot of application areas such as transistors [10], electrochromic devices [11], light-emitting devices [12], batteries [13], adsorption materials [14], sensors and biosensors [15,16]. Electrochemical sensor platforms based on such materials are widely used in the detection of biomolecules due to their long-term stability, low detection limits and wide linear ranges and reproducibility. However, the conductivity of polythiophene decreases during long-time usage. Thus, the decreased conductivity limits its industrial applications. The electrochemical stability of polythiophene should be increased by introducing an alkoxyl group (such as ether group). This group decreases the polymerization potential of thiophene due to its electron-donating character. The lower oxidizing potential provides a more stable polymer structure. In the case of ether-substituted thiophene, 3-alkoxy, 3,4-alkoxy and pseudocrown ether thiophenes are the important compounds to be considered. Besides, studying polythiophenes with long-side-chain substituents show electrical properties similar to that of polythiophenes because of the distortion in the polymer chain. Hence, many scientists are interested in poly-3,4-(crown ether) thiophene (PEDOT) with a short chain. The electrical stability of polythiophene is also increased by co-polymerization, and this leads to an increase in the biosensitive performance of polythiophene-based sensors [4,17,18,19,20,21].

Lactose (β-d-galactopyranosyl-(1 → 4)-d-glucose) is a disaccharide found in significant amounts in mammalian milk (∼4.7% in cow’s milk and ∼7% in breast milk) [22]. Lactose concentration in milk is important for the evaluation of raw/processed milk quality. Low lactose level in raw milk can be an indicator of mastitis infection. The effective analysis of lactose is also significant during the processing of milk and/or whey to different dairy products [23].

There are only a few studies on thiophene-based lactose sensors. In a study by Sharma et al. [24], amperometric biosensor has been developed by immobilization of lactase and galactose oxidase enzymes on poly(3-hexylthiophene)/stearic acid Langmuir–Blodgett (LB) films, and it has been proposed that it can be used to determine the lactose/galactose ratio in the food and biological fluids. Recently, we reported the polypyrrole/PEDOT copolymer using electrochemical polymerization in biosensor application for lactose determination. The resulting electrochemical method was totally characterized in terms of its limit of detection (1.4 × 10 −5 M) and response time of biosensor (8–10 s) [23]. Thiophene is of low cost than polypyrrole, and the redox potential of polythiophene is higher than polypyrrole. However, polythiophene has lower stability during charge and discharge cycles [25]. Copolymerization of thiophene and 3,4-ethylenedioxythiophene (EDOT) potentially will improve the stability of polythiophene. Thus, the usage of thiophene and EDOT copolymer during sensor fabrication will be a promising alternative to develop low-cost lactose biosensor. Although there are some studies on biosensors using polythiophene and its copolymers in the literature [26,27], no biosensors have been developed for lactose determination to the best of our knowledge.

2 Materials and methods

2.1 Materials

Thiophene (Aldrich) was purified by distillation at reduced pressure before use. 3,4-EDOT (Aldrich) was used without further purification. Galactose oxidase (GaOx, EC 1.1.3.4, 1,79,000 units/g, type VII-S from Aspergillus niger; Sigma) and β-galactosidase (EC 3.2.1.23, ≥8,000 units/g solid, lactase from Aspergillus oryzae; Sigma) were used as biocomponents to modify polymer modified glassy carbon (GC) disc electrode. NaH2PO4·2H2O (Riedel De Haen) and Na2HPO4·7H2O (Riedel De Haen) were used to prepare the buffer solution. Alumina polishing suspension agglomerate (0.05 cr micron; Baikowski) was used as an electrode polisher. Double-distilled water was used to prepare the buffer solution. All other compounds were of analytical reagent grade.

2.2 Instrumental

Fourier transform infrared spectroscopy (FTIR) spectrum was obtained using FTIR spectrophotometer between 400 and 4,000 cm−1 with a 4 cm−1 resolution on a PerkinElmer model (Beaconsfield, Buckinghamshire, HP91QA, England). Scanning electron microscopy (SEM) was performed using Phillips XL-30S FEG scanning electron microscope. Polymerization studies and biosensor measurements were conducted in a three-electrode cell equipped with potentiostat/galvanostat (CompactStat, Ivium Technologies, Netherlands). Polymer-modified GC disc electrode was used as a working electrode, and platinum wire and Ag/AgCl electrodes were used as counter and reference electrodes, respectively. Indium thin oxide electrode was used for the deposition of polymer in the analysis of FTIR and SEM.

2.3 Fabrication of electrode

The GC working electrode was polished with alumina polishing suspension and washed with ethanol and phosphate buffer solutions. Electrochemical copolymerization of thiophene and EDOT was performed using acetonitrile containing LiClO4. Th and EDOT monomers (total concentration was 0.5 M) were polymerized by the cyclic voltammetric method in the range of −0.10 to 1.50 V with three cycles at room temperature (Figure 1). After electropolymerization, the electrode was washed several times with acetonitrile to remove any remaining monomer. A total of 2.94 mg of galactose oxidase and 2 mg of β-galactosidase were dissolved in 500 µL of phosphate buffer solution (pH 6.7). The appropriate amount of glutaraldehyde with enzyme solution was attached to the polymer-modified electrode by the dropping and drying method. It was then stored at 4°C in the phosphate buffer (pH 6.7). To find the best lactose sensing, various molar ratios of the Th and EDOT monomers (in the range 20–80%) were tried. The highest response was provided at 80% EDOT in copolymer, and this Th/EDOT ratio was selected for the novel lactose biosensor fabrication. The similar procedure was applied to the working electrode that consists of PEDOT to estimate lactose. Since polythiophene cannot be polymerized under these conditions, biosensor experiments have not been conducted.

Figure 1 Copolymerization of EDOT/Th and working mechanism of the enzyme electrode.
Figure 1

Copolymerization of EDOT/Th and working mechanism of the enzyme electrode.

  1. Ethical approval: The conducted research is not related to either human or animal use.

3 Results and discussion

3.1 FTIR results

Figure 2 shows the FTIR spectrum of PEDOT and EDOT/Th (80–20%) copolymer to indicate the formation of the copolymer structure. The bands between 1198 and 1089 cm−1 correspond to C═O═C asymmetric and symmetric stretching of the ethylenedioxy group in PEDOT spectra [28]. The bands at 1198 and 1180 cm−1 together form a shoulder at 1186 cm−1 in the spectra of copolymer. The bands at 684 and 690 cm−1 are attributed to typical C–S stretching [29]. The bands at 1514 and 1515 cm−1 show the C═C stretching for PEDOT and copolymer, respectively [30]. The band corresponding to the C–C stretching of the quinoidal structure of the thiophene ring was observed at 1325 cm−1 for the copolymer, whereas at 1352 cm−1 for the PEDOT [31]. The presence of this band indicates the better polymerization of thiophene in the copolymer structure [32]. There is an effective red shift for this band in the spectra of copolymer. It shows that the formation of copolymer decreases the structural energy of polymer [33]. Similar effect has been encountered at 684 cm−1 in the spectra of copolymer.

Figure 2 FTIR spectra of PEDOT and EDOT/Th copolymer.
Figure 2

FTIR spectra of PEDOT and EDOT/Th copolymer.

3.2 SEM results

Figure 3a and b shows SEM images of PEDOT and EDOT/Th copolymer. Figure 3a shows that PEDOT has the vesicular structure with lap-straked globules about 0.2 µm that create batches [34]. That structure has a lot of gaps and pores, which is a desired property to immobilize the enzyme. However, shown clearly in Figure 3b, the EDOT/Th copolymer structure is also porous, but it became more layered, regular and homogeneous. The smoothness of the surface morphology ensures that the electron skipping phenomenon is easy on both the chain and between chains and layers.

Figure 3 SEM images of (a) PEDOT and (b) EDOT/Th copolymer.
Figure 3

SEM images of (a) PEDOT and (b) EDOT/Th copolymer.

The ability of PEDOT to arrest the enzyme and facilitate the electron transport of the copolymer structure suggests that it would be appropriate to use the copolymer as a lactose biosensor. This is also evident from the fact that the copolymer responds better to lactose versus PEDOT.

3.3 Cyclic voltammetry (CV) studies

Figure 4a shows the cyclic voltammograms of formation of PEDOT, PTh and EDOT/Th copolymer. All experiments were carried out in unstirred solution at the fixed scan rate of 50 mV/s. The onset point of the cyclic voltammograms of PEDOT and copolymer begins at 0.8 V, while it starts just about 1.2 V at cyclic voltammogram of PTh. The knot observed for all polymers is typical of the electrosynthesis of conducting polymers. It is clearer for PEDOT and copolymer because the CV of the copolymer shows similar redox behavior and oxidation potentials with PEDOT. Besides, the maximum current value of copolymer is at the average value of both monomers according to their CV curves. These electrochemical behaviors are attributed to the formation of copolymer structure onto the GC electrode.

Figure 4 (a) Cyclic formation voltammograms of PEDOT, PTh and EDOT/Th copolymer. (b) Cyclic voltammograms of copolymer-modified and enzyme immobilized copolymer-modified GC electrodes with 50 mV/s scan rate in the buffer solution.
Figure 4

(a) Cyclic formation voltammograms of PEDOT, PTh and EDOT/Th copolymer. (b) Cyclic voltammograms of copolymer-modified and enzyme immobilized copolymer-modified GC electrodes with 50 mV/s scan rate in the buffer solution.

The electrochemical responses of both copolymer-modified and enzyme immobilized copolymer-modified GC electrodes were examined using the CV method. The scanning rate of 50 mV/s is applied to take CVs of the electrodes as shown in Figure 4b. At the beginning, the copolymer-modified GC electrode was immersed into buffer solution and −0.1 to 1.0 V was applied to this system. The same procedure was carried out for enzyme immobilized copolymer-modified GC electrode. There was a difference between the cyclic voltammograms of electrodes. As shown in Figure 4b, the oxidation and reduction potentials of copolymer were shift to the left with the presence of enzyme. This result supported the immobilization of enzyme to the copolymer surface.

CV is a useful tool to estimate quantitative information about a redox system in solution. The value of the potential scanning rate between working and reference electrodes is changed at each cycle. The expression of the peak current in a reversible system at 298 K is given by the Randles–Sevcik equation [35,36].

ip=(2.69×105)⋅n3/2⋅A⋅D1/2⋅Co⋅v1/2,

where ip is the peak current (A), n is the number of electrons exchanged during the redox process (n = 2 as shown in Figure 1), D is the diffusion coefficient (m2/s), Co is the concentration of the analyte (mol/m3), A is the area of the electrode (m2), and ν is the experimental scan rate (V/s). In CV, this equation describes the effect of the scanning speed on peak current. The peak current depends not only on the diffusion properties of the concentration and electroactive species but also on the scanning speed [37]. Figure 5(a–h) is used to determine whether the cyclic voltammograms of the enzyme immobilized copolymer-modified and copolymer-modified working electrodes continue their stability depending on the scanning rate (25–250 mV/s). Anodic peak currents were increased with the scanning speed. This shows that the copolymer is very well attached to the electrode and still maintains similar stability after the enzyme has been attached. Besides, the linearity of plot indicates that the electrochemical process is diffusion assisted and quite reversible and stable even at high scanning rate [38]. In addition, it was observed that the anodic peak potentials are linear with the logarithm of scan rate at higher scan rates from 100 to 250 mV/s (Figure 5). These results suggest the quasi-reversible electron transfer system for both enzyme immobilized copolymer-modified and copolymer-modified working electrodes [39].

Figure 5 Cyclic voltammograms (I–V), current versus square root of scan speed (I−ν1/2), potential versus ln of scan rate (E−ln ν) and current versus scan rate (I−ν) of copolymer-modified (a–d) and enzyme immobilized copolymer-modified (e–h) GC electrodes with various scanning rates.
Figure 5

Cyclic voltammograms (I–V), current versus square root of scan speed (I−ν1/2), potential versus ln of scan rate (E−ln ν) and current versus scan rate (I−ν) of copolymer-modified (a–d) and enzyme immobilized copolymer-modified (e–h) GC electrodes with various scanning rates.

3.4 Lactose detection

Electrochemical cell and electrodes used in lactose determination are the same as those used in copolymer synthesis. The response of the enzyme electrode was determined in the range of −0.1 to 1.0 V by the CV method according to the current values to be obtained at +0.12 V, in which lactose is oxidized against the known amounts of lactose addition as shown in Figure 6 [40]. To determine the response of the enzyme-modified electrode, first, a voltammogram was taken in the lactose-free buffer solution. Then, the known amount of lactose solution was added to the buffer solution, and cyclic voltammogram was recorded. This process was continued until there was no current increase at +0.12 V. The lactose added to the working medium is oxidized in the O2-saturated buffer solution coupled with β-galactosidase and galactose oxidase enzymes immobilization onto the polymer according to equations (1)–(3). The lactose concentration spent during the enzymatic reactions is proportional to the current change. Studies were repeated at various working parameters and optimum operating conditions of the electrode were determined.

(1)Lactose+H2O⟶β-galGlucose+Galactose
(2)Galactose+O2⟶GaOxd-Galacto-hexodialdose+H2O2
(3)H2O2→O2+2H++2e−
Figure 6 Typical cyclic voltammetric responses of β-gal/GaOx immobilized film of EDOT/Th copolymer to lactose in the buffer solution (pH 6.7).
Figure 6

Typical cyclic voltammetric responses of β-gal/GaOx immobilized film of EDOT/Th copolymer to lactose in the buffer solution (pH 6.7).

3.5 Effect of copolymer ratio and pH

To determine the optimum copolymer ratio for lactose determination, the amount of EDOT in copolymer was varied between 20% and 80% and the response of the enzyme electrode was measured. The effect of homopolymers (PTh and PEDOT) was also examined to make comparison. Since polythiophene did not accumulate on the electrode under these conditions, the effect of polythiophene could not be determined. Among PEDOT and copolymer-modified working electrodes, 80% EDOT:20% Th copolymer-modified working electrode has shown the maximum current value against lactose concentration. Figure 7a shows the effect of the copolymer composition on the response of the enzyme electrode.

Figure 7 (a) Effect of the EDOT molar ratio on the response of the enzyme electrode. (b) Effect of pH on the response of the enzyme electrode.
Figure 7

(a) Effect of the EDOT molar ratio on the response of the enzyme electrode. (b) Effect of pH on the response of the enzyme electrode.

pH is one of the most important parameters to be examined for enzyme biosensors as it affects the working performance of the enzyme. Therefore, the pH of the buffer solution was changed from 6 to 8. Figure 7b shows the pH dependence of the Th/EDOT copolymer-modified enzyme electrode to lactose in 0.1 M NaH2PO4 buffer solution. The current increased from pH 6.0 until 6.7, and after that value, it decreased gently until pH 8.0. The developed lactose biosensor exhibited maximum sensitivity at pH 6.7. That pH value is also nearly the pH value of the milk. In subsequent studies, the buffer pH of 6.7 was used.

3.6 Effect of coating cycle number

The coating thickness of the copolymer on the working electrode has been optimized by using the cycle number of the CV method, which is used at polymerization of copolymer onto the working electrode. When the polymer layer is too thin, its interaction with the enzyme solution decreases and only less enzyme is retained on the surface. Therefore, the sensor response is reduced. When the layer is too thick, the transmission of electrons is restricted. As a result, the response of the enzyme electrode against lactose decreases. Therefore, the determination of the optimum coating thickness is important for the performance of the enzyme electrode. As shown in Figure 8a, the highest current response to lactose was obtained by coating the copolymer on the working electrode surface in 3 cycles.

Figure 8 Effect of (a) coating cycles and (b) enzyme amount on the response of the enzyme electrode.
Figure 8

Effect of (a) coating cycles and (b) enzyme amount on the response of the enzyme electrode.

3.7 Effect of enzyme concentration

The effect of the enzyme pair (galactose oxidase and β-galactosidase) on the electrode response was investigated by changing the amounts provided that their ratios remained constant among themselves (Figure 8b). The highest current response was obtained in a solution containing 4.41 mg of galactose oxidase and 3 mg of β-galactosidase. However, this current value is very close to the current value obtained for a solution containing 2.94 mg of galactose oxidase and 2 mg of β-galactosidase. Therefore, considering that the sensor should be economical, 2.94 mg of galactose oxidase and 2 mg of β-galactosidase enzyme solution were used in the following studies.

3.8 Effect of temperature

The temperature is an efficient factor on the response of the enzyme electrode. Therefore, it is important to determine the effect of the temperature on the working performance of the copolymer-modified enzyme electrode. Figure 9 shows the current values obtained for the biosensor at different temperatures. This figure also shows that the current value increased linearly up to 50°C and reached the maximum value at this point. This result is better than the result previously found for the biosensor developed using this enzyme system for the determination of lactose [24]. After this value, the current values decreased considerably because of the various conformations attributed to temperature for the immobilized enzyme. However, enzymes are known to be able to denature at high temperatures. Although the maximum current response was obtained at 50°C by the working electrode, we used ambient temperature for measurements due to the long-term thermal stability of the enzymes [41].

Figure 9 Effect of temperature on the response of the enzyme electrode at +0.12 V in the range of −0.1 to 1.0 V applied potential, pH 6.7.
Figure 9

Effect of temperature on the response of the enzyme electrode at +0.12 V in the range of −0.1 to 1.0 V applied potential, pH 6.7.

Using the experimental data in the range in which the reaction rate increased with the temperature, the activation energy of the reaction carried out with the immobilized β-galactosidase and the galactose oxidase was determined using the Arrhenius equation. For this purpose, ln I values against 1/T were plotted (not shown here). The activation energy of β-galactosidase and galactose oxidase enzyme systems was found to be 38.00 kJ/mol. This value is comparable to the value found with the free enzyme [42]. According to the experimental results, we can say that the EDOT/Th copolymer supplies a suitable working medium for β-galactosidase and galactose oxidase enzyme systems, which make the sensor stable even at high temperatures.

3.9 Effect of substrate concentration

The prerequisite for a healthy measurement with enzyme electrodes is to obtain current values proportional to the substrate concentration in the measuring medium. The substrate concentration range in which this condition is met is defined as the linear operating range of the enzyme electrode, and in practice, this range is desirable to be broad. After optimizing the working conditions, the response of the prepared biosensor to the standard lactose solution was examined. Figure 10 shows the response of the modified working electrode as a function of each 100 μL of 0.02 M lactose solution in the range of −0.1 to 1.0 V by the CV method according to the current values to be obtained at +0.12 V (pH 6.7, three coating cycles, 25°C, with the molar ratio of 80% EDOT:20% Th).

Figure 10 Effect of lactose concentration on response and linear working range (insider graph) for the modified electrode at +0.12 V in range of −0.1 to 1.0 V applied potential, pH 6.7.
Figure 10

Effect of lactose concentration on response and linear working range (insider graph) for the modified electrode at +0.12 V in range of −0.1 to 1.0 V applied potential, pH 6.7.

As shown in Figure 10, the developed enzyme electrode has given proportional current values to lactose concentration up to 1.72 mM. Therefore, the linear working limit of the prepared enzyme electrode was determined as 1.72 mM lactose concentration. On the other hand, the electrode response to the lactose concentration reaches a constant value of about 2.17 mM, and there is no increase in the current value at higher concentrations. This shows that the enzyme in the polymer film reaches saturation against the substrate at a concentration of 2.17 mM lactose for the electrode prepared under the conditions of the measuring medium. Therefore, diffusion restriction in the electrode activity will not be important at lactose concentration of 2.17 mM and higher under these conditions. The detection limit of the modified enzyme electrode was found as 1.9 × 10−5 M lactose concentration. Besides, the sensitivity of the enzyme electrode was also calculated from the plot of current density (current/area) against concentration, which was 0.06 μA/mM cm2. This value is comparable with the study by Marrakci et al. [43]. The maximum reaction rate (Vmax) of the copolymer modified was detected at 500 µA.

The relevance between the inverse of the current value (i−1) and the inverse of lactose concentration (C−1) was plotted according to the Lineweaver–Burk form of the Michaelis–Menten equation, which is not shown here [44]. The Michaelis–Menten constant is an important parameter for characterizing the enzyme electrode. This constant shows that the rate of conversion of the substrate to the product depends on the rate of degradation of the enzyme substrate complex. As the Km value decreases, the interaction between the enzyme and the substrate increased [45]. In this study, the apparent Michaelis  –  Menten constant was calculated for copolymer-modified enzyme-entrapped working electrode using the Lineweaver–Burk equation. The value of 0.20 mM was about ten times lower than that found in the literature for the free enzyme system (2.30 mM) [46]. This result shows that the polymer structure does not lead to diffusion restriction. It may also indicate that the electronic activity of the EDOT/Th copolymer has the synergistic effect on the response of the enzyme system. Table 1 presents the comparison of some lactose biosensor performances with biosensor developed in this study for lactose determination. As a result, the lactose biosensor based on the EDOT/Th copolymer has various advantages, such as broad linear range with a low detection limit, thermal stability, fast response, low  KM (means robust relation between enzyme and substrate), simple and economic fabricating procedure.

Table 1

Performance values of some lactose sensors

MethodElectrode modifierEnzymeaDetection limit and/or linear working rangeSensitivity (µA/mM cm2)Ref.
PhotoelectrochemicalGold nanoparticles, MnO2 and g-C3N4 decorated TiO2GOx/β-GAL0.23 µM, 0.008–2.5 mM1.66[47]
AmperometricPolymer multilayer (cellobiose dehydrogenase [CDH])GOx/CAT10–100 µM—[48]
ConductometricThin-film conductometric sensorGOx/β-GAL1 × 10−4 M0.01[43]
Up to 14 mM
Cyclic voltammetryPt/graphene/P(1,5-DAN)GOx/β-GAL1.3 μg/mL (3.8 μM)1.33[49]
250 nM/0.5–200 mM
Gold and silver nanoparticles (NPs)CDG3.5 mM5.4[50]
10 to 300 mM
PEDOT/PTh copolymerβ-GAL/GAOx1.9 × 10−5 M0.06This study
Up to 1.72 mM
  1. a

    GOx, glucose oxidase; CAT, catalase; β-GAL, beta-galactosidase; GAOx, galactose oxidase; CDG, cellobiose dehydrogenase.

3.10 Interferences and reproducibility

The effect of some commonly encountered species that could intervene electrochemically on the current response of lactose biosensor to lactose was investigated. Ascorbic acid and uric acid were chosen to investigate the effect of these species on the response of the enzyme electrode. It was determined that the effect of ascorbic and uric acids on the electrode response was insignificant (Figure 11). Similar results were reported by Gürsoy et al. [51].

Figure 11 Effect of interferents on the response of lactose biosensor at +0.12 V in the range of −0.1 to 1.0 V applied potential, pH 6.7.
Figure 11

Effect of interferents on the response of lactose biosensor at +0.12 V in the range of −0.1 to 1.0 V applied potential, pH 6.7.

The reproducibility of the biosensor was performed by the seven different biosensors prepared under the same conditions (Figure 12). The results showed that the biosensor had a good reproducibility with the variation coefficient of 9.8%.

Figure 12 Reproducibility of the lactose biosensor at +0.12 V in the range of −0.1 to 1.0 V applied potential, pH 6.7.
Figure 12

Reproducibility of the lactose biosensor at +0.12 V in the range of −0.1 to 1.0 V applied potential, pH 6.7.

4 Conclusion

This study indicates the usability of EDOT/Th copolymer-modified galactose oxidase/β-galactosidase entrapped enzyme electrodes for the determination of lactose. This biosensor is an alternative to determine lactose in cheaper, faster and simple way. Copolymerization of monomers was achieved on the GC electrode by CV in the range of −0.10 to 1.50 V at room temperature. The growth of the copolymer film was checked by CV, FTIR and SEM analysis. The appropriate amount of glutaraldehyde and enzyme solution was attached to the polymer-modified electrode. After optimization of working conditions of the electrode, linear working range and detection limit were calculated to be up to 1.72 mM and 1.9 × 10−5 M, respectively. The developed lactose biosensor has a very fast response time (4–5 s) due to the fast electron transport system of copolymer. KM values of immobilized (0.02 mM) and free enzymes (2.30 mM) indicate that there are no diffusional limitations and denaturating effect in the immobilization procedure of enzymes. Besides, the influences of ascorbic acid and uric acid, which are the major interferents in the milk, on the response biosensor have no significant effect. Further studies are needed to show the applicability of the biosensor to determine lactose concentration in milk samples.

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Acknowledgments

This work was supported by Burdur Mehmet Akif Ersoy University, Scientific Research Projects Commission (Project No. 0341-NAP-16).

  1. Author contributions: SSG and OG performed the study design, supervised the experimental work, carried out the literature search and wrote the manuscript; AY and GCC performed the laboratory experiments and contributed to the data processing. All the authors read and approved the final manuscript.

  2. Conflict of interest: The authors declare no conflict of interest.

References

[1] Ramya R, Muthukumaran P, Wilson J. Electron beam-irradiated polypyrrole decorated with Bovine serum albumin pores: simultaneous determination of epinephrine and l-tyrosine. Biosens Bioelectron. 2018;108:53–61.10.1016/j.bios.2018.02.044Search in Google Scholar

[2] Shirakawa H, Louis EJ, Macdiarmid AG, Chiang CK, Heeger AJ. Synthesis of electrically conducting organic polymers: halogen derivatives of polyacetylene, (CH)x. J Chem Soc Chem Commun. 1977;16:578–80.10.1039/c39770000578Search in Google Scholar

[3] Naseri M, Fotouhi L, Ehsani A. Recent progress in the development of conducting polymer-based nanocomposites for electrochemical biosensors applications: a mini-review. Chem Rec. 2018;18:599–618.10.1002/tcr.201700101Search in Google Scholar

[4] Zhang Z, Liao M, Lou H, Hu Y, Sun X, Peng H. Conjugated polymers for flexible energy harvesting and storage. Adv Mater. 2018;30:1704261.10.1002/adma.201704261Search in Google Scholar

[5] Yamamoto T, Sanechika K, Yamamoto A. Preparation of thermostable and electric-conducting poly(2,5-thienylene). J Polym Sci Polym Lett Ed. 1980;18:9–12.10.1002/pol.1980.130180103Search in Google Scholar

[6] Lin JW‐P, Dudek LP. Synthesis and properties of poly(2,5‐thienylene). J Polym Sci A Polym Chem. 1980;18:2869–73.10.1002/pol.1980.170180910Search in Google Scholar

[7] Talu M, Kabasakaloglu M, Oskovi HR. Electrochemical copolymerization of thiophene and aniline. J Polym Sci A Polym Chem. 1996;34:2981.10.1002/(SICI)1099-0518(199610)34:14<2981::AID-POLA16>3.0.CO;2-GSearch in Google Scholar

[8] Özçiçek NP, Pekmez K, Holze R, Yıldız A. Spectroelectrochemical investigations of aniline-thiophene copolymers in acetonitrile. J Appl Polym Sci. 2003;90:3417–23.10.1002/app.13035Search in Google Scholar

[9] Liu H, Ge J, Ma E, Yang L. Advanced biomaterials for biosensor and theranostics. In: Yang L, Bhaduri SB, Thomas J, editors. Biomaterials in Translational Medicine. Webster: Elsevier Inc.; 2019. p. 213–55.10.1016/B978-0-12-813477-1.00010-4Search in Google Scholar

[10] Hsieh GW, Lin ZR, Hung CY, Lin SY, Yang CR. Graphene-induced enhancement of charge carrier mobility and air stability in organic polythiophene field effect transistors. Org Electron. 2018;54:27–33.10.1016/j.orgel.2017.12.024Search in Google Scholar

[11] Guven N, Sultanova H, Ozer B, Yucel B, Camurlu P. Tuning of electrochromic properties of electrogenerated polythiophenes through Ru(ii) complex tethering and backbone derivatization. Electrochim Acta. 2020;329:135134.10.1016/j.electacta.2019.135134Search in Google Scholar

[12] Lai C, Guo W, Tang X, Zhang G, Pan Q, Pei M. Cross-linking conducting polythiophene with yellow-green light-emitting properties and good thermal stability via free radical polymerization and electropolymerization. Synth Met. 2011;161:1886–91.10.1016/j.synthmet.2011.06.028Search in Google Scholar

[13] Aydin M, Esat B, Kiliç Ç, Köse ME, Ata A, Yilmaz F. A polythiophene derivative bearing TEMPO as a cathode material for rechargeable batteries. Eur Polym J. 2011;47:2283–94.10.1016/j.eurpolymj.2011.09.002Search in Google Scholar

[14] Chen J, Zhang L, Zhu J, Wang N, Feng J, Yan W. Adsorption of polythiophene/TiO2 composite for Zn(ii), Pb(ii) and Cu(ii): selectivity and synergistic effect investigation. Appl Surf Sci. 2018;459:318–26.10.1016/j.apsusc.2018.08.008Search in Google Scholar

[15] Uygun A. DNA hybridization electrochemical biosensor using a functionalized polythiophene. Talanta. 2009;79:194–8.10.1016/j.talanta.2009.03.049Search in Google Scholar PubMed

[16] Wen Y, Xu J, Liu M, Li D, Lu L, Yue R, et al. A vitamin C electrochemical biosensor based on one-step immobilization of ascorbate oxidase in the biocompatible conducting poly(3,4-ethylenedioxythio-phene)-lauroylsarcosinate film for agricultural application in crops. J Electroanal Chem. 2012;674:71–82.10.1016/j.jelechem.2012.03.021Search in Google Scholar

[17] Ates M. A review study of (bio)sensor systems based on conducting polymers. Mater Sci Eng C. 2013;33:1853–9.10.1016/j.msec.2013.01.035Search in Google Scholar PubMed

[18] Travas-Sejdic J, Aydemir N, Kannan B, Williams DE, Malmstrom J. Intrinsically conducting polymer nanowires for biosensing. J Mater Chem. 2014;2:4593–609.10.1039/C4TB00598HSearch in Google Scholar

[19] Jain R, Jadon N, Pawaiya A. Polypyrrole based next generation electrochemical sensors and biosensors: a review. TrAC Trends Anal Chem. 2017;97:363–73.10.1016/j.trac.2017.10.009Search in Google Scholar

[20] Šetka M, Drbohlavová J, Hubálek J. Nanostructured polypyrrole-based ammonia and volatile organic compound sensors. Sensors. 2017;17:562.10.3390/s17030562Search in Google Scholar PubMed PubMed Central

[21] Wang G, Han R, Su X, Li Y, Xu G, Luo X. Zwitterionic peptide anchored to conducting polymer PEDOT for the development of antifouling and ultrasensitive electrochemical DNA sensor. Biosens Bioelectron. 2017;92:396–401.10.1016/j.bios.2016.10.088Search in Google Scholar

[22] Mattar R, Mazo DFC, Carrilho FJ. Lactose intolerance: diagnosis, genetic, and clinical factors. Clin Exp Gastroenterol. 2012;5:113–21.10.2147/CEG.S32368Search in Google Scholar

[23] Gursoy O, Sen Gursoy S, Cogal S, Celik Cogal G. Development of a new two-enzyme biosensor based on poly(pyrrole-co-3,4-ethylenedioxythiophene) for lactose determination in milk. Polym Eng Sci. 2018;58:839–48.10.1002/pen.24632Search in Google Scholar

[24] Sharma SK, Singhal R, Malhotra BD, Sehgal N, Kumar A. Lactose biosensor based on Langmuir–Blodgett films of poly(3-hexyl thiophene). Biosens Bioelectron. 2004;20:651–7.10.1016/j.bios.2004.03.020Search in Google Scholar

[25] Chang C-C, Her L-J, Hong J-L. Copolymer from electropolymerization of thiophene and 3,4-ethylenedioxythiophene and its use as cathode for lithium ion battery. Electrochim Acta. 2005;50:4461–8.10.1016/j.electacta.2005.02.008Search in Google Scholar

[26] Shoja Y, Rafati AA, Ghodsi J. Polythiophene supported MnO2 nanoparticles as nano-stabilizer for simultaneously electrostatically immobilization of d-amino acid oxidase and hemoglobin as efficient bio-nanocomposite in fabrication of dopamine bi-enzyme biosensor. Mater Sci Eng C. 2017;76:637–45.10.1016/j.msec.2017.03.155Search in Google Scholar

[27] Pilo M, Farre R, Lachowicz JI, Masolo E, Panzanelli A, Sanna G, et al. Design of amperometric biosensors for the detection of glucose prepared by immobilization of glucose oxidase on conducting (poly) thiophene films. J Anal Methods Chem. 2018;1849439.10.1155/2018/1849439Search in Google Scholar

[28] Dehaudt J, Beouch L, Peralta S, Plesse C, Aubert P-H, Chevrot C, et al. Facile route to prepare film of poly(3,4-ethylene dioxythiophene)–TiO2 nanohybrid for solar cell application. Thin Solid Films. 2011;519:1876–81.10.1016/j.tsf.2010.10.052Search in Google Scholar

[29] Xu SH, Li SY, Wei YX, Zhang L, Xu F. Improving the photocatalytic performance of conducting polymer polythiophene sensitized TiO2 nanoparticles under sunlight irradiation. React Kinet Mech Cat. 2010;101:237–49.10.1007/s11144-010-0222-ySearch in Google Scholar

[30] Garreau S, Louam G, Leliant S, Buisson JP, Froyer G. Optical study and vibrational analysis of the poly(3,4-ethylenedioxythiophene) (PEDT). Synth Met. 1999;101:312–3.10.1016/S0379-6779(98)01146-1Search in Google Scholar

[31] Tran-Van F, Garreau S, Louarn G, Froyer G, Chevrot C. Fully undoped and soluble oligo(3,4-ethylenedioxythiophene)s: spectroscopic study and electrochemical characterization. J Mater Chem. 2001;11:1378–82.10.1039/b100033kSearch in Google Scholar

[32] Uygun A, Yavuz AG, Sen S, Omastová M. Polythiophene/SiO2 nanocomposites prepared in the presence of surfactants and their application to glucose biosensing. Synth Met. 2009;159:2022–8.10.1016/j.synthmet.2009.07.009Search in Google Scholar

[33] Tamanai A, Beck S, Pucci A. Mid-infrared characterization of thiophene-based thin polymer films. Displays. 2013;34:399–405.10.1016/j.displa.2013.08.005Search in Google Scholar

[34] Eren E, Celik G, Uygun A, Tabaciarova J, Omastova M. Synthesis of poly(3,4-ethylenedioxythiophene)/titanium dioxide nanocomposites in the presence of surfactants and their properties. Synth Met. 2012;162:1451–8.10.1016/j.synthmet.2012.06.014Search in Google Scholar

[35] Randles JEB. A cathode ray polarograph. Part II. – the current––voltage curves. Trans Faraday Soc. 1948;44:327–38.10.1039/TF9484400327Search in Google Scholar

[36] Ševčík A. Oscillographic polarography with periodical triangular voltage. Collect Czechoslov Chem Commun. 1948;13:349–77.10.1135/cccc19480349Search in Google Scholar

[37] Zanello P. Inorganic Electrochemistry: Theory, Practice and Application. UK: The Royal Society of Chemistry; 2003.Search in Google Scholar

[38] Cha J, Han JI, Choi Y, Yoon DS, Oh KW, Lim G. DNA hybridization electrochemical sensor using conducting polymer. Biosens Bioelectron. 2003;18:1241–7.10.1016/S0956-5663(03)00088-5Search in Google Scholar

[39] Singh A, Sinsinbar G, Choudhary M, Kumar V, Pasricha R, Verma HN, et al. Graphene oxide-chitosan nanocomposite based electrochemical DNA biosensor for detection of typhoid. Sens Actuators B. 2013;185:675–84.10.1016/j.snb.2013.05.014Search in Google Scholar

[40] Safina G, Ludwig R, Gorton L. A simple and sensitive method for lactose detection based on direct electron transfer between immobilised cellobiose dehydrogenase and screen-printed carbon electrodes. Electrochim Acta. 2010;55:7690–5.10.1016/j.electacta.2009.10.052Search in Google Scholar

[41] Göktug T, Sezgintürk MK, Dinçkaya E. Glucose oxidase-β-galactosidase hybrid biosensor based on glassy carbon electrode modified with mercury for lactose determination. Anal Chim Acta. 2005;551:51–56.10.1016/j.aca.2005.07.021Search in Google Scholar

[42] Rothlisberger U, Carloni P, Doclo K, Parrinello M. A comparative study of galactose oxidase and active site analogs based on QM/MM Car-Parrinello simulations. J Biol Inorg Chem. 2000;5:236–50.10.1007/s007750050368Search in Google Scholar PubMed

[43] Marrakci M, Dzyadevych SV, Lagarde F, Martelet C, Jaffrezic-Renault N. Conductometric biosensor based on glucose oxidase and beta-galactosidase for specific lactose determination in milk. Mater Sci Eng C. 2008;28:872–5.10.1016/j.msec.2007.10.046Search in Google Scholar

[44] Shu FR, Wilson GS. Rotating ring-disk enzyme electrode for surface catalysis studies. Anal Chem. 1976;48:1679–86.10.1021/ac50006a014Search in Google Scholar PubMed

[45] Michaelis L, Menten M. Die Kinetik der invertinwirkun. Biochem Ztg. 1913;49:333–69.Search in Google Scholar

[46] Ansari SA, Satar R, Alam F, Alqahtani MH, Chaudhary AG, Naseer MI, et al. Cost effective surface functionalization of silver nanoparticles for high yield immobilization of aspergillus oryzae β-galactosidase and its application in lactose hydrolysis. Process Biochem. 2012;47:2427–33.10.1016/j.procbio.2012.10.002Search in Google Scholar

[47] Çakiroğlu B, Demirci YC, Gökgöz E, Özacar M. A photoelectrochemical glucose and lactose biosensor consisting of gold nanoparticles, MnO2 and g-C3N4 decorated TiO2. Sens Actuators B. 2019;282:282–9.10.1016/j.snb.2018.11.064Search in Google Scholar

[48] Lopez F, Ma S, Ludwig R, Schuhmann W, Ruf A. A polymer multilayer based amperometric biosensor for the detection of lactose in the presence of high concentrations of glucose. Electroanalysis. 2017;29:154–61.10.1002/elan.201600575Search in Google Scholar

[49] Nguyen BH, Nguyen BT, Vu HV, Nguyen CV, Nguyen DT, Nguyen LT, et al. Development of label-free electrochemical lactose biosensor based on graphene/poly(1,5-diaminonaphthalene) film. Curr Appl Phys. 2016;16:135–40.10.1016/j.cap.2015.11.004Search in Google Scholar

[50] Bollella P, Schulz C, Favero G, Mazzei F, Ludwig R, Gorton L, et al. Green synthesis and characterization of gold and silver nanoparticles and their application for development of a third generation lactose biosensor. Electroanalysis. 2017;29:77–86.10.1002/elan.201600476Search in Google Scholar

[51] Gürsoy O, Çelik G, Gürsoy SŞ. Electrochemical biosensor based on surfactant doped polypyrrole (PPy) matrix for lactose determination. J Appl Polym Sci. 2013;131:40200.10.1002/app.40200Search in Google Scholar

Received: 2020-04-28
Revised: 2020-06-28
Accepted: 2020-07-07
Published Online: 2020-08-11

© 2020 Songul Sen Gursoy et al., published by De Gruyter

This work is licensed under the Creative Commons Attribution 4.0 International License.

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https://doi.org/10.1515/chem-2020-0100
Keywords for this article
copolymerization; 3,4-ethylenedioxythiophene; lactose; polythiophene; sensor
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  3. Kinetic models of the extraction of vanillic acid from pumpkin seeds
  4. On the maximum ABC index of bipartite graphs without pendent vertices
  5. Estimation of the total antioxidant potential in the meat samples using thin-layer chromatography
  6. Molecular dynamics simulation of sI methane hydrate under compression and tension
  7. Spatial distribution and potential ecological risk assessment of some trace elements in sediments and grey mangrove (Avicennia marina) along the Arabian Gulf coast, Saudi Arabia
  8. Amino-functionalized graphene oxide for Cr(VI), Cu(II), Pb(II) and Cd(II) removal from industrial wastewater
  9. Chemical composition and in vitro activity of Origanum vulgare L., Satureja hortensis L., Thymus serpyllum L. and Thymus vulgaris L. essential oils towards oral isolates of Candida albicans and Candida glabrata
  10. Effect of excess Fluoride consumption on Urine-Serum Fluorides, Dental state and Thyroid Hormones among children in “Talab Sarai” Punjab Pakistan
  11. Design, Synthesis and Characterization of Novel Isoxazole Tagged Indole Hybrid Compounds
  12. Comparison of kinetic and enzymatic properties of intracellular phosphoserine aminotransferases from alkaliphilic and neutralophilic bacteria
  13. Green Organic Solvent-Free Oxidation of Alkylarenes with tert-Butyl Hydroperoxide Catalyzed by Water-Soluble Copper Complex
  14. Ducrosia ismaelis Asch. essential oil: chemical composition profile and anticancer, antimicrobial and antioxidant potential assessment
  15. DFT calculations as an efficient tool for prediction of Raman and infra-red spectra and activities of newly synthesized cathinones
  16. Influence of Chemical Osmosis on Solute Transport and Fluid Velocity in Clay Soils
  17. A New fatty acid and some triterpenoids from propolis of Nkambe (North-West Region, Cameroon) and evaluation of the antiradical scavenging activity of their extracts
  18. Antiplasmodial Activity of Stigmastane Steroids from Dryobalanops oblongifolia Stem Bark
  19. Rapid identification of direct-acting pancreatic protectants from Cyclocarya paliurus leaves tea by the method of serum pharmacochemistry combined with target cell extraction
  20. Immobilization of Pseudomonas aeruginosa static biomass on eggshell powder for on-line preconcentration and determination of Cr (VI)
  21. Assessment of methyl 2-({[(4,6-dimethoxypyrimidin-2-yl)carbamoyl] sulfamoyl}methyl)benzoate through biotic and abiotic degradation modes
  22. Stability of natural polyphenol fisetin in eye drops Stability of fisetin in eye drops
  23. Production of a bioflocculant by using activated sludge and its application in Pb(II) removal from aqueous solution
  24. Molecular Properties of Carbon Crystal Cubic Structures
  25. Synthesis and characterization of calcium carbonate whisker from yellow phosphorus slag
  26. Study on the interaction between catechin and cholesterol by the density functional theory
  27. Analysis of some pharmaceuticals in the presence of their synthetic impurities by applying hybrid micelle liquid chromatography
  28. Two mixed-ligand coordination polymers based on 2,5-thiophenedicarboxylic acid and flexible N-donor ligands: the protective effect on periodontitis via reducing the release of IL-1β and TNF-α
  29. Incorporation of silver stearate nanoparticles in methacrylate polymeric monoliths for hemeprotein isolation
  30. Development of ultrasound-assisted dispersive solid-phase microextraction based on mesoporous carbon coated with silica@iron oxide nanocomposite for preconcentration of Te and Tl in natural water systems
  31. N,N′-Bis[2-hydroxynaphthylidene]/[2-methoxybenzylidene]amino]oxamides and their divalent manganese complexes: Isolation, spectral characterization, morphology, antibacterial and cytotoxicity against leukemia cells
  32. Determination of the content of selected trace elements in Polish commercial fruit juices and health risk assessment
  33. Diorganotin(iv) benzyldithiocarbamate complexes: synthesis, characterization, and thermal and cytotoxicity study
  34. Keratin 17 is induced in prurigo nodularis lesions
  35. Anticancer, antioxidant, and acute toxicity studies of a Saudi polyherbal formulation, PHF5
  36. LaCoO3 perovskite-type catalysts in syngas conversion
  37. Comparative studies of two vegetal extracts from Stokesia laevis and Geranium pratense: polyphenol profile, cytotoxic effect and antiproliferative activity
  38. Fragmentation pattern of certain isatin–indole antiproliferative conjugates with application to identify their in vitro metabolic profiles in rat liver microsomes by liquid chromatography tandem mass spectrometry
  39. Investigation of polyphenol profile, antioxidant activity and hepatoprotective potential of Aconogonon alpinum (All.) Schur roots
  40. Lead discovery of a guanidinyl tryptophan derivative on amyloid cascade inhibition
  41. Physicochemical evaluation of the fruit pulp of Opuntia spp growing in the Mediterranean area under hard climate conditions
  42. Electronic structural properties of amino/hydroxyl functionalized imidazolium-based bromide ionic liquids
  43. New Schiff bases of 2-(quinolin-8-yloxy)acetohydrazide and their Cu(ii), and Zn(ii) metal complexes: their in vitro antimicrobial potentials and in silico physicochemical and pharmacokinetics properties
  44. Treatment of adhesions after Achilles tendon injury using focused ultrasound with targeted bFGF plasmid-loaded cationic microbubbles
  45. Synthesis of orotic acid derivatives and their effects on stem cell proliferation
  46. Chirality of β2-agonists. An overview of pharmacological activity, stereoselective analysis, and synthesis
  47. Fe3O4@urea/HITh-SO3H as an efficient and reusable catalyst for the solvent-free synthesis of 7-aryl-8H-benzo[h]indeno[1,2-b]quinoline-8-one and indeno[2′,1′:5,6]pyrido[2,3-d]pyrimidine derivatives
  48. Adsorption kinetic characteristics of molybdenum in yellow-brown soil in response to pH and phosphate
  49. Enhancement of thermal properties of bio-based microcapsules intended for textile applications
  50. Exploring the effect of khat (Catha edulis) chewing on the pharmacokinetics of the antiplatelet drug clopidogrel in rats using the newly developed LC-MS/MS technique
  51. A green strategy for obtaining anthraquinones from Rheum tanguticum by subcritical water
  52. Cadmium (Cd) chloride affects the nutrient uptake and Cd-resistant bacterium reduces the adsorption of Cd in muskmelon plants
  53. Removal of H2S by vermicompost biofilter and analysis on bacterial community
  54. Structural cytotoxicity relationship of 2-phenoxy(thiomethyl)pyridotriazolopyrimidines: Quantum chemical calculations and statistical analysis
  55. A self-breaking supramolecular plugging system as lost circulation material in oilfield
  56. Synthesis, characterization, and pharmacological evaluation of thiourea derivatives
  57. Application of drug–metal ion interaction principle in conductometric determination of imatinib, sorafenib, gefitinib and bosutinib
  58. Synthesis and characterization of a novel chitosan-grafted-polyorthoethylaniline biocomposite and utilization for dye removal from water
  59. Optimisation of urine sample preparation for shotgun proteomics
  60. DFT investigations on arylsulphonyl pyrazole derivatives as potential ligands of selected kinases
  61. Treatment of Parkinson’s disease using focused ultrasound with GDNF retrovirus-loaded microbubbles to open the blood–brain barrier
  62. New derivatives of a natural nordentatin
  63. Fluorescence biomarkers of malignant melanoma detectable in urine
  64. Study of the remediation effects of passivation materials on Pb-contaminated soil
  65. Saliva proteomic analysis reveals possible biomarkers of renal cell carcinoma
  66. Withania frutescens: Chemical characterization, analgesic, anti-inflammatory, and healing activities
  67. Design, synthesis and pharmacological profile of (−)-verbenone hydrazones
  68. Synthesis of magnesium carbonate hydrate from natural talc
  69. Stability-indicating HPLC-DAD assay for simultaneous quantification of hydrocortisone 21 acetate, dexamethasone, and fluocinolone acetonide in cosmetics
  70. A novel lactose biosensor based on electrochemically synthesized 3,4-ethylenedioxythiophene/thiophene (EDOT/Th) copolymer
  71. Citrullus colocynthis (L.) Schrad: Chemical characterization, scavenging and cytotoxic activities
  72. Development and validation of a high performance liquid chromatography/diode array detection method for estrogen determination: Application to residual analysis in meat products
  73. PCSK9 concentrations in different stages of subclinical atherosclerosis and their relationship with inflammation
  74. Development of trace analysis for alkyl methanesulfonates in the delgocitinib drug substance using GC-FID and liquid–liquid extraction with ionic liquid
  75. Electrochemical evaluation of the antioxidant capacity of natural compounds on glassy carbon electrode modified with guanine-, polythionine-, and nitrogen-doped graphene
  76. A Dy(iii)–organic framework as a fluorescent probe for highly selective detection of picric acid and treatment activity on human lung cancer cells
  77. A Zn(ii)–organic cage with semirigid ligand for solvent-free cyanosilylation and inhibitory effect on ovarian cancer cell migration and invasion ability via regulating mi-RNA16 expression
  78. Polyphenol content and antioxidant activities of Prunus padus L. and Prunus serotina L. leaves: Electrochemical and spectrophotometric approach and their antimicrobial properties
  79. The combined use of GC, PDSC and FT-IR techniques to characterize fat extracted from commercial complete dry pet food for adult cats
  80. MALDI-TOF MS profiling in the discovery and identification of salivary proteomic patterns of temporomandibular joint disorders
  81. Concentrations of dioxins, furans and dioxin-like PCBs in natural animal feed additives
  82. Structure and some physicochemical and functional properties of water treated under ammonia with low-temperature low-pressure glow plasma of low frequency
  83. Mesoscale nanoparticles encapsulated with emodin for targeting antifibrosis in animal models
  84. Amine-functionalized magnetic activated carbon as an adsorbent for preconcentration and determination of acidic drugs in environmental water samples using HPLC-DAD
  85. Antioxidant activity as a response to cadmium pollution in three durum wheat genotypes differing in salt-tolerance
  86. A promising naphthoquinone [8-hydroxy-2-(2-thienylcarbonyl)naphtho[2,3-b]thiophene-4,9-dione] exerts anti-colorectal cancer activity through ferroptosis and inhibition of MAPK signaling pathway based on RNA sequencing
  87. Synthesis and efficacy of herbicidal ionic liquids with chlorsulfuron as the anion
  88. Effect of isovalent substitution on the crystal structure and properties of two-slab indates BaLa2−xSmxIn2O7
  89. Synthesis, spectral and thermo-kinetics explorations of Schiff-base derived metal complexes
  90. An improved reduction method for phase stability testing in the single-phase region
  91. Comparative analysis of chemical composition of some commercially important fishes with an emphasis on various Malaysian diets
  92. Development of a solventless stir bar sorptive extraction/thermal desorption large volume injection capillary gas chromatographic-mass spectrometric method for ultra-trace determination of pyrethroids pesticides in river and tap water samples
  93. A turbidity sensor development based on NL-PI observers: Experimental application to the control of a Sinaloa’s River Spirulina maxima cultivation
  94. Deep desulfurization of sintering flue gas in iron and steel works based on low-temperature oxidation
  95. Investigations of metallic elements and phenolics in Chinese medicinal plants
  96. Influence of site-classification approach on geochemical background values
  97. Effects of ageing on the surface characteristics and Cu(ii) adsorption behaviour of rice husk biochar in soil
  98. Adsorption and sugarcane-bagasse-derived activated carbon-based mitigation of 1-[2-(2-chloroethoxy)phenyl]sulfonyl-3-(4-methoxy-6-methyl-1,3,5-triazin-2-yl) urea-contaminated soils
  99. Antimicrobial and antifungal activities of bifunctional cooper(ii) complexes with non-steroidal anti-inflammatory drugs, flufenamic, mefenamic and tolfenamic acids and 1,10-phenanthroline
  100. Application of selenium and silicon to alleviate short-term drought stress in French marigold (Tagetes patula L.) as a model plant species
  101. Screening and analysis of xanthine oxidase inhibitors in jute leaves and their protective effects against hydrogen peroxide-induced oxidative stress in cells
  102. Synthesis and physicochemical studies of a series of mixed-ligand transition metal complexes and their molecular docking investigations against Coronavirus main protease
  103. A study of in vitro metabolism and cytotoxicity of mephedrone and methoxetamine in human and pig liver models using GC/MS and LC/MS analyses
  104. A new phenyl alkyl ester and a new combretin triterpene derivative from Combretum fragrans F. Hoffm (Combretaceae) and antiproliferative activity
  105. Erratum
  106. Erratum to: A one-step incubation ELISA kit for rapid determination of dibutyl phthalate in water, beverage and liquor
  107. Review Articles
  108. Sinoporphyrin sodium, a novel sensitizer for photodynamic and sonodynamic therapy
  109. Natural products isolated from Casimiroa
  110. Plant description, phytochemical constituents and bioactivities of Syzygium genus: A review
  111. Evaluation of elastomeric heat shielding materials as insulators for solid propellant rocket motors: A short review
  112. Special Issue on Applied Biochemistry and Biotechnology 2019
  113. An overview of Monascus fermentation processes for monacolin K production
  114. Study on online soft sensor method of total sugar content in chlorotetracycline fermentation tank
  115. Studies on the Anti-Gouty Arthritis and Anti-hyperuricemia Properties of Astilbin in Animal Models
  116. Effects of organic fertilizer on water use, photosynthetic characteristics, and fruit quality of pear jujube in northern Shaanxi
  117. Characteristics of the root exudate release system of typical plants in plateau lakeside wetland under phosphorus stress conditions
  118. Characterization of soil water by the means of hydrogen and oxygen isotope ratio at dry-wet season under different soil layers in the dry-hot valley of Jinsha River
  119. Composition and diurnal variation of floral scent emission in Rosa rugosa Thunb. and Tulipa gesneriana L.
  120. Preparation of a novel ginkgolide B niosomal composite drug
  121. The degradation, biodegradability and toxicity evaluation of sulfamethazine antibiotics by gamma radiation
  122. Special issue on Monitoring, Risk Assessment and Sustainable Management for the Exposure to Environmental Toxins
  123. Insight into the cadmium and zinc binding potential of humic acids derived from composts by EEM spectra combined with PARAFAC analysis
  124. Source apportionment of soil contamination based on multivariate receptor and robust geostatistics in a typical rural–urban area, Wuhan city, middle China
  125. Special Issue on 13th JCC 2018
  126. The Role of H2C2O4 and Na2CO3 as Precipitating Agents on The Physichochemical Properties and Photocatalytic Activity of Bismuth Oxide
  127. Preparation of magnetite-silica–cetyltrimethylammonium for phenol removal based on adsolubilization
  128. Topical Issue on Agriculture
  129. Size-dependent growth kinetics of struvite crystals in wastewater with calcium ions
  130. The effect of silica-calcite sedimentary rock contained in the chicken broiler diet on the overall quality of chicken muscles
  131. Physicochemical properties of selected herbicidal products containing nicosulfuron as an active ingredient
  132. Lycopene in tomatoes and tomato products
  133. Fluorescence in the assessment of the share of a key component in the mixing of feed
  134. Sulfur application alleviates chromium stress in maize and wheat
  135. Effectiveness of removal of sulphur compounds from the air after 3 years of biofiltration with a mixture of compost soil, peat, coconut fibre and oak bark
  136. Special Issue on the 4th Green Chemistry 2018
  137. Study and fire test of banana fibre reinforced composites with flame retardance properties
  138. Special Issue on the International conference CosCI 2018
  139. Disintegration, In vitro Dissolution, and Drug Release Kinetics Profiles of k-Carrageenan-based Nutraceutical Hard-shell Capsules Containing Salicylamide
  140. Synthesis of amorphous aluminosilicate from impure Indonesian kaolin
  141. Special Issue on the International Conf on Science, Applied Science, Teaching and Education 2019
  142. Functionalization of Congo red dye as a light harvester on solar cell
  143. The effect of nitrite food preservatives added to se’i meat on the expression of wild-type p53 protein
  144. Biocompatibility and osteoconductivity of scaffold porous composite collagen–hydroxyapatite based coral for bone regeneration
  145. Special Issue on the Joint Science Congress of Materials and Polymers (ISCMP 2019)
  146. Effect of natural boron mineral use on the essential oil ratio and components of Musk Sage (Salvia sclarea L.)
  147. A theoretical and experimental study of the adsorptive removal of hexavalent chromium ions using graphene oxide as an adsorbent
  148. A study on the bacterial adhesion of Streptococcus mutans in various dental ceramics: In vitro study
  149. Corrosion study of copper in aqueous sulfuric acid solution in the presence of (2E,5E)-2,5-dibenzylidenecyclopentanone and (2E,5E)-bis[(4-dimethylamino)benzylidene]cyclopentanone: Experimental and theoretical study
  150. Special Issue on Chemistry Today for Tomorrow 2019
  151. Diabetes mellitus type 2: Exploratory data analysis based on clinical reading
  152. Multivariate analysis for the classification of copper–lead and copper–zinc glasses
  153. Special Issue on Advances in Chemistry and Polymers
  154. The spatial and temporal distribution of cationic and anionic radicals in early embryo implantation
  155. Special Issue on 3rd IC3PE 2020
  156. Magnetic iron oxide/clay nanocomposites for adsorption and catalytic oxidation in water treatment applications
  157. Special Issue on IC3PE 2018/2019 Conference
  158. Exergy analysis of conventional and hydrothermal liquefaction–esterification processes of microalgae for biodiesel production
  159. Advancing biodiesel production from microalgae Spirulina sp. by a simultaneous extraction–transesterification process using palm oil as a co-solvent of methanol
  160. Topical Issue on Applications of Mathematics in Chemistry
  161. Omega and the related counting polynomials of some chemical structures
  162. M-polynomial and topological indices of zigzag edge coronoid fused by starphene
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