High-performance strategy for the construction of electrochemical biosensor for simultaneous detection of miRNA-141 and miRNA-21 as lung cancer biomarkers.

In this study, the dual signal-labeled hairpin-structured DNA (dhDNA)-based probes have been developed to construct a novel nano-biosensor. This one hairpin-structured probe consists of a thiolated methylene blue-labeled hairpin capture probe (MB-HCP) as an inner reference probe and a ferrocene-modified anti-miRNA-21 DNA probe (Fc-AP-21). This novel integrated structure of MB-HCP and Fc-AP-21 was designed on one sensing interface for sensitive and simultaneous detection of the miRNA-141 and miRNA-21 in one single assay. The proposed strategy has a good ability to reduce the interference of environmental factors and it was designed to control the initial responses of Fc-AP to MB-HCP ((IFc/IMB)0) at a 1:1 ratio, which is desirable for further increase in the sensitivity and signal-to-noise ratio of the biosensor operation. Besides, the biosensor was first prepared by immobilizing the dhDNA (Fc-AP-21/MB-HCP) onto the modified glassy carbon electrode. After hybridization with the anti-miRNA-141 complementary sequence (ACP-141), the dhDNA structure was compelled to open and form the final structure of the biosensor. Also, the miRNA-141 and miRNA-21 dissociate duplex structures due to the highly matched sequences between the miRNA-141 and ACP-141 and the miRNA-21 and Fc-AP-21. A linear relationship was found between the logarithm of miRNA-141 and miRNA-21 concentrations and the signal changes. This feature was used to detect the two miRNAs. This sensitive biosensor provided low detection limits of 0.89 and 1.24 fM for the miRNA-141 and miRNA-21, respectively. Also, it has wide linear ranges of 2.0 to 105 fM, with highly selective and accurate results for its application in plasma samples. Therefore, this strategy can be promising as a suitable platform for simultaneous and early detection of various cancer biomarkers.

Synthesis and application of a carbon composite containing molecularly imprinted poly(methacrylic acid) for efficient removal of fenpyroximate pesticide.

This work describes fabrication steps of the carbon composite based on molecular imprinted poly(methacrylic acid) (MIP-CC) as a new adsorbent for the selective removal of fenpiroxymate pesticide (Fen). The prepared composite was characterized using Brunauer-Emmett-Teller (BET), zeta sizer and Field Emission Scanning Electron Microscopy (FESEM) techniques. The influence of operational parameters such as solution pH, contact time, amount MIP for preparation of carbon composite and amount MIP- CC toward removal of Fen have been evaluated and optimized via central composite design (CCD) as an optimization tool of response surface method. The optimum removal (87%) was achieved at pH 6.5, 1.53 g/L carbon composite prepared with 3.4 wt % MIP at 70 min. The maximum adsorption of Fen by the fabricated MIP-CC was 254 mg/g. Compared with the corresponding non-imprinted polymer (NIP-CC), the MIP-CC exhibited higher adsorption capacity and outstanding selectivity toward Fen. Langmuir isotherm best fitted the adsorption equilibrium data of MIP-CC and the kinetics followed a pseudo-second-order model. The calculated thermodynamic parameters showed that adsorption of Fen pesticide was spontaneous and exothermic under the studied conditions.

A ratiometric electrochemical DNA-biosensor for detection of miR-141.

A sensitive biosensor for the detection of miR-141 has been constructed. The DNA-biosensor is prepared by first immobilizing the thiolated methylene blue-labeled hairpin capture probe (MB-HCP) on two-layer nanocomposite film graphene oxide-chitosan@ polyvinylpyrrolidone-gold nanourchin modified glassy carbon electrode. We used the hematoxylin as an electrochemical auxiliary indicator in the second stage to recognize DNA hybridization via the square wave voltammetry (SWV) responses that record the accumulated hematoxylin on electrode surfaces. The morphology and chemical composition of nanocomposite was characterized using TEM, FE-SEM, and FT-IR techniques. The preparation stages of the DNA-biosensor were screened by electrochemical impedance spectroscopy and cyclic voltammetry. The proposed DNA-biosensor can distinguish miR-141 from a non-complementary and mismatch sequence. A detection limit of 0.94 fM and a linear range of 2.0 -5.0 × 105 fM were obtained using SWV for miR-141 detection. The working potential for methylene blue and hematoxylin was -0.28 and + 0.15 V vs. Ag/AgCl, respectively. The developed biosensor can be successfully used in the early detection of non-small cell lung cancer (NSCLC) by directly measuring miR-141 in human plasma samples. This novel DNA-biosensor is of promise in early sensitive clinical diagnosis of cancers with miR-141 as its biomarker.

Nanocomposite of electrochemically reduced graphene oxide and gold nanourchins for electrochemical DNA detection.

A nanocomposite of graphene oxide and gold nanourchins has been used here to modify the surface of a screen-printed carbon electrode to enhance the sensitivity of the electrochemical DNA detection system. A specific single-stranded DNA probe was designed based on the target DNA sequence and was thiolated to be self-assembled on the surface of the gold nanourchins placed on the modified electrode. Doxorubicin was used as an electrochemical label to detect the DNA hybridisation using differential pulse voltammetry (DPV). The assembling process was confirmed using scanning electron microscopy (SEM) imaging, cyclic voltammetry (CV), and the EIS method. The high sensitivity of the proposed system led to a low detection limit of 0.16 fM and a wide linear range from 0.5 to 950.0 fM. The specificity of the DNA hybridisation and the signalling molecule (haematoxylin) caused very high selectivity towards the target DNA than other non-specific sequences.

Platelet-rich fibrin-loaded PCL/chitosan core-shell fibers scaffold for enhanced osteogenic differentiation of mesenchymal stem cells.

Here, we fabricated the platelet-rich fibrin (PRF)-loaded PCL/chitosan (PCL/CS-PRF) core-shell nanofibrous scaffold through a coaxial electrospinning method. Our goal was to evaluate the effect of CS-RPF in the core layer of the nanofibrous on the osteogenic differentiation of human mesenchymal stem cells (HMSCs). The elastic modulus of PCL/CS-PRF core-shell scaffold (44 MPa) was about 1.5-fold of PCL/CS scaffold (25 MPa). The specific surface area of the scaffolds increased from 9.98 m2/g for PCL/CS scaffold to 16.66 m2/g for the PCL/CS-PRF core-shell nanofibrous scaffold. Moreover, the release rate of PRF from PCL/CS-PRF nanofibrous scaffold was measured to be 24.50% after 10 days which showed slow and sustained release of PRF from the nanofibrous. The formation of Ca-P on the surface of scaffold immersed in simulated body fluid solution indicated the suitable osteoconductivity of PCL/CS-PRF core-shell nanofibrous scaffold. Also, the value of ALP activity and calcium deposited on the surface of PCL/CS-PRF core-shell nanofibrous scaffold were 81.97 U/L and 40.33 µg/scaffold, respectively after 14 days, which confirmed the significantly higher amounts of ALP and calcium deposition on the scaffold containing PRF compared to PCL/CS scaffold. Due to higher hydrophilicity and porosity of PCL/CS-PRF core-shell nanofibrous scaffold compared to PCL/CS scaffold, a better bone cell growth on surface of PCL/CS-PRF scaffold was observed. The Alizarin red-positive area was significantly higher on PCL/CS-PRF scaffold compared to PCL/CS scaffold, indicating more calcium deposition and osteogenic differentiation of HMSCs in the presence of PRF. Our findings demonstrate that PCL/CS-PRF core-shell scaffolds can provide a strong construct with improved osteogenic for bone tissue engineering applications.

Fabrication of an electrochemical sensor with Au nanorods-graphene oxide hybrid nanocomposites for in situ measurement of cloxacillin.

In recent years, considering the increasing use of antibiotics, and their continued entry into the environment, extensive research has been conducted on the impact of antibiotics on human health, water resources, and the environment. In this study, a suitable method has been proposed for detecting and elimination the trace amounts of the antibiotic cloxacillin in aqueous. For identify trace amounts of cloxacillin in solution, a new electrochemical nanosensor based on a screen printed carbon electrode (SPCE) modified with gold nanorods/graphene oxide was proposed. This nanosensor, which was prepared by self-assembling method, was capable of measuring cloxacillin in the 5.0-775.0 nM with a detection limit of 1.6 nM. In order to reduce the amount of antibiotics in the environment, a novel carbon nanocomposite based on sol-gel method was prepared and its application as a high-capacity adsorbent for the removal of cloxacillin was studied. In the antibiotic removal experiments, the effect of pH, contact time, different mass ratios of SWCNT and amount of nanocomposite adsorbent were also optimized by response surface methodology (RSM). The prepared nanosensor and synthesized carbon nanocomposites were then characterized by commonly identical techniques involve SEM, EDAX, BET and FT-IR. The presented nanosensor was successfully used for the in situ determination of Clox in adsorptive tests with reliable recovery. As well, the AuNR/GO/SPC electrode presented well stability, repeatability and reproducibility. In addition, good performance and high adsorption capacity make developed adsorbent as a suitable case for the removal of water-soluble pharmaceutical contaminants.

Voltammetric sensing of oxacillin by using a screen-printed electrode modified with molecularly imprinted polyaniline, gold nanourchins and graphene oxide.

An imprinted electrochemical sensor was developed for the determination of the antibiotic oxacillin (OXC). A screen-printed carbon electrode (SPCE) was modified with gold nanourchin and graphene oxide, and then aniline was electro-polymerized in the presence of OXC to obtain a molecular imprint on the SPCE. The morphologies in sequential modification processes and the electrochemical behavior of the modified SCPE were characterized by field emission scanning electron microscopy and cyclic voltammetry. The performance of the sensor was evaluated by differential pulse voltammetry. At a typical peak potential of 0.82 mV (vs. Ag/AgCl), response is linear in the 0.7-575 nM OXC concentration range. The electrochemical sensitivity is 97.6 nA nM -1 cm -2, and the detection limit is 0.2 nM. The relative of replicate assays is 2.6% (for n = 6) at an OXC concentration level of 200 nM. The sensor is sensitive and selective. It was successfully applied for the detection of OXC in spiked cow's milk. Schematic presentation of electropolymerization of aniline on sreen-printed carbon electrode (SPCE) modified with graphene oxide (GO) and gold nanouchins (GNU) for voltammetric sensing of oxacillin.

Determination of cefixime using a novel electrochemical sensor produced with gold nanowires/graphene oxide/electropolymerized molecular imprinted polymer.

Quantitative analysis of antibiotics is very important because these drugs are widely used to prevent or treat various diseases. Cefixime (CEF, a semi-synthetic antibiotic and the third generation of cephalosporin) is a bactericidal medicine that prevents formation of cell walls in bacteria as well as their growth and proliferation. It, thus, causes the death of bacteria. Antibiotics such as CEF are generally determined by chromatography and spectroscopy techniques. Electrochemical sensors are one of the fast, convenient and low-cost tools for measuring this type of compounds. In this research, an electrochemical sensor was constructed by modifying a glassy carbon electrode (GCE) with expanded graphene oxide and gold nanowires, and then its surface was electropolymerized with a molecular imprinted polymeric layer of polyaniline. The morphological characterization of the obtained film was carried out by scanning and transmission electron microscopy (SEM and TEM). The proposed sensor was analytically characterized on the purpose of comparing it to other modified GCEs. The sensor could work linearly for the concentration range of 20.0-950.0 nM and with a limit of detection of 7.1 nM. It was successfully applied to determine CEF traces in biological samples (i.e. serum and urine) with excellent recovery percentages.

An electrochemical aptasensor for staphylococcal enterotoxin B detection based on reduced graphene oxide and gold nano-urchins.

Detection of staphylococcal enterotoxin B (SEB) as a bacterial toxin causing severe food poisoning is of great importance. Herein, we developed an electrochemical aptasensor for SEB detection using a screen printed electrode modified with reduced graphene oxide (rGO) and gold nano-urchins (AuNUs). Afterward, the single-stranded DNA probe was attached to the surface of AuNUs on the modified electrode and then the specific aptamer was attached to the probe. In the presence of SEB molecules, the aptamer detached from the electrode surface and after applying the electrochemical signal generator, hematoxylin and the peak current of differential pulse voltammetry (DPV) were recorded. Due to the intercalation mechanism of hematoxylin-DNA interaction, the detachment of aptamer from electrode surface decreased the DPV peak current and the calibration graph (peak current vs SEB concentration) can be used for quantification of SEB. The cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) and also field emission scanning electron microscope imaging were used for electrode characterization. Selectivity experiments of the developed aptasensor showed a very distinct difference between SEB and other nonspecific molecules. A wide linear range from 5.0 to 500.0 fM was achieved and the detection limit was calculated as 0.21 fM. The performance of the aptasensor was checked in spiked food samples as simulated real samples and the results showed no significant difference compared to the synthetic samples. Results of selectivity and repeatability of the aptasensor were satisfactory. In addition, better recovery percentages and also lower standard deviation of aptasensor compared to a commercial ELISA kit of SEB detection proved the superior performance of the proposed aptasensor.

Nano-biosensor based on reduced graphene oxide and gold nanoparticles, for detection of phenylketonuria-associated DNA mutation.

Phenylketonuria (PKU)-associated DNA mutation in newborn children can be harmful to his health and early detection is the best way to inhibit consequences. A novel electrochemical nano-biosensor was developed for PKU detection, based on signal amplification using nanomaterials, e.g. gold nanoparticles (AuNPs) decorated on the reduced graphene oxide sheet on the screen-printed carbon electrode. The fabrication steps were checked by field emission scanning electron microscope imaging as well as cyclic voltammetry analysis. The specific alkanethiol single-stranded DNA probes were attached by self-assembly methodology on the AuNPs surface and Oracet blue was used as an intercalating electrochemical label. The results showed the detection limit of 21.3 fM and the dynamic range of 80-1200 fM. Moreover, the selectivity results represented a great specificity of the nano-biosensor for its specific target DNA oligo versus other non-specific sequences. The real sample simulation was performed successfully with almost no difference than a synthetic buffer solution environment.

A highly sensitive miR-195 nanobiosensor for early detection of Parkinson's disease.

Early detection of Parkinson's disease (PD), as a dangerous neurodegenerative disease, is a key factor in the therapy or prevention of further development of this disease. We developed an electrochemical nanobiosensor for early detection of PD based on the quantification of circulating biomarker, miR-195. Exfoliated graphene oxide (EGO) and gold nanowires (GNWs) were used to modify the surface of screen-printed carbon electrode. A single-strand thiolated probe was designed for specific hybridization with target miRNA (miR-195), and doxorubicin was used as an electrochemical indicator for differential pulse voltammetry measurements. The results of scanning electron microscope imaging and cyclic voltammetry experiments confirmed the accuracy of the working electrode modification steps. The results of analytical performance nanobiosensor showed a high sensitivity of the biosensing with 2.9 femtomolar detection limit and dynamic range of 10.0-900.0 femtomolar. In addition, good selectivity for target miRNA over non-specific oligonucleotides (one and three base replacement in target miRNA, and non-complementary) was achieved. The results of real human serum analysis did not show any interference in the function of the biosensor. Based on the results, the miR-195 electrochemical nanobiosensor could be suggested for clinicians in the medical diagnosis of PD.

A nanobiosensor composed of Exfoliated Graphene Oxide and Gold Nano-Urchins, for detection of GMO products.

Genetically Modified Organisms, have been entered our food chain and detection of these organisms in market products are still the main challenge for scientists. Among several developed detection/quantification methods for detection of these organisms, the electrochemical nanobiosensors are the most attended which are combining the advantages of using nanomaterials, electrochemical methods and biosensors. In this research, a novel and sensitive electrochemical nanobiosensor for detection/quantification of these organisms have been developed using nanomaterials; Exfoliated Graphene Oxide and Gold Nano-Urchins for modification of the screen-printed carbon electrode, and also applying a specific DNA probe as well as hematoxylin for electrochemical indicator. Application time period and concentration of the components have been optimized and also several reliable methods have been used to assess the correct assembling of the nanobiosensor e.g. field emission scanning electron microscope, cyclic voltammetry and electrochemical impedance spectroscopy. The results shown the linear range of the sensor was 40.0-1100.0 femtomolar and the limit of detection calculated as 13.0 femtomolar. Besides, the biosensor had good selectivity towards the target DNA over the non-specific sequences and also it was cost and time-effective and possess ability to be used in real sample environment of extracted DNA of Genetically Modified Organism products. Therefore, the superiority of the aforementioned specification to the other previously published methods was proved adequate.

An electrochemical DNA biosensor based on Oracet Blue as a label for detection of Helicobacter pylori.

An innovative method of a DNA electrochemical biosensor based on Oracet Blue (OB) as an electroactive label and gold electrode (AuE) for detection of Helicobacter pylori, was offered. A single-stranded DNA probe with a thiol modification was covalently immobilized on the surface of the AuE by forming an Au-S bond. Differential pulse voltammetry (DPV) was used to monitor DNA hybridization by measuring the electrochemical signals of reduction of the OB binding to double-stranded DNA (ds-DNA). Our results showed that OB-based DNA biosensor has a decent potential for detection of single-base mismatch in target DNA. Selectivity of the proposed DNA biosensor was further confirmed in the presence of non-complementary and complementary DNA strands. Under optimum conditions, the electrochemical signal had a linear relationship with the concentration of the target DNA ranging from 0.3nmolL(-1) to 240.0nmolL(-1), and the detection limit was 0.17nmolL(-1), whit a promising reproducibility and repeatability.

A sensitive DNA biosensor fabricated from gold nanoparticles and graphene oxide on a glassy carbon electrode.

A sensitive electrochemical DNA biosensor was developed for Helicobacter pylori (H. pylori) detection using differential pulse voltammetry. Single-stranded DNA probe was immobilized on a graphene oxide/gold nanoparticles modified glassy carbon electrode (GO/AuNPs/GCE). A hybridization reaction was conducted with the target DNA and the immobilized DNA on the electrode surface. Oracet blue (OB) was selected for the first time as a redox indicator for amplifying the electrochemical signal of DNA. Enhanced sensitivity was achieved through combining the excellent electric conductivity of GO/AuNPs and the electroactivity of the OB. The DNA biosensor displayed excellent performance to demonstrate the differences between the voltammetric signals of the OB obtained from different hybridization samples (non-complementary, mismatch and complementary DNAs). The proposed biosensor has a linear range of 60.0-600.0 pM and a detection limit of 27.0 pM for detection of H. pylori. In addition, the biosensor have responded very well in the simulated real sample evaluations, signifying its potential to be used in future clinical detection of the H. pylori bacteria.

An electrochemical nanobiosensor for plasma miRNA-155, based on graphene oxide and gold nanorod, for early detection of breast cancer.

Circulating miRNAs are emerging as novel reliable biomarkers for early detection of cancer diseases. Through combining the advantages of electrochemical methods and nanomaterials with the selectivity of the oligo-hybridization-based biosensors, a novel electrochemical nanobiosensor for plasma miR-155 detection have demonstrated here, based on thiolated probe-functionalized gold nanorods (GNRs) decorated on the graphene oxide (GO) sheet on the surface of the glassy carbon electrode (GCE). The reduction signals of a novel intercalating label Oracet Blue (OB), were measured by differential pulse voltammetry (DPV) method. The transmission electron microscope (TEM) imaging, UV-vis spectrophotometry, cyclic voltammetry (CV), field emission scanning electron microscope (FE-SEM) imaging and energy dispersive spectroscopy (EDS) were proved the right synthesis of the GNRs and correct assembly of the modified electrode. The electrochemical signal had a linear relationship with the concentration of the target miRNA ranging from 2.0 fM to 8.0 pM, and the detection limit was 0.6 fM. Furthermore, the nanobiosensor showed high Specificity, and was able to discriminate sharply between complementary target miRNA, single-, three-base mismatch, and non-complementary miRNA. Alongside the outstanding sensitivity and selectivity, this nanobiosensor had great storage ability, reproducibility, and showed a decent response in the real sample analysis with plasma. In conclusion, the proposed electrochemical nanobiosensor could clinically be used in the early detection of the breast cancer, by direct detection of the plasma miR-155 in real clinical samples, without a need for sample preparation, RNA extraction and/or amplification.

Fabrication of a novel electrochemical sensor for determination of hydrogen peroxide in different fruit juice samples.

A new hydrogen peroxide (H2O2) sensor is fabricated based on a multiwalled carbon nanotube-modified glassy carbon electrode (MWCNT-GCE) and reactive blue 19 (RB). The charge transfer coefficient, α, and the charge transfer rate constant, ks, of RB adsorbed on MWCNT-GCE were calculated and found to be 0.44 ± 0.01 Hz and 1.9 ± 0.05 Hz, respectively. The catalysis of the electroreduction of H2O2 by RB-MWCNT-GCE is described. The RB-MWCNT-GCE shows a dramatic increase in the peak current and a decrease in the overvoltage of H2O2 electroreduction in comparison with that seen at an RB modified GCE, MWCNT modified GCE, and activated GCE. The kinetic parameters such as α and the heterogeneous rate constant, k', for the reduction of H2O2 at RB-MWCNT-GCE surface were determined using cyclic voltammetry. The detection limit of 0.27µM and three linear calibration ranges were obtained for H2O2 determination at the RB-MWCNT-GCE surface using an amperometry method. In addition, using the newly developed sensor, H2O2 was determined in real samples with satisfactory results.

Delphinidin immobilized on silver nanoparticles for the simultaneous determination of ascorbic acid, noradrenalin, uric acid, and tryptophan.

In the present study, the fabrication of a new modified electrode for electrocatalytic oxidation of noradrenalin, based on the delphinidin immobilized on silver nanoparticles modified glassy carbon electrode. Cyclic voltammetry was used to investigate the redox properties of this modified electrode. The surface charge transfer rate constant (ks) and the charge transfer coefficient (α) for the electron transfer between the glassy carbon electrode and the immobilized delphinidin were calculated. The differential pulse voltammetry exhibited two linear dynamic ranges and a detection limit of 0.40µM for noradrenalin determination. Moreover, the present electrode could separate the oxidation peak potentials of ascorbic acid, noradrenalin, uric acid, and tryptophan in a mixture. The usefulness of this nanosensor was also investigated for the determination of ascorbic acid, noradrenalin, and uric acid in pharmaceutical and biological fluid samples with satisfactory results.

The comparison of sonochemistry, electrochemistry and sonoelectrochemistry techniques on decolorization of C.I Reactive Blue 49.

In this paper, the ability of three decolorization techniques including sonochemistry, electrochemistry and sonoelectrochemistry for decolorization of C.I Reactive Blue 49 in aqueous solutions have been compared. Various parameters affecting decolorization efficiency, such as pH, initial concentration of the dye, the decolorization time, H2O2 concentration and effect of applied potential on electrochemistry and sonoelectrochemistry, were evaluated. For further comparison, the methods were evaluated based on their ability in COD removal percentage. The maximum COD removal at the optimum condition of each method were 36.0%, 68.0%, 87.8% and 76.2% for sonochemistry, electrochemistry, sonoelectrochemistry with H2O2 and sonoelectrochemistry without H2O2, respectively. The result was an environment friendly method for removal of C.I Reactive Blue 49 from aqueous solutions.

Electrocatalytic determination of dopamine in the presence of uric acid using an indenedione derivative and multiwall carbon nanotubes spiked in carbon paste electrode.

In the present study, a modified carbon paste electrode (CPE) containing multi-wall carbon nanotubes and an indenedione derivative(IMWCNT-CPE) was constructed and was successfully used for dopamine(DA) electrocatalytic oxidation and simultaneous determination of DA and uric acid (UA). Cyclic voltammograms of the IMWCNT-CPE show a pair of well-defined and reversible redox. The obtained results indicate that the peak potential of DA oxidation at IMWCNT-CPE shifted by about 65 and 185 mV toward the negative values compared with that at a MWCNT and indenedione modified CPE, respectively. The electron transfer coefficient, α, and the heterogeneous electron transfer rate constant, k', for the oxidation of DA at IMWCNT-CPE were calculated 0.4±0.01 and (1.13±0.03)×10(-3) cm s(-1), respectively. Furthermore, differential pulse voltammetry (DPV) exhibits two linear dynamic ranges of 1.9-79.4 µM, and 79.4-714.3 µM and a detection limit of 0.52 µM for DA determination. Then IMWCNT-CPE was applied to the simultaneous determination of DA and UA with DPV. Finally, the activity of the modified electrode was also investigated for determination of DA and UA in real samples, such as injection solution of DA and urine, with satisfactory results.

Electrosynthesis of an imidazole derivative and its application as a bifunctional electrocatalyst for simultaneous determination of ascorbic acid, adrenaline, acetaminophen, and tryptophan at a multi-wall carbon nanotubes modified electrode surface.

In this research, the electrosynthesis of 4-(1H-benzo[d]imidazol-2-ylthio)-5-methylbenze-1,2-diol (as an imidazole derivative) is reported. An imidazole derivative multi-wall carbon nanotube modified glassy carbon electrode (IMWCNT-GCE) was constructed and used as an excellent bifunctional electrocatalyst for oxidation of ascorbic acid (AA) and adrenaline (AD). Cyclic voltammetry was used to calculate the surface electron transfer rate constant, k(s), and the electron transfer coefficient, α, for the electron transfer between MWCNT-GCE and the electrodeposited imidazole derivative. The kinetic parameters such as the electron transfer coefficient, α, and the heterogeneous rate constant, k', for the oxidation of AA and AD at the IMWCNT-GCE surface were estimated. The modified electrode was found quite effective for the simultaneous determination of AA, AD, acetaminophen (AC), and tryptophan (Trp) in a mixture solution. The detection limits of AA and AD were calculated as 0.96 µM and 0.38 µM, respectively. Finally, IMWCNT-GCE was satisfactorily used for the determination of AA, AD, and AC in pharmaceutical samples.