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The electrochemical preparation of nanostructured polymeric network consisted of poly(o-phenylenediamine)-multi-walled carbon nanotube (PoPD-MWCNT) on a disposable and commonly used pencil graphite electrode (PGE) was demonstrated. The obtained PoPD-MWCNT/PGE electrode was prepared via one-step electropolymerization using cyclic voltammetry (CV) and characterized by CV and electrochemical impedance spectroscopy (EIS). Surfaces topographies of the electrodes were investigated with scanning electron microscopy (SEM) in order to differentiate electrode modifications. The modified electrode highly improved the electrochemical properties of the PoPD/PGE and PGE. The fabrication process of the modified electrode was reproducible with a relative standard deviation of 3.8% (n = 3). Afterwards, sensitive detection of mitomycin C was performed based on the interaction of double-stranded DNA (dsDNA) immobilized on PoPD-MWCNT/PGE with mitomycin C. Thus, a detailed investigation of the interaction of dsDNA immobilized PoPD-MWCNT/PGEs with mitomycin C were also evaluated at various interaction intervals from 0 to 30 min in an efficient process. This promising electrode provided a linear concentration range for mitomycin C from 0.5 mg L−1 to 25 mg L−1 with a low limit of detection, 0.012 mg L−1, and a limit of quantification, 0.039 mg L−1, based on the guanine oxidation peaks using differential pulse voltammetry (DPV) (n = 3). The recoveries were also determined in spiked serum and satisfactory results emphasized the use of the electrode for clinical applications. [ABSTRACT FROM AUTHOR]

Conducting polymer coatings have offered functionalized surfaces having good electrical, mechanical, and physical properties. In this work, electrochemical preparation and characterization of polypyrrole/polypyrrole‐3‐carboxylic acid (PPy/PPa) copolymer onto single‐use pencil graphite electrodes (PGEs) were described and detailed. Then, the application of these electrodes was demonstrated for the detection a commonly used analgesic, acetaminophen (AC) (paracetamol). Copolymer was deposited onto PGEs using cyclic voltammetry (CV) between +0.0 V and +1.0 V versus Ag/AgCl. Experimental conditions such as the effect of monomer ratios (3:1–6:1) and cyclic scans (1 cycle to 10 cycles) on electropolymerization were examined. Coated surfaces were characterized with CV and scanning electron microscopy. Electrochemical response of the electrode in AC at various pH values was evaluated. Then, AC detection was performed based on the oxidation signal of the drug at about +0.55 V versus Ag/AgCl using differential pulse voltammetry in buffer and body fluid (serum). [ABSTRACT FROM AUTHOR]

Abstract: Poly‐L‐lysine is one of the biocompatible polymers having amino and carboxyl groups in its structure. This attractive feature of poly‐L‐lysine makes it very convenient for bioactive molecule attachment. This study details the preparation of poly‐L‐lysine‐based pencil graphite electrodes (PLL/PGEs) and use of the coated electrodes for direct ultrasensitive DNA hybridization detection. In the first part of this study, poly‐L‐lysine coated electrodes were prepared using L‐lysine as the monomer by cyclic voltammetry (CV) with different cyclic scans. The effect of these cyclic scans during the electropolymerization was investigated. Coated electrodes were characterized by cyclic voltammetry, electrochemical impedance spectroscopy (EIS) and scanning electron microscopy (SEM). Then, one‐pot preparation of poly‐L‐lysine composites with graphene (GN) and multi‐walled carbon nanotubes (MWCNTs) onto the pencil graphite electrodes were achieved. Electrochemical responses of these 3 electrodes were compared. After all, electrochemical DNA hybridization was performed using the poly‐L‐lysine‐based electrodes prepared at optimum polymerization condition. The PLL/PGE coated electrode presented a good linear response in the target concentration range of 1.0×10−13 to 1.0×10−6 with a detection limit of 2.25×10−14 using differential pulse voltammetry as the detection method. We believe that poly‐L‐lysine‐based surfaces will be useful for further clinical applications. [ABSTRACT FROM AUTHOR]

In this work, electropolymerization of 5-phenyl dipyrromethane (DPM) and electrochemical behavior of the obtained polymer were performed. The monomer was electropolymerized in a solution of DPM and 0.1 M tetra- n-butyl ammonium perchlorate/dichloromethane supporting electrolyte/solvent solution system on a Pt electrode by cyclic voltammetry technique. The polymeric film was then characterized by scanning electron microscopy, atomic force microscopy, fourier transform infrared-attenuated total reflectance, nuclear magnetic resonance spectroscopy, differential scanning calorimetry and alternative current impedance techniques. [ABSTRACT FROM AUTHOR]

Highlights: [•] Fast, controllable and simple preparation of the modified surfaces was performed. [•] CB modified PGEs was used for the first time in the literature for dye–protein interaction. [•] Alternative route was shown compared to classical time-consuming methods. [•] Good selectivity and sensitivity were obtained for CB–BSA interaction. [Copyright &y& Elsevier]

Herein, we report a simple and inexpensive way for the fabrication of an ultramicroelectrode and present its characterization by electrochemical techniques. The fabrication of polyaniline UME involves only two steps: modification of a gold (Au) electrode by self assembled monolayers (SAM) and then electrodeposition of polyaniline film on this thiol-coated Au electrode by using cyclic voltammetry and constant potential electrolysis methods. Two types of self-assembled monolayers (4-mercapto-1-butanol, MB, and 11-mercaptoundecanoic acid, MUA) were used, respectively, to see the effect of chain length on microelectrode formation. Microelectrode fabrication and utility of the surface was investigated by cyclic voltammetric measurements in a redox probe. The thus prepared polyaniline microelectrode was then used for DNA immobilization. Discrimination between double-stranded DNA (dsDNA) and single-stranded DNA (ssDNA) was obtained with enhanced electrochemical signals compared to a polyaniline-coated Au electrode. Different modifications on the electrode surfaces were examined using scanning electron microscopy (SEM). [ABSTRACT FROM AUTHOR]

Abstract: Electrochemical characterization of redox polymer for monitoring of adenine was described in this study using poly(vinylferrocenium) (PVF+) modified platinum (Pt) electrode. Scanning electron microscope (SEM) was used for the surface characterization. The electrochemical behaviors of polymer modified and adenine immobilized polymer modified electrodes were investigated by using cyclic voltammetry (CV) and differential pulse voltammetry (DPV). In order to obtain more sensitive and improved electrochemical signals, analytical parameters such as the effects of polymeric film thickness, immobilization time of adenine, pH and adenine concentration were examined on the response of the polymer modified electrode. Alternating current (AC) impedance spectroscopy was used for the characterization of polymer modified and adenine immobilized polymer modified electrodes. The effect of possible interferents on the response of the electrode was examined. [Copyright &y& Elsevier]

Abstract: A novel N-phenylboronic acid substituted polypyrrole based sensor for saccharide detection was investigated. As the first time, 3-(1H-pyrrol-1-yl)phenylboronic acid was synthesized and used for the preparation of sensing surface on platinum (Pt) electrode by using electrochemical cyclic voltammetry technique (CV). Characterization of the monomer and the polymer were performed using NMR, FTIR, TOF-MS, SEM and AFM. The applicability of this sensor was examined for potentiometric detection of saccharides (d-glucose, d-fructose, d-galactose, d-lactose and d-sucrose). The binding interaction between polypyrrole–phenylboronic acid and saccharides was followed in the order of d-fructose> d-glucose> d-galactose> d-lactose> d-sucrose. The effect of pH on the binding interaction of d-glucose and d-fructose to phenylboronic acid was investigated. The best interaction was obtained at pH 12.0. Reusability of the sensor was tested and it was observed that there was no response change up to 10 usages. These results indicate that polypyrrole based type sensors can be developed for designing new reusable biosensors. [Copyright &y& Elsevier]