Search

This work details the preparation of gold nanoparticles/single-walled carbon nanotubes/polyaniline composite-modified disposable pencil graphite electrode (AuNPs/SWCNTs/PANI/PGEs), and its application for electrochemical DNA sensing. Disposable pencil graphite electrode was modified with single-walled carbon nanotubes/polyaniline composite via one-step electropolymerization of aniline solution containing well-dispersed single-walled carbon nanotubes. AuNPs were then immobilized onto the SWCNTs/PANI/PGE. Electrochemical results exhibited improved sensitivity for DNA detection with AuNPs/SWCNTs/PANI/PGE compared to the SWCNTs/PANI/PGE, PANI/PGE or unmodified PGE due to the strong interaction between AuNPs, SWCNTs, and PANI based on the effective degree of electron delocalization. Cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) were used to characterize the prepared electrode. Thiol-linked ssDNA was immobilized onto the AuNPs/SWCNTs/PANI/PGE for DNA detection. Experimental parameters such as the concentration of AuNPs and ssDNA were investigated to optimize the experimental conditions. [ABSTRACT FROM AUTHOR]

A poly(vinylferrocene) (PVFc)/cellulose acetate (CA) fibers were obtained using an electrospinning method. The electrospinning process was controlled in situ with a quartz crystal microbalance (QCM) system. Fiber formation was observed through adjusting PVFc concentration. Morphological characteristics depending on the changes of atomic % ratio value of PVFc/CA electrospun fibers was investigated by scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy analysis. Electrochemical behavior of PVFc/CA electrospun fibers was investigated by using cyclic voltammetry measurements based on the Fc/Fc redox couple. The results indicated that PVFc deployed in/on the CA fibers and aggregated arbitrarily on the QCM electrode. The new PVFc/CA electrospun fibers were used for anion sensing. [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]

Poly(vinylferrocenium) (PVF) modified gold (Au) electrode was developed in this study for the electrochemical sensing of deoxyribonucleic acid (DNA) hybridization based on the oxidation signals of polymer and guanine, and also for the electrochemical investigation of interaction of anticancer drug, mitomycin C (MC) and DNA immobilized onto PVF modified Au electrode. PVF modified Au electrode was prepared by electrooxidation of poly(vinylferrocene) PVF at +0.7 V versus Ag/AgCl reference electrode. The polymer modified electrode and DNA immobilized polymer modified electrode were characterized by X-ray photoelectron (XPS), Fourier transform infrared-attenuated total reflentance (FTIR-ATR) and alternating current (AC) impedance spectroscopy. For application studies, differential pulse voltammetry (DPV) technique was used. [ABSTRACT FROM AUTHOR]

The aim of our study was to determine the effect of recombinant human erythropoietin (rhEPO) on cyclosporine (CsA) nephrotoxicity. Twenty-six female Wistar rats were injected with 15 mg/kg subcutaneous CsA and intraperitoneal saline/rhEPO for 28 days. Four groups were formed: Group 1 ( n = 5), a control group; Group 2 ( n = 7), CsA + saline; Group 3 ( n = 7), CsA + low dose (20 U/kg per day) rhEPO; Group 4 ( n = 7), CsA + high dose (100 U/kg per day) rhEPO. Body weights, creatinine clearance, urinary protein/creatinine, hematocrit, serum creatinine levels, histopathological parameters, apoptosis and lipid peroxidation tests were compared between the three groups. Body weights and renal functions were similar in Groups 2, 3 and 4 rats but significantly lower than the values found for the control group at the end of the study. The hematocrit was significantly different between the four groups, showing a positive association with the strength of the injected rhEPO doses. Tubular and arteriolar damage was significantly lower in Groups 3 and 4 rats than in Group 2 rats, while chronic changes were similar between the three groups. TUNEL-positive cells and thiobabarbituric acid reacting substances(TBARS) levels were significantly higher in Group 2 rats, whereas superoxide dismutase levels were significantly lower in Group 2 rats than in those of the other three groups. Low or high dose rhEPO had no significant protective effects on body weight, renal functions, chronic fibrotic changes, but both doses reduced tubular and arteriolar changes, apoptotis and oxidative stress. [ABSTRACT FROM AUTHOR]

The effect of haematocrit and β-carotene levels on the serum total bilirubin measurement in two analytical methods was studied as an example of the impact of practical analytical quality in medical decision making. The precision characteristics of the two methods were very similar. Based upon the significant difference in the correlation coefficient in a method comparison study before and after 20% trimming of the data, an interference effect study was performed. Haemoglobin (expressed as haematocrit) and β-carotene were the substances studied to explain the observed differences. The bilirubin test results from the Wako bilirubinometer were easily affected ( n=19; X( S): 13.83±2.43; t=–6.17; P=0.000) and more elevated than in the Vitros dry chemistry systems ( n=18; X( S): 12.72±2.21; t=–2.48; P=0.017), due to the presence of β-carotene (>200 μg/dl). [ABSTRACT FROM AUTHOR]

This study describes the preparation, characterization, and biosensing applications of Radio Frequency (RF) plasma-modified magnetic micro/M/Janus micromotors. In the first part of the study, two different Janus micromotors were fabricated. Firstly, Fe3O4 magnetic micro/particles were functionalized with –OH groups under plasma treatment, and then Fe3O4 and Fe3O4-OH NPs/Platinum (Pt) (Fe3O4/Pt and Fe3O4-OH/Pt) micromotors were prepared by Pt coating of one side of Fe3O4 and Fe3O4-OH nanoparticles using by RF magnetron sputtering method. The work is the first example of RF rotating plasma preparation of modified magnetic nano/particle-based motors. Thus, it is of great interest to nano/micromachinery field. The synthesized micromotors were characterized by scanning electron microscopy (SEM) and energy-dispersive X-Ray spectroscopy (EDX) analysis. The dependence of the mobility of the motors on fuel concentration was evaluated. High speeds of 255 μm s− 1 and 128 μm s− 1 at 5% hydrogen peroxide (H2O2) were observed for Fe3O4/Pt and Fe3O4-OH/Pt micromotors, respectively. Besides these remarkable values, long lifetimes of 15 min with Fe3O4/Pt micromotors and 20 min with Fe3O4-OH/Pt micromotors were achieved. In the second part of the study, these Janus micromotors were used in miRNA-21 biosensing. The changes in the fluorescence intensity and in the speed of micromotors were examined after hybridization. Performances of these two novel micromotors were compared to present their potential use in early cancer diagnosis. Promising results with the functionalized Fe3O4-OH/Pt micromotors were obtained. [ABSTRACT FROM AUTHOR]