Fabrication and Application of a New Modified Electrochemical Sensor Using Newly Synthesized Calixarene-Grafted Mwcnts for Simultaneous Determination of Cu(II) and Pb(II).

A rapid, simple, selective and highly sensitive simultaneous determination of Cu(II) and Pb(II) via newly fashioned 5,11,17,23-tetra-tert-butyl-25,27-dihydrazinamidecarbonylmethoxy-26,28-dihydroxycalix[4]arene-grafted multi-walled carbon nanotubes-modified carbon paste electrode (CNT-Calix/CPE) by differential pulse anodic stripping voltammetry (DPASV) has been introduced. It was observed that CNT-Calix/CPE exhibits higher selectivity and stability for Cu(II) and Pb(II). Different operational parameters such as pH, deposition potential/time, pulse amplitude (5, -1.0 V vs. Ag/AgCl, 300 s, 2 s, 0.05 V) were also optimized for calculation and statistical evaluation of linear range, detection limit and limit of quantification. Interference study shows that the electrode is highly selective for the simultaneous determination of Cu(II) and Pb(II). Standard addition method was used to apply CNT-Calix/CPE in waste water, plant leaves and soft drinks and it was found that the concentration of Cu(II) and Pb(II) were corresponding to standardized values.

Interaction between ketoconazole and human serum albumin on epoxy modified magnetic nanoparticles for drug delivery.

Superparamagnetic iron oxide nanoparticles (SPIONs) were modified with [3-(2,3-epoxy-propoxy)propyl] trimethoxy silane, which resulted in formation of epoxy groups on the particles surface. The epoxy functionalized SPIONs can bind to human serum albumin (HSA). The binding amount of HSA to epoxy modified SPIONs was found to be as 32.7 microM for 1 mg epoxy modified SPIONs at 280 and 342 nm of excitation and emission wavelengths by using fluorescence spectroscopy. Interaction of ketoconazole with HSA immobilized epoxy functionalized SPIONs was studied at 300 and 390 nm of excitation and emission wavelengths, respectively. Binding mechanism of ketoconazole and HSA was identified by Stern-Volmer equation. Thermodynamic parameters (deltaH, deltaS and deltaG) were also estimated for the interaction. Therefore, the nature of the binding forces was found to be as hydrophobic interaction. Protein and drug attachments were also examined by Infrared spectroscopy (IR) and Scanning Electron Microscopy (SEM). This study show that prepared albumin-based magnetic nanoparticles carrier systems represents an attractive strategy for drug delivery.

Synthesis and characterization of novel nano-chitosan Schiff base and use of lead (II) sensor.

A new kind of nano-chitosan Schiff base ligand (CHNS) with particle size of 34 nm was formed by the reaction between the 2-amino groups of glucosamine residue of nano-chitosan and a 2,5-dihydroxybenzaldehyde. The chemical structures of the nano-chitosan and nano-chitosan Schiff base were characterized by FT-IR spectra, particle sizer, zeta potential, and elemental analysis. A new, simple and effective chemically modified carbon paste electrode with CHNS was prepared and used as a lead (II) sensor. The prepared electrode was characterized using scanning electronic microscopy (SEM-EDX) and cyclic voltammetry (CV). The modified electrode showed only one oxidation peak in the anodic scan at -0.34 V (vs. Ag/AgCl) for the oxidation of lead (II). The dedection limit (LOD) was calculated as 1.36×10(-7) for a 10-min preconcentration time at pH 6.0.

Determination of defensin HNP-1 in human saliva of patients with oral mucosal diseases.

Saliva is a biological fluid that is easily obtainable and that can give useful information both in systemic and oral diseases. In this study, a chromatographic method was applied to determine the amount of defensin HNP-1 in human saliva of patients with oral mucosal diseases before and after treatments and compared with controls. Defensin human neutrophil peptide-1 (HNP-1) was identified and confirmed. The concentration of HNP-1 in saliva was determined by comparing the area of eluted HNP-1 with that of HNP-1 standard. Linear calibration range of defensin HNP-1 was 0.10 to 0.90 µg/10 µL with R(2) values of 0.996. The concentrations of HNP-1 in the saliva of patients with oral lichen planus, Behçet's disease, and recurrent apthous stomatitis were 33.6 ± 10.6, 15.5 ± 7.6, and 36.3 ± 9.5 µg mL(-1) (mean ± S.D.), respectively. The salivary defensin-1 concentration was significantly higher in patients with oral mucosal diseases than in healthy volunteers; furthermore, in patients with oral mucosal diseases, the concentration was significantly higher before treatment than after treatment.