Synthesis of nickel-doped ceria nanospheres for in situ profiling of Warfarin sodium in biological media.

Venous thromboembolism is one of the major disorders, which is significantly increased the mortality and morbidity rate. Warfarin sodium (WFS) is the most extensively prescribed drug for the prevention of thromboembolic diseases however, it has a narrow therapeutic index. Recently, many methods for detecting and monitoring the level of WFS have been proposed. However, the electrochemical method has gained more interest than the other traditional method due to its ease of operation. This article describes the hydrothermal synthesis of nickel-doped cerium oxide (CeO2@Ni) nanospheres for the selective electrochemical determination of WFS. Various spectroscopic techniques have been used to analyze the chemical composition, and surface morphology of CeO2@Ni nanospheres. Further, the prepared CeO2@Ni nanospheres modified electrode demonstrated excellent electrocatalytic behavior for WFS detection, with an ultralow detection limit of 6.3 × 10-9 M, a linear range of 1.0 × 10-8 M to 1.51 × 10-4 M and 1.51 × 10-4 M to 9.51 × 10-4 M, and a higher sensitivity of 2.9986 µA µM-1 cm2. Therefore, we believe that the CeO2@Ni nanosphere electrocatalyst can serve as a potential electrode catalyst for the sensing of WFS in real-time applications.

Voltammetric determination of catechol and hydroquinone at poly(murexide) modified glassy carbon electrode.

The electrochemical study of Catechol (CC) was studied in presence of Hydroquinone (HQ) using poly(murexide) modified glassy carbon electrode (MGCE) by cyclic voltammetric study. The modified electrode exhibited good affirmative response towards the electro chemical oxidation of CC in presence of HQ in 0.2 M phosphate buffer solution at the physiological of pH 7.4. The influence of scan rate, concentration and pH parameters were examined with the cyclic voltammetric method. The modified electrode showed good selectivity and sensitivity with an advantage of interference study and free determination of selected analytes in this experiment. Finally a simple, sensitive and selective method was developed for the determination of dihydroxybenzene isomeric compounds.

Modeling of ion permeation in calcium and sodium channel selectivity filters.

Structure-function studies have shown that it is possible to convert a sodium channel to a calcium-selective channel by a single amino acid substitution in the selectivity filter locus. Ion permeation through the "model selectivity filter" was modeled with a reduced set of functional groups representative of the constituent amino acid side chains. Force-field minimizations were conducted to obtain the energy profile of the cations as they get desolvated and bind to the "model selectivity filter." The calculations suggest that the ion selectivity in the calcium channel is due to preferential binding, whereas in the sodium channel it is due to exclusion. Energetics of displacement of a bound cation from the calcium "model selectivity filter" by another cation suggest that "multi-ion mechanism" reduces the activation barrier for ion permeation. Thus, the simple model captures qualitatively most of the conduction characteristics of sodium and calcium channels. However, the computed barriers for permeation are fairly large, suggesting that ion interaction with additional residues along the transport path may be essential to effect desolvation.