To be structural materials, the critical size is always a bottleneck of bulk metallic glasses (BMGs) due to the cooling rate restriction. Here, we report a developed alloy of Zr46Cu30.14Ag8.36Al8Be7.5, which can be cast into amorphous rods in 73 mm diameter by copper mould casting. The strong glass forming ability of this alloy is closely related to the Be addition, which not only suppresses the phase separation happening in the as-cast Be-free BMG but also sustains low Gibbs free energy difference for crystallization. This finding will stimulate more interests in developing BMGs and their industrial applications.

No abstract

A horseradish peroxidase (HRP) biosensor was constructed by one step electrodeposition method and the direct electrochemistry of HRP in the biosensor was studied. In the biosensor HRP was immobilized on surface of the glassy carbon electrode (GCE) during the process of the gold nanoparticles (AuNPs) deposition with the help of surfactant cetyltrimethylammonium bromide (CTAB), through which HRP-CTAB-AuNPs/GCE was successfully constructed. HRP-CTAB-AuNPs/GCE can directly catalyze the reduction of peroxides without the electron mediator. SEM and electron dispersive spectroscopy (EDS) were used to characterize the modified electrode. The preparation process of the modified electrode was studied by electrochemical impedance spectroscopy. The electrochemical properties of the modified electrode to hydrogen peroxide, tert-butyl hydroperoxide and cumyl hydroperoxide were studied by electrochemical cyclic voltammetry and current-time curve. Results showed that the modified electrode exhibited good catalytic performances for the detection of hydrogen peroxide, tert-butyl hydroperoxide and cumyl hydroperoxide. The sensitivities for H 2 O 2 , tert-butyl hydroperoxide and cumyl hydroperoxide are 0.0187 A • L/mol, 0.000340A • L/mol and 0.0052 A • L/mol, respectively. The detection limits are 2.3 × 10 −7 mol/L, 8.6 × 10 −6 mol/L and 3.6 × 10 −6 mol/L, respectively.

No abstract

The preparation and application of reagentless electrochemical thrombin molecularly imprinted sensors were studied using multiwalled carbon nanotubes as sensitivity-enhanced materials. The molecularly imprinted polymer film was prepared by the electropolymerization of o-phenylenediamine with thrombin as the template molecule onto the surface of multiwalled carbon nanotubes modified glassy carbon electrode. After removing thrombin, the poly-o-phenylenediamine molecularly imprinted film was obtained with specific recognition for thrombin. Using the poly-o-phenylenediamine molecularly imprinted polymers as the electron probe, the electrochemical molecularly imprinted sensor was fabricated for the detection of the protein thrombin. Under optimized experimental conditions, the sensor exhibited a good linear response from 10.0 fg/mL to 1.0 μg/mL for thrombin, with correlation coefficient 0.999 and a low detection limit of 1.7 fg/mL. The fabricated molecularly imprinted sensor can be applied to the detection of thrombin in actual sample bovine serum with satisfactory results.