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Engineering hollow and porous platinum nanostructures using biomolecular templates is currently a significant focus for the enhancement of their facet-dependent optical, electronic, and electrocatalytic properties. However, remains a formidable challenge due to lack of appropriate biomolecules to have a structure-function relationship with nanocrystal facet development. Herein, human hemoglobin found to have facet-binding abilities that can control the morphology and optical properties of the platinum nanoclusters (Pt NCs) by regulation of the growth kinetics in alkaline media. Observations revealed the growth of unusual polyhedra by shape-directed nanocluster attachment along a certain orientation accompanied by Ostwald ripening and, in turn, yield well-dispersed hollow single-crystal nanotetrahedrons, which can easily self-aggregated and crystallized into porous and polycrystalline microspheres. The spontaneous, biobased organization of Pt NCs allow the intrinsic aggregation-induced emission (AIE) features in terms of the platinophilic interactions between Pt(II)-Hb complexes on the Pt(0) cores, thereby controlling the degree of aggregation and the luminescent intensity of Pt(0)@Pt(II)−Hb core−shell NCs. The Hb-Pt NCs exhibited high-performance electrocatalytic oxygen reduction providing a fundamental basis for outstanding catalytic enhancement of Hb-Pt catalysts based on morphology dependent and active site concentration for the four-electron reduction of oxygen. The as-prepared Hb-Pt NCs also exhibited high potential to use in cellular labeling and imaging thanks to the excellent photostability, chemical stability, and low cytotoxicity.

A new modified electrode, FMGCE, was prepared by electrodeposition of fisetin (F) at the surface of a preactivated glassy carbon electrode. Cyclic voltammetry was used to investigate the electrochemical properties of this electrode. The charge transfer rate constant, k s , and transfer coefficient, a s , for electron transfer between electrode substrate and surface deposited F were calculated as 16.34 s À1 and 0.54, respectively. The electrode ability towards the electrocatalytic oxidation of dihydronicotinamide adenine dinucleotide (NADH) and ascorbic acid (AA) was also studied using cyclic voltammetry and chronoamperometry as diagnostic techniques. The catalytic currents of NADH and AA were used for determination of heterogeneous rate constant, k h , of these substrates oxidation at the surface of modified electrode. The diffusion coefficients of both substrates were also estimated using chronoamperometric results. Finally, FMGCE was used as voltammetric and amperometric sensors for determination of NADH and AA in quiet and moving solutions respectively. The calculated limit of detection of NADH and AA by voltammetry were 0.06 and 0.05 mM, respectively. While, these values decrease to 2.4 and 1.8 mM, respectively for an amperometric procedure. The latter method was used successfully for quantification of AA in some real samples.

This article described the synthesis of triazine-based dendrimers with poly(ethylene glycol) core by convergent method. Compound 1 was prepared by coupling of amino group of diethanolamine with cyanuric chloride in dry THF (tetrahydrofuran). Reaction of compound 1 with p-aminobenzylamine resulted in compound 2. Compound 4 was synthesized using coupling reaction of amino group of compound 2 with cyanuric chloride, then coupling of amine groups of p-aminobenzylamine with compound 3 in the hybrid solvents. The final dendrimer (den-OH) were synthesized using reaction of dendron 4 with compound 5. Ethylene diaminetetraacetic acid modified final dendrimer were successfully prepared via coupling ethylene diaminetetraacetic acid dianhydride and den-OH. The growth of dendrons and their structures were investigated by using usual spectroscopy methods and elemental analysis. The chelating behavior and sorption capacities of triazine dendrimers were determined in relation to pH dependency for some metal ions such as Cu þ2 , Ni þ2 , and Zn þ2 using atomic absorption methods.