Electrochemical and CD-spectroelectrochemical studies of the interaction between BSA and the complex [Cu(Bztpen)]2+, (Bztpen = (N-benzyl-N, N', N'-tris (pyridin-2-ylmethyl) ethylenediamine)

In this work we report the electrochemical, spectroscopical and spectro-electrochemical studies of a model complex [Cu^ΙΙ(Bztpen)]²⁺, (Bztpen = (N-benzyl-N,N',N'-tris(pyridin-2-ylmethyl)ethylenediamine) in order to propose a methodology to evaluate the interaction of potential metal based anticancer agents during electron transfer processes, with transport proteins such as Bovine Serum Albumin (BSA). It was possible to establish a reversible electron transfer [Cu^ΙΙ(Bztpen)]²⁺ +1e → [Cu^Ι(Bztpen)]⁺ and a weak interaction energy between BSA and [Cu^ΙΙ(Bztpen)] and [Cu^Ι(Bztpen)] species, with no adsorption of protein over the electrode surface. Circular Dichroism (CD) Spectroelectrochemistry, not reported before, reveals no significant changes in BSA structure during the electron transfer [Cu^ΙΙ(Bztpen)]²⁺ + 1e → [Cu^Ι(Bztpen)]⁺. CD experiments at variable temperature for BSA denaturalization in the absence and in the presence of [Cu^ΙΙ(Bztpen)]²⁺, shown no change in thermodynamic parameters due to low interaction between the transport protein and copper complex.

Tailoring N and S Heteroatoms Through Rational Design in Carbon Nanotubes-Graphene Composites for Enhanced Zn-Air Battery Performance

Cathodic materials significantly influence the performance, durability, and sustainability of primary zinc-air batteries (ZABs). This study focuses on the rational design of highly active metal-free composites by tailoring the content of N and S heteroatoms in carbon nanotube-graphene (CNTG) composites. The oxygen reduction reaction (ORR) tests showed onset potentials (Eo) of 0.88 V (N-CNT) and 0.89 V (N-graphene) for individual materials and 0.92 V for the N-CNTG composite, highlighting the advantage of using a composite materialThe N content varied with dicyandiamide and urea, displaying changes in the surface area and N content (7.09 vs. 5.30 at. %), and in pyridinic and quaternary N species. The N content varied with dicyandiamide and urea, showing changes in the surface area and N content (7.09 vs. 5.30 at. %), and in pyridinic and quaternary N species. The abundance of pyridinic-N species in N-CNTG using urea enabled a higher ORR activity (Eo=0.92 V). The S incorporation through thiourea improved the Eo to 0.94 V (Pt/C=1.03 V). And, the combination of urea and thiourea resulted in a highly active and durable N,S-CNTG material, displaying a Eo of 0.96 V, and an activity loss of 8.7 % (Pt/C=25.4 %) after 2000 cycles. In ZAB mode, this material displayed a voltage of 1.35 V, a power density of 107 mW cm-2, and a specific capacity of 1060 mA h g-1.