Electrodeposition of nanoMnO(2) from mineral leach liquor and the investigation on conformational changes of hemoglobin induced by the nanomaterial

Abstract

The electrodeposition of manganese dioxide from purified leach liquor obtained by reduction leaching of polymetallic manganese nodules using sucrose as a reductant in H2SO4 medium followed by 2 stages purification process was described. The role of cationic additive on the morphology and electrochemical properties were investigated by using Cetyltrimethylammonium bromide (CTAB) (0-500 mg dm(-3)). The orthorhombic phase of gamma-MnO2 was confirmed from the XRD patterns of as prepared electrolytic manganese dioxide (EMD). The effect of CTAB on EMD has been investigated in terms of morphology, current efficiency (CE) and energy consumption. In addition to this, for the first time we have studied the interactions of EMD with hemoglobin (Hb). Herein, the molecular interactions between Hb and nano EMD prepared at an optimum condition were explored using various spectroscopic techniques including UV-vis absorption, fluorescence, and circular dichroism. Various quantitative parameters such as association/dissociation constants, binding cooperativity were determined to illustrate the biomolecular interactions. Our results suggest that hemoglobin remains structurally stable in the bioconjugates formed by the simple adsorption method. However, at higher temperature, hemoglobin was found to adopt an unfolded conformational state both in free form and bioconjugates. This work would be helpful in designing of safe nanoparticles (NPs) for biomedical applications.