Exploring the interaction of synthesized nickel oxide nanoparticles through hydrothermal method with hemoglobin and lymphocytes: Bio-thermodynamic and cellular studies

The NiO NPs were synthesized by hydrothermal method and their interaction with Hb was investigated by employing fluorescence, UV–vis absorption techniques as well as docking studies. Also, the cytotoxic impacts of NiO NPs against human lymphocytes were examined by different cellular assays. The TEM, DLS and XRD investigations showed that the size of crystalline NiO NPs is less than 50 nm with a high colloidal stability. Analysis of the fluorescence quenching of Hb incubated with different concentrations of NiO NPs suggested that both static and dynamic quenching are involved in the spontaneous (∆G = −22.00 kJ/mol) formation of Hb-NiO NP complex through hydrogen bonding and van der Waals interactions (∆H = −46.16 kJ/mol, T∆S = −24.16 kJ/mol). Molecular docking also showed that NiO nanoclusters with different sizes bind to hydrophilic residues of Hb with different binding affinities. The UV–vis absorption further demonstrated that the Tm shifted to lower values in the presence of high concentrations of NiO NPs. Moreover, the cellular assay displayed that NiO NPs resulted in enhancement of cell mortality, LDH release, caspase-3 activity, ROS level, cell cycle arrest, and apoptosis/necrosis. These data can provide essential details in elucidating the nature of the reaction between NPs and the biological system.