Search

Abstract Herein, the thermodynamic parameters of tau upon interaction with NiO NPs were determined by fluorescence spectroscopy. Also, molecular docking studies were run to explore the binding affinities of NiO NPs clusters with different sizes of 30 Å and 50 Å toward tau. Also, cytotoxic activity of NiO NPs against SH-SY5Y was determined by MTT, LDH, caspase-9/3 activity, and expression of apoptotic Bax and Bcl-2 genes assays. DLS study showed that NiO solution had a good colloidal stability. Fluorescence study revealed that K SV values were 2.95 ± 0.35 × 104, 3.31 ± 0.59 × 104 and 3.92 ± 0.65 × 104 at 298 K, 310 K and 315 K, respectively. Also, ∆ G° (kJ/mol), ∆ H° (kJ/mol) and T∆ S° (kJ/mol) values were − 13.27 ± 1.57, 1.98 ± 0.14, 15.25 ± 2.01, respectively at 298 K. Theoretical studies depicted that affinity of 5O3T segment toward NiO NP (30 Å) is higher than NiO NP (50 Å) and the proportion of Lys residues are higher in the docked pose of NiO NP (30 Å)/5O3T complex than NP (50 Å)/5O3T complex. Moreover, NiO NPs demonstrated a significant increase in the mortality of SH-SY5Y cells in an apoptotic manner. This study determined that NiO NPs may mediate the formation of electrostatic interactions with tau and induction of undesired harmful effects on neurons. [ABSTRACT FROM AUTHOR]

Abstract Nickel oxide nanoparticles (NiO NPs) have been used in the biological and medical sciences. However, their toxic effects against biological systems such as nervous system have not been well studied. Therefore, the adverse effect of NiO NPs on tau structure was investigated by fluorescence and CD spectroscopic methods as well as TEM study. Also, molecular dynamic study was run to extend the experimental data. Cytotoxic activity of NiO NPs against SH-SY5Y cell was determined by trypan blue exclusion, cell morphology, ROS, and apoptosis assays. ANS, Nile red, ThT assays and electron micrograph investigation revealed that NiO NPs can increase the hydrophobic portions of tau and induce the formation of amorphous tau aggregates. Far and near CD spectroscopic methods revealed that NiO NPs can change the secondary and tertiary structure of tau, respectively. Theoretical studies depicted that NiO NPs lead to folding of tau structure. In the cellular view, NiO NPs induced significant mortality and morphological effects against SH-SY5Y cells. NiO NPs also provided a significant impact on generating intracellular ROS and apoptosis induction. This study determined that NiO NPs could mediate the induction of some undesired effects on the nervous system. Highlights • NiO NPs increased the hydrophobic portions of tau. • NiO NPs induced the formation of amorphous tau aggregates. • NiO NPs induced significant mortality and morphological effects against SH-SY5Y cells. [ABSTRACT FROM AUTHOR]

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. • The NiO NPs were synthesized by hydrothermal method. • Both static and dynamic quenching are involved in the interaction of NiO NPs and Hb. • NiO nanoclusters with different sizes bind to hydrophilic residues of Hb. • Tm shifted to lower values in the presence of higher concentrations of NiO NPs. • NiO NPs resulted in induction of apoptosis in lymphocytes. [ABSTRACT FROM AUTHOR]