Interaction of iron nanoparticles with nervous system: an in vitro study

Abstract

Nanoparticles (NPs) are one of the interesting and widely studying issues mainly because of their particular physico-chemical features and broad applications in the field of biomedical sciences, such as diagnosis and drug delivery. In this study, the interaction of iron nanoparticles (Fe–NPs) with Tau protein and PC12 cell, as potential nervous system models, was investigated with a range of techniques including dynamic light scattering, intrinsic fluorescence spectroscopy, circular dichroism, [(3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-tetrazolium-bromid] assay, and acridine orange/ethidium bromide (AO/EB) dual staining method. An inverse correlation between Stern and Volmer constant (K_SV) and temperature indicated a probable static quenching mechanism occurred between Tau protein and Fe–NPs. The number of binding site (n = 0.86) showed that there is almost one binding site of Fe–NP per protein. The negative values of ∆H (−53.21 kJ/mol) and T∆S (−42.44 kJ/mol) revealed that Fe–NPs interacts with Tau protein with dominate role of hydrogen bonds and van der Waals interactions and this interaction was spontaneous (∆G = −10.77 kJ/mol). Also, Fe–NPs stabilized the random coil structure of Tau protein. Moreover, Fe–NPs reduced PC12 cells viability by fragmentation of DNA in an apoptotic manner. In conclusion, induced conformational changes of Tau protein and cytotoxicity of PC12 cells by Fe–NP were revealed to be in a concentration and time-dependent manner.

Keywords:

• iron nanoparticle
• Tau protein
• interaction
• thermodynamic
• cell viability

Acknowledgment

The financial support of the Islamic Azad University of Pharmaceutical Science, Tehran, Iran is gratefully acknowledged. Tau protein was kindly gifted by Dr. Koroush shahpasand form Rouyan Institute of Tehran, Iran. The authors would like to thank Ebtesam Ahmadizadeh for English editing of this paper.