ABSTRACT
Human exposure to nanoparticles (NPs) is inevitable as NPs become more widely applied and, as a result, nanotoxicology study is now gaining attention. Herein, the interaction of zero valent iron NPs (ZVFe-NPs) with human hemoglobin (Hb) was evaluated using a variety of techniques including fluorescence spectroscopy, far circular dichroism (CD) spectroscopy as well as docking study. Also, the cytotoxicity of ZVFe-NPs on the human lymphocyte cell line as a model of blood system cell line was investigated by 3-(4, 5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT), acridine orange/ethidium bromide (AO/EB) staining, flow cytometry, and real-time PCR assays. Fluorescence studies revealed that ZVFe-NPs bind to Hb via hydrogen bonds and induced conformational changes of Hb in a static denaturation mechanism. CD experiment showed that Hb retained its native structure in the presence of ZVFe-NP. Molecular docking study also demonstrated that polar residues of Hb provide convenient medium to establish hydrogen bonds with water molecules on ZVFe-NP surface. Likewise, it was also revealed that ZVFe-NPs impaired the viability of lymphocyte cells through apoptotic pathway. For NPs to move into the clinical area, it is crucial that nanotoxicology research provide pivotal information about the adverse effect of NPs against biological systems.
Subject(s)
Biophysical Phenomena , Hemoglobins/chemistry , Iron/chemistry , Metal Nanoparticles/chemistry , Molecular Docking Simulation , Apoptosis , Circular Dichroism , Hemoglobins/metabolism , Humans , Iron/metabolism , Lymphocytes/metabolism , Metal Nanoparticles/ultrastructure , Models, Biological , Molecular Conformation , Protein Binding , Spectrometry, Fluorescence , Spectroscopy, Fourier Transform Infrared , ThermodynamicsABSTRACT
Interestingly pharmaceutical sciences are using nanoparticles (NPs) to design and develop nanomaterials-based drugs. However, up to recently, it has not been well realized that NPs themselves may impose risks to the biological systems. In this study, the interaction of silver nanoparticles (AgNPs) with tau protein and SH-SY5Y neuroblastoma cell line, as potential nervous system models, was examined with a range of techniques including intrinsic fluorescence spectroscopy, circular dichroism (CD) spectroscopy, 3-(4,5-dimethylthiazol-2-Yl)-2,5-diphenyltetrazolium bromide (MTT) assay, and acridine orange/ethidium bromide (AO/EB) dual staining method. Fluorescence study showed that AgNPs with a diameter of around 10-20 nm spontaneously form a static complex with tau protein via hydrogen bonds and van der Waals interactions. CD experiment revealed that AgNPs did not change the random coil structure of tau protein. Moreover, AgNPs showed to induce SH-SY5Y neuroblastoma cell mortality through fragmentation of DNA which is a key feature of apoptosis. In conclusion, AgNPs may induce slight changes on the tau protein structure. Also, the concentration of AgNPs is the main factor which influences their cytotoxicity. Since, all adverse effects of NPs are not well detected, so probably additional more specific testing would be needed.
