Investigating the Interaction of Silicon Dioxide Nanoparticles with Human Hemoglobin and Lymphocyte Cells by Biophysical, Computational, and Cellular Studies

Abstract

Nanoparticles (NPs) have received great attention in biological and medical applications because of their unique features. However, their induced adverse effects on the biological system are not well-explored. Herein, the interaction of silicon dioxide nanoparticles (SiO NPs) with human hemoglobin (Hb) and lymphocyte cell line was evaluated under physiological conditions by multispectroscopic [intrinsic and synchronous fluorescence spectroscopy and circular dichrosim (CD)], molecular docking, and cellular [3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyl-tetrazolium bromide (MTT) and acridine orange/ethidium bromide (AO/EB) staining] methods. Transmission electron microscopy and dynamic light scattering revealed the nanosized and spherical shaped SiO particle. The fluorescence and lifetime decay results indicated that SiO NPs quenched the intrinsic intensity of Hb through a static quenching mechanism. The binding affinity of SiO NPs toward Hb was directly correlated with temperature. The sign of thermodynamic parameters demonstrated that hydrophobic forces played a pivotal role in the interaction of SiO NPs with Hb. The results of synchronous fluorescence experiments displayed that Tyr residues are moved to a more hydrophilic microenvironment. Molecular docking studies exhibited that SiO and Si NPs were bound to Hb primarily by hydrophobic residues. The findings from CD data verified no alteration in the secondary structure of Hb upon binding to SiO NPs. The human lymphocyte cell line was treated with SiO NPs at varying concentrations and time intervals and the cytotoxicity assays by MTT and AO/EB staining showed that cell viability was reduced by the SiO NP-induced apoptosis mechanism in a dose and time-dependent manner. Therefore, it may be suggested that comprehensive details regarding the interaction of NPs and biological systems such as cells and proteins can provide useful information in the development of NP-based systems.

Biophysical, docking, and cellular studies on the effects of cerium oxide nanoparticles on blood components: in vitro

“…Synchronous fluorescence spectroscopy depends on a multitude of factors such as distance between the donor and acceptor and polarity around residues. 35,36 Synchronous fluorescence spectroscopy demonstrates the microenvironmental alterations of Tyr and Trp residues when the Δλ (λem−λex) is 20 and 60 nm, respectively. The effect of CNPs on the synchronous fluorescence spectra of HHb is depicted in Figure 7A and B.…”

“…The displacement of the helix structure of protein and a corresponding movement of aromatic residues to the different polar environment increases the overlap between positive and negative CD bands and finally results in reduced intensity of CD bands. HHb has 30 Phe (33,36,43,46,98,117,128,182,183,186,212,226,244,259,263,320,323,330,333,385,404,415,469,470,473,499,513,531,546, and 550), six Trp (14,156,178,301,443, and 465), and 12 Tyr residues (24,42,140,176,271,286,311,329,427,463,558, and 573; Figure 10).…”

Biophysical, bioinformatical, cellular, and molecular investigations on the effects of graphene oxide nanosheets on the hemoglobin structure and lymphocyte cell cytotoxicity

“…41 The interaction of nanodiamond and silicon dioxide NPs with Hb also showed secondary and tertiary structural changes of Hb. 42,43 It has been shown that fullerene NPs synthesized by different methods induce various impacts on human serum albumin and bovine serum albumin conformations. The crucial difference between the two investigations was the fabrication methods of fullerene NPs, and principal differences between the main NPs fabricated by the two methods were the NP size distributions.…”

“…cD study CD spectroscopy has been widely employed as a simple and sensitive method for exploring structural changes of protein after addition of ligands such as nanoparticles (NPs). 26 The CD bands of Hb show two characteristic minima at 222 and 208 nm, featuring the dominant α-helix structure of Hb. 26 Indeed, any changes to the helical structure of Hb result in protein dysfunction.…”

“…26 The CD bands of Hb show two characteristic minima at 222 and 208 nm, featuring the dominant α-helix structure of Hb. 26 Indeed, any changes to the helical structure of Hb result in protein dysfunction. Therefore, determining the percentage of the secondary structure of Hb in the presence of varying concentrations of NGOs can provide useful information regarding the adverse effects of NGOs on the native structure of Hb.…”