The Effect of Particle Size on the Cytotoxicity of Amorphous Silicon Dioxide: An in Vitro Toxicological Study.

Athena Rafieepour,Habibollah Peirovi,Mansour R.Azari,Fariba Khodagholi,Yousef Mohammadian,Jalal Pourahmad Jaktaji,Yadollah Mehrabi

doi:10.31557/apjcp.2021.22.2.325

Abstract

Introduction:Amorphous silicon dioxide (A-SiO2) is abundant in the Earth’s crust, the A-SiO2 nano and microparticles are released into the air through industrial and manufacturing activities. Due to the limited available toxicological information, the objective of the present study was to evaluate the toxicity of different sizes of A-SiO2 particles on the A549 cell-lines in an in vitro study. Materials and Methods:The A-SiO2 particles in two categories of nano (10-100 nm) and micro (< 5um) were used in this study. The human lung A549 cell-line was exposed to either nano- or micro-sized A-SiO2 particles at 10, 50, 100, and 250 μg/ml, and the effects were investigated. Results:The cytotoxicity of A-SiO2 nano and microparticles in both 24- and 72-hour exposure times resulted in decreased cell survival, mitochondrial membrane potential, and increased ROS generation which was concentration-time dependent (P <0.05) but glutathione content was not affected in a time-dependent manner. Cytotoxicity of nanoparticles, contrary to the previous study, was not higher than microparticles in the comparable dose and exposure times. Conclusion:The rate of ROS generation in the A549 cell-line exposed to A-SiO2 nanoparticles was higher than microparticles. And at the same time, cell survival for exposed cells to A-SiO2 nano and microparticles were higher for nanoparticles in shorter exposure periods and was inversely concentration- and time-dependent. Further studies on exploring the effect of size and its possible toxic mechanism are recommended to achieve a more credible risk assessment.

Highlights

Amorphous silicon dioxide (A-SiO2) is abundant in the Earth’s crust, the A-SiO2 nano and microparticles are released into the air through industrial and manufacturing activities
The cytotoxicity of A-SiO2 nano and microparticles in both 24- and 72-hour exposure times resulted in decreased cell survival, mitochondrial membrane potential, and increased ROS generation which was concentration-time dependent (P
Since most of the toxicological information of nanoparticles has been derived from experiments on the animal species (Szalay, 2012b), the present study was designed to investigate the effect of SiO2 particles on the human pulmonary cell-line

Summary

Introduction

Amorphous silicon dioxide (A-SiO2) is abundant in the Earth’s crust, the A-SiO2 nano and microparticles are released into the air through industrial and manufacturing activities. The human lung A549 cell-line was exposed to either nano- or micro-sized A-SiO2 particles at 10, 50, 100, and 250 μg/ml, and the effects were investigated. Conclusion: The rate of ROS generation in the A549 cell-line exposed to A-SiO2 nanoparticles was higher than microparticles. Particles in fine and nanometer sizes can pass through the membrane and damage vital organs systemically (Hillyer and Albrecht, 2001; Donaldson et al, 2004; Fischer and Chan, 2007), the mechanism of this effect is not clear, and some researchers believe that nanoparticles do not differ significantly in their toxic effects compared to microparticles (Karlsson et al, 2009). The production of nanoparticles and their widespread use in modern science, in comparison with microparticles, has increased the human exposure to these materials both intentionally and accidentally (Peixe et al, 2015).

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