In Vitro Toxicity of TiO2:SiO2 Nanocomposites with Different Photocatalytic Properties.

Rossella Bengalli,Magda Blosi,Anna Costa,Paride Mantecca,Simona Ortelli,Luisa Fiandra

doi:10.3390/nano9071041

Abstract

The enormous technological relevance of titanium dioxide (TiO2) nanoparticles (NPs) and the consequent concerns regarding potentially hazardous effects that exposure during production, use, and disposal can generate, encourage material scientists to develop and validate intrinsically safe design solution (safe-by-design). Under this perspective, the encapsulation in a silica dioxide (SiO2) matrix could be an effective strategy to improve TiO2 NPs safety, preserving photocatalytic and antibacterial properties. In this work, A549 cells were used to investigate the toxic effects of silica-encapsulated TiO2 having different ratios of TiO2 and SiO2 (1:1, 1:3, and 3:1). NPs were characterized by electron microscopy and dynamic light scattering, and cell viability, oxidative stress, morphological changes, and cell cycle alteration were evaluated. Resulting data demonstrated that NPs with lower content of SiO2 are able to induce cytotoxic effects, triggered by oxidative stress and resulting in cell necrosis and cell cycle alteration. The physicochemical properties of NPs are responsible for their toxicity. Particles with small size and high stability interact with pulmonary cells more effectively, and the different ratio among silica and titania plays a crucial role in the induced cytotoxicity. These results strengthen the need to take into account a safe(r)-by-design approach in the development of new nanomaterials for research and manufacturing.

Highlights

Nanotechnology is growing tremendously fast, and it has led to the creation of a new class of materials, called nanomaterials (NMs), which are nowadays present in everyday life goods
Silica coating increases the photocatalytic activity of titania NPs and at the same time reduces the potential toxic effects induced by TiO2
The current application of photoactive TiO2 nanoparticles in many industrial fields raises the crucial issue of their safety both for workers, in the production sites, and end-users

Summary

Introduction

Nanotechnology is growing tremendously fast, and it has led to the creation of a new class of materials, called nanomaterials (NMs), which are nowadays present in everyday life goods. There is a growing concern about the safety of these NMs, due to the increasing release in the market and their consequent intentional and unintentional emission into the environment In this perspective, to guarantee a sustainable development of these new technologies, the environmental and health safety issues should be addressed in parallel. Under UV light irradiation, the physical properties of TiO2 change, promoting the decomposition of organic and inorganic compounds. For these properties, TiO2 is highly employed as a photocatalytic agent in a variety of applications, such as pollution remediation in air and water, sterilization, and production of self-cleaning surfaces. TiO2 NPs have been identified as efficient sensitizers for photodynamic and sonodynamic cancer therapy, especially upon functionalization with antibodies aimed to optimize the selective distribution to target cells [4]

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