A Systematic Comparative Study of the Toxicity of Semiconductor and Graphitic Carbon-Based Quantum Dots Using In Vitro Cell Models

Abstract

A comparative, fully parallel study of nanoparticles (NPs) toxicity by in vitro cell viability is shown looking for reliable comparability of nanotoxicological results, a well-recognized bottleneck in the context. This procedure is suitable to compare toxicity of similar NPs, as well as the influence on toxicity of the size, surface, and other characteristics. As a case of study, semiconductor (SQDs) and graphitic-carbon quantum dots (CQDs) with identical surface groups and size were evaluated. All experiments were conducted at same conditions, involving two types of cells (mouse fibroblasts (3T3-L1) and carcinoma human hepatocellular cells (HepG2)) and different extracellular components (in the absence or presence of fetal bovine serum (FBS)). Cell viability demonstrated the excellent biocompatibility of CQDs compared to SQDs, which caused higher percentage of cell death at lower concentrations, as predicted but never clearly demonstrated. However, our comparative studies established that the toxicity of SQDs and CQDs are cellular type-dependent, and the absence or presence of serum proteins reduces the minimal concentration necessary of NPs to produce toxicity.