Nanotoxicity assessment of quantum dots: from cellular to primate studies

Abstract

Tremendous research efforts have been devoted to fabricating high quality quantum dots (QDs) for applications in biology and medicine. Much of this research was pursued with an ultimate goal of using QDs in clinical applications. However, a great deal of concern has been voiced about the potential hazards of QDs due to their heavy-metal content. Many studies have demonstrated toxicity of various QDs in cell culture studies. However, in a smaller number of studies using small animal models (mice and rats), no abnormal behaviour or tissue damage was noticed over periods of months after the systemic administration of QDs. Nevertheless, the correlation of these results with the potential for negative effects of QD on humans remains unclear. Many urgent questions must be answered before the QDs community moves into the clinical research phase. This review provides an overview of the toxicity assessment of QDs, ranging from cell culture studies to animal models and discusses their findings. Guidelines for using various nonhuman primate models for QD toxicity studies are highlighted. This review article is intended to promote the awareness of current developments of QD applications in biology, the potential toxicity of QDs, and approaches to minimizing toxicity.

Cationic Silicon Nanocrystals with Colloidal Stability, pH‐Independent Positive Surface Charge and Size Tunable Photoluminescence in the Near‐Infrared to Red Spectral Range

“…In particular, the toxicity of heavy‐metal‐based nanocrystals has been subject to intense scrutiny 4, 5, 6, 7. In recent years, silicon nanocrystals (ncSi) have been proposed and demonstrated as potentially nontoxic alternatives to established II–VI (e.g., CdSe/Te, ZnS/Se), III–V (e.g., InP), I–III–VI (e.g., CuInS/Se), and IV–VI (e.g., PbS/Se) nanocrystal systems for fluorescent labeling 4, 8, 9, 10…”

Facilitating Translational Nanomedicine via Predictive Safety Assessment

“…To date, the most commonly used QDs in biomedical research are cadmium (Cd)-based QDs. 58,60 However, their toxicological impact is a major concern that has hindered further clinical applications. The dissolution and release of heavy-metal Cd ions play a major role on their cytotoxicity.…”

“…Because QDs could remain in the liver and spleen for more than 90 days 65 and their clearance is slow, this could result in severe subchronic cytotoxicity to the RES system, such as oxidative stress, genotoxicity, and neurotoxicity. 60,64 Therefore, novel designs that could more effectively inhibit their dissolution, as well as expedite their body clearance, could help to transit their application into clinic.…”

Interaction of polymer-coated silicon nanocrystals with lipid bilayers and surfactant interfaces

“…However, concerns about the potential toxicity of many such materials [3,4] are generating a significant amount of interest focused on finding nontoxic alternatives. At the same time, the emergence of colloidal nanocrystals for a variety of applications -flat-panel displays, solid-state lighting, and photovoltaics -ensures that they are poised to enter the environment, yet many questions about their impact remain unresolved [7].…”

“…Fluorescent nanoparticles, in particular, offer a unique platform for labeling and detection across a range of biologically relevant settings [2], with perhaps the most highly touted class of such materials being the semiconductor nanocrystals [3,4].…”