Immunotoxicity assessment of CdSe/ZnS quantum dots in macrophages, lymphocytes and BALB/c mice

Xiaomei Wang,Xuedan Zhu,Wenxiao Jiang,Guimiao Lin,Qijun Huang,Marie Chia-Mi Lin,Jiefeng Li,Jinglin Tian,Ken-Tye Yong

doi:10.1186/s12951-016-0162-4

Abstract

BackgroundThe toxicity of CdSe/ZnS quantum dots (QDs) in the environment and biological systems has become a major concern for the nanoparticle community. However, the potential toxicity of QDs on immune cells and its corresponding immune functions remains poorly understood. In this study, we investigated the immunotoxicity of CdSe/ZnS QDs using the in vitro in macrophages and lymphocytes and in vivo in BALB/c mice.ResultsOur results indicated that macrophages treated with 1.25 or 2.5 nM QDs exhibited decreased cell viability, increased levels of reactive oxygen species (ROS), elevated apoptotic events, altered phagocytic ability, and decreased release of TNF-α and IL-6 by upon subsequent stimulation with Lipopolysaccharide (LPS). In contrast, lymphocytes exposed to QDs exhibited enhanced cell viability, increased release of TNF-α and IL-6 following exposure with CpG-ODN, and decreased transformation ability treatment in response to LPS. To study the in vivo effects in mice, we showed that QDs injection did not cause significant changes to body weight, hematology, organ histology, and phagocytic function of peritoneal macrophages in QDs-treated mice. In addition, the QDs formulation accumulated in major immune organs for more than 42 days. Lymphocytes from QDs-treated mice showed reduced cell viability, changed subtype proportions, increased TNF-α and IL-6 release, and reduced transformation ability in response to LPS.ConclusionsTaken together, these results suggested that exposures to CdSe/ZnS QDs could suppress immune-defense against foreign stimuli, which in turn could result in increased susceptibility of hosts to diseases.Electronic supplementary materialThe online version of this article (doi:10.1186/s12951-016-0162-4) contains supplementary material, which is available to authorized users.

Highlights

The toxicity of CdSe/ZnS quantum dots (QDs) in the environment and biological systems has become a major concern for the nanoparticle community
As the adherent ability of lymphocytes is poor and cells are easy to detach from the cultured dishes, we determined the uptake of CdSe/ZnS QDs by lymphocytes using flowcytometry assay instead of confocal imaging
The in vitro toxicity tests in combination with in vivo immunotoxicity in biological systems will play a pivotal role in assessing the toxicity of QDs and understanding the molecular mechanisms of nanotoxicity of QDs

Summary

Introduction

The toxicity of CdSe/ZnS quantum dots (QDs) in the environment and biological systems has become a major concern for the nanoparticle community. We investigated the immunotoxicity of CdSe/ ZnS QDs using the in vitro in macrophages and lymphocytes and in vivo in BALB/c mice. Many unique optical features of QDs make them useful for applications in biological and medical fields. Published reports have provided limited information about the toxicity of QDs to cells, and most toxicological assessments were performed using in vitro and in vivo models [2,3,4]. Little is known about the molecular mechanisms of the QDs-induced toxicity effects on immune cells [9]. In comparison to in vitro investigations, there has been little information about QDs-induced in vivo toxicity [10, 11]. The consequent biological effects on immune functions were rarely addressed on the QDs exposure or accumulation in the reticuloendothelial organs

Methods

Results

Conclusion