Effects of Carboxylated Multiwalled Carbon Nanotubes on the Function of Macrophages

Xia Dong,Lanxia Liu,Hailing Zhang,Xigang Leng,Dunwan Zhu,Yingxin Li

doi:10.1155/2015/638760

Abstract

Multiwalled carbon nanotubes (MWCNTs) have tremendous potential in many areas of research and applications. Modification of MWCNTs with carboxyl group is one of the widely used strategies to increase their water dispersibility. However, the effect of carboxylation of MWCNTs on their interaction with macrophages remains unclear. The current study compared the impact of pristine MWCNTs (p-MWCNTs) and carboxylic acid functionalized MWCNTs (MWCNTs-COOH) on RAW264.7 cells by looking at the cell viability, phagocytic activity, production of cytokines (IL-1β, IL-10, IL-12, and TNF-α), and intracellular reactive oxygen species (ROS). It was revealed that exposure to either p-MWCNTs or MWCNTs-COOH induced decreased viability of murine macrophage RAW 264.7 cells and moderately elevated phagocytic activity of murine peritoneal macrophages, but no statistical significance was found between the two groups. Increased production of ROS in macrophages was induced after exposure to either p-MWCNTs or MWCNTs-COOH. However, no significantly elevated production of cytokines (IL-1β, IL-10, IL-12, and TNF-α) was observed from RAW 264.7 cells after exposure to the CNTs. Those data suggested that modification with carboxyl group did not exert obvious impact on the interaction of MWCNTs with macrophages.

Highlights

Carbon nanotubes (CNTs), which are usually classified into single-walled carbon nanotubes (SWCNTs) and multiwalled carbon nanotubes (MWCNTs) [1], have won enormous popularity in nanotechnology for their unique properties and applications
The effects of carboxylic acid functionalized CNTs on macrophages are of great interest due to the pivotal role macrophages play in the interaction between the body and foreign particulate substances including CNTs
Albeit there have been several studies reporting the interaction between pristine CNTs and macrophages, little information has been accumulated regarding the impact of carboxylic acid functionalized CNT on macrophages

Summary

Introduction

Carbon nanotubes (CNTs), which are usually classified into single-walled carbon nanotubes (SWCNTs) and multiwalled carbon nanotubes (MWCNTs) [1], have won enormous popularity in nanotechnology for their unique properties and applications. The rapid development of nanotechnology has renewed potential applications within commercial, environmental, and medical sectors, including electronic devices, polymer composites, enzymatic films, scaffolds for tissue engineering, and nanoscale constructs for intracellular drug/gene delivery or tracking and detecting diseases [2,3,4,5,6]. A number of in vivo and in vitro studies have been conducted to evaluate the biological impacts of CNTs. In vivo studies demonstrated that intratracheally introduced CNTs induced granulomas in rat and mice lungs [7, 8]. Studies on the cytotoxicity of CNTs against a variety of cell lines revealed that CNTs induced elevated release of IL-8 in human epidermal keratinocytes [9], DNA damage in mouse embryonic stem cells [10], apoptosis of T lymphocyte [11], and reduced proliferation of rat aortic smooth muscle cells [12]

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Methods

Results