Effects of charge and surface defects of multi-walled carbon nanotubes on the disruption of model cell membranes.
The direct contact between multi-walled carbon nanotubes (MWCNTs) and cell membranes causes membrane disruption, potentially leading to cytotoxicity. However, the role of electrostatic forces and MWCNT properties is still open to debate. In this study, the influences of charge and MWCNT surface defects on membrane disruption were investigated by microscopy and a quartz crystal microbalance with dissipation monitoring (QCM-D). Positively/negatively charged giant unilamellar vesicles (GUVs) and supported lipid bilayers (SLBs) were made as model cell membranes. Negatively charged MWCNTs disrupted the GUVs containing positively charged lipids, which confirmed the electrostatically mediated interaction. However, the mass loss was detected from the negatively charged SLBs after MWCNT exposure, which suggests the extraction of phospholipids. The defect degree of MWCNTs correlated with their adhesion amount on the membranes. Both the oxygenated functional groups and unoxidized dangling carbon bonds were active sites for MWCNT-membrane interactions. The MWCNTs were observed to be engulfed inside the GUVs. The results clearly demonstrate that phospholipid extraction by MWCNTs could occur in electrostatically repulsive conditions, and MWCNT defects were active binding sites whether or not they were oxygenated. Our findings should be helpful in the design and safe applications of carbon nanomaterials.
Environment Research Institute, Shandong University, Jinan 250100, China. Electronic address: jiangw@sdu.edu.cn.
Wei
W
Jiang
Environment Research Institute, Shandong University, Jinan 250100, China.
Qi
Q
Wang
State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Jiangsu 210023, China.
Xiaolei
X
Qu
Environment Research Institute, Shandong University, Jinan 250100, China.
Lixin
L
Wang
Environment Research Institute, Shandong University, Jinan 250100, China.
Xiaoran
X
Wei
State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Jiangsu 210023, China.
Dongqiang
D
Zhu
Department of Environmental Science, Zhejiang University, Hangzhou 310058, China.
Kun
K
Yang
Carbon nanotubes; Charge; Defects; Membrane disruption; Model cell membranes