The Research On The Mechanism Of The Interaction Between Functional Single-walled Carbon Nanotubes And Human Plasma Proteins

With the widespread uses of carbon nanotubes in biomedical and biotechnological applications,and the growing concerns about nanotoxicity of these engineered nanoparticles,the importance of protein–nanoparticle interaction has not been well stressed.Protein in blood binds to carbon nanotubes through non-covalent interaction to form protein corona which greatly affects the biological characteristics and blood biocompatibility of carbon nanotubes.Firstly,we investigated the interactions of different functionalizedSWCNTs?carboxylated SWCNTs,hydroxylated SWCNTs,aminated SWCNTs?with human serum albumin?HSA?.It was found that the HSA adsorption capacities followed the order,carboxylated SWCNTs>hydroxylated SWCNTs>aminated SWCNTs,which positively related to the Stern–Volmer quenching constant K_SVV and the binding constant K.At the same time,the conformation of HSA changed after the addition of different functionalized SWCNTs.Additional HepG 2 cellular cytotoxicity assays revealed that the stronger adsorption capacity of HSA on carboxylated SWCNTs resulted in more reduced cytotoxicity for the protein-coated SWCNTs,while the weaker binding capacities of HSA on hydroxylated and aminated SWCNTs had less effect on the cytotoxicity.These studies suggest that different functionalized CNTs can influnce the protein binding ability,thus reducing the cytotoxicity of CNTs.Secondly,we investigated the binding of common plasma proteins?i.e.human immunoglobulin G?IgG?,human serum albumin?HSA?and fibrinogen?FG??to carboxylated SWCNTs,and evaluated the effect of these different protein coronas on cytotoxicity to endothelial cells and immune response to neutrophils in the bloodstream.Measurements of adsorption parameters revealed tight binding of proteins to SWCNTs and the SWCNTs adsorption capacities followed the order FG>HSA>IgG.In addition,the basic residues?Arg,Lys,His?were found to play an important role in the formation of protein-SWCNTs corona complexes and determine their adsorption capacity.Consistent with the higher protein adsorption capacity,FG more significantly reduced the cytotoxicity of CNTs to human umbilical vein endothelial cells than the other two proteins.However,only treatment of SWCNTs with IgG resulted in the enhancement of CNT-induced myeloperoxidase?MPO?release?i.e.neutrophil activation?in neutrophils,while MPO-dependent degradation of CNTs induced less cytotoxicity than initial nanomaterials.Consistent with these effects of protein coronas,the presence of serum attenuated the cytotoxicity of CNTs and CNTs could induce neutrophil activation in human blood plasma.Our study demonstrates the ability of adsorbed plasma proteins to influence cytotoxicity and neutrophil response caused by CNTs in the bloodstream.These findings will be helpful to clarify the mechanism of interactions of functionalized SWCNTs with human serum proteins,and provide more insight into the understanding of how to design the safe nanoparticles in biomedical applications.