The Effect Of Functionalization Induced By Ion Beam On Cell And Blood Compatibility Of Multi-Walled Carbon Nanotubes

The multiwalled carbon nanotubes (MWCNTs) prepared by chemical vapor deposition (CVD) were sprayed on SiO2substrate. Then, the thinner carbon nitride (CNX) coatings with different N/C atomic composition ratios were deposited on MWCNTs by ion beam assisted deposition (IBAD). And laboratory-made MWCNTs were also bombarded with N ions by Kaufman gun. These two methods change MWCNTs’superhydrophobic character to superhydrophilic, which improve the cytocompatibility and hemocompatibility of MWCNTs. This paper studied the law between structural features, biocompatibility and preparation process parameters of the two functionalized multi-walled carbon nanotubes.X-ray photoelectron spectroscopy analysis (XPS) indicated0.12,0.21and0.27of N/C atomic ratios on CNx coatings, and7.81%,8.16%,9.28%of N atomic percentages on nitrogen-bombarding MWCNTs. The water contact angles of MWCNTs with CNc coatings and nitrogen-bombarding MWCNTs all drop below65°, indicating MWCNTs’ superhydrophobic character (128.89°) to superhydrophilic.Cytocompatibility in vitro tests were performed on MWCNTs, MWCNTs with CNX coatings and nitrogen-bombarding MWCNTs by mouse fibroblast cells (L929) and human endothelial cells (EAHY926). The scanning electron microscope (SEM) was employed to observe cell morphology on these materials. Results showed that MWCNTs with CNx coatings and nitrogen-bombarding MWCNTs stimulate cell growth and proliferation of cell culture. In addition, the cell adhesion numbers increased with increasing the N/C atomic ratio of MWCNTs with CNX coatings and nitrogen concentration of nitrogen-bombarding MWCNTs. Compared with the irregular cells on MWCNTs, typical triangular cells adhered to the surface of MWCNTs with CN0.27coatings and nitrogen-bombarding MWCNTs with N atomic percentages of9.28%. The adhered cells spread flat with rich pseudopod and microvilli. Especially, the best cytocompatibility on nitrogen-bombarding MWCNTs was both probably related to the positive contribution of N atomic and the three-dimensional network configuration.We also evaluated the blood compatibilities of the two functionalized materials by hemolysis test, platelet conglutination test and kinetic-clotting test. These results indicate that the two functionalized materials all have good hemocompatibility. MWCNTs with CNx coatings show low hemolytic rate (0.70-3.12%), less adhesion and activation of platelets (15.63-21.88%) and long kinetic blood-clotting time (27-50min). The nitrogen-bombarding MWCNTs also show low hemolytic rate (0%), less adhesion and activation of platelets (50.92-64.60%). But the clotting time of the nitrogen-bombarding MWCNTs are shorter than MWCNTs, which indicate the hemocompatibility of MWCNTs with CNX coatings are better than nitrogen-bombarding MWCNTs.