磁性奈米碳管之製備以及與A549和HeLa細胞之交互作用

Abstract

奈米碳管能夠吸收近紅外光將其轉換成熱能以及具有良好的生物相容性和表面易修飾生物分子之特性，由於這些獨特的特性使得奈米碳管成為多功能性生物載體及熱殺死癌細胞的最佳選擇。若能將氧化鐵奈米粒子填入到奈米碳管中，就可以藉由磁性有效的分離出碳管。因此，在這裡我們利用化學氣相沉積法和化學共沉澱法合成出磁性奈米碳管做為生醫應用的材料。我們利用MTT分析法研究磁性奈米碳管對A549和HeLa細胞是否具有毒性。當磁性奈米碳管的濃度低於2 µg/µL時，其對A549細胞具有一個良好的生物相容性。此外，這個研究也證實了在試管內的磁性奈米碳管被波長808 nm的近紅外光連續照射會引起局部的加熱導致大量的細胞死亡。另外，我們也研究癌細胞攝取磁性奈米碳管的機制。癌細胞培養16小時之後，我們發現在沒有葉酸的培養液中癌細胞攝取磁性奈米碳管的數量多於含有葉酸的培養液並且將癌細胞與胞吞抑制劑一起培養，發現並不會影響癌細胞攝取磁性奈米碳管。因此，癌細胞攝取的機制或許不依賴胞吞作用。

Carbon nanotubes (CNTs) have strong absorbances in near-infrared (NIR) region, a great biocompatibility and the surface can be modified easily by biomolecular. These unique properties make CNTs promising candidates for multifunctional biological transporters and thermal cancer cell killers. Incorporating Fe3O4 nanoparticles into the CNTs can enhance effective CNT separation by magnetism. Therefore, here we report the synthesis of magnetic carbon nanotubes (MCNTs) by using chemical vapor deposition (CVD) and chemical coprecipitation for biomedical applications. We investigated the cytotoxic effects of MCNTs using A549 and HeLa cancer cells with MTT [(3-(4,5-Dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide] assay. We found that MCNTs, below 2 µg/µL, have a very good biocompatibility for A549 cells. Furthermore, this work demonstrates that continuous 808 nm NIR radiations triggered extensive cell death in the presence of MCNTs because of the excessive local heating in vitro. In addition, we also studied cellular uptake of MCNTs mechanism. It was found that the cellular uptake was much higher in cells exposed to MCNT in an FA-free culture medium than those in a culture medium with FA after incubation 16 h. We found that incubation with endocytosis inhibitor agent did not influence cellular uptake of MCNTs. It is clear that the uptake mechanism is likely to be an endocytosis-independent pathway.