Yudasaka Masako, Zhang Minfang, Matsumura Sachiko, Yuge Ryota, Ichihashi Toshinari, Irie Hiroshi, Shiba Kiyotaka, Iijima Sumio
Nanotechnology. 2015 May 15;26(19):195102. doi: 10.1088/0957-4484/26/19/195102.
The properties of nanocarbons change from hydrophobic to hydrophilic as a result of coating them with dispersants, typically phospholipid polyethylene glycols, for biological studies. It has been shown that the dispersants remain attached to the nanocarbons when they are injected in mice and influence the nanocarbons' biodistribution in vivo. We show in this report that the effects of dispersants also appear at the subcellular level in vivo. Carbon nanohorns (CNHs), a type of nanocarbon, were dispersed with ceramide polyethylene glycol (CPEG) and intravenously injected in mice. Histological observations and electron microscopy with energy dispersive x-ray analysis revealed that, in liver and spleen, the lysosome membranes were damaged, and the nanohorns formed a complex with hemosiderin in the lysosomes of the macrophages. It is inferred that the lysosomal membrane was damaged by sphigosine generated as a result of CPEG decomposition, which changed the intra lysosomal conditions, inducing the formation of the CPEG-CNH and hemosiderin complex. For comparison, when glucose was used instead of CPEG, neither the nanohorn–hemosiderin complex nor lysosomal membrane damage was found. Our results suggest that surface functionalization can control the behavior of nancarbons in cells in vivo and thereby improve their suitability for medical applications.
在生物学研究中，通过用分散剂（通常是磷脂聚乙二醇）包覆纳米碳，可使其性质从疏水性转变为亲水性。研究表明，当纳米碳注入小鼠体内时，分散剂仍附着在纳米碳上，并影响其在体内的生物分布。我们在本报告中表明，分散剂的作用在体内亚细胞水平也会出现。碳纳米角（CNHs）作为一种纳米碳，用神经酰胺聚乙二醇（CPEG）分散后静脉注射到小鼠体内。组织学观察以及带有能量色散X射线分析的电子显微镜显示，在肝脏和脾脏中，溶酶体膜受损，并且纳米角在巨噬细胞的溶酶体中与含铁血黄素形成了复合物。据推测，溶酶体膜因CPEG分解产生的鞘氨醇而受损，这改变了溶酶体内的条件，诱导形成了CPEG-CNH和含铁血黄素复合物。作为对照，当使用葡萄糖代替CPEG时，未发现纳米角-含铁血黄素复合物以及溶酶体膜损伤。我们的结果表明，表面功能化可以控制纳米碳在体内细胞中的行为，从而提高它们在医学应用中的适用性。
