應用於循環腫瘤細胞捕獲及光熱/光動力治療之標靶奈米金籠修飾磁性載體

Abstract

百分之九十的癌症病患會因為癌細胞轉移而死亡，而循環腫瘤細胞在轉移過程中扮演重要角色。標靶血液中循環腫瘤細胞可以中斷癌細胞擴散及降低癌症死亡的可能性。在此，我們利用具有磁性及光敏感特性載體來捕獲並同時破壞流體中的癌細胞。奈米金籠(Gold nanocages, AuNCs)在波長為808奈米的光源照射下可以產生高溫引起癌細胞壞死，或是在915和940奈米的光源下產生高活性氧分子(Singlet oxygen, 1O2)使細胞凋亡。載體的加熱效率可以使溫度提高至超過攝氏五十度。藉由磷光發散光譜及螢光指示劑(Singlet oxygen sensor green, SOSG)來確定用近紅外光照射載體可以產生高活性氧分子。為了提高載體的標靶效率，載體表面架接可以辨別老鼠乳癌細胞上皮細胞黏著分子的抗體。細胞實驗中，利用螢光指示劑證明細胞內自由基濃度被提高九倍，除此之外，加入抑制劑可以減少細胞內自由基產生。細胞毒性分析顯示載體具有很高的生物相容性，而在照光的情況下，光熱及光動力治療確實可以抑制癌細胞生長。最後，在微流道實驗中，外部磁場成功捕獲癌細胞並同時給予光照治療破壞被吸附的細胞。這樣的模式可以用來定點清除血液中循環腫瘤細胞。

Metastasis is associated with 90 % of cancer-related deaths and circulating tumor cells (CTCs) play an important role as an intermediate during the metastatic invasion. Targeting CTCs when they are transiting in the blood circulation could disrupt cancer dissemination and reduce the probability of cancer death. Herein, we introduce a magnetic photosensitive nanocarrier, gold nanocages-conjugated thiol-magnetic nanocarriers (GTMNCs) to trap and destroy cancer cells in situ in flow. Gold nanocages (AuNCs) are able to induce hyperthermia which results in cancer cells necrosis under 808 nm irradiation and sensitize singlet oxygen (1O2) formation to activate apoptosis program upon NIR illumination (940 nm LED, 915 nm laser). The temperature of the suspension of GTMNCs raised to more than 50 oC under 808 nm laser light. 1O2 phosphorescence emission and singlet oxygen sensor green (SOSG) fluorescent probe were used to confirm the 1O2 generation upon NIR illumination. As GTMNCs were functionalized with anti-epithelial cell adhesion molecule (EpCAM) antibody to specifically target mouse breast cancer cell (4T1), in vitro experiments demonstrated 9-fold increase in intracellular ROS levels by quantifying SOSG and dihydroethidium (DHE) fluorescence. Scavengers were also used as negative control. Cytotoxicity assay indicates that GTMNCs are high biocompatibility in dark until photoirradiation for performing photothermal therapy (PTT) and photodynamic therapy (PDT). Further magnetic enrichment of 4T1 cells and simultaneous photodestruction in the microfluidic channel using the GTMNCs proved a potential methodology of phototherapy for CTCs removal.