製備己二銅釓奈米微粒當作細胞追蹤劑之研究

幹細胞可遷移(migration)至器官損傷處進行修復，並因其自我更新(self-renewing)及分化(differentiation)的潛力而備受矚目，成為再生醫學中細胞治療(cell-based therapy)的熱門選擇。目前在幹細胞治療上已有許多成功的案例，然而其功能及作用機制上仍需更進一步的了解，所以追蹤治療中的幹細胞則成為相當重要的事。本研究選用核磁共振(Magnetic Resonance Imaging, MRI)為造影工具，主要是由於MRI是非侵入式的檢查及擁有優良的3D影像解像能力。並以臨床上常使用的增影劑Gd合成奈米微粒，來標定幹細胞達到追蹤的目的。並希望在未來可以經由此方式追蹤幹細胞，研究其在細胞治療中的角色以及作用機制。在材料製備上是用氯化釓(Gadolinium Chloride)螯合3,4-己二酮 (3,4-Hexanedione)而成已二酮釓(GdH)，並藉由水包油型微乳化的方法(oil-in-water micro emulsion)製備出疏水性的GdH奈米微粒。再將GdH奈米微粒與幹細胞共同培養，細胞與奈米微粒接觸之後，以胞噬作用將GdH奈米微粒攝入胞內，希望藉由GdH奈米微粒的疏水性質，加強其進入細胞的機率。並利用MRI進行造影，偵測出GdH奈米微粒標定之幹細胞影像。實驗結果顯示，我們以成功製備出100 nm 左右的GdH奈米微粒。300μg/mL濃度以下的GdH奈米微粒具有良好生物相容性，此濃度對照MRI影像，在200μg/mL濃度即有影像增強的效果，且影像增強能力比市售的Gd-DTPA更好。以TEM證實GdH奈米微粒可藉胞噬作用標定在幹細胞上，且由ICP-MS測出相同培養時間下，相較於Gd-DTPA，GdH有較好的標定能力。在細胞的MRI能夠偵測的到訊號，再配合幹細胞表面抗原的鑑定，證實幹細胞在標定上GdH奈米微粒之後，仍保有其免疫特徵。因此GdH奈米微粒應是一可行的幹細胞追蹤劑。

關鍵字

釓；奈米微粒；幹細胞；核磁共振；幹細胞追蹤劑

並列摘要

Stems cells are multipotent cells which are capable of self-renewing and differetiating into multipotent cell lineages. The therapeutic application of stem cells in many diseases has been widely studied in the past few years. However, the actual function and movement of stem cells after injection into human body remains unknown. In order to determine the function and movement of therapeutic stem cells, it is crucial to develop a technique to trace these therapeutic stem cells. MRI is the most utilized modality for tracking stem cells in vivo because of its safety and 3-dimensional capabilities. Gadolinium is one of the most effective MRI contrast agent in clinical. The purpose of this study is to synthesize Gd nanoparticles, which can permeate cell membrane for labeling the cells as a cell tracker. Gadolinium hexanedione (GdH), which was synthesized by complexion of Gd3+ with 3,4-hexanedione, was used as the nanoparticle matrix. By the combination of GdH matrix and emulsifying wax, GdH nanoparticles (GdH-NPs) were obtained from oil-in-water microemulsion technique. The stem cells were labeled by culture with hydrophobic GdH-NPs and detected by MRI. From the result of this study, the size of synthesized particles was about 100 nm. GdH-NPs were biocompatible when the concentration was under 300μg/ml. Moreover, GdH-NPs had greater ability of image enhancement than the commercialized Gd-DTPA. The TEM image of labeled stem cells showed that GdH-NPs was accumulated in the cells by endocytic pathway. The accumulation behavior of GdH-NPs and Gd-DTPA were analyzed by ICP-MS and GdH-NPS showed a better labeling ability than Gd-DTPA. Labeled stem cells showed better signal in the result to cellular MRI. In order to evaluate possible adverse effect of GdH-NPs, we examined the immunophenotypes of labeled cells and the immunophenotypes of stem cells labeled with GdHNPs showed no difference with control group. In this study, GdH NPs are synthesized with a nano-scale size and show a good biocompatibility. In conclusion, GdH-NP has a great potential as a stem cell tracker in the near future.

並列關鍵字

Gadolinium ； anoparticle ； mesenchymal stem cell ； MRI ； cell tracker

參考文獻

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製備己二銅釓奈米微粒當作細胞追蹤劑之研究

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