以光學同調斷層掃描探討癌細胞球團攝入金奈米顆粒的行為

Abstract

我們使用光學同調斷層掃描技術來研究細胞球體對金奈米顆粒的攝取過程。我們使用三種類型的金奈米顆粒，包括兩種金奈米棒和一種金奈米環，它們在光學同調斷層掃描操作波長1060 nm處具有顯著的侷部表面電漿子共振。我們分析沿著深度的光學同調斷層掃描信號強度分佈，得出細胞球團中金奈米顆粒的濃度分佈。早期的金奈米顆粒攝取行為，我們假設金奈米顆粒的濃度沿著深度指數衰減來構建簡單模型，以擬合金奈米顆粒攝取前30分鐘中的光學同調斷層掃描信號強度分佈。以此估計金奈米顆粒進入細胞球團穿透深度隨時間變化。在最初的30分鐘內，穿透深度大約為20微米，即2-3層細胞。我們也使用光學同調斷層掃描系統掃描長時間攝取金奈米棒的細胞球團。我們發現，細胞球團的攝取行為包括增殖細胞的內吞作用和胞吐作用以及細胞球體中休眠細胞層中金奈米顆粒的擴散過程。

We use the optical coherence tomography (OCT) scan technique to study the uptake process of Au nanoparticles (NPs) by a cell spheroid. By using three types of Au NP, including two gold nanorod (GNR) and one gold nanoring samples, which have significant localized surface plasmon resonances at the OCT operation wavelength (1060 nm), we analyze the OCT signal intensity profiles along the depth in a cell spheroid for understanding the Au NP concentration distribution in the cell spheroid. In studying the Au NP uptake behavior in the early stage, we build a simple model by assuming an exponential decay of Au NP concentration along depth for fitting the OCT signal intensity profiles in the first 30 min of Au NP incubation. The penetration depth of Au NPs into a cell spheroid can be calibrated. In the first 30 min, generally the penetration depth is around 20 microns, i.e., 2-3 layers of cell. We also use the OCT system to scan the cell spheroids incubated with GNRs for long times. It is found that the uptake behaviors of a cell spheroid include the endocytosis and exocytosis processes of the proliferating cells and the diffusion process of Au NPs in the quiescent cell layer in the cell spheroid.