用於三維細胞培養系統之雙波長光聲分子顯微鏡

Abstract

了解治療細胞與腫瘤間的交互作用，有助於發展如免疫治療的細胞治療。不同於二維細胞培養技術，三維細胞培養系統提供更擬真的細胞環境用以觀察細胞過程及了解生物機制。然而，傳統純光學的分子影像技術像是共軛焦顯微鏡、雙光子顯微鏡在觀測三維微環境下的生物現象有明顯的缺點。因此，在滿足三維細胞培養系統前提下，本文建構出一套可用於細胞追蹤以及細胞型態描繪的雙波長光聲分子顯微系統（波長為523 nm以及800 nm），並運用金奈米粒子作為外源性的光聲對比劑。以奈米金球標定胞殺性T細胞以及以奈米金桿標定肝癌細胞，特化其細胞分別對523 nm以及 800 nm雷射的選擇性吸收予以鑑別。實驗結果顯示，雙波長光聲分子顯微系統可在三維微環境下有效觀測經標定的T細胞分布以及描繪出經標定的肝腫瘤球輪廓。

With the knowledge of cell interaction between tumor and therapeutic cells, it can help to develop cell-based therapeutic strategies such as immunotherapy. In contrast to traditional two-dimensional (2D) cell cultures, a three-dimensional (3D) cell culture system better mimics the cell environment for observation of cellular processes and understanding biological mechanisms. However, conventional molecular imaging methods such as confocal microscopy and two-photon microscopy hardly depict cell processes in 3D models. Thus, we have developed dual-wavelength photoacoustic molecular microscopy for 3D cell culture systems for visualizing cell distribution and morphology. We employed gold nanoparticles (AuNPs) as wavelength-dependent contrast agents in our dual-wavelength optical resolution photoacoustic microscope, with the wavelength of 523 nm and 800 nm, for visualizing CD8+ cytotoxic T lymphocytes (CTLs) in an in vitro 3D tumor microenvironment. Targeted CTLs with avidin-conjugated gold nanospheres (AuNSs) and hepatocellular carcinoma labeled with gold nanorods (AuNRs) were distinguishable by their distinct absorption spectra under 523-nm and 800-nm laser irradiation. We successfully showed that dual-wavelength OR-PAM can map the distribution of CTLs with AuNSs under 523-nm irradiation and the 3D morphology of tumorspheres with AuNRs under 800-nm irradiation in an in vitro 3D microenvironment.