金属增强荧光(MEF)理论一直是近年来研究的热点。通过研究光谱测量、细胞共聚焦成像和流式细胞术(FCM)等方法来定量分析不同长径比(3.1~6.5)的金纳米双锥对光敏剂铝酞菁(AlPcS)的荧光和光动力疗法(PDT)效果的增强效应。荧光光谱和共聚焦成像结果表明, 高长径比的金纳米双锥使铝酞菁的荧光强度大大增强, 最大增强因子为6; 低长径比的金纳米双锥由于其等离子共振带与铝酞菁的荧光带接近, 因此使铝酞菁的荧光强度大大降低。Hela细胞(人上皮宫颈癌细胞)的凋亡测定结果显示: 金纳米双锥的加入, 特别是高长径比的金纳米双锥的加入, 使得铝酞菁的载药率和产生单线态氧的能力提高, 从而降低了Hela细胞的存活率, 增强了铝酞菁的光动力疗法效果。本实验为表面增强荧光的研究提供了一个新的途径, 并扩展了金属纳米粒子在生命科学领域的应用。

Metal-enhanced fluorescence (MEF) theory is a hot research topic in recent years. In this study, the fluorescence intensity and photon dynamic treatment (PDT) enhancement of gold nanobipyramids (Au NBPs) with different aspect ratios (3.1-6.5) to photosensitizer AlPcS is quantitively analyzed using spectral measurement, cell confocal imaging and flow cytometry method (FCM). The results of flourscence spectrum and confocal imaging show that Au NBPs with high aspect ratios can greatly enhance the fluorescence intensity of AlPcS, and the maximum enhancement factor is 6. Au NBPs with low aspect ratio can greatly reduce the fluorescence intensity of AlPcS, because its plasma resonance band is close to the fluorescence band of AlPcS. Hela cells (human epithelial cervical cancer cells) apoptosis measurements show that the join of Au NBPs, especially Au NBPs with high aspect ratios, improves drug-loading rate and singlet oxygen production of AlPcS. Then the survival rate of Hela cell is reduced and PDT effect of AlPcS is enhanced. These results provide a new avenue for the research of surface-enhancement fluorescence and expand the bioapplications of metal nanoparticles.