State Key Laboratory on Integrated Optoelectronics, College of Electronic Science and Engineering, Jilin University, Changchun 130012, Jilin, China.
Department of Biomedical Engineering, Southern University of Science and Technology, Shenzhen 518055, Guangdong, China.
Anal Chem. 2021 May 11;93(18):7071-7078. doi: 10.1021/acs.analchem.1c00548. Epub 2021 Apr 27.
There is a great deal of interest in the development of nanoparticles for biomedicine. The question of how many nanoparticles are taken up by cells is important for biomedical applications. Here, we describe a fluorescence method for the quantitative measurement of the cellular uptake of polymer dots (Pdots) and a further estimation of intracellular Pdots photosensitizer for fluorescence imaging and photodynamic therapy. The approach relies on the high brightness, excellent stability, minimal aggregation quenching, and metalloporphyrin doping properties of the Pdots. We correlated the single-cell fluorescence brightness obtained from fluorescence spectrometry, confocal microscopy, and flow cytometry with the number of endocytosed Pdots, which was validated by inductively coupled plasma mass spectrometry. Our results indicated that, on average, ∼1.3 million Pdots were taken up by single cells that were incubated for 4 h with arginine 8-Pdots (40 μg/mL, ∼20 nm diameter). The absolute number of endocytosed Pdots of individual cells could be estimated from confocal microscopy by comparing the single-cell brightness with the average intensity. Furthermore, we investigated the cell viability as a result of an intracellular Pdots photosensitizer, from which the half maximal inhibitory concentration was determined to be ∼7.2 × 10 Pdots per cell under the light dose of 60 J/cm. This study provides an effective method for quantifying endocytosed Pdots, which can be extended to investigate the cellular uptake of various conjugated polymer carriers in biomedicine.
人们对纳米颗粒在生物医学中的发展非常感兴趣。细胞摄取多少纳米颗粒对于生物医学应用非常重要。在这里，我们描述了一种用于定量测量聚合物点（Pdots）细胞摄取的荧光方法，并进一步估算了用于荧光成像和光动力治疗的细胞内 Pdots 光敏剂。该方法依赖于 Pdots 的高亮度、优异的稳定性、最小的聚集猝灭和金属卟啉掺杂特性。我们将荧光光谱法、共聚焦显微镜和流式细胞术获得的单细胞荧光亮度与通过电感耦合等离子体质谱法验证的内吞 Pdots 数量相关联。我们的结果表明，平均而言，在用精氨酸 8-Pdots（40 μg/mL，约 20 nm 直径）孵育 4 小时后，单个细胞摄取了约 130 万个 Pdots。通过比较单细胞亮度与平均强度，可以从共聚焦显微镜中估计单个细胞内吞 Pdots 的绝对数量。此外，我们还研究了细胞活力作为细胞内 Pdots 光敏剂的结果，从中确定在光剂量为 60 J/cm 时，半最大抑制浓度约为每个细胞 7.2×10 Pdots。这项研究提供了一种定量内吞 Pdots 的有效方法，可以扩展到研究生物医学中各种共轭聚合物载体的细胞摄取。
