Cauzzo Jennifer, Jayakumar Nikhil, Ahluwalia Balpreet Singh, Ahmad Azeem, Škalko-Basnet Nataša
Drug Transport and Delivery Research Group, Department of Pharmacy, Faculty of Health Sciences, University of Tromsø The Arctic University of Norway, N-9037 Tromsø, Norway.
Optical Nanoscopy Research Group, Department of Physics and Technology, Faculty of Science and Technology, University of Tromsø The Arctic University of Norway, N-9037 Tromsø, Norway.
Pharmaceutics. 2021 Apr 21;13(5):590. doi: 10.3390/pharmaceutics13050590.
The rapid development of nanomedicine and drug delivery systems calls for new and effective characterization techniques that can accurately characterize both the properties and the behavior of nanosystems. Standard methods such as dynamic light scattering (DLS) and fluorescent-based assays present challenges in terms of system's instability, machine sensitivity, and loss of tracking ability, among others. In this study, we explore some of the downsides of batch-mode analyses and fluorescent labeling, while introducing quantitative phase microscopy (QPM) as a label-free complimentary characterization technique. Liposomes were used as a model nanocarrier for their therapeutic relevance and structural versatility. A successful immobilization of liposomes in a non-dried setup allowed for static imaging conditions in an off-axis phase microscope. Image reconstruction was then performed with a phase-shifting algorithm providing high spatial resolution. Our results show the potential of QPM to localize subdiffraction-limited liposomes, estimate their size, and track their integrity over time. Moreover, QPM full-field-of-view images enable the estimation of a single-particle-based size distribution, providing an alternative to the batch mode approach. QPM thus overcomes some of the drawbacks of the conventional methods, serving as a relevant complimentary technique in the characterization of nanosystems.
纳米医学和药物递送系统的快速发展需要新的有效表征技术，这些技术能够准确地表征纳米系统的性质和行为。诸如动态光散射（DLS）和基于荧光的分析等标准方法在系统稳定性、机器灵敏度以及跟踪能力丧失等方面存在挑战。在本研究中，我们探讨了批处理模式分析和荧光标记的一些缺点，同时引入定量相显微镜（QPM）作为一种无标记的补充表征技术。脂质体因其治疗相关性和结构多功能性而被用作模型纳米载体。脂质体在非干燥设置中的成功固定使得在离轴相显微镜中能够进行静态成像。然后使用相移算法进行图像重建，提供高空间分辨率。我们的结果表明，QPM具有定位亚衍射极限脂质体、估计其大小以及随时间跟踪其完整性的潜力。此外，QPM全场图像能够估计基于单粒子的大小分布，为批处理模式方法提供了一种替代方案。因此，QPM克服了传统方法的一些缺点，在纳米系统表征中作为一种相关的补充技术发挥作用。
