Long-term fate tracking and quantitative analyzing of nanoparticles in stem cells with bright-field microscopy

The evolution of nanotechnology gives impetus to the regenerative medicine growth, which has led to the great research interest in studying the interaction between stem cells and nanoparticles (NPs). The study of intracellular fate of NPs is generally consisted of two aspects: the dynamic tracking of NPs (NPs localization and transportation) and the quantification of intracellular NPs content. However, there is a lack of tools that could satisfy both requirements at the same time. In this work, Prussian blue nanoparticles (PBNPs) were chosen as model probes to study the fate of NPs in living cells. By combining the live cell imaging system with proposed quantification method (pixel-based colorimetry method), we realized a long-term monitoring and dynamic quantitation of PBNPs in living stem cells at the single-cell level. NPs fate tracking and quantitative analysis have visualized the asymmetrical inheritance of PBNPs in two daughter cells during mitosis and the reduction of PBNPs during interphase, which is mainly attributed by lysosomal digestion. As demonstrated by our results, we identified three factors that contributed to the PBNPs load change within one cell cycle: asymmetric cell inheritance (92.78%; 59.19% vs 33.59% in two cells), lysosomal digestion (6.93%), and exocytosis (0.29%). In summary, this study provided detailed insight of NPs' fate in cell cycles which is essential for rational design of NPs in the future. (c) 2022 Published by Elsevier Ltd.

Automated summary

The evolution of nanotechnology has driven the growth of regenerative medicine and sparked great interest in studying the interaction between stem cells and nanoparticles. This study used Prussian blue nanoparticles as model probes to investigate the fate of nanoparticles in living cells. By combining live cell imaging and a pixel-based colorimetry method, the researchers achieved long-term monitoring and dynamic quantification of nanoparticles in living stem cells at the single-cell level. The results revealed the asymmetrical inheritance of nanoparticles during mitosis and their reduction during interphase, mainly due to lysosomal digestion. This study provides important insights into the fate of nanoparticles in cell cycles, which are essential for the rational design of nanoparticles in the future.