Intracellular Dynamics and Fate of Polystyrene Nanoparticles in A549 Lung Epithelial Cells Monitored by Image (Cross-) Correlation Spectroscopy and Single Particle Tracking

Abstract

Novel insights in nanoparticle (NP) uptake routes of cells, their intracellular trafficking and subcellular targeting can be obtained through the investigation of their temporal and spatial behavior. In this work, we present the application of image (cross-) correlation spectroscopy (IC(C)S) and single particle tracking (SPT) to monitor the intracellular dynamics of polystyrene (PS) NP in the human lung carcinoma A549 cell line. The ensemble kinetic behavior of NP inside the cell was characterized by temporal and spatiotemporal image correlation spectroscopy (TICS and STICS). Moreover, a more direct interpretation of the diffusion and flow detected in the NP motion was obtained by SPT by monitoring individual NP. Both techniques demonstrate that the PS NP transport in A549 cells is mainly dependent on microtubule-assisted transport. By applying spatiotemporal image cross-correlation spectroscopy (STICCS), the correlated motions of NP with the early endosomes, late endosomes and lysosomes are identified. PS NP were equally distributed among the endolysosomal compartment during the time interval of the experiments. The cotransport of the NP with the lysosomes is significantly larger compared to the other cell organelles. In the present study we show that the complementarity of ICS-based techniques and SPT enables a consistent elaborate model of the complex behavior of NP inside biological systems.