Influence of the PM Water-Soluble Compound on the Biophysical Properties of A549 Cells.

Understanding the influence of fine atmospheric particles (PM) on cellular biophysical properties is an integral part for comprehending the mechanisms underlying PM-induced diseases because they are closely related to the behaviors and functions of cells. However, hitherto little work has been done in this area. In the present work, we aimed to interrogate the influence of the PM water-soluble compound (PM-WSC) on the biophysical performance of a human lung carcinoma epithelial cell line (A549) by exploring the cellular morphological and mechanical changes using atomic force microscopy (AFM)-based imaging and nanomechanics. AFM imaging showed that PM-WSC treated cells exhibited evidently reduced lamellipodia and an increased height when compared to the control group. AFM nanomechanical measurements indicated that the treated cells had higher elastic energy and lower adhesion work than the control group. Our western blot assay and transmission electron microscopy (TEM) results revealed that after PM-WSC treatment, the contents of cytoskeletal components (β-actin and β-tubulin) increased, but the abundance of cell surface microvilli decreased. The biophysical changes of PM-WSC-treated cells measured by AFM can be well correlated to the alterations of the cytoskeleton and surface microvilli identified by the western blot assay and TEM imaging. The above findings confirm that the adverse risks of PM on cells can be reliably assessed biophysically by characterizing the cellular morphology and nanomechanics. The demonstrated technique can be used to diminish the gap of our understanding between PM and its harmful effects on cellular functions.