Biophysical and Biochemical Regulation of Cell Dynamics in Magnetically Assembled Cellular Structures.

Soluble signaling molecules and extracellular matrix (ECM) regulate cell dynamics in various biological processes. Wound healing assays are widely used to study cell dynamics in response to physiological stimuli. However, traditional scratch-based assays can damage the underlying ECM-coated substrates. Here, we use a rapid, non-destructive, label-free magnetic exclusion technique to form annular aggregates of bronchial epithelial cells on tissue-culture treated (TCT) and ECM-coated surfaces within 3 h. The cell-free areas enclosed by the annular aggregates are measured at different times to assess cell dynamics. The effects of various signaling molecules, including epidermal growth factor (EGF), oncostatin M, and interleukin 6, on cell-free area closures are investigated for each surface condition. Surface characterization techniques are used to measure the topography and wettability of the surfaces. Further, we demonstrate the formation of annular aggregates on human lung fibroblast-laden collagen hydrogel surfaces, which mimic the native tissue architecture. The cell-free area closures on hydrogels indicate that the substrate properties modulate EGF-mediated cell dynamics. The magnetic exclusion-based assay is a rapid and versatile alternative to traditional wound healing assays.