The impact of fibronection stripe patterns on the cellular and nuclear morphology of fibroblasts

The effect of biochemical environmental signals on cell mechanisms has been the subject of numerous studies for a long time. However, the in-vitro studies of biophysical cues on cells and tissues have recently become a popular focus of research. The development of micro-fabrication techniques has allowed the study of certain aspects of cell-substrate interactions in a more detailed form. Micro-topographical patterns on the cell substrates have been used to study many cell functions such as cell migration, adhesion, gene expression, cell division and differentiation. An understanding of cell-substrate interactions and the potential ability to control the interactions have very important applications in the field of tissue engineering and regenerative medicine. We have fabricated ridge-groove micro patterns on polydimethylsiloxane (PDMS) substrates with different ridge widths (8μm, 10μm, 12 μm, 25μm and 50μm) using standard photolithography technique. We used these patterns to print fibronectin stripes on PDMS substrates. NIH/3T3 fibroblast cells were cultured on these stripes and the dynamics of morphological changes were monitored in steady spreading phase (S-phase). Our data revealed that the thickness of the cell, measured by confocal microscopy, is considerably larger (approximately 40%) among the cells spreading on narrower stripes (8μm, 10μm and 12μm) compared to the cells expanding on wider (including control) patterns. The number of perinuclear actin stress fibers is significantly lower among narrower stripes which probably explains the cell thickness results. Confocal microscopy revealed that the cellular volume increases during cell adhesion processes and volume increase is positively correlated with the width of stripes. Nuclear volume also increases considerably during cell adhesion; however, confining cells on fibronectin stripes reduces nuclear volume enlargement independent from the of stripe size.