Engineering Cell Adhesion Dynamics for Esophageal Tissue Engineering
Vincent Chan, Chemical and Biomolecular Engineering, Nanyang Technological Unuversity, 50 Nanyang Avenue, Singapore, 639798, Singapore, Sandy Chian, Mechanical and Aerospace Engineering, Nanyang Technological Unuversity, 50 Nanyang Avenue, Singapore, 639798, Singapore, and Buddy Ratner, University of Washington, Bagley, Box 351720, Seattle, WA 98195.
A major challenge in esophageal tissue engineering is the design of biomaterial for promoting adhesion of primary esophageal cells. Tracking the biophysical responses of esophageal cells against the change of biomaterials properties will aid the design of tailored scaffold for esophagus regeneration. In this study, the adhesion contact dynamics of porcine esophageal epithelial cells seeded on chemically grafted chitosan surface (CHI) in real time is probed with confocal-reflectance interference contrast microscopy (C-RICM) in conjunction with phase contrast microscopy. In the absence of extracellular matrix (ECM) protein, all cells fail to develop adhesion contact on CHI although they are physically bound on the surface. By coating CHI with fibronectin (CHI-FN) or elastin (CHI-ES), strong adhesion contact of epithelial cells evolve against time of cell seeding until they reached a steady state. The initial cell deformation rate of cells is 0.0138 min-1 and 0.0151 min-1 on CHI-FN and CHI-ES, respectively. Interestingly, the steady-state adhesion energy of epithelial cells on CHI-FN is 1.73 times larger than that on CHI-ES. Moreover, immunostaining of actin for primary epithelial cells on CHI-FN shows the transformation from microfilament meshes at cell periphery to stress fiber throughout the cytoplasm from 50 to 130 minutes after cell seeding. At the same time, vinculin staining demonstrated the formation of focal adhesion of the cells on CHI-FN after 130 minutes of cell seeding. Interestingly, the presence of elastin leads to focal adhesion formation but fails to induce stress fiber formation. Overall, our study reveals that esophageal cell adhesion dynamics can be engineered by modifying a model biomaterial with ECM proteins.