Dual requirements of extracellular matrix protein and chitosan for inducing adhesion contacte volution of esophageal epithelia

Abstract

It has been recently shown that chitosan (CHI)/collagen prostheses induced epithelization at the esophagus site of animal model. However, little is known on the biophysical mechanisms of cell adhesion on CHI-based material pertaining to esophagus tissue engineering. In this study, the adhesion contact dynamics of porcine esophageal epithelial cells seeded on CHI surface is probed using confocal-reflectance interference contrast microscopy in conjunction with phase-contrast microscopy. First of all, cells fail to form any adhesion contact on either CHI or elastin (ES)-coated surface. On CHI coated with fibronectin (CHI-FN) or elastin (CHI-ES), strong adhesion contact of cells evolved over time until they reached a steady-state level. The initial cell deformation rates of cells on CHI-FN and CHI-ES are 0.0138 and 0.0151 min(-1), respectively. Interestingly, cells on fibronectin (FN) coated substrate transiently form strong adhesion contact and eventually undergo deadhesion. Moreover, the steady-state adhesion energy of epithelial cells on CHI-FN is 1.73 and 148 times larger than that on CHI-ES and FN, respectively. The actin of cells on CHI-FN transforms from microfilament meshes at cell periphery to stress fibers throughout the cytoplasm during cell seeding. At the same time, vinculin staining demonstrated the evolution of focal adhesion complexes in cells on CHI-FN after 130 min of seeding. Interestingly, CHI-ES induces the formation of focal adhesion complexes in a lesser extent in cell but fails to lead to stress fiber formation. Overall, our study reveals that long-term adhesion contact evolution of esophageal epithelia is only triggered by both extracellular matrix protein and chitosan.