The surface proteomic signature of a biomaterial determines its interaction with epithelial

Abstract

Event Abstract Back to Event The surface proteomic signature of a biomaterial determines its interaction with epithelial Mohamed Nur Abdallah1, Sara Abdollahi2, Ghada Abughanam3, Marco Laurenti1, Yizhi Xiao4, Walter Siqueira4, Simon Tran3, Marta Cerruti2 and Faleh Tamimi1 1 McGill University, Faculty of Dentistry, Canada 2 McGill University, Department of Mining and Materials Engineering, Canada 3 McGill University, Craniofacial Tissue Engineering - Faculty of Dentistry, Canada 4 Western University, Department of Biochemistry and School of Dentistry, Canada Introduction: Surgical reconstruction of defects caused by infection, trauma or cancer relies heavily on the regeneration of the overlying epithelium and soft tissues, since they prevent bacterial penetration to deeper tissues. In fact, a main reason for the failure of craniofacial reconstructions is the lack of soft tissue regeneration. Several materials have been used for soft tissue reconstruction; however, most of them present unpredictable results and it is not well understood why some of them promote better soft tissue attachment than others. Basement membrane (BM) proteins are crucial for the interaction of epithelial cells with underlying tissues. Thus, we hypothesized that the adsorption of BM proteins on the surface of a biomaterial determines its interaction with epithelial cells. We investigated the interaction of biodegradable polymers with BM proteins and soft tissue cells (epithelial cells and fibroblasts), and optimized this interaction by surface functionalzation. Also, we developed a method to fabricate scaffolds of the optimized polymer with customized shape and porosity for epithelial and soft tissue regeneration. Materials and methods: The interaction of three biodegradable polymers (poly-DL-lactic-acid (PDLLA), alginate (ALG) and polycaprolactone (PCL)) with BM proteins was assessed using proteomic techniques such as bicinchoninic acid protein assay and liquid chromatography electrospray ionization tandem mass spectrometry (LC-ESI-MS). Human gingival epithelial cells and dermal fibroblasts were cultured on the polymers to evaluate cell viability. The most biocompatible polymer was functionalized with amine or phosphate groups using diazonium chemistry and was assessed using the previous methods. Next, we developed a process to customize the shape and porosity of the optimized polymer. We investigated the use of flexible elastomeric materials (silicone, polyurethane and polyether) to create molds for casting the polymer. The precision and porosity of the scaffolds were enhanced using the particulate-leaching method and were assessed using micro-computed tomography.Data was analyzed using ANOVA, and Student’s t-test. Non-parametric data was evaluated using non-parametric tests. Statistical significance was set at P<0.05. Results and discussion: PDLLA adsorbed the highest amount of BM proteins, and presented the highest epithelial cell viability, while PCL showed the lowest adsorption and worst cell viability (Fig.1). Compared to PCL, both PDLLA and ALG adsorbed high amounts of proteins and demonstrated high fibroblast viability (Fig.1). Surface functionalization affected protein adsorption and cell behaviour on PDLLA. Both amination and phosphonation of PDLLA surfaces adsorbed similar amounts of BM proteins and improved the fibroblast viability; however, only aminated-PDLLA increased the concentration of adhesive proteins and enhanced the viability of epithelial cells (Fig.1). These results suggest that the adsorption of BM proteins, particularly adhesive proteins (e.g. laminin), is important for epithelial cell but not for fibroblasts. Polyether was found to be compatible with the PDLLA solvent and was used to create molds for casting scaffolds with customizable shape and porosity (Fig.2). These scaffolds could be used for soft tissue reconstruction. Conclusion: The adsorption of basement membrane proteins is critical for epithelial cell interaction with biomaterials. Surface amination promotes epithelial cell attachment by the enhancing the adsorption of adhesive basement membrane proteins. Aminated-PDLLA is a good candidate for soft tissue regeneration and can be customized using polyether molds. The Canadian Institutes of Health Research; The Natural Sciences and Engineering Research Council of Canada; The Canada Foundation for Innovation; The Network for Oral and Bone Health Research; The Canadian Imperial Bank of Commerce; The Faculty of Dentistry of McGill University