Osteoblast Adhesion on Tissue Engineering Scaffolds Made by Bio-Manufacturing Techniques

Abstract

Scientific exploration into understanding and developing relationships between three-dimensional (3D) scaffolds prepared by rapid prototyping (RP) and cellular response has focused primarily on end results targeting osteoblast proliferation and differentiation. Here at the National Institute of Standards and Technology (NIST), we take a systems approach to developing relationships between material properties and quantitative biological responses. This study in particular focuses on the screening of parameters controlled by RP techniques and their ability to trigger signalling events leading to cell adhesion. This pioneering research in our group also characterizes the in vitro cell-material interactions of 2D films and 3D scaffolds. From there, one can postulate on contributory factors leading to cell migration, proliferation, and differentiation. In summary, we believe that the quantitative information from this fundamental investigation will enhance our knowledge of the interactions between cells and 3D material interfaces with respect to formation of focal adhesions. This work consists of two sections — the application of imaging techniques for 3D characterization of properties and culturing of osteoblasts for size and shape determination. This includes quantifying the number of focal adhesion sites. We are using 3D RP polycaprolactone (PCL) scaffolds as this surrogate model in which to compare 2D to 3D material performance and cell interactions. Using RP bio-manufacturing techniques to fabricate tissue engineering scaffolds allows for control of pore size, strut size, and layer thickness, therefore providing adjustable parameters to study which can potentially influence, or even dynamically modulate, cellular adhesion. Imaging results after culturing for 24 h showed differences in cell morphology and spreading relative to the different structures. The focal adhesion response also varied, indicating an apparent loss of organization in 3D scaffolds compared to 2D surfaces. See Results and Discussion for details.