242 - A scale down design for mechanistic understanding of cell-scaffold interactions

Abstract

Understanding the complex cell colonisations within porous 3D biomaterials, is still a fundamental challenge in tissue engineering. It is especially difficult to assess cell-cell and cell-biomaterial interactions at the single- or multiple-cell level during tissue culture using common optical microscopes, due to their limited focus depth, the relative ‘large’ size and complex structures of 3D biomaterials. To combat this we deconstructed the complex 3D environment into thin sections using TEM grids, which were situated inside novel miniaturised bioreactors. Thus the cells cultured on the thin modular substrate can be imaged at the single cell level using conventional microscopic techniques. Human dermal fibroblasts cultured on these modular substrates were imaged through different optical microscopes during cell culture. Complicated dynamic processes were observed to be utilised by both individual and coordinated cells to bridge and segment porous structures. Further in-situ analysis via SEM and TEM provided high-quality micrographs of cell-cell and cell-biomaterial interactions at the micro-scale, and also illustrated the relation between different mechanical states of the cells and the internal cytoskeletal structures at nano-scale. Thus this novel scale-down design was able to improve the mechanistic understanding of cell colonisation within porous biomaterials, which could be difficult to obtain using other cell or tissue culture systems.