Measuring the Material Properties of the Engineered Tissue

Abstract

The objective of this study is to determine the mechanical properties of the fibroblast-populated collagen lattices as the dermal-equivalent engineered tissue. Fibroblasts reorganize the collagen matrix by applying the traction and tensile forces that are important for the homeostatic morphology and material properties of the extracellular matrix. During development, the collagen lattices undergo dramatic compaction and contraction processes that lead to changes in their elastic properties. The mechanical properties of the tissue in turn affect cell differentiation and functions. In this study, we designed and built a microsphere-based magnetic indentation system to measure the regional material properties of the engineered tissue during development or treatment. The indentation forces were controlled by varying the magnetic forces on the ferric microsphere under either permanent or electro magnets. The resultant tissue indentation was directly visualized by an optical coherence tomography imaging system. In a preliminary set of experiments on engineered tissue a micro-Newton indentation forces have been applied and resulting indentation has been measured. It was determined that changes in the elastic properties of the tissue during development are correlated to the increased compaction and contraction of the tissue by the fibroblasts. The technique and results will shed new light on the biomechanics and mechanobiology of the tissue in developmental or during wound healing.