A tracer metric numerical model for predicting tortuosity factors in three-dimensional porous tissue scaffolds

One of the critical functions of a tissue-engineered construct is to be able to provide adequate nutrient and oxygen supply into the interior of the construct. An insufficient supply will lead to slower cellular proliferation rates and eventual apoptosis. The supply of the nutrients is largely governed by the transport properties of the construct which in turn is dependent on the porosity, tortuosity and surface chemistry of the tissue construct. The design and fabrication of scaffolds with tailored properties is thus a crucial step in the growth of tissue within their host environment. This paper discusses the development of a numerical characterization technique to measure the three-dimensional tortuosity factors for any given interconnected porous design. Tortuosity factors are obtained in the three orthogonal principal directions for several candidate unit cell architectures. The proposed numerical technique has been validated with models of known tortuosity. The developed technique will provide a basis for the study of transport properties of the designed scaffold and its effect on cellular function and response through the development of dynamic culture bioreactors.