Mechanical Properties of Collagen, Fibrin and Collagen-Fibrin Networks

Abstract

The macroscopic mechanical properties of bio-engineered tissues are inextricably linked to their microstructure. Often, their microstructure is a complex arrangement of several different components (e.g. collagen, fibrin) that interact with each other to give a tissue its overall properties. These microstructural complexities are further compounded by the dynamic cell interactions with the extracellular matrix (ECM). Our group [1] uses fibrin as the starting scaffold material for cell seeding and tissue growth; over time, the underlying microstructure undergoes dynamic remodeling as the fibrin network is degraded and gradually replaced with collagen. Currently, we have a modeling framework that incorporates a single-component microstructure network to predict the mechanical properties of the engineered tissue [2]. However, this model is unable to capture the transient intermediate stages of tissue growth, during which the tissue is composed of interpenetrating collagen and fibrin networks at varying compositions. In this work, we have incorporated a second network into our model and compared these modeling results with experimental data obtained from uniaxial tests on acellular collagen-fibrin co-gels. This work represents one step in the progression of our model to capture better the relationships between tissue microstructure and macroscopic mechanical properties, with the ultimate goal of developing a comprehensive model framework for rational design of functional engineered tissues.