In vivo Magnetic Resonance Elastography of mesenchymally derived constructs

The multidisciplinary field of tissue engineering (TE) aims to create biological substitutes to restore, maintain, or enhance the function of tissue or whole organs, in which the mechanical properties of replacements are critical to their structure and function. Several techniques have been investigated for measuring the mechanical properties of developing tissues and organs; however, current methods are destructive. The goal of this work is to apply high resolution Magnetic Resonance Elastography (μMRE) technique with 100 μm in-plane resolution to address a critical problem in TE: nondestructive monitoring and characterization of growing mesenchymal stem cells (MSCs)-based tissue engineered constructs. In this study, μMRE is used to assess the development of osteogenic and adipogenic constructs implanted in immunodeficient nude mice. In vivo MRE experiments were conducted at 9.4 T (400 MHz for protons) using an 89 mm vertical bore magnet. Multiple shear waves were presented in the adipogenic constructs in comparison to the osteogenic constructs. This study demonstrated that μMRE can be used to non-invasively monitor the growth and development of various types of engineered tissues in vivo.