Dynamic mechanical properties of the tissue-engineered matrix associated with individual chondrocytes

作者：Lee BoBae; Han Lin; Frank Eliot H; Chubinskaya Susan; Ortiz Christine; Grodzinsky Alan J^*

来源：Journal of Biomechanics, 2010, 43(3): 469-476.

DOI：10.1016/j.jbiomech.2009.09.053

• Chondrocytes
• AFM
• Dynamic compression
• Pericellular matrix
• Growth factors
• Nanomechanics
• Tissue engineering

The success of cell-based tissue engineering approaches in restoring biological function will be facilitated by a comprehensive fundamental knowledge of the temporal evolution of the Structure and properties of the newly synthesized matrix. Here, we quantify the dynamic oscillatory mechanical behavior of the engineered matrix associated with individual chondrocytes cultured in vitro for LIP to 28 days in alginate scaffolds. The magnitude of the complex modulus (|E*|) and phase shift (delta) were measured in Culture medium using Atomic Force Microscopy (AFM)-based nanoindentation in response to an imposed oscillatory deformation (amplitude similar to 5 nm) as a function of frequency (f=1-316 Hz), probe tip geometry (2.5 mu m radius sphere and 50 nm radius square pyramid), and in the absence and presence of growth factors (GF, insulin growth factor-1. IGF-1, and osteogenic protein-1, OP-1). |E*| for all conditions increased nonlinearly with frequency dependence approximately f(1/2) and ranged between similar to 1 and 25 kPa. This result, along with theoretical calculations of the characteristic poroelastic relaxation frequency, f(p), (similar to 50-90 Hz) suggested that this time-dependent behavior was governed primarily by fluid flow-dependent poroelasticity, rather than flow-independent viscoelastic processes associated with the solid matrix. |E*(f)| increased, (f) decreased, and the hydraulic permeability. k. decreased with time in Culture and with growth factor treatment. This trend of a more elastic-like response was thought to be associated with increased macromolecular biosynthesis, density, and a more mature matrix structure/organization.

• 出版日期2010-2-10
• 单位MIT