Mechanical Stimulation of MC3T3 Osteoblastic Cells in a Bone Tissue-Engineering Bioreactor Enhances Prostaglandin E₂Release

Influence of a novel calcium-phosphate coating on the mechanical properties of highly porous collagen scaffolds for bone repair

“…Fabrication techniques such as rapid prototyping (Landers et al 2002) and solid freeform fabrication (Porter et al 2001, Weiss 2001) have been used to fabricate pure calcium-phosphate scaffolds. However, porosities of only 60-70% (Vance et al 2005) and 80-85% (Kim et al 2005) are reported. With a similar CP process and commercially available Gelfix scaffolds, Yaylaoglu et al, Kose et al and Du et al claim similar material results to our study of precipitated CP to a collagen scaffold (Du et al 2000, Kose et al 2004, Yaylaoglu et al 1999.…”

Influence of flow rate and scaffold pore size on cell behavior during mechanical stimulation in a flow perfusion bioreactor

“…However, static culturing regimes neglect the important role of biomechanical stimuli in the normal formation, development and homeostasis of bone tissue: the effects of which are clearly observed when normal, physiologically relevant levels of mechanical stimulation are removed (Morey and Baylink, 1978;Zerwekh et al, 1998). Therefore, in-vitro bone tissue cultivation strategies have sought to enhance the osteogenic differentiation of cell-seeded constructs by employing mechanical stimulation via flow-perfusion (Bancroft et al, 2002;Cartmell, S. et al, 2003;Keogh et al, 2011;Sikavitsas et al, 2003;Sikavitsas et al, 2005;Vance et al, 2005). We have successfully employed an in-house designed perfusion bioreactor to examine the effects of mechanical stimulation on gene expression levels of key osteogenic markers for MC3T3 (pre-osteoblasts) cell-seeded collagen-GAG (CG) scaffolds subjected to a range of fluid flow regimes and for exposure times of 1h to 14 days Partap et al, 2009;Plunkett et al, 2010).…”

“…Computational modelling has shown that bridged cells can experience up to 500 fold greater levels of cytoskeletal deformation than flat cells under the same flow conditions (Jungreuthmayer et al, 2009b); their alignment to the direction of flow creates a greater level of resistance and at the extreme end of the scale one can consider them to behave like a sail in the wind. We hypothesise it is this increased cytoskeletal deformation of bridging cells that promotes osteogenesis at lower mean shear stress levels () (~1-100x10 -3 Pa) in highly porous scaffolds compared to 2D (0.1-1.5Pa) (McCoy and O'Brien, 2010), or scaffolds with very large pore sizes where a flat morphology type dominates (Vance et al, 2005). Furthermore, assuming constant cell properties (e.g integrin density), bridged cells would be expected to have fewer integrin-matrix interactions as they have smaller surface areas of attachment, resulting in a reduced adhesive force.…”

Osteoblast Response to Rest Periods During Bioreactor Culture of Collagen–Glycosaminoglycan Scaffolds

“…In one 3D study, Vance et al 20 found that prostaglandin E 2 (PGE 2 ) release increased with the use of a short bout of oscillatory flow in combination with steady flow. In vivo, rest-inserted loading remains to be optimized, 21 and in vitro, further experiments are needed to examine the role of rest period duration.…”