Bioreactor-based bone tissue engineering: The influence of dynamic flow on osteoblast phenotypic expression and matrix mineralization

Abstract

An important issue in tissue engineering concerns the possibility of limited tissue ingrowth in tissue-engineered constructs because of insufficient nutrient transport. We report a dynamic flow culture system using high-aspect-ratio vessel rotating bioreactors and 3D scaffolds for culturing rat calvarial osteoblast cells. 3D scaffolds were designed by mixing lighter-than-water (density, <1 g͞ml) and heavier-than-water (density, >1 g͞ml) microspheres of 85:15 poly(lactide-co-glycolide). We quantified the rate of 3D flow through the scaffolds by using a particle-tracking system, and the results suggest that motion trajectories and, therefore, the flow velocity around and through scaffolds in rotating bioreactors can be manipulated by varying the ratio of heavier-than-water to lighter-than-water microspheres. When rat primary calvarial cells were cultured on the scaffolds in bioreactors for 7 days, the 3D dynamic flow environment affected bone cell distribution and enhanced cell phenotypic expression and mineralized matrix synthesis within tissue-engineered constructs compared with static conditions. These studies provide a foundation for exploring the effects of dynamic flow on osteoblast function and provide important insight into the design and optimization of 3D scaffolds suitable in bioreactors for in vitro tissue engineering of bone.

Porous Structures: In situ Porous Structures: A Unique Polymer Erosion Mechanism in Biodegradable Dipeptide‐Based Polyphosphazene and Polyester Blends Producing Matrices for Regenerative Engineering (Adv. Funct. Mater. 17/2010)

“…[23, 34] However, for large porous structures the use of a bioreactor might be essential for complete cell infiltration, because the preformed structures present nutrient and oxygen diffusion limitations. [35] A 12-week of blend degradation in vivo resulted in a porosity of 82-87% which is structurally similar to cancellous bone. Furthermore, the sphere size increases with the increase of polyphosphazene composition in the blend, whereas no significant changes to porosity were observed.…”

Nano-ceramic Composite Scaffolds for Bioreactor-based Bone Engineering

“…At Days 7, 14, 21, and 28, samples were removed from bioreactors and DNA quantities, alkaline phosphatase (ALP) secretion, and calcium deposition were quantified and compared. The sample sizes were determined based on previously published results [7,44,60].…”

“…To overcome this problem, a variety of dynamic culture systems have been used including perfusion bioreactors [45,56], spinner flasks [32,58], roller bottles [26], and rotating wall bioreactors [55,59]. The high-aspect ratio vessel (HARV) bioreactor is a low-shear, high-mass transfer system that improves cell-seeded bone tissue-engineering scaffold performance [6,9,60]. Although the HARV bioreactor has been used for the dynamic culturing of osteoblast [60] and preosteoblast cells [7,11], it is unclear how human mesenchymal stem cells (HMSCs) behave in HARV bioreactors.…”

“…The high-aspect ratio vessel (HARV) bioreactor is a low-shear, high-mass transfer system that improves cell-seeded bone tissue-engineering scaffold performance [6,9,60]. Although the HARV bioreactor has been used for the dynamic culturing of osteoblast [60] and preosteoblast cells [7,11], it is unclear how human mesenchymal stem cells (HMSCs) behave in HARV bioreactors.…”

Evaluation of bioreactor-cultivated bone by magnetic resonance microscopy and FTIR microspectroscopy

“…Typically, constructs are grown under perfusion conditions either in a columnar (3) or rotating bioreactor (4) to promote the formation of bone throughout the scaffold. A better understanding of the regulatory role of various endogenous growth factors and mechanical loading conditions could greatly improve the quality of bioreactor-derived bone (5).…”