29 - Effects of Pore Size on Mechanical Properties and Osteoblast Behavior in Bioglass Composite Scaffolds
University of California, Davis
Composite scaffolds, like those incorporating hydroxyapatite (HA), ?-tricalcium phosphate (TCP), or bioactive glass (Bioglass 45S€, BG) alongside a degradable polymer, are promising alternatives to autografts for treatment of bone defects. Unlike autografts, these scaffolds are tailorable, require only one surgery, and promote self-healing. Bioactive glass (BG) has an exceptional ability to improve physical properties of poly(lactide-co-glycolide) (PLG) scaffolds and stimulate differentiation of human mesenchymal stromal cells (MSC) into osteoblasts. In order to optimize BG composite scaffolds we investigated the effect of pore size on cellular growth and differentiation. I hypothesized that 500?m pores will be the approximate upper bound for cell-friendly pore size, and that 500-800?m pore scaffolds will inhibit cellular growth relative to the 125-300?m and 300-500?m conditions; larger pores may force the cells to adhere to pore walls and grow in two dimensions, as opposed to stretching across the pore and growing in three dimensions. Furthermore, the 300-500?m scaffolds may give more room for nutrient diffusion and cell expansion than smaller pores, making them most optimal for bone tissue engineering. To test MSC proliferation, DNA content was quantified at 7, 14, and 21 days, and osteogenic response was measured by alkaline phosphatase (ALP) activity and gene expression.