Abstract

Capillary Forces and Bone Regeneration in Bone Scaffolds

Amy J. Wagoner Johnson, Associate Professor, Department of Mechanical Science and Engineering, University of Illinois at Urbana-Champaign

More than 1.5 million people undergo bone graft procedures annually in the US to repair defects that will not heal spontaneously. These defects severely decrease quality of life and are an economic burden to those affected and to the health care system. The already considerable demand is growing rapidly as the population ages and life expectancy increases. The biggest technical and scientific challenge to treating these defects is in achieving complete osteointegration. There are promising approaches that combine scaffolds with exogenous cells and growth factors; however, these approaches are complex, expensive, and are still often considered to be too risky to the patient. Our approach is to use capillary action to impregnate biphasic calcium phosphate (BCP) scaffolds that have macro and microporosity, with cells at the time of implantation. Three groups of samples, DRY, WET, and samples without micropores (NMP), were implanted for 3 weeks and then imaged using microcomputed tomography and assessed by histology. WET samples had microporosity, but were infiltrated with PBS prior to implantation.  After three weeks, the average bone volume fraction was the same for DRY versus WET, and both were greater than NMP. However, the distribution of bone and the depth of bone growth was significantly enhanced for DRY samples compared to WET and NMP. The results have important implications in scaffold design and use of this mechanism will help to address the challenge of incomplete osteointegration in scaffold-based bone repair. Further, it will do so without the use of growth factors or exogenous cells.