Brown University School of Engineering

Joint Materials/Solid Mechanics Seminar Series “Capillary forces for self-seeding micropores and trapping cells in CaP bone scaffolds”

Add event to my Google calendar Add event to my Google calendar Share this event on facebook E-mail this event
Thursday, December 06, 2012 4:00pm - 5:00pm

Joint Materials/Solid Mechanics Seminar Series “Capillary forces for self-seeding micropores and trapping cells in CaP bone scaffolds” A. J. Wagoner Johnson Mechanical Science and Engineering University of Illinois at Urbana-Champaign Abstract: CaP materials have been used for decades as coatings on medical devices that interface with bone. Porous CaPs can serve as fillers in bony defects or as scaffolds for bone regeneration in defects caused by diseases like cancer or by traumatic injuries. The most severe defects, complex and/or critical size defects, do not heal with current treatments of allograft, autograft, or synthetic graft. It is these defects that can cause severe disfigurement and loss of function. Research in scaffold-based bone regeneration focuses on using CaPs and other materials to repair these severe defects. Our interest is specifically in the role of microporosity, or microstructure, in stimulating and controlling bone growth in scaffolds with porosity at multiple length scales. Our previous work, and that of others, showed that microporosity enhances bone growth in vivo though the specific mechanism(s) have been elusive for almost a decade. This ambiguity is common in the area of scaffold-based tissue regeneration due to the complexity of the systems of interest, the inability to precisely control scaffold characteristics, and the difficulty in recapitulating the in vivo environment in an in vitro setting. We recently identified a specific mechanism that we propose is the driving force for the enhanced bone regeneration. Capillary forces generated by the microporous network deform the cells and draw them into the pores, effectively self-seeding the CaP scaffolds and trapping the cells. We propose that this occurs at the time of implantation and provides the initial conditions in the defect microenvironment that enhance regeneration. I will describe our recent in vitro and in vivo experiments supporting this hypothesis and show that penetration is cell-type dependent due to the range in cell size and stiffness, and that we can change pore size, fraction, and interconnection size each independently to change penetration. The work suggests that the microporous network could be optimized to self-load heterogeneous cell populations to further enhance regeneration, which is advantageous in treating not only the most severe defects but all bony defects. Thursday, December 6, 2012 4:00-5:00 pm B&H Room 168