LMGP Seminar : Pr. Amy WAGONER - Microstructure-induced capillary forces for seeding cells in rigid substrates

Calcium phosphate (CaP) materials have been used for decades in medical devices that interface with bone. Porous CaPs can serve as fillers in bony defects caused by cancer, congenital defects, or traumatic injuries. Some of these defects result in severe disfigurement and loss of function. The most severe, those that are complex and/or critical size defects, do not heal with current treatments of allograft, autograft, or synthetic graft.
Our interest is specifically in the role of microporosity (<50 microns), or microstructure, in stimulating and controlling bone growth in CaP bone scaffolds with porosity at multiple length scales. Previous work has shown that microporosity enhances bone growth in vivo though the specific mechanism(s) have been elusive.
We propose a specific mechanism as the driving force for the enhanced bone regeneration. Capillary forces generated by the microporous network deform cells and draw them into the pores, effectively self-seeding the scaffolds and trapping the cells.  We propose that this occurs at 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. We have found that penetration is cell-type dependent due to variations in cell size and stiffness, and that we can manipulate penetration depth. The work suggests that the microporous network could be optimized to self-load heterogeneous cell populations to further enhance regeneration and to add another dimension of control in drug delivery.
I will also briefly introduce other work in my lab relating to cell-cell and cell-material interactions and to mechanics of soft tissue for applications in pre-term birth.

Short BIO