Allografts are important alternatives to autografts for treating defects after major bone loss. Bone growth factors have both
local autocrine and paracrine effects and regulate the growth, proliferation, and differentiation of osteoprogenitor cells.
To study the effects of prolonged, continuous, local delivery of growth factors on bone growth, we developed a new microelectromechanical
system (MEMS) drug delivery device. Bone marrow cells from mice were seeded on mouse allograft discs and cultured in osteogenic
media with osteogenic protein 1 (OP-1) and/or basic fibroblast growth factor (FGF-2) delivered from MEMS devices for 6 weeks.
We monitored bone formation by changes of bone volume using micro-CT scanning and release of osteocalcin using ELISA. The
data suggest the MEMS devices delivered constant concentrations of OP-1 and FGF-2 to the media. Bone marrow cells grew on
the allografts and increased bone volume. Addition of OP-1 increased bone formation whereas FGF-2 decreased bone formation.
Local delivery of growth factors over a prolonged period modulated the differentiation of osteoprogenitor cells on allograft
bone.
One of more of the authors (SBG) have received funding from the Musculoskeletal Transplant Foundation.
Each author certifies that his or her institution has approved the animal protocol for this investigation and that all investigations
were conducted in conformity with ethical principles of research.