Porous microspheres have the potential for use as injectable bone fillers to obviate
the need for open surgery. Successful bone fillers must be able to support
vascularisation since tissue engineering scaffolds often cease functioning soon after
implantation due to a failure to vascularise rapidly. Here, we test the angiogenic
potential of a tissue engineered bone filler based on a photocurable acrylate-based
high internal phase emulsion (HIPE). Highly porous microspheres were fabricated
via two processes, which were compared. One was taken forward and investigated
for its ability to support human mesenchymal progenitor cells and angiogenesis in a
chorioallantoic membrane (CAM) assay. Porous microspheres with either a narrow
or broad size distribution were prepared via a T-junction microfluidic device or by a
controlled stirred-tank reactor of the HIPE water in oil in water (w/o/w), respectively.
Culture of human embryonic stem cell-derived mesenchymal progenitor (hES-MP)
cells showed proliferation over 11 days and formation of cell-microsphere aggregates.
In-vitro, hES-MP cells were found to migrate into microspheres through their
surface pores over time. The presence of osteoblasts, differentiated from the hES-MP
cells, was evidenced through the presence of collagen and calcium after 30 days.
Microspheres pre-cultured with cells were implanted into CAM for 7 days and compared
with control microspheres without pre-cultured cells. The hES-MP seeded
microspheres supported greater angiogenesis, as measured by the number of blood
vessels and bifurcations, while the empty scaffolds attracted host chick cell ingrowth.
This investigation shows that controlled fabrication of porous microspheres has the
potential to create an angiogenic, bone filling material for use as a cell delivery
vehicle.
CORE (COnnecting REpositories)
CORE (COnnecting REpositories)