Composite Bone Scaffolds for Tunable Drug Delivery
Manifold possibilities exist to release different growth
factors, proteins and drugs in a controlled manner from the composite scaffolds
so that they can be used not only to engineer rapid bone regeneration but also
for effective treatment of different bone related diseases such as
osteomyelitis. We have developed various composites cements consisting of bone
cements and degradable bio-polymers microspheres and micro-filaments. We have
demonstrated that the inclusion of various polymers results in a highly
inter-connected porous network. This porous microstructure of the scaffold has
been found to be instrumental in facilitating cell infiltration and bone
formation. In addition, the in-vitro release of the model agent, vancomycin,
from the composite cements suggests that drug association with composite
scaffolds can be tuned to control the release kinetics. Further, we have shown
the release lasting for longer than 10 weeks from the composite cements in
which vancomycin is encapsulated in PLGA microspheres. We have also
demonstrated that these porous bone scaffolds can be re-infiltrated with
smaller, BMP-2-releasing alginate microspheres and coated with PDGF-releasing
alginate hydrogels to deliver a programmed schedule of these growth factors to
cell cultures. The chosen delivery schedule of PDGF and BMP-2 has shown to be
effective in stimulating cell infiltration of the scaffold, generating
angiogenic tubule network formation, and promoting ALP expression, indicating
the potential for this hybrid scaffold system to supply the cues to orchestrate
vascularized bone regeneration.
PLGA-Cement scaffold before (0 day) and
after dissolution of PLGA microspheres (30 days).
ENGINEERING: Part A, Volume 23, Numbers 23 and 24, 1382 (2017).
SCIENCE AND ENGINEERING C 59, 92–101(2016).