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).

1.            TISSUE ENGINEERING: Part A, Volume 23, Numbers 23 and 24, 1382 (2017).

2.            MATERIALS SCIENCE AND ENGINEERING C 59, 92–101(2016).