Heparin/Poly-L-lysine-coated 3D-printed PLGA scaffolds as drug carriers for local immune modulation in bone regeneration

Immune responses after injury play a critical role in bone regeneration. Initiation of inflammation at early stages of repair triggers tissue formation and remodeling; however, uncontrolled
inflammation underlies a catabolic effect on tissues as commonly seen in arthritis where inflammation breaks down tissues and hinders regeneration. Our ultimate goal is to design a novel approach on bone scaffolds for which biodegradable scaffolds are loaded with inflammatory cytokines for local immunomodulation as well as bone regeneration. We employed nanoparticles (NPs) composed of heparin (Hep) and poly-L-lysine (PLL) as cytokine drug carriers adhered on 3D-printed poly(lactic-co-glycolic acid) (PLGA) scaffolds. The entire drug delivery system was composed by using a layer-bylayer (LBL) technique. One challenge in the implementation of this technology in clinical drug delivery is the maximization of particle surface concentration on the PLGA surface. Here, we report our approach to create nanoparticle-coated PLGA scaffolds and improve surface coverage.