Preparation and performance of porous hydroxyapatite/poly(lactic-co-glycolic acid) drug-loaded microsphere scaffolds for gentamicin sulfate delivery

The prevention/treatment of osteomyelitis infection by combining the local antibiotic delivery system with the bone regeneration scaffold can effectively overcome the drawbacks of systemic antibiotic administration and realize the full cycle control of drug release. Herein, by introducing sodium carboxymethyl cellulose (SCMC) cross-linking agent to improve the binding force of poly(lactic-co-glycolic acid) (PLGA) microspheres and porous hydroxyapatite (HAp) bone scaffold. The porous HAp/PLGA drug-loaded microsphere bone scaffold for gentamicin sulfate (GS) delivery was successfully prepared. The optimal preparation parameters, drug release characteristics, SCMC enhancement mechanism, antibacterial properties and bone cell activity of porous HAp/PLGA drug-loaded microsphere bone scaffolds were comprehensively investigated. The results showed that the 0.1% SCMC-modified porous HAp/PLGA drug-loaded microsphere bone scaffold has a cumulative drug release of 45.0 ± 0.90% on the first day, which is about 20% lower than that of pure PLGA drug-loaded microspheres. Moreover, its drug release can be sustained and stably released for more than 17 d, which is attributed to the enhancement of the binding force between the microspheres and HAp by SCMC (combination for more than 3 weeks). Meanwhile, the diameter of the antibacterial ring expanded from the initial 10 ± 0.50 to 28 ± 1.2 mm after 14 d, which also indicated the sustained and stable release of GS. Alamar Blue analysis results showed that 0.1% SCMC-modified composite bone scaffold is beneficial to the proliferation activity of bone cells, and its 14 day activity increased by 20%. The above results indicate that the SCMC-modified composite bone scaffold has the potential to treat/prevent osteomyelitis.