Optimized bone regeneration based on sustained release from three‐dimensional fibrous PLGA/HAp composite scaffolds loaded with BMP‐2

TLDR

Critical bone defects remain challenging, and engineered biomaterials combined with growth factors provide a promising alternative for bone repair and regeneration. The study investigates whether electrospun PLGA/HAp fibrous scaffolds loaded with BMP‑2 can enhance bone regeneration by varying BMP‑2 loading methods and HAp content to modulate release profiles. Scaffolds were fabricated with different BMP‑2 loading strategies and HAp contents, their mechanical strength and nanoparticle distribution were characterized, and their in vivo performance was evaluated in nude mice over six weeks using serum BMP‑2, ALP activity, X‑ray, and histological analyses. The scaffolds exhibited favorable morphology, mechanical strength, and homogeneous HAp dispersion, preserved BMP‑2 bioactivity, and enhanced new bone formation and defect healing, demonstrating their promise for bone regeneration.

Abstract

Contemporary treatment of critical bone defect remains a significant challenge in the field of orthopedic surgery. Engineered biomaterials combined with growth factors have emerged as a new treatment alternative in bone repair and regeneration. Our approach is to encapsulate bone morphogenetic protein-2 (BMP-2) into a polymeric matrix in different ways and characterize their individual performance in a nude mouse model. The main objective of this study is to examine whether the PLGA/HAp composite fibrous scaffolds loaded with BMP-2 through electrospinning can improve bone regeneration. The hypothesis is that different loading methods of BMP-2 and different HAp contents in scaffolds can alternate the release profiles of BMP-2 in vivo, therefore modify the performance of scaffolds in bone regeneration. Firstly, mechanical strength of scaffolds and HAp nanoparticles distribution in scaffolds were investigated. Secondly, nude mice experiments extended to 6 weeks were carried out to test the in vivo performance of these scaffolds, in which measurements, like serum BMP-2 concentration, ALP activity, X-ray qualification, and H&E/IHC tissue staining were utilized to monitor the growth of new bone and the changes of the corresponding biochemical parameters. The results showed that the PLGA/HAp composite scaffolds developed in this study exhibited good morphology/mechanical strength and HAp nanoparticles were homogeneously dispersed inside PLGA matrix. Results from the animal experiments indicate that the bioactivity of BMP-2 released from the fibrous PLGA/HAp composite scaffolds is well maintained, which further improves the formation of new bone and the healing of segmental defects in vivo. It is concluded that BMP-2 loaded PLGA/HAp composite scaffolds are promising for bone healing.