Injectable bone substitute based on chitosan with polyethylene glycol polymeric solution and biphasic calcium...

Injectable bone substitutes are being explored to address challenges in bone regeneration. Prior research has shown that biphasic calcium phosphate composites can support bone healing. However, the injectability and mechanical properties of such materials remain unclear. No prior work had resolved how varying microsphere size and polymeric ratios affect injectability. This gap motivated the development of a new injectable formulation. The need for a non-cytotoxic and biodegradable material is well established. Current methods often fail to balance injectability with structural integrity. This paper contributes a novel approach using coacervation and polymeric solutions.

The aim was to develop an injectable bone substitute with controlled microsphere size and injectability. The specific problem addressed is the difficulty in achieving both injectability and structural stability in bone grafts. The motivation stems from the clinical need for materials that can be delivered precisely to bone defects. The study focused on combining biphasic calcium phosphate with chitosan and polyethylene glycol. The researchers aimed to optimize the ratio of solid and liquid phases. They also sought to evaluate the material's biocompatibility and in vivo performance. The method involved coacervation to form the solid phase. The goal was to assess how varying parameters affect the material's properties.

The solid phase was created using coacervation with Hydroxyapatite and beta-Tricalcium Phosphate. Sodium alginate was removed during sinterization to form the microspheres. The microsphere size varied based on flow rate during production. These microspheres were then combined with a polymeric solution. The solution included chitosan and polyethylene glycol in different ratios. The injectability was tested by measuring the force required for removal. The material was assessed for cytotoxicity using standard assays. In vivo testing was conducted using tibial bone defects in rabbits.

The microsphere size distribution was influenced by the flow rate during coacervation. The injectability varied depending on the ratio of solid to liquid phases. The force required for removal did not compromise injection accuracy. Cytotoxicity tests showed the material was non-toxic to cells. In vivo results at 30 and 60 days showed enhanced bone repair. The biomaterial was gradually absorbed over the evaluated periods. Bone regeneration was more pronounced in treated groups. The material maintained structural integrity during the healing process.

The authors proposed that the injectable bone substitute can be tailored for specific applications. They suggested that varying microsphere size and polymeric ratios affects injectability. The material's non-cytotoxic nature supports its potential for clinical use. The in vivo results indicate that the biomaterial promotes bone regeneration. The gradual absorption aligns with the healing timeline. The method allows for controlled delivery into bone defects. The study supports the use of biphasic calcium phosphate with chitosan and polyethylene glycol. The findings suggest that this approach could be adapted for different bone repair scenarios.