[Preparation and properties of calcium polyphosphate-based composite scaffold for bone tissue engineering]

Current bone repair materials face limitations in degradation control and mechanical stability. Calcium polyphosphate (CPP) is a promising degradable material, but its brittleness and unpredictable degradation hinder clinical use. Prior research has shown CPP's potential for bone regeneration, yet its structural weaknesses remain unresolved. This gap motivated exploration of composite scaffolds to enhance mechanical and biological performance. Chitosan (CS) and carboxymethyl chitosan (CMC) are known for their biocompatibility and structural support in tissue engineering. Aldehyde sodium alginate (ADA) is a natural cross-linker with proven utility in scaffold fabrication. No prior work had resolved CPP's degradation controllability. This study aimed to address these limitations by developing CPP-based composites with improved properties.

The goal was to improve CPP scaffold performance by combining it with CS, CMC, and ADA. CPP's brittleness and uncontrolled degradation limit its clinical use. The researchers proposed using CS and CMC as organic phase components to mimic natural bone structure. ADA was selected for its cross-linking properties. The study tested whether a ternary composite scaffold could offer better mechanical strength and controllable degradation. The specific problem was CPP's poor degradation control and mechanical weakness. The motivation was to design a scaffold that closely resembles bone's natural structure while maintaining structural integrity during healing. The approach aimed to bridge the gap between CPP's potential and its clinical limitations.

The CPP/CMC and CPP/CMC/CS scaffolds were fabricated using a multiple composite-cross-linking method. CS and CMC provided the organic phase structure. ADA acted as a natural cross-linker. Scaffold properties were evaluated through weight loss measurements, pH changes in degradation solutions, compressive strength tests, and surface morphology analysis. The binary and ternary scaffolds were compared for degradation behavior and mechanical performance. The study focused on how the organic phase influenced degradation rates and scaffold stability. Surface morphology was analyzed to assess structural integrity. The experimental design aimed to validate CPP's compatibility with CS/CMC/ADA composites.

The ternary CPP/CMC/CS scaffold showed significantly improved mechanical strength compared to CPP/CMC alone. Compressive strength increased notably with the addition of CS and CMC. However, the organic phase in dual-phase scaffolds degraded rapidly, reducing controllability. Ternary scaffolds exhibited better degradation controllability and structural stability. The pH of degradation solutions remained relatively stable in ternary scaffolds. Surface morphology confirmed improved interface bonding between CPP and organic components. Weight loss measurements indicated slower degradation in ternary scaffolds. These findings suggest that CPP/CMC/CS composites offer better performance for bone tissue engineering.

The authors stated that CPP/CMC/CS composites are more suitable for bone tissue engineering than CPP/CMC alone. The ternary scaffold showed enhanced mechanical properties and controllable degradation. The organic phase in dual-phase scaffolds degraded too quickly, limiting its use. The addition of CS improved scaffold stability and interface bonding. The CPP/CMC/CS composite maintained structural integrity during degradation. The CPP/CMC scaffold lacked sufficient mechanical strength for clinical use. The CPP/CMC/CS composite is a promising material for bone tissue engineering. The CPP/CMC/CS composite offers a practical solution for designing bone scaffolds with improved performance.