An injectable pH neutral bioactive glass-based bone cement with suitable bone regeneration ability.

Current bone cements face limitations in pH stability and regeneration capacity. Prior research has shown that acidic cements can cause tissue irritation. No prior work had resolved the need for neutral pH materials that still support bone growth. This gap motivated the development of new injectable cements. Existing options like calcium phosphate cement have acceptable mechanical properties but lack optimal biological activity. The challenge remains in balancing physicochemical traits with regeneration potential. Researchers propose that combining bioactive glass with calcium sulfate could improve outcomes. This paper introduces a novel composite material designed to address these limitations.

The aim was to develop and evaluate a pH-neutral injectable bone cement for improved bone regeneration. The specific problem is the lack of materials that combine suitable mechanical strength with biological activity. This study sought to optimize a composite of phosphosilicate glass and calcium sulfate hemihydrate. The motivation stems from the clinical need for better options in bone defect repair. Researchers tested different compositions to find the most effective formulation. The goal was to identify a cement that supports both osteogenesis and angiogenesis. The study focused on comparing new materials with established controls like CPC and Genex®. The ultimate purpose was to determine if the new cement could serve as a viable clinical option.

The study used a composite of phosphosilicate bioactive glass and α-calcium sulfate hemihydrate. Three compositions were tested: 10P/90C, 30P/70C, and 50P/50C. Physicochemical properties were analyzed for each formulation. Rabbit femoral condyle models were used for in vivo testing at 4, 8, and 12 weeks. Micro-CT and histological analyses assessed bone regeneration. In vitro experiments involved MC3T3-E1 and HUVEC cells to evaluate osteogenesis and angiogenesis. Compressive strength was measured to assess mechanical suitability. The best-performing composition was selected based on both biological and mechanical data.

The 30P/70C composition showed optimal compressive strength of 3.5 ± 0.3 MPa. In vivo tests revealed superior bone regeneration compared to other formulations. Micro-CT scans showed enhanced new bone formation in the 30P/70C group. Histological analysis confirmed better tissue integration and reduced inflammation. In vitro, the 30P/70C extract increased MC3T3-E1 cell viability and ALP activity. Calcium mineral deposition was higher in cells exposed to 30P/70C. mRNA and protein levels of osteogenic markers were elevated in this group. HUVECs showed increased proliferation and angiogenesis when treated with 30P/70C extracts.

The 30P/70C formulation was identified as the most effective based on both mechanical and biological criteria. The authors propose that this composition offers suitable operability and compressive strength. It supports cancellous bone substitute requirements as per clinical standards. The in vivo results suggest that the new cement promotes better bone regeneration than existing options. In vitro data further support its osteogenic and angiogenic potential. The pH-neutral nature of the cement may reduce tissue irritation compared to acidic alternatives. The researchers suggest that this material could be suitable for treating large bone defects. They propose that the 30P/70C cement has potential for clinical use in orthopedic trauma.