Injectable chelate-setting hydroxyapatite cement prepared by using chitosan solution: Fabrication, material...

Injectable bone cements are widely studied for their potential in minimally invasive bone repair. Traditional cements often lack sufficient injectability or mechanical strength for clinical applications. Prior research has shown that hydroxyapatite (HAp) is a promising bone substitute due to its similarity to natural bone composition. However, achieving optimal injectability and setting behavior remains a challenge. The use of chitosan as a mixing solution has been explored for its biocompatibility and gel-forming properties. No prior work had resolved how to combine chitosan with HAp to produce a cement with both injectability and sufficient mechanical strength. This gap motivated the development of a new cement formulation using chitosan and inositol phosphate (IP6). The need for a material that can be injected and set in situ is clear in orthopedic and dental applications. Existing methods often require complex processing steps or compromise on mechanical performance. The novelty of this approach lies in the use of chelate bonding to enhance cement properties.

The aim of this study was to develop an injectable hydroxyapatite cement using chitosan as a mixing solution and IP6 as a chelating agent. The researchers sought to optimize the material properties of the cement by varying the ball-milling duration of the HAp powder and the concentration of IP6. The primary objective was to achieve a cement with sufficient injectability and compressive strength for clinical use. The study also aimed to evaluate the biocompatibility and osteoconductivity of the cement in vitro and in vivo. The motivation for this work was the need for a cement that can be delivered through minimally invasive techniques while maintaining structural integrity. The researchers focused on the role of IP6 in forming chelate bonds that could enhance cement stability. The study also aimed to assess the impact of surface modification on cement performance. The ultimate goal was to provide a new injectable bone cement with favorable mechanical and biological properties.

The researchers prepared hydroxyapatite (HAp) powder by ball-milling with zirconium oxide beads of varying sizes. The powder was first milled for 5 minutes with 10 mm beads, followed by 60 minutes with 2 mm beads. After milling, the powder was surface-modified using a 5000 ppm IP6 solution. The modified HAp powder was mixed with a 2.5 mass% chitosan solution to fabricate the injectable cement. The setting time and compressive strength of the cement were measured using standard methods. The effects of ball-milling duration and IP6 concentration on cement properties were systematically evaluated. In vitro biocompatibility was tested using an osteoblast cell model, while in vivo osteoconductivity was assessed using a pig tibia model. The study used a controlled experimental design to isolate the effects of each variable on the cement's performance. The researchers focused on the chelate-bonding capability of IP6 to enhance cement stability.

The injectable cement was successfully fabricated using HAp powder modified with IP6 and mixed with chitosan. The cement had a setting time of 36.3 ± 4.7 minutes and a compressive strength of 19.0 ± 2.1 MPa. The ball-milling process significantly influenced the cement's injectability and mechanical strength. The cement showed favorable biocompatibility in vitro, as demonstrated by osteoblast cell viability. In vivo testing in a pig tibia model confirmed the cement's osteoconductivity. The IP6 concentration and ball-milling duration were key factors in determining cement performance. The chitosan solution played a critical role in the injectability of the cement. The results suggest that the combination of IP6 and chitosan can produce a cement with both injectability and sufficient mechanical strength. The study provides evidence that the proposed method can be used to develop a new injectable bone cement.

The study demonstrated that an injectable hydroxyapatite cement can be successfully prepared using chitosan and IP6. The cement exhibited favorable injectability, mechanical strength, biocompatibility, and osteoconductivity. The ball-milling process and IP6 concentration were found to be important factors in determining cement properties. The results suggest that the proposed method can be used to develop a new injectable bone cement suitable for clinical applications. The researchers propose that the chelate-bonding capability of IP6 enhances cement stability and performance. The study provides evidence that the combination of IP6 and chitosan can produce a cement with both injectability and sufficient mechanical strength. The findings support the potential use of this cement in minimally invasive bone repair procedures. The authors suggest that further research is needed to evaluate the long-term performance of the cement in clinical settings.