Hydroxyapatite reinforced poly(3-hydroxybutyrate) and poly(3-hydroxybutyrate-co-3-hydroxyvalerate) based degradable...

Area of Science:

• Biomaterials Science
• Polymer Science
• Orthopedic Engineering

Background:

• Biodegradable polymers like Poly(3-hydroxybutyrate) (P3HB) and its copolymers are explored for bone tissue engineering applications.
• Hydroxyapatite (HAp) incorporation can enhance the mechanical properties and bioactivity of polymer scaffolds.
• Developing effective bone plates requires materials with suitable mechanical strength and in-vitro stability.

Purpose of the Study:

• To prepare and characterize Poly(3-hydroxybutyrate) (P3HB) and its copolymers with 3-hydroxyvalerate (PHBV) composites containing hydroxyapatite (HAp).
• To evaluate the mechanical properties and in-vitro degradation behavior of these HAp-containing composites for potential bone plate applications.
• To identify the optimal composition for bone plate development based on mechanical performance and stability.

Main Methods:

• Poly(3-hydroxybutyrate) (P3HB), PHBV8, and PHBV22 copolymers were prepared with 5% and 15% (w/w) hydroxyapatite (HAp) via injection molding.
• Mechanical properties, including flexural and tensile strengths, were assessed for the prepared composites.
• In-vitro aging tests were conducted by incubating bone plates in phosphate-buffered saline (PBS) at 37°C, followed by mechanical testing and Scanning Electron Microscopy (SEM) analysis.

Main Results:

• Composites with lower valerate content (P3HB) and 15% (w/w) HAp exhibited superior flexural and tensile strengths compared to other formulations.
• Flexural strengths for 15% HAp-loaded P3HB, PHBV8, and PHBV22 were 78.28, 63.45, and 39.38 MPa, respectively.
• Mechanical properties showed an initial sharp decrease within 24 hours of PBS incubation, followed by gradual changes or stability over a month, with no significant material erosion observed via SEM.

Conclusions:

• Poly(3-hydroxybutyrate) (P3HB) loaded with 15% hydroxyapatite (HAp) demonstrates the most favorable mechanical properties for potential bone plate applications.
• The prepared HAp-containing P3HB composites show acceptable in-vitro stability, with initial mechanical property changes that stabilize over time.
• Further in-vivo testing is warranted to fully assess the suitability of 15% HAp-loaded P3HB as a bone plate material.