New Three-Dimensional Bioactive Reinforcing Filler for Improving the Properties of Biomedical Polymers: Synthesis and Application.

In general, the efficiency of reinforcement for filler-based composites is greatly influenced by the filler properties. While much research has been conducted on filler percentage and filler-matrix bonding quality, there is not much research directed to the effect of filler geometry. Therefore, the aim of this article is to examine how a three-dimensional (3D) bioactive filler influences the strength enhancement of biomedical polymers. This was accomplished by first synthesizing highly regular dandelion-like hydroxyapatite (DHA) as a 3D bioactive filler using an optimized hydrothermal method, followed by surface modification with silane molecules. Poly(3-hydroxybutyrate--3-hydroxyvalerate) (PHBV) was then used as a biomedical polymer model to fabricate solution-casted composites by using the as-synthesized DHA particles. The results showed that the composites loaded with the surface-modified DHA particles had significantly higher tensile strength and elastic modulus compared to the neat PHBV and composites having irregular particles. In addition to the mechanical properties, our research found that the 3D DHA filler had a significant impact on the biological characteristics of the PHBV, such as water wettability, biodegradability, bioactivity, and in vitro cell response. These findings suggested that particle geometry can play a more significant role in affecting the biological and mechanical performance of biomedical polymers than previously thought.