No abstract

In this work, three different particle sizes of hydroxyapatites (HA) were synthesized, and these three types of HA were combined with poly(amino acid) (PAA) to form composites (PAA/HA) by phase separation technique. XRD, FT-IR, SEM, EDS, and XPS analyses were utilized to characterize the structure and morphology of the synthesized three HA particles and composites. Results revealed that HAs with three different particle sizes (short rod (HA1), long rod in nanoscale (HA2), and long rod in micron level (HA3)) were successfully prepared and there was an interface interaction between PAA and HA in composites. Mechanical tests showed that the difference of HA in size played an important role in mechanical performance of the composites. Furthermore, the long rod nano-HA showed the highest enhancement in flexural yield strength at 81.3% for PAA/HA2 compared with pure PAA. After 28 days of immersion in PBS, PAA, and its composites showed good stability, and the mechanical performance of all composites were remained unchanged. The cell culture results showed all composites were cytocompatible, cells attached on the materials well with excellent morphology. Thus, it could be concluded that particle size influenced mechanical properties of PAA/HA composites, without impacting their cytocompatibility and degradation behavior.

Bone defects in the load‐bearing area require bone reconstruction using strong biomaterial with mechanical properties like cortical bone. Herein, the high‐strength/high‐modulus polyvinyl alcohol fiber (PVA) was first designed to incorporate into poly(amino acid) (PAA)/hydroxyapatite (HA) to obtain a new poly(amino acid)/hydroxyapatite/polyvinyl alcohol fiber (PAA/HA/PVA) composite via a melt extrusion process. To improve the interfacial adhesive performance, the titanate coupling agent HY‐109 [isopropyl tris(dodecylbenzenesulfonyl) titanate] was used for simultaneously graft modification of the PVA fiber and HA (TPVA, THA). The effect of their components on the mechanical properties and degradation ability were investigated by electromechanical universal testing machine and in vitro phosphate buffer solution soaking. The results indicated that the PAA/30THA/20TPVA composite had the most ideal mechanical and degradation properties, which far exceed those of PAA and PAA/THA composite. In addition, in vitro simulated body fluid immersion and cell culture experiment showed the PAA/THA/TPVA composites boosted in vitro bioactivity and exhibited excellent cytocompatibility and osteogenic activity in cell attachment, proliferation, alkaline phosphatase activity, matrix mineralization, and osteogenesis‐related gene expression. These reports demonstrated that the developed PAA/THA/TPVA composite displayed comprehensive performance optimizations, which showed its potential as a novel biomaterial to be applied as load‐bearing implant in the field of orthopedics.