The study of the relationship between mechanical properties and in-vitro biodegradability in polylactic acid-hydroxyapatite (PLA/HA) nanocomposites in simulated body fluid

Mohamad Gowdini¹ Mehdi Karevan² Peiman Mosaddegh³

1) M.Sc Graduate, Mechanical Engineering Department, Isfahan University of Technology
2) Assistant Professor of Mechanical Engineering, Isfahan University of Technology
3) Associate Professor of Mechanical Engineering, Isfahan University of Technology

IOI Code : XCAZ-EFHZG
Publication : 2nd. International Congress on science & Engineering - paris(parisconf.com)
Abstract :
    Polylactic acid (PLA) and calcium phosphate ceramic composite are widely accepted in medical applications and are mainly replacing metal soft tissue fixation devices, such as interference screws and suture anchors. However, the critical disadvantages of poor biological properties and poor mechanical strength compared to metal devices have left much to be desired in bio-absorbable orthopedic implant materials. In order to develop a more ideal composite material based on polylactic acid, hydroxyapatite (HA) nanoparticles were used as the reinforcing material. Consequently, it is important to understand its behavior in a physiological environment as well as maintaining its mechanical strength. Injection molded mechanical testing specimens were fully immersed in a phosphate buffered saline (PBS) solution as a simulated body fluid, and mechanical strength was evaluated at 0, 8, 16, and 24 weeks. Simulated body fluid (PBS) pH measurements were recorded of the fluid in the vicinity of degrading composites. The results indicated that with the addition of 5 wt% HA nanoparticles, the flexural strength was maintained and 81.5% of the tensile strength was retained in-vitro through 16 weeks. Furthermore, the pH of the fluid in the vicinity of PLA/HA composite was maintained throughout the 24 weeks in all samples excluding the 50 wt%. The results from the present study, therefore, suggest the use of HA nanoparticles may have a strong impact on future orthopedic fixation devices.

Keywords : hydroxyapatite polylactic acid in vitro degradation mechanical evaluation