Biodegradable Pla/Ha Composite Material Production and Mechanical Characterization for Temporary Implant Applications

Abstract

Hard tissues in the human body are damaged due to age, trauma, and bone diseases. Metal implants/prostheses are traditionally preferred to repair and treat these damaged tissues. Today, metals and their alloys meet the mechanical requirements of the musculoskeletal system well. However, the need to develop alternative composite materials has increased since metals are very stiff materials compared to bone. Problems such as stress shielding, and aseptic loosening can arise due to their high modulus of elasticity, and the need for secondary revision operations for such reasons. Also, the metal implant/prostheses should be removed after the healing that causes the undesirable secondary operation. In this study, polylactic acid (PLA) and hydroxyapatite (HA)-based composite materials were produced and their mechanical characteristics evaluated for possible implant applications. In addition, the PLA/HA composite materials stayed in Artificial Body Fluid (ABF) at different times, and the change in the mechanical properties were determined. PLA granules and HA powders were mixed in different ratios of weight (weight ratio 1:0, 9:1, 7:3, and 1:1) to produce 80 samples using the solvent casting technique. PLA was dissolved with chloroform in a magnetic stirrer at 200 rpm and room temperature, and then nano HA was added and mixed until homogeneity was achieved. After casting and drying, the samples were cut into appropriate standard sizes. The samples were subjected to biodegradability in-vitro test. In the results of this study, the modulus of elasticity increased with the increase of HA in the samples; however, the yield strength, ultimate strength, and yield strain of the samples decreased. In addition, it was observed that the existence of HA decreases the rate of degradation; therefore, the percentage of weakening in mechanical strength decreased in the measurements made at the end of the 15th day. According to these results, it was concluded that PLA/HA biodegradable composites can be developed to use as implant/prosthesis material.