Effect of the Introduction of a Carboxylic Acid Group onto the Surface of a Three-dimensional Porous Poly (lactic acid) Scaffold on Apatite Deposition

Abstract

Scaffolds are important in engineering biomaterials for tissue and bone regeneration. In this study, a three-dimensional porous poly (lactic acid) (PLA) scaffold was fabricated using a method of salt leaching followed by freeze drying. A carboxylic acid group (COOH) was introduced onto all surfaces of a three-dimensional (3D) porous PLA scaffold (PLA-COOH) to test whether this polar organic acid had an effect on apatite attachment and deposition in Hanks' balanced salt solution (HBSS, pH=7.4) compared to PLA alone. Water adsorption in phosphate-buffered saline (PBS) was also examined between PLA-COOH and PLA by varying immersion time to evaluate whether there is an effect of COOH on the rate and degree of degradation. In contrast to PLA scaffold alone that allowed for apatite deposition only on its surface, the PLA-COOH scaffold also allowed for apatite formation on the surface of the barrier walls within the pores of the scaffold. Although PBS immersion eventually degraded both porous PLA and PLA-COOH scaffolds, we did not observe any specific difference in the rate or degree of degradation between them. These results suggest that the COOH group introduced into the porous PLA scaffold is an improvement on the PLA biomaterial for effective and efficient bone regeneration.