Hydroxyapatite Formation on Acrylic Acid-grafted Porous PLLA Scaffolds in Simulated Body Fluid

This study focused on the effect of surface-modification of 3D poly(L-lactic acid) (PLLA) scaffolds in the formation of hydroxyapatite (HA) crystals in simulated body fluid (SBF). PLLA scaffolds were subjected to plasma treatment and simultaneous grafting of acrylic acid (AA). When three different substrates, such as PLLA control, PLLA-HA, and PLLA-PAA-HA were analyzed, HA crystals on the surface of AA-grafted PLLA were identified better in size and distribution. The major compositions of HA, calcium and phosphorus were confirmed in the ESCA analysis of PLLA-PAA-HA. Significantly reduced water contact angles were identified with PLLAHA and PLLA-PAA-HA as compared to PLLA control. When osteoblasts were cultivated in different 3D PLLA scaffolds, good cell attachment was seen from scanning electron microscopy (SEM) micrographs and osteoblasts appeared to be well spread and aggregated on the HA-formed scaffold. Once the total cell number was determined, the highest cellularity was noted with the PLLA-PAA-HA during 4-week culture. The difference was statistically significant between PLLA-PAA-HA and PLLA control or PLLA-HA. This study indicates that functional carboxylic groups could greatly facilitate HA crystal formation and that HA-formed polymer scaffolds can find favorable applications in bone tissue engineering.