Early Cell Adhesion of Periodontal Ligament Stem Cells on 3D Printed Polylactic Acid/Hydroxyapatite Scaffolds: An In Vitro Study

Polylactic acid (PLA) and its composites with hydroxyapatite (HA) have been studied in the field of bone repair applications. The objective of this study was to evaluate the biocompatibility of PLA/HA at different concentrations and to analyze early adhesion of periodontal ligament stem cells (PDLSCs). Cells were seeded in two 24-well plates, each containing six disk-shaped samples of PLA/HA (10%, 15% and 20%) and six control samples and then examined using scanning electron microscopy. Twelve 96-well plates were prepared with different elution concentrations (1/1, 1/2, 1/4, and 1/8) to assess biocompatibility using MTT cell viability and Hoechst 33342 assays at 24, 48, and 72 h. PLA/HA 20% showed the highest early adhesion (<i>p</i> = 0.0057), with cells adopting a more elongated morphology. The MTT assay revealed no differences in viability between concentrations (<i>p</i> = 0.6196), whereas the Hoechst assay demonstrated the highest viability for PLA/HA 20% (<i>p</i> < 0.0001). Overall, PLA promoted cell adhesion, with the 20% formulation providing the greatest adhesion. All concentrations maintained high viability, and longer culture time enhanced both adhesion and viability.