Regenerative potential of a polylactic acid/nano hydroxyapatite scaffold functionalized with fucoidan and dental pulp mesenchymal stem cells in a rat mandibular defect model

This study evaluated bone regeneration using a composite scaffold of polylactic acid (PLA) and nano-hydroxyapatite (nHA) surface-coated with fucoidan (FCD) in a rat mandibular defect model. PLA/nHA scaffolds were fabricated by solvent casting/particulate leaching and subsequently coated with FCD (PLA/nHA@FCD). Scaffolds were characterized by SEM, FTIR, XRD, TGA, mechanical testing, and water contact angle measurement. Cytocompatibility was assessed using an MTT assay with dental pulp mesenchymal stem cells (DP-MSCs). In vivo, mandibular defects were treated with (i) empty control, (ii) PLA/nHA, (iii) PLA/nHA@FCD, (iv) PLA/nHA + DP-MSCs/conditioned medium, and (v) PLA/nHA@FCD + DP-MSCs/conditioned medium. After 8 weeks, bone regeneration was evaluated by histology, histomorphometry, and CBCT. SEM demonstrated a uniform porous architecture without particle agglomeration. FTIR and XRD confirmed incorporation of scaffold components. FCD coating increased compressive strength (≈135%) and hydrophilicity (contact angle decreased from 65.37 ± 3.77° to 44.78 ± 2.18°). DP-MSC viability on PLA/nHA@FCD was ∼1.6-fold higher than on PLA/nHA. In vivo, FCD coating alone did not markedly improve regeneration, whereas PLA/nHA@FCD combined with DP-MSCs/conditioned medium significantly enhanced new bone formation compared with other groups. Overall, PLA/nHA@FCD combined with DP-MSCs-derived bioactivity promoted mandibular bone regeneration in rats.