Development of PHB-based bio-nanocomposite films with enhanced bioactivity and cytocompatibility for alveolar bone regeneration.

Alveolar bone regeneration remains a significant challenge in dentistry and maxillofacial surgery due to the limited availability of autografts and the complexity of restoring the native bone microenvironment. In the present study, multifunctional bio-nanocomposite films composed of polyhydroxybutyrate (PHB), LAPONITE® nanoclay (LAP), and guar gum (GG) were fabricated by the solvent-casting technique and investigated as potential bioresorbable films for alveolar bone regeneration. Structural and physiological characteristics, characterized using FESEM, EDX, FTIR, XRD, and TGA confirmed the successful incorporation of LAPONITE® within the PHB/GG matrix and revealed significant modifications in the morphology, crystallinity, thermal behaviour, and surface characteristics of the films. The incorporation of LAPONITE® increased film thickness from 0.056 ± 0.005 mm in the control to 0.156 ± 0.007 mm in 10 wt% and significantly influenced the mechanical performance and porous microstructure of the bio-nanocomposites. Among the investigated formulations, the 5 wt% bio-nanocomposite film exhibited the most balanced combination of porous morphology, mechanical strength (123.90 ± 4.25 MPa), biomineralization behaviour, controlled degradation profile, antimicrobial activity, and cytocompatibility. In vitro biomineralization studies demonstrated the progressive formation of an apatite-like mineral layer following immersion in simulated body fluid (SBF), while degradation studies indicated a controlled mass-loss behaviour over 28 days. Antimicrobial evaluation against S. aureus demonstrated that the developed bio-nanocomposite films exhibited antimicrobial activity. Cytocompatibility assessment using MG-63 cells confirmed that all bio-nanocomposite films were non-toxic, with the 3-5 wt% formulations exhibiting the most favourable cellular response. Collectively, the developed PHB/LAPONITE®/guar gum bio-nanocomposite films demonstrated a favourable combination of structural integrity, mechanical performance, bioactivity, antimicrobial properties, and cytocompatibility, highlighting their potential for alveolar bone regeneration applications.