Characterization and Osteoblast Response of Composite Scaffold (HA-Collagen-S. littoralis-PVA) for Bone Regeneration

This study aimed to evaluate the in vitro biocompatibility, physicochemical characteristics, and in vivo biological performance of the composite scaffold (hydroxyapatite [HA]-collagen-S. littoralis-polyvinyl alcohol [PVA]).

In vitro assays were conducted on 7F2 preosteoblast cells to assess osteoblast viability and proliferation. Scanning electron microscopy (SEM) was then used to determine the optimal concentration identified by these assays. The composite scaffold was also characterized using Fourier transform infrared (FT-IR) spectroscopy, SEM, and X-ray diffraction (XRD). In vivo evaluation was performed using a Sprague-Dawley rat calvarial defect model, with a control group without a scaffold and a treatment group receiving the composite scaffold, at 3, 7, 14, 21, and 28 days to assess osteoblast counts and histological features associated with later stages of bone healing.

In vitro results demonstrated a progressive increase in 7F2 viability and proliferation up to 72 hours, with the optimal concentration at 1,500 ppm. These findings were consistent with SEM observations. FT-IR confirmed the presence of characteristic functional groups with molecular interactions among components. SEM showed a porous structure with good interconnectivity that supported cell adhesion. XRD indicated the presence of crystalline HA and amorphous organic phases, supporting mechanical stability and biocompatibility. Histological analysis showed earlier osteoblast recruitment in the composite scaffold group, peaking at day 7, followed by reduced osteoblast numbers at day 28, suggesting progression toward later stages of bone healing. In contrast, the control group exhibited a delayed osteoblast peak at day 14 and persistent fibrous tissue. In vivo statistical analysis demonstrated significantly higher osteoblast counts in the scaffold group than in controls (p < 0.05 at days 3, 7, 14, and 21), indicating an enhanced early osteogenic response.

The composite scaffold (HA-collagen-S. littoralis-PVA) demonstrated structural properties, biocompatibility, and biological performance that support osteoconduction and osteogenesis, highlighting its potential as an innovative biomaterial for bone regeneration in dental, oral, and maxillofacial tissue engineering.