Fabrication of ACP-CCS-PVA composite membrane for a potential application in guided bone regeneration

Abstract

The barrier membranes of guided bone regeneration (GBR) have been widely used in clinical medicine to repair bone defects. However, the unmatched mechanical strength, unsuitable degradation rates, and insufficient regeneration potential limit the application of the current barrier membranes. Here, amorphous calcium phosphate-carboxylated chitosan-polyvinyl alcohol (ACP-CCS-PVA) composite membranes are fabricated by freeze-thaw cycles, in which the ATP-stabilized ACP nanoparticles are uniformly distributed throughout the membranes. The mechanical performance and osteogenic properties are significantly improved by the ACP incorporated into the CCS-PVA system, but excess ACP would suppress cell proliferation and osteogenic differentiation. Our work highlights the pivotal role of ACP in GBR and provides insight into the need for biomaterial fabrication to balance mechanical strength and mineral content.

Fig. 1. TEM and SAED patterns of the ATP-stabilized ACP nanoparticles.

Fig. 2. (a) SEM of the ACP nanoparticles. (b) The EDS spectra show the element composition of ACP nanoparticles. (c) SEM of the CCS–PVA composite membrane. (d) The EDS spectra show the element composition of the CCS–PVA composite membrane. (e) SEM of the ACP–CCS–PVA composite membrane. (f) The EDS spectra show the element composition of the ACP–CCS–PVA composite membrane.

Fig. 3. (a) FTIR spectra and (b) XRD patterns of the ACP nanoparticles, the CCS–PVA composite membranes, and the ACP–CCS–PVA composite membranes.

Fig. 4. (a) TGA curves, (b) degradation, (c) calcium ion, and (d) phosphate ion release curves of composite membranes.

Fig. 5. (a) Mechanical properties testing device diagram. (b) Composite membranes' tensile modulus and stress–strain curves were obtained in (c) dry and (d) wet conditions (*P < 0.05, **P < 0.01, n = 3).

Fig. 6. (a) CCK-8 assay results of CCS–PVA, 10 wt%, and 20 wt% ACP–CCS–PVA composite membranes. The ALP activity (b) and staining (c) were on the 7th and 14th days. (d) The alizarin red staining was on the 14th and 21st days (*P < 0.05, **P < 0.01, n = 3).

Fig. 7. The mRNA expression of osteogenesis-related genes was analyzed after incubated for 14 days (*P < 0.05, **P < 0.01, ***P < 0.001, n = 3).