Fabrication and characterization of a semi-rigid shell barrier system made of polycaprolactone and biphasic calcium phosphate: A novel barrier system for bone regeneration.

Abstract

Nowadays, no barrier membrane serves all purposes of bone augmentation. This study aimed to fabricate a semi-rigid shell barrier system composed of a semi-rigid shell and a covering membrane or a semi-resorbable barrier membrane, based on polycaprolactone (PCL) and biphasic calcium phosphate (BCP) for guided bone regeneration (GBR). A shell and a covering membrane were fabricated by a solvent casting technique based on PCL (70) and BCP (30). The experimental groups were a semi-rigid shell, an airdried membrane, a buffered membrane, and a commercial d-PTFE as a control. Physico-chemical, mechanical properties, and in vitro biocompatibility with osteoblasts and fibroblasts cells were evaluated in all groups. The fabricated materials had rough surfaces with a homogeneous distribution of BCP particles on one side and a smooth surface on the opposite side. The airdried membrane presented a rougher surface on both top and bottom sides (Sq = 605.45 nm, 556.82 nm) than the semi-rigid shell (310.74 nm, 424.56 nm) and the buffered membrane (277.9 nm, 306.98 nm), respectively. The pore sizes of the airdried membrane (25-40 μm) were larger than the semi-rigid shell (5-40 μm) and the buffered membrane (5-25 μm). The porosities of the airdried and buffered membranes (∼40%) were higher than the semi-rigid shell (∼20%) significantly (p < 0.05). All fabricated materials were hydrophilic, with the lowest water contact angle in the semi-rigid shell (54.7° ± 3.06°), then the airdried (61.15° ± 4.76°), and the buffered (75.74° ± 2.8°) respectively. The semi-rigid shell resisted a higher load on compressive force (18.82 ± 2.72 N) than the d-PTFE membrane (4.23 ± 0.5 N). The tensile stress of the buffered membrane (2.544 ± 0.19 MPa) was not different from the d-PTFE (2.908 ± 0.12 MPa) but was higher than the airdried membrane (1.302 ± 0.13 MPa) significantly (P < 0.05). The airdried membrane had reached 100% swelling ability within 1 h, which was significantly faster than the buffered membrane (12 h) and the semi-rigid shell (7 days), and they were slowly degraded by lysozyme at 6 months (airdried: 24.88% ± 0.96%, buffered: 13.67% ± 0.55%, and semi-rigid: 8.62% ± 0.88%). All fabricated membranes showed no toxicity to osteoblast and fibroblast cells. The semi-rigid shell and the covering membranes demonstrated suitable physical and mechanical properties, and biocompatibility, and can be assembled as the novel semi-rigid shell barrier system for bone regeneration.